ArticleLiterature Review

The Value of Oxygen Desaturation Index for Diagnosing Obstructive Sleep Apnea: A Systematic Review

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Abstract

Objectives Intermittent hypoxemia is a risk factor for developing complications in obstructive sleep apnea (OSA) patients. The objective of this systematic review was to identify articles evaluating the accuracy of the oxygen desaturation index (ODI) as compared with the apnea–hypopnea index (AHI) and then provide possible values to use as a cutoff for diagnosing adult OSA. Study Design Systematic Review of Literature. Methods PubMed, the Cochrane Library, and SCOPUS databases were searched through November 2019. Results Eight studies (1,924 patients) met criteria (age range: 28–70.9 years, body mass index range: 21.9–37 kg/m², and AHI range: 0.5–62 events/hour). Five studies compared ODI and AHI simultaneously, and three had a week to months between assessments. Sensitivities ranged from 32% to 98.5%, whereas specificities ranged from 47.7% to 98%. Significant heterogeneity was present; however, for studies reporting data for a 4% ODI ≥ 15 events/hour, the specificity for diagnosing OSA ranged from 75% to 98%, and only one study reported the positive predictive value, which was 97%. Direct ODI and AHI comparisons were not made because of different hypopnea scoring, different oxygen desaturation categories, and different criteria for grading OSA severity. Conclusion Significant heterogeneity exists in studies comparing ODI and AHI. Based on currently published studies, consideration should be given for diagnosing adult OSA with a 4% ODI of ≥ 15 events/hour and for recommending further evaluation for diagnosing OSA with a 4% ODI ≥ 10 events/hour. Screening with oximetry may be indicated for the detection of OSA in select patients. Further study is needed before a definitive recommendation can be made. Laryngoscope, 2020

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... However, portable monitors (PM) for PSG type III can be used at home (5) at a much more affordable cost (6). In addition, other confounding factors exist in the diagnosis of OSA; these include the positional component, body mass index (BMI), sex, age, and associated comorbidities (7)(8)(9). ...
... As OSA is a disease with a high prevalence (1,25) and is still largely unknown to the general population, it is assumed that simpler diagnostic methods, which can be offered to a large part of the population, can provide advantageous results (7,9). In Brazil, the rate of OSA underdiagnosis is high and that the Brazilian public unified health system has diagnosed OSA in only 0.07% of the population (25). ...
... The use of oximetry has been extensively investigated in the last decade as an auxiliary method in OSA diagnosis by expanding access to diagnosis, thereby improving the quality of life of more vulnerable populations (24,25). The results of this study, as well as the existing literature (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)19,21,(25)(26)(27)(28)(29)(30), indicate that, greater the degree of apnea, greater the chances of correct diagnosis based on ODI. A recent systematic review (7) demonstrates the methodological heterogeneity with respect to the following: criterion for ODI (3% and 4%), cut-off point for the classification of the degree of apnea, and the different statistical methods used. ...
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Objectives: Owing to the fact that obstructive sleep apnea (OSA) is an underreported disease, the strategy used for the diagnosis of OSA has been extensively dissected to devise a simplified process that can be accessed by the public health services. Polysomnography (PSG) type I, the gold standard for the diagnosis of OSA, is expensive and difficult to access by low-income populations. In this study, we aimed to verify the accuracy of the oxyhemoglobin desaturation index (ODI) in comparison to the apnea-hypopnea index (AHI) using a portable monitor. Methods: We evaluated 94 type III PSG home test results of 65 elderly patients (69.21±6.94 years old), along with information, such as the body mass index (BMI) and sex, using data obtained from a clinical trial database. Results: A significant linear positive correlation (r=0.93, p<0.05) was observed between ODI and AHI, without any interference from sex, BMI, and positional component. The sensitivity of ODI compared to that of AHI increased with an increase in the severity of OSA, while the specificity of ODI in comparison to that of AHI was high for all degrees of severity. The accuracy of ODI was 80.7% for distinguishing between patients with mild and moderate apnea and 84.4% for distinguishing between patients with moderate and severe apnea. Conclusion: The ODI values obtained in uncontrolled conditions exhibited high sensitivity for identifying severe apnea compared to the AHI values, and correctly identified the severity of OSA in more than 80% of the cases. Thus, oximetry is promising strategy for diagnosing OSA.
... 22 The oxygen desaturation index (ODI) is a measure of the number of times per hour that oxygen saturation decreases per hour, which was defined as the total number of at least 4% oxygen desaturations per total sleep time in hours. 23,24 The mean oxygenation saturation (mean SpO 2 ) was defined as the mean pulse oxygen saturation during the sleep period at night. The percentage of sleep duration with SpO 2 < 90% (TS90) and lowest nocturnal oxygen saturation (LSpO 2 ) were also determined as previously reported. ...
... 29,30 Useful oximetric measures related to OSA include ODI, LSpO 2 , mean SpO 2 , and TS90. 23 The European Sleep Apnea Database (ESADA) study stated ODI and nocturnal mean SpO 2 were better predictors of HbA1c levels than AHI among 2375 nondiabetic subjects who had undergone PSG. 24 Available study also indicated that nocturnal hypoxemia from OSA was associated with poorer glycemic control in the extremely obese subjects. ...
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Purpose: This study aimed to investigate the effects of obstructive sleep apnea (OSA) on the pancreatic β-cells dysfunction and their implications in the glucose dysmetabolism of overweight and obese nondiabetic young adults. Materials and methods: The cross-sectional analysis included 422 subjects (261 males/161 females) with the mean age of 27.77 ± 7.51 years and average body mass index (BMI) of 34.84 ± 5.69 kg/m2. All subjects underwent polysomnography (PSG), oral glucose tolerance-insulin releasing test (OGTT-IRT) and serum glycosylated hemoglobin A1 (HbA1c) measurement. The glucose metabolism and pancreatic β-cell function in relation to measures of OSA were determined adjustment for important confounders such as age and sex. Results: OSA subjects accounted for 54.91% in the normal glucose tolerance (NGT) group and 72.11% in the prediabetes (preDM) group (P =0.001). HbA1c was the highest in the preDM subjects with severe OSA. In the NGT subjects, the 1-h glucose level significantly elevated with the OSA severity, and the homeostasis model assessment-β (HOMA-β) was negatively related to nocturnal mean SpO2 (P <0.05). In the preDM subjects, HOMA-β, early phase insulinogenic index (∆I30/∆G30), total area under the curve of insulin in 180 min (AUC-I180), and the oral disposition index (DIO) were the lowest in the severe OSA group. DIO was associated with higher oxygen desaturation index (ODI) and lower nocturnal mean SpO2, and AUC-I180 was negatively related to TS90 (P <0.05). Conclusion: Our study indicated higher prevalence of OSA in overweight and obese nondiabetic young adults, especially preDM subjects. The impaired glucose tolerance was observed early after glucose intake in the NGT subjects. OSA induces compensatory increase in the pancreatic β-cell function in the NGT subjects, while pancreatic β-cell dysfunction is present in the preDM subjects with severe OSA.
... The best cutoff for ODI to predict moderate-to-severe and severe sleep apnea was chosen by comparing the predictive parameters of 3 commonly used ODI cutoffs (ODI ≥5, ODI ≥10, and ODI ≥15 events/h) reported in the literature. 24,25 Sensitivity of at least 70% was considered adequate to maximize the predictive performance. High sensitivity was prioritized over specificity, because in clinical setting, it will enable identification of most patients with sleep apnea. ...
... However, the proposed ODI cutoff in this study is lower than the previous studies in surgical and sleep clinic populations, in which they recommended using ODI ≥10 events/h in predicting moderate-to-severe sleep apnea. 20,24,34 Compared to previous studies, our population is distinctly different as these patients have both central and OSA. We found that 59% had sleep apnea (AHI ≥5) (72% obstructive, 20% central, and 8% indeterminate sleep apnea) with a high prevalence of moderate (23%) and severe sleep apnea (31%), 7 whereas the other studies evaluated oximetry for isolated OSA. ...
Article
Background: Long-term use of opioids for treatment of chronic pain is associated with significant risks including worsening unrecognized or untreated sleep apnea that may increase morbidity and mortality. Overnight oximetry has been validated for predicting sleep apnea in surgical and sleep clinic patients. The objective of the study was to assess the predictive accuracy of oxygen desaturation index (ODI 4%) from home overnight oximetry when compared to apnea hypopnea index (AHI) from polysomnography for predicting sleep apnea in patients taking opioids for chronic pain. Methods: This was a planned post hoc analysis of a prospective cohort study conducted at 5 pain clinics. Patient characteristics and daily morphine milligram equivalent (MME) dose were recorded. All consented patients underwent home overnight oximetry (PULSOX-300i, Konica Minolta Sensing, Inc, Osaka, Japan) and in-laboratory polysomnography. The predictive performance of ODI 4% from oximetry was assessed against AHI from polysomnography. Results: Among 332 consented patients, 181 with polysomnography and overnight oximetry data were analyzed. The mean age and body mass index of 181 patients were 52 ± 13 years and 29 ± 6 kg/m2, respectively, with 40% men. The area under the receiver operating curve for ODI to predict moderate-to-severe sleep apnea (AHI ≥15 events/h) and severe sleep apnea (AHI ≥30 events/h) was 0.82 (95% confidence interval [CI], 0.75-0.88) and 0.87 (95% CI, 0.80-0.94). ODI ≥5 events/h had a sensitivity of 85% (95% CI, 74-92) and specificity of 57% (95% CI, 52-61) to predict moderate-to-severe sleep apnea. ODI ≥15 events/h had a sensitivity of 71% (95% CI, 55-83) and specificity of 88% (95% CI, 84-91) to predict severe sleep apnea. Conclusions: Overnight home oximetry has a high predictive performance in predicting moderate-to-severe and severe sleep apnea in patients on opioids for chronic pain. It is a useful additional tool for health care providers for the screening of sleep apnea in this high-risk group.
... Oximetry has been validated to screen patients against apnea-hypopnea index (AHI) from lab-PSG and portable devices. These studies are mostly limited to sleep clinic patients from a single centre [9][10][11][12][13]. The predictive performance of the overnight oximetry is not known for at-risk surgical patients undergoing major non-cardiac surgery. ...
... Oximetry serves as a simple tool to identify these at-risk surgical patients to ensure optimal perioperative management. A recent systematic review on patients referred to sleep clinic also recommended using ODI �15 events per hour for predicting OSA but ODI �10 events per hour for further evaluation of OSA [9]. Although there has been a number of studies to predict OSA using oximetry [10,11,16,17], this is the first study to show that overnight pulse oximetry is a valid screening tool in predicting OSA in surgical patients with cardiovascular risk factors. ...
Article
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Introduction: In adults with cardiovascular risk factors undergoing major noncardiac surgery, unrecognized obstructive sleep apnea (OSA) was associated with postoperative cardiovascular complications. There is a need for an easy and accessible home device in predicting sleep apnea. The objective of the study is to determine the predictive performance of the overnight pulse oximetry in predicting OSA in at-risk surgical patients. Methods: This was a planned post-hoc analysis of multicenter prospective cohort study involving 1,218 at-risk surgical patients without prior diagnosis of sleep apnea. All patients underwent home sleep apnea testing (ApneaLink Plus, ResMed) simultaneously with pulse oximetry (PULSOX-300i, Konica Minolta Sensing, Inc). The predictive performance of the 4% oxygen desaturation index (ODI) versus apnea-hypopnea index (AHI) were determined. Results: Of 1,218 patients, the mean age was 67.2 ± 9.2 years and body mass index (BMI) was 27.0 ± 5.3 kg/m2. The optimal cut-off for predicting moderate-to-severe and severe OSA was ODI ≥15 events/hour. For predicting moderate-to-severe OSA (AHI ≥15), the sensitivity and specificity of ODI ≥ 15 events per hour were 88.4% (95% confidence interval [CI], 85.7-90.6) and 95.4% (95% CI, 94.2-96.4). For severe OSA (AHI ≥30), the sensitivity and specificity were 97.2% (95% CI, 92.7-99.1) and 78.8% (95% CI, 78.2-79.0). The area under the curve (AUC) for moderate-to-severe and severe OSA was 0.983 (95% CI, 0.977-0.988) and 0.979 (95% CI, 0.97-0.909) respectively. Discussion: ODI from oximetry is sensitive and specific in predicting moderate-to-severe or severe OSA in at-risk surgical population. It provides an easy, accurate, and accessible tool for at-risk surgical patients with suspected OSA.
... Based on the ODI, patients were divided into three groups: mild (5)(6)(7)(8)(9)(10)(11)(12)(13)(14), moderate (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29), and severe (≥30). Patients with an ODI < 5 ...
... Intermittent chronic hypoxemia is a risk factor for serious complications related to OSAS, such as neurocognitive deterioration. 23 It causes inflammation, oxidative stress, endothelial dysfunction, and increased sympathetic activation, contributing to multi-organ comorbidities. 24 Recurrent episodes of hypoxia-reoxygenation are associated with high levels of pro-inflammatory markers, including tryptophan and kynurenine. ...
Article
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Objectives This study aimed to compare serum levels of brain-derived neurotrophic factor (BDNF) and neurofilament light (NfL) chain in normal individuals and patients with mild and moderate-severe obstructive sleep apnea syndrome (OSAS). Methods We enrolled 81 subjects referred to Otorhinolaryngology (Ear-Nose-Throat), Gazi University Faculty of Medicine, between 2017 and 2019. Based on the severity of OSAS, patients were divided into three groups: group 1 with mild OSAS (apnea-hypopnea index [AHI] 5-15; n = 26), group 2 with moderate-severe OSAS (AHI > 15; n = 32), and group 3 with normal individuals (AHI scores < 5; n = 23). Results Serum NfL and BDNF levels were evaluated together with the clinical data for all subjects. Significant differences were seen in the oxygen desaturation index (ODI), apnea index, hypopnea index, sleep efficiency, and NfL levels (P < .05) between the three groups. In the moderate-severe group, NfL levels showed a significant positive correlation with apnea index (P < .05, r = .389), hypopnea index (P < .05, r = .455), and ODI (P = .04; r = .362). Conclusions Our findings clarify the pathophysiology of OSAS in cases of repetitive hypoxia and chronic neuronal damage. Based on our results, we recommend that in addition to BDNF, NfL should also be evaluated in different and larger patient cohorts.
... OSA has been shown to be associated with a variable degree of nasal inflammation, and uvular mucosal congestion and airway hyper-reactivity due to intermittent hypoxemia may trigger upper airway inflammation [2]. A recent study has reported unstable breathing during the phenomenon known as rapid-eye movement (REM) rebound, with changes in sleep status after induction of general anesthesia, and that patients with OSA present a particularly high perioperative airway risk [3]. Therefore, we should pay special attention to airway management in the presence of dentofacial deformity, from the viewpoint of OSA, during the early perioperative period of orthognathic surgery. ...
... Patients with skeletal class II malocclusion and mandibular hypoplasia have an increased risk of OSA due to anatomical constriction of the upper respiratory tract [2,4]. Although patients with skeletal class III malocclusion have a significantly larger pharyngeal airway space and a larger anterior-posterior dimension than patients with skeletal class II malocclusion [3,5], some cases of postoperative OSA have been reported after mandibular setback in patients with skeletal class III and without previous OSA symptoms [4][5][6][7]. Undiagnosed "silent" OSA in dentofacial deformity has been reported as well [8]. ...
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Purpose The incidence of obstructive sleep apnea (OSA) immediately after surgery in patients with dentofacial deformities without previous OSA remains unknown. We aimed to perioperatively evaluate factors associated with oxygen desaturation index (ODI) during sleep, 7 days after bilateral splitting ramus osteotomy (BSSRO) in patients without previous OSA. Methods Fifty-one patients (15 males, 36 females) with dentofacial deformities, scheduled to undergo BSSRO, were included. Polysomnography was performed before orthognathic surgery. Perioperative OSA was evaluated with peripheral arterial tonometry on the day of surgery and 1, 2, 3, 4, and 7 days postoperatively. Rapid eye movement (REM) sleep periods and the ODI were measured. Factors associated with perioperative ODI after surgery were statistically analyzed. Results REM sleep periods were significantly decreased on the day of surgery and significantly increased at 4 and 7 days postoperatively, compared to the preoperative period. ODI increased on the day of surgery, decreased after 1 day, and increased again at 4 and 7 days postoperatively. ODI on the day of surgery was significantly increased due to increased preoperative ODI, overjet, and SN-MP angle and decreased SNA and SNB angle. ODI at 7 days postoperatively was significantly increased due to increased REM sleep periods and decreased SN-MP and gonial angle. ODI was increased in response to REM sleep periods 7 days after BSSO. Conclusion Airway management in patients with dentofacial deformity should be given more attention by preoperative assessment for OSA, even in the absence of previous OSA, until 7 days postoperatively due to REM rebound.
... In the past decade, oximetry has shown to have promising diagnostic validity in predicting sleep apnea. 26 In the general and bariatric populations, the addition of overnight oximetry with a screening questionnaire was shown to improve the diagnostic parameters for detecting sleep apnea. 17 18 27-29 Overnight oximetry using wearable pulse oximeters improve the convenience of monitoring patients' oxygen levels during sleep in their natural environment (ie, at home). ...
Article
Background There is an increased risk of sleep apnea in patients using opioids for chronic pain. We hypothesized that a simple model comprizing of: (1) STOP-Bang questionnaire and resting daytime oxyhemoglobin saturation (SpO 2 ); and (2) overnight oximetry will identify those at risk of moderate-to-severe sleep apnea in patients with chronic pain. Method Adults on opioids for chronic pain were recruited from pain clinics. Participants completed the STOP-Bang questionnaire, resting daytime SpO 2 , and in-laboratory polysomnography. Overnight oximetry was performed at home to derive the Oxygen Desaturation Index. A STOP-Bang score ≥3 or resting daytime SpO 2 ≤95% were used as thresholds for the first step, and for those identified at risk, overnight oximetry was used for further screening. The Oxygen Desaturation Index from overnight oximetry was validated against the Apnea-Hypopnea Index (≥15 events/hour) from polysomnography. Results Of 199 participants (52.5±12.8 years, 58% women), 159 (79.9%) had a STOP-Bang score ≥3 or resting SpO 2 ≤95% and entered the second step (overnight oximetry). Using an Oxygen Desaturation Index ≥5 events/hour, the model had a sensitivity of 86.4% and specificity of 52% for identifying moderate-to-severe sleep apnea. The number of participants who would require diagnostic sleep studies was decreased by 38% from Step 1 to Step 2 of the model. Conclusion A simple model using STOP-Bang questionnaire and resting daytime SpO 2 , followed by overnight oximetry, can identify those at high risk of moderate-to-severe sleep apnea in patients using opioids for chronic pain. Trial registration number NCT02513836 .
... The oxygen desaturation index (ODI), developed in line with the diagnostic simplifications for OSA, which is determined by the isolation of the oximetry channel from the full PSG, has been reported to possess a high sensitivity and specificity for the detection of OSA in children and adults (12,13). However, a recent systematic review showed a large discrepancy in the sensitivities and specificities of the ODI obtained from pulse oximeters compared to the reference apnea-hypopnea index (AHI) (14). These observations explain why pulse oximetry is largely viewed as a screening tool (15). ...
Article
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OBJECTIVES: Obstructive sleep apnea (OSA) is a common but largely underdiagnosed condition. This study aimed to test the hypothesis that the oxygen desaturation index (ODI) obtained using a wireless high-resolution oximeter with a built-in accelerometer linked to a smartphone with automated cloud analysis, Overnight Digital Monitoring (ODM), is a reliable method for the diagnosis of OSA. METHODS: Consecutive patients referred to the sleep laboratory with suspected OSA underwent in-laboratory polysomnography (PSG) and simultaneous ODM. The PSG apnea-hypopnea index (AHI) was analyzed using the criteria recommended and accepted by the American Academy of Sleep Medicine (AASM) for the definition of hypopnea: arousal or ≥3% O2 desaturation (PSG-AHI3%) and ≥4% O2 desaturation (PSG-AHI4%), respectively. The results of PSG and ODM were compared by drawing parallels between the PSG-AHI3% and PSG-AHI4% with ODM-ODI3% and ODM-ODI4%, respectively. Bland-Altman plots, intraclass correlation, receiver operating characteristics (ROC) and area under the curve (AUC) analyses were conducted for statistical evaluation. ClinicalTrial.gov: NCT03526133. RESULTS: This study included 304 participants (men: 55%; age: 55±14 years; body mass index: 30.9±5.7 kg/m2; PSG-AHI3%: 35.3±30.1/h, ODM-ODI3%: 30.3±25.9/h). The variability in the AASM scoring bias (PSG-AHI3% vs PSG-AHI4%) was significantly higher than that for PSG-AHI3% vs ODM-ODI3% (3%) and PSG-AHI4% vs ODM-ODI4% (4%) (9.7, 5.0, and 2.9/h, respectively; p
... An overview of the oxygenation values is provided by Table IV, where ODI≤ 3% and ODI≤ 4% represent the Oxygen Desaturation Index (ODI), defined as the number of times per hour of sleep that the blood's oxygen level drop by a certain percentage from the baseline. From recent literature, screening with oximetry may be indicated for the detection of OSA in select patients [16]. However, further study is needed before a definitive recommendation can be made. ...
Article
Polysomnography (PSG) is the current gold standard for the diagnosis of sleep disorders. However, this multiparametric sleep monitoring tool also has some drawbacks, e.g. it limits the patient's mobility during the night and it requires the patient to come to a specialized sleep clinic or hospital to attach the sensors. Unobtrusive techniques for the detection of sleep disorders such as sleep apnea are therefore gaining increasing interest. Remote photoplethysmography using video is a technique which enables contactless detection of hemodynamic information. Promising results in near-infrared have been reported for the monitoring of sleep-relevant physiological parameters pulse rate, respiration and blood oxygen saturation. In this study we validate a contactless monitoring system on eight patients with a high likelihood of relevant obstructive sleep apnea, which are enrolled for a sleep study at a specialized sleep center. The dataset includes 46.5 hours of video recordings, full polysomnography and metadata. The camera can detect pulse and respiratory rate within 2 beats/breaths per minute accuracy 92% and 91% of the time, respectively. Estimated blood oxygen values are within 4 percentage-points of the finger-oximeter 89% of the time. These results demonstrate the potential of a camera as a convenient diagnostic tool for sleep apnea, and sleep disorders in general.
... This contribution Research on the use of existing and development of new oximetry biomarkers has mainly focused on the diagnosis of OSA, as echoed by five recent reviews in this field [7][8][9][10][11] . Although this paper will naturally somewhat overlap with these reviews, we present a new comprehensive review focusing on the physiological interpretation and clinical use of oximetry biomarkers, in the spirit of the work of Malik et al. 3 in the field of HRV analysis. ...
Article
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Pulse oximetry is routinely used to non-invasively monitor oxygen saturation levels. A low oxygen level in the blood means low oxygen in the tissues, which can ultimately lead to organ failure. Yet, contrary to heart rate variability measures, a field which has seen the development of stable standards and advanced toolboxes and software, no such standards and open tools exist for continuous oxygen saturation time series variability analysis. The primary objective of this research was to identify, implement and validate key digital oximetry biomarkers (OBMs) for the purpose of creating a standard and associated reference toolbox for continuous oximetry time series analysis. We review the sleep medicine literature to identify clinically relevant OBMs. We implement these biomarkers and demonstrate their clinical value within the context of obstructive sleep apnea (OSA) diagnosis on a total of n = 3806 individual polysomnography recordings totaling 26,686 h of continuous data. A total of 44 digital oximetry biomarkers were implemented. Reference ranges for each biomarker are provided for individuals with mild, moderate, and severe OSA and for non-OSA recordings. Linear regression analysis between biomarkers and the apnea hypopnea index (AHI) showed a high correlation, which reached $$\overline R ^2 = 0.82$$ R ¯ 2 = 0.82 . The resulting python OBM toolbox, denoted “pobm”, was contributed to the open software PhysioZoo ( physiozoo.org ). Studying the variability of the continuous oxygen saturation time series using pbom may provide information on the underlying physiological control systems and enhance our understanding of the manifestations and etiology of diseases, with emphasis on respiratory diseases.
... An increase in the number of false negatives would likely lead to a higher rate of perioperative and postoperative complications, especially cardiovascular and respiratory problems, as well as admission to intensive care [12,13,15]. Our results are similar to those previously reported in the literature [26], showing high sensitivity and specificity. Therefore, at-home continuous overnight pulse oximetry might be useful to identify patients with OSA who need CPAP treatment before bariatric surgery. ...
Article
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Purpose Screening for obstructive sleep apnea (OSA) is recommended in patients scheduled for bariatric surgery because continuous positive airway pressure (CPAP) therapy in patients with moderate-to-severe OSA reduces postoperative complications. However, cardiorespiratory polygraphy (CRP) and polysomnography (PSG) are expensive and time-consuming. The present study aimed to assess whether at-home continuous overnight pulse oximetry can be used to diagnose moderate-to-severe OSA in patients scheduled for bariatric surgery. Methods In this prospective observational study, we enrolled consecutive patients scheduled for bariatric surgery. Patients with no prior OSA diagnosis were evaluated using the ESS, SBQ, and preoperative at-home CRP. Correlations were calculated between AHI and oximetry parameters. For each oximetry parameter, a receiver-operating characteristic (ROC) curve was generated to identify optimal cut-off values for diagnosing moderate-to-severe OSA. Results In total, 117 patients were included. The oxygen desaturation index was the most correlated oximetry parameter; the optimal cut-off value for diagnosing moderate-to-severe OSA was 23.9. The sensitivity and specificity were 80 and 92%, respectively. The area under the ROC curve was 0.935. Conclusions At-home continuous overnight pulse oximetry could be used to screen moderate-to-severe OSA in patients scheduled for bariatric surgery because it would allow clinicians to implement early CPAP therapy and avoid preoperative PSG or CRP.
... Oxymetric measures can be extracted from pulse oximetry, including mean oxygen saturation, percentage of time with oxygen saturation < 90%, and oxygen desaturation index (ODI). A systematic review evaluated the diagnostic accuracy of ODI for SDB, significant heterogeneity exists among studies with sensitivities ranged from 32% to 98.5%, while specificities ranged from 47.7% to 98% (18). Furthermore, studies have revealed that hypoxemia, rather than AHI, were well associated with cardiovascular risk (19,20). ...
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Background Polysomnography (PSG) is the gold standard for diagnosis of sleep-disordered breathing (SDB). But it is impractical to perform PSG in all patients with diabetes. The objective was to develop a clinically easy-to-use prediction model to diagnosis SDB in patients with diabetes. Methods A total of 440 patients with diabetes were recruited and underwent overnight PSG at West China Hospital. Prediction algorithms were based on oxygen desaturation index (ODI) and other variables, including sex, age, body mass index, Epworth score, mean oxygen saturation, and total sleep time. Two phase approach was employed to derivate and validate the models. Results ODI was strongly correlated with apnea-hypopnea index (AHI) (r s = 0.941). In the derivation phase, the single cutoff model with ODI was selected, with area under the receiver operating characteristic curve (AUC) of 0.956 (95%CI 0.917–0.994), 0.962 (95%CI 0.943–0.981), and 0.976 (95%CI 0.956–0.996) for predicting AHI ≥5/h, ≥15/h, and ≥30/h, respectively. We identified the cutoff of ODI 5/h, 15/h, and 25/h, as having important predictive value for AHI ≥5/h, ≥15/h, and ≥30/h, respectively. In the validation phase, the AUC of ODI was 0.941 (95%CI 0.904–0.978), 0.969 (95%CI 0.969–0.991), and 0.949 (95%CI 0.915–0.983) for predicting AHI ≥5/h, ≥15/h, and ≥30/h, respectively. The sensitivity of ODI ≥5/h, ≥15/h, and ≥25/h was 92%, 90%, and 93%, respectively, while the specificity was 73%, 89%, and 85%, respectively. Conclusions ODI is a sensitive and specific tool to predict SDB in patients with diabetes.
... According to this review, a diagnosis of OSAS should be consid-ered with a 4% ODI of ≥ 15 events/hour; further evaluation is instead required with a 4% ODI ≥ 10 events/hour. Screening is recommended for the detection of OSAS associated with cardiovascular risk in middle-aged men without comorbidities 17 . In fact, untreated OSAS, in addition to causing depressive symptoms and reduced quality of social, economic and family life, can cause sudden death, uncontrolled hypertension, coronary heart disease and congestive heart failure 18 . ...
Objective: This study reports our experience in a selected cohort of patients affected by mild-moderate OSAS, without tonsillar obstruction, and treated with pharyngoplasty. Methods: In a case-control retrospective study, we compared modified expansion sphincter pharyngoplasty (MESP) to modified barbed reposition pharyngoplasty (MBRP) in adult patients with oropharyngeal transversal collapse with a BMI ≤ 30 kg/m2, and mild-moderate obstructive sleep apnoea syndrome (OSAS). A clinical evaluation, including collection of anthropometric data and sleep endoscopy, was performed. Six months after surgery, symptoms recording, clinical evaluation and polysomnography (PSG) were repeated. Results: We enrolled 20 patients: 10 treated with MESP and 10 treated with MBRP. Mean apnoea-hypoapnoea index (AHI) was 22.8 (± 5.63). We observed in both groups a significant reduction of AHI and oropharyngeal obstruction (p = 0.01), with a success rate, according with Sher's criteria, of 90% for MESP and 80% for MBRP, respectively. Post-surgical pain and snoring reduction were significantly lower with MBRP. Conclusions: We recorded similar success rates for both techniques. MBRP may be considered better than MESP due to less surgical time, no potential mucosal damage, absence of knots, and faster recovery with less pain.
... The collapse of the upper airway during sleep is the hallmark of OSA and breathing is interrupted for at least 10 seconds [1,2]. Complete cessation of breathing is repeated many times during sleep, due to which the amount of oxygen in the blood decreases and several systems are adversely affected [3]. ...
... The other consequences of OSA are due to the alterations in gas exchange during sleep [14]. The oxygen saturation in OSA patients is lower than in healthy patients [15], which can lead to cardiovascular effects [16] in both the short or long term [17]. The most common cardiovascular effects related to OSA are hypertension [18], stroke [19], sudden and unexpected death [20], and arrhythmia [21]. ...
Article
Objective: The mandibular advancement device (MAD) is currently suggested in patients with mild to moderate obstructive sleep apnea (OSA). This study investigated the effects of a new fully customizable MAD-type device called, "It Makes You Sleep" (IMYS), in patients with mild to moderate OSA. Methods: Sixteen patients (14 men and 2 women; mean age 62; SD ± 11 years) were retrospectively enrolled. Each patient received home sleep apnea testing (HSAT) at baseline (T0) and after three months (T1) of IMYS treatment. The Apnea-Hypopnea Index (AHI), the Oxygen Desaturation Index (ODI), the Minimum Oxygen Saturation (minSO2) and the Medium Oxygen Saturation (medSO2) were analyzed. Results: From T0 to T1, the IMYS treatment showed a significant reduction of AHI and ODI and a significant increase of minSO2 and medSO2. Conclusion: The IMYS appliance is an effective device for treating mild or moderate OSA.
... However, it is known that in OSAS oxygen desaturations are more associated to drowsiness than AHI. 30 Patients with MS showed a worse sleep quality, in terms of duration, efficiency, and architecture compared to healthy subjects. As shown by Buratti et al, 31 the course of MS may be influenced by sleep quality, possibly because of the role of sleep in some oligodendrocyte functions, such as myelination. ...
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Background: Multiple sclerosis (MS) represents a risk factor for sleep disorders, but there are conflicting results about the prevalence and severity of sleep-related breathing disorders (SRBD) in MS. Most available data come from self-administered questionnaires. Objective: To conduct a polysomnographic study in MS focused on SRBD, compared to a group of healthy controls (HC), also considering the neuroimaging findings. To evaluate the impact of SRBD on vigilance, fatigue and depression in MS. Methods: In this cross-sectional, observational, instrumental study, 67 MS patients (men/women: 20/47; mean age: 50.6±8.2 years) underwent PSG and maintenance of wakefulness test. Findings were compared to 67 age-, sex-, BMI-matched HC, by using parametric (Student's t-test) and nonparametric statistics (chi-squared test). A subgroup analysis was then performed, evaluating the influence of brainstem (mesencephalic, pontine and medullary) lesions at neuroimaging on instrumental and clinical data: MS patients with at least one brainstem lesion vs MS patients without vs HC. Results: The frequency of SRBD was comparable in MS patients and HC. No MS patient had a central apnea index ≥2/h. The respiratory disturbance index (RDI) did not correlate to clinical parameters such as fatigue and depression. Patients with MS were drowsier than HC (47% vs 26%, p = 0.019) and showed a worse sleep pattern, in terms of duration, efficiency and architecture. Conclusion: Our study does not provide evidence of an association between MS-specific symptoms such as fatigue, sleepiness, depression and central or obstructive apneas, even in the presence of brainstem lesions.
... For example, Ulysses et al. [17] used time spent below a certain level saturation (TSA), the saturation variability index and other indicators to evaluate AHI, and compared the diagnostic performance of SA under different metrics. The oxygen desaturation index (ODI) is defined as the number of oxyhemoglobin desaturation below a certain threshold [18]. Ling et al. [19] found that the use of ODI improved the accuracy of moderate and severe OSA detection. ...
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Sleep apnea (SA) is a common sleep disorder which could impair the human physiological system. Therefore, early diagnosis of SA is of great interest. The traditional method of diagnosing SA is an overnight polysomnography (PSG) evaluation. When PSG has limited availability, automatic SA screening with a fewer number of signals should be considered. The primary purpose of this study is to develop and evaluate a SA detection model based on electrocardiogram (ECG) and blood oxygen saturation (SpO2). We adopted a multimodal approach to fuse ECG and SpO2 signals at the feature level. Then, feature selection was conducted using the recursive feature elimination with cross-validation (RFECV) algorithm and random forest (RF) classifier used to discriminate between apnea and normal events. Experiments were conducted on the Apnea-ECG database. The introduced algorithm obtained an accuracy of 97.5%, a sensitivity of 95.9%, a specificity of 98.4% and an AUC of 0.992 in per-segment classification, and outperformed previous works. The results showed that ECG and SpO2 are complementary in detecting SA, and that the combination of ECG and SpO2 enhances the ability to diagnose SA. Therefore, the proposed method has the potential to be an alternative to conventional detection methods.
... The other consequences of SRBD are due to the alterations in gas exchange during sleep [6]. The oxygen saturation in SRBD patients is lower than in healthy patients [7], and this factor can lead to cardiovascular effects in both the short and the long term [8]. The purpose of this Special Issue is to provide an overview of recent advances in SRBD monitoring and assessment, including: the design, development and application of advanced evaluation methods; and treatment based on cutting edge scientific knowledges. ...
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The term “sleep-related breathing disorders” (SRDB) comprehends a spectrum of pathologic conditions characterized by abnormal respiration during sleep, that can affect both adults and growing subjects. The expanding knowledge on this topic has revealed that impaired sleeping and breathing have profound effects on many systemic functions, therefore a modern approach requires the collaboration of different professionals like the otorhinolaryngologist, pneumologist, neurologist, cardiologist, psychologist, dentist, and many others. The real prevalence of such conditions is unknown, especially in children, even though a growing awareness can be found among Governments, researchers, and public opinion, especially for the social implications that SRDB can have. Moreover, recent studies have raised attention on comorbidities that can be associated with SRDB, influencing each other. Regarding the current international situation, it would be interesting to evaluate the progress of COVID-19 disease in SRDB patients. Defining the state-of-the-art knowledge on all the conditions orbiting around SRDB, from all points of view—aetiology, diagnosis, clinical management, interdisciplinarity, public health management—would be of great interest and impact to improve future research and the quality of life of SRDB patients.
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Objectives To characterize and evaluate the estimation of oxygen saturation measured by a wrist-worn reflectance pulse oximeter during sleep. Methods Ninety-seven adults with sleep disturbances were enrolled. Oxygen saturation was simultaneously measured using a reflectance pulse oximeter (Galaxy Watch 4 [GW4], Samsung, South Korea) and a transmittance pulse oximeter (polysomnography) as a reference. The performance of the device was evaluated using the root mean squared error (RMSE) and coverage rate. Additionally, GW4-derived oxygen desaturation index (ODI) was compared with the apnea-hypopnea index (AHI) derived from polysomnography. Results The GW4 had an overall RMSE of 2.3% and negligible bias of -0.2%. A Bland-Altman density plot showed good agreement between the GW4 and the reference pulse oximeter. RMSEs were 1.65 ± 0.57%, 1.76 ± 0.65%, 1.93 ± 0.54%, and 2.93 ± 1.71% for normal (n = 18), mild (n = 21), moderate (n = 23), and severe obstructive sleep apnea (n = 35), respectively. The data rejection rate was 26.5%, which was caused by fluctuations in contact pressure and the discarding of data less than 70% of saturation. A GW4-ODI ≥5/h had the highest ability to predict AHI ≥15/h with sensitivity, specificity, accuracy, and area under the curve of 89.7%, 64.1%, 79.4%, and 0.908, respectively. Conclusions This study evaluated the estimation of oxygen saturation by the GW4 during sleep. This device complies with both Food and Drug Administration and International Organization for Standardization standards. Further improvements in the algorithms of wearable devices are required to obtain more accurate and reliable information about oxygen saturation measurements.
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Background Obstructive sleep apnea (OSA) is one of the common sleep-related breathing disorders in children. However, polysomnography (PSG) is an expensive and labor-intensive diagnostic modality that may not always be feasible, especially in low-income countries or in non-tertiary hospitals. Portable monitors (PMs), a new approach for OSA diagnosis, have become more widely used with lower intolerance and cost in recent years. We aimed to analyze the diagnostic performance of Level IV PMs compared with PSG for the diagnosis of pediatric OSA. Methods PubMed and Embase databases were searched for studies published in English up to December 31, 2020 evaluating the diagnostic accuracy of Level IV PMs against the apnea-hypopnea index (AHI) measured using overnight in-laboratory polysomnography (PSG) in children and adolescents. A random-effects bivariate model was used to estimate the summary sensitivity and specificity of oximetry-based statistical classifiers. A qualitative evaluation of studies was performed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) rating. Results In total, 20 studies involving 7,062 participants were included in this systematic review. Among these articles, 7 studies (oximetry based on new mathematical classifiers) involving 5,098 individuals satisfied the criteria for quantitative synthesis. Compared with AHI evaluation measured by PSG, different PM systems achieved diagnostic accuracy with variable degrees of success. A meta-analysis showed a pooled sensitivity of 74% (95% confidence interval [CI]: 66–80%) and pooled specificity of 90% (95% CI: 85–94%). The area under the summary receiver operating characteristic (SROC) curve was 0.89 (95% CI: 0.86–0.92). Conclusion This study showed the potential of Level IV PMs for screening pediatric OSA patients. Oximetry based on new mathematical classifiers may provide a simple and effective alternative to PSG in the diagnosis of pediatric OSA especially in the context of appropriate clinical evaluation.
Article
Objective This study aimed to evaluate nocturnal oximetry approaches in identifying obstructive sleep apnea (OSA) among bariatric surgical candidates. Methods This was a cross-sectional study involving adult bariatric patients who were undergoing in-lab polysomnography and who were previously screened with the GOAL questionnaire. OSA severity was established as any OSA, moderate/severe OSA, and severe OSA. Oximetry data were evaluated as oxygen saturation (average and nadir), oxygen desaturation index (ODI) at 3%, and proportion of time spent with oxygen saturation <90%. Associations between oximetry data and the apnea-hypopnea index (AHI) were assessed by Spearman correlation index (r), linear regression, logistic regression, and discrimination. Results All oximetry values were significantly correlated with the AHI among 1,178 individuals, with the ODI emerging as the better parameter (r = 0.911, p < 0.001). Using linear regression, the ODI was the only predictor of the AHI (β = 0.952, p < 0.001). In the multivariate analysis, the ODI was the only independent parameter predicting OSA at all severity levels. In addition, the ODI exhibited excellent discrimination to predict OSA and displayed improved performance among individuals screened as being at high risk versus those at low risk with the GOAL instrument. Conclusions The ODI emerges as a valid surrogate predictor of the AHI, particularly among those screened as being at high risk for OSA.
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Study objective Obstructive sleep apnea (OSA) is known to be associated with postoperative cardiovascular events in patients undergoing major non-cardiac surgery. The objective of the study is to determine whether preoperative oximetry-derived hypoxemia predicts postoperative cardiovascular events in surgical patients with unrecognized obstructive sleep apnea. Design and setting The study was a planned post hoc analyses of a multicenter prospective cohort study. Patients The inclusion criteria were patients ≥45 years old undergoing major non-cardiac surgery with cardiovascular risk factors. Interventions and measurements All patients underwent pre-operative pulse oximetry (PULSOX-300i, Konica-Minolta Sensing, Inc). The severity of OSA was classified based on oxygen desaturation index (ODI) (mild: ≥5 to <15, moderate: ≥15 to <30, and severe OSA: ≥30 events/h). The 30 days cardiovascular events were a composite of myocardial injury, cardiac death, congestive heart failure, thromboembolism, atrial fibrillation, and stroke. Main results For 1218 patients with mild, moderate, or severe OSA (mean age: 67.2 ± 9.3 years; body mass index: 27.0 ± 5.3 kg/m²), the rate of postoperative cardiovascular events was 16.4%, 25.2%, and 29.8% respectively. The multivariable analysis showed that preoperative oxygen desaturation index (ODI) ≥30 events per hour {adjusted hazard ratio (aHR) 1.63 [95% confidence interval (CI): 1.05–2.53]}, and cumulative time spent during sleep with oxygen saturation below 80% (CT80) ≥10 min {aHR 1.79 [95% CI: 1.28–2.50]} were independent predictors of 30-day postoperative cardiovascular events. Conclusions Preoperative ODI ≥30 events per hour and CT80 ≥ 10 min are associated with increased risk of postoperative cardiovascular events. Preoperative screening using oximetry helps in risk stratification for unrecognized sleep apnea. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT01494181
Article
Background Air pollution may be a contributing risk factor for obstructive sleep apnea (OSA). However, the health effects of co-exposure to multiple air pollutants on OSA patients remain unclear. Objectives To assess the joint effect of multi-pollutants on sleep disordered breathing (SDB) parameters in patients with or without OSA and identify the dominant pollutants. Methods A total of 2524 outpatients from April 2020 to May 2021 were recruited in this cross-sectional study. Ambient air pollutants data were obtained from the nearest central monitoring stations to participant's residential address. SDB parameters were measured by the ApneaLink devices, including apnea-hypopnea index (AHI), hypopnea index (HI), oxygen desaturation index (ODI), average oxygen saturation (SpO2), percentage sleep time with <90% saturation (T90), and desaturation. Bayesian kernel machine regression (BKMR) was applied to evaluate the effects of multiple pollutants. Results Significant associations were observed between air pollutants and SDB parameters (including increases in AHI, HI, ODI, and desaturation) among patients with OSA. Co-exposure to air pollutants was positively correlated with AHI, HI, and ODI. PM10 and O3 dominated the effects of pollutants mixtures on OSA, with the highest posterior inclusion probabilities (PIP) values of 0.592 and 0.640, respectively. Stratified analysis showed that, compared to male patients with OSA, stronger effects on the SDB parameters were observed in female patients. Stronger associations were also found in the warm season than those in the cold season. Conclusion Co-exposure to air pollutants was associated with SDB parameters among patients with OSA, PM10 and O3 might play the dominant roles.
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Turkish Thoracic Society Early Career Members Taskforce Group’s Virtual Congress Notes, Part I: ERS 2020 Virtual Congress Available from: https://www.toraks.org.tr/site/community/downloads/tS5bMgnfB14Yh_5n
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Importance The efficacy of surgical treatments for obstructive sleep apnea (OSA) is variable when considering only the Apnea Hypopnea Index as the treatment end point. However, only a few studies have shown an association between these procedures and improved clinically relevant outcomes, such as cardiovascular, endocrine, and neurological sequelae of OSA. Objective To evaluate the association of surgery for OSA with clinically relevant outcomes. Design, Setting, and Participants This retrospective cohort study used the Truven MarketScan Database from January 1, 2007, to December 31, 2015, to identify all patients diagnosed with OSA who received a prescription of continuous positive airway pressure (CPAP), were 40 to 89 years of age, and had at least 3 years of data on file. Data were analyzed September 19, 2019. Interventions Soft tissue and skeletal surgical procedures for the treatment of OSA. Main Outcomes and Measures The occurrence of cardiovascular, neurological, and endocrine complications was compared in patients who received CPAP alone and those who received surgery. High-dimensionality propensity score matching was used to adjust the models for confounders. Kaplan-Meier survival analysis with a log-rank test was used to compare differences in survival curves. Findings A total of 54 224 patients were identified (33 405 men [61.6%]; mean [SD] age, 55.1 [9.2] years), including a cohort of 49 823 patients who received CPAP prescription alone (mean [SD] age, 55.5 [9.4] years) and 4269 patients who underwent soft tissue surgery (mean [SD] age, 50.3 [7.0] years). The median follow-up time was 4.47 (interquartile range, 3-8) years after the index CPAP prescription. In the unadjusted model, soft tissue surgery was associated with decreased cardiovascular (hazard ratio [HR], 0.92; 95% CI, 0.86-0.98), neurological (HR, 0.49; 95% CI, 0.39-0.61), and endocrine (HR, 0.80; 95% CI, 0.74-0.86) events. This finding was maintained in the adjusted model (HR for cardiovascular events, 0.91 [95% CI, 0.83-1.00]; HR for neurological events, 0.67 [95% CI, 0.51-0.89]; HR for endocrine events, 0.82 [95% CI, 0.74-0.91]). Skeletal surgery (n = 114) and concomitant skeletal and soft tissue surgery (n = 18) did not demonstrate significant differences in rates of development of systemic complications. Conclusions and Relevance In this cohort study, soft tissue surgery for OSA was associated with lower rates of development of cardiovascular, neurological, and endocrine systemic complications compared with CPAP prescription in a large convenience sample of the working insured US adult population. These findings suggest that surgery should be part of the early treatment algorithm in patients at high risk of CPAP failure or nonadherence.
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Obstructive sleep apnea hypoventilation syndrome (OSAHS) is a common sleep breathing disorder closely associated with cardiovascular disease. However, the respiratory sleep and related cardiovascular parameters on the apnea and hypopnea index (AHI) and life quality of primary snoring are unclear. We launched a cohort study focused on the association between respiratory sleep and cardiovascular-related parameters and apnea and hypopnea index, incorporating data from 218 patients with primary snoring in our medical center between Jun 1, 2015, and Apr 1, 2016. Thirty patients from Sichuan Cancer Hospital were used for validation. Patients with longer apnea time were more likely to progress to higher AHI (> 30) than controls (OR = 5.66, 95% CI = [2.79, 11.97], p < 0.001). Similarly, if patients have a higher value of diastolic blood pressure, they will also have a higher AHI (> 30) (HR [95% CI] = 3.42 [1.14, 13.65], p = 0.043). According to multivariate analysis, longest apnea time, the mean percentage of SaO2, and neckline length were independent risk factors of overall survival. A predictive model developed based on these factors above yielded a favorable agreement (C-index = 0.872) on the calibration curve. Thirty patients conducted external validation from Sichuan Cancer Hospital, displaying an AUC of 0.833 (0.782–0.884). Increased diastolic blood pressure and apnea time affect AHI level. An AHI prediction model based on these factors above can help clinicians predict the risk of high AHI events.
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Background: Polysomnography (PSG) is currently the "gold standard" for the diagnosis of the sleep apnoea hypopnoea syndrome (SAHS). Nocturnal oximetry (NO) has been used with contradictory results. A prospective study was performed to determine the accuracy of NO as a diagnostic tool and to evaluate the reduction in the number of PSGs if the diagnosis of SAHS had been established by this method. Methods: Two hundred and seventy five patients with a clinical suspicion of SAHS were admitted to undergo, in the same night, full PSG and NO. Desaturation was defined as a fall in the haemoglobin saturation level (SaO(2)) to lower than 4% from the baseline level and an oxygen desaturation index per hour (ODI) was obtained in each patient with three cut off points: >/= 5 (ODI-5), >/= 10 (ODI-10), and >/= 15 (ODI-15). Results: SAHS was diagnosed in 216 patients (194 men). After withdrawing patients with abnormal lung function (forced expiratory volume in one second (FEV(1)) lower than 80% predicted), sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV) of NO were: ODI-5 (80%, 89%, 97%, 48%); ODI-10 (71%, 93%, 97%, 42%); ODI-15 (63%, 96%, 99%, 38%). The accuracy for each ODI was 0.81, 0.75, and 0.70, respectively. If NO had been considered as a diagnostic tool and PSG had been performed only in patients with a negative NO (false negative and true negative) and those with a positive NO and abnormal pulmonary function tests, 135/275 (ODI-5), 156/275 (ODI-10), and 170/275 (ODI-15) PSGs would have been performed, a reduction of 140, 119, and 105, respectively. Conclusion: Nocturnal oximetry in patients with suspected SAHS and normal spirometric values permits the institution of therapeutic measures in most patients.
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Obstructive sleep apnoea syndrome (OSAS) is a disorder that leads to metabolic abnormalities and increased cardiovascular risk. The aim of this study was to identify early laboratory markers of cardiovascular disease through analysis of oxidative stress in normal subjects and patients with OSAS. A prospective study was designed to compare outcomes of oxidative stress laboratory tests in 20 adult patients with OSAS and a control group of 20 normal subjects. Laboratory techniques for detecting and quantifying free radical damage must be targeted to assess the pro-oxidant component and the antioxidant in order to obtain an overall picture of oxidative balance. No statistical differences in age, sex distribution, or BMI were found between the two groups (p>0.05). There were significant differences in the apnoea/hypopnoea index (AHI) between OSAS patients and the control group (p<0.05). Statistically significant differences in isoprostane, advanced oxidation protein products (AOPP) and non-protein bound iron (NPBI) levels were found between the study and control groups. No significant difference in the levels of thiol biomarkers was found between the two groups. The main finding of the present study was increased production of oxidative stress biomarkers in OSAS patients. The major difference between thiols and other oxidative stress biomarkers is that thiols are antioxidants, while the others are expressions of oxidative damage. The findings of the present study indicate that biomarkers of oxidative stress in OSAS may be used as a marker of upper airway obstructive episodes due to mechanical trauma, as well as a marker of hypoxaemia causing local oropharyngeal inflammation.
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Background: Diagnosing obstructive sleep apnea (OSA) is clinically relevant because untreated OSA has been associated with increased morbidity and mortality. The STOP-Bang questionnaire is a validated screening tool for OSA. We conducted a systematic review and meta-analysis to determine the effectiveness of STOP-Bang for screening patients suspected of having OSA and to predict its accuracy in determining the severity of OSA in the different populations. Methods: A search of the literature databases was performed. Inclusion criteria were: 1) Studies that used STOP-Bang questionnaire as a screening tool for OSA in adult subjects (>18 years); 2) The accuracy of the STOP-Bang questionnaire was validated by polysomnography-the gold standard for diagnosing OSA; 3) OSA was clearly defined as apnea/hypopnea index (AHI) or respiratory disturbance index (RDI) ≥ 5; 4) Publications in the English language. The quality of the studies were explicitly described and coded according to the Cochrane Methods group on the screening and diagnostic tests. Results: Seventeen studies including 9,206 patients met criteria for the systematic review. In the sleep clinic population, the sensitivity was 90%, 94% and 96% to detect any OSA (AHI ≥ 5), moderate-to-severe OSA (AHI ≥15), and severe OSA (AHI ≥30) respectively. The corresponding NPV was 46%, 75% and 90%. A similar trend was found in the surgical population. In the sleep clinic population, the probability of severe OSA with a STOP-Bang score of 3 was 25%. With a stepwise increase of the STOP-Bang score to 4, 5, 6 and 7/8, the probability rose proportionally to 35%, 45%, 55% and 75%, respectively. In the surgical population, the probability of severe OSA with a STOP-Bang score of 3 was 15%. With a stepwise increase of the STOP-Bang score to 4, 5, 6 and 7/8, the probability increased to 25%, 35%, 45% and 65%, respectively. Conclusion: This meta-analysis confirms the high performance of the STOP-Bang questionnaire in the sleep clinic and surgical population for screening of OSA. The higher the STOP-Bang score, the greater is the probability of moderate-to-severe OSA.
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This study proposes a method of automatically classifying sleep apnea/hypopnea events based on sleep states and the severity of sleep-disordered breathing (SDB) using photoplethysmogram (PPG) and oxygen saturation (SpO2) signals acquired from a pulse oximeter. The PPG was used to classify sleep state, while the severity of SDB was estimated by detecting events of SpO2 oxygen desaturation. Furthermore, we classified sleep apnea/hypopnea events by applying different categorisations according to the severity of SDB based on a support vector machine. The classification results showed sensitivity performances and positivity predictive values of 74.2% and 87.5% for apnea, 87.5% and 63.4% for hypopnea, and 92.4% and 92.8% for apnea + hypopnea, respectively. These results represent better or comparable outcomes compared to those of previous studies. In addition, our classification method reliably detected sleep apnea/hypopnea events in all patient groups without bias in particular patient groups when our algorithm was applied to a variety of patient groups. Therefore, this method has the potential to diagnose SDB more reliably and conveniently using a pulse oximeter.
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Objectives In its guidelines on the use of portable monitors to diagnose obstructive sleep apnoea, the American Academy of Sleep Medicine endorses home polygraphy with type III devices recording at a minimum airflow the respiratory effort and pulse oximetry, but advises against simple pulse oximetry. However, oximetry is widely available and simple to use in the home. This study was designed to compare the ability of the oxygen desaturation index (ODI) based on oximetry alone with a stand-alone pulse oximeter (SPO) and from the oximetry channel of the ApneaLink Plus (ALP), with the respiratory disturbance index (RDI) based on four channels from the ALP to predict the apnoea–hypopnoea index (AHI) from laboratory polysomnography. Design Cross-sectional diagnostic accuracy study. Setting Sleep medicine practice of a multispecialty clinic. Participants Patients referred for laboratory polysomnography with suspected sleep apnoea. We enrolled 135 participants with 123 attempting the home sleep testing and 73 having at least 4 hours of satisfactory data from SPO and ALP. Interventions Participants had home testing performed simultaneously with both a SPO and an ALP. The 2 oximeter probes were worn on different fingers of the same hand. The ODI for the SPO was calculated using Profox software (ODISOX). For the ALP, RDI and ODI were calculated using both technician scoring (RDIMAN and ODIMAN) and the ALP computer scoring (RDIRAW and ODIRAW). Results The receiver–operator characteristic areas under the curve for AHI ≥5 were RDIMAN 0.88 (95% confidence limits 0.81–0.96), RDIRAW 0.86 (0.76–0.94), ODIMAN 0.86 (0.77–0.95), ODIRAW 0.84 (0.75–0.93) and ODISOX 0.83 (0.73–0.93). Conclusions We conclude that the RDI and the ODI, measured at home on the same night, give similar predictions of the laboratory AHI, measured on a different night. The differences between the two methods are small compared with the reported night-to-night variation of the AHI.
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Aim: The aim of our study was to evaluate the sensitivity and specificity of Nocturnal Oximetry (NO) as a diagnostic screening tool for obstructive sleep apnoea hypopnoea syndrome (OSAHS), compared with polysomnography (PSG) as the gold standard. Methodology: 63 patients with clinical suspicion of OSAHS and exclusion of respiratory disease underwent PSG and NO. We then determined NO sensitivity, specificity, positive (PPV) and negative predictive values (NPV). Results: OSAHS was diagnosed in 47 patients with a mean age of 54 years. In the evaluation of the percentage of Total Sleep Time (TST) with oxygen desaturation below 90%, we found significant differences between patients with OSAHS (25.4 ± 29.7%) and without OSAHS (1 ± 1.5%), p
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Polysomnography (PSG) is treated as the gold standard for diagnosing obstructive sleep apnea (OSA). However, it is labor-intensive, time-consuming, and expensive. This study evaluates validity of overnight pulse oximetry as a diagnostic tool for moderate to severe OSA patients. A total of 699 patients with possible OSA were recruited for overnight oximetry and PSG examination at the Sleep Center of a University Hospital from Jan. 2004 to Dec. 2005. By excluding 23 patients with poor oximetry recording, poor EEG signals, or respiratory artifacts resulting in a total recording time less than 3 hours; 12 patients with total sleeping time (TST) less than 1 hour, possibly because of insomnia; and 48 patients whose ages less than 20 or more than 85 years old, data of 616 patients were used for further study. By further considering 76 patients with TST < 4 h, a group of 540 patients with TST ≥ 4 h was used to study the effect of insufficient sleeping time. Alice 4 PSG recorder (Respironics Inc., USA) was used to monitor patients with suspected OSA and to record their PSG data. After statistical analysis and feature selection, models built based on support vector machine (SVM) were then used to diagnose moderate and moderate to severe OSA patients with a threshold of AHI = 30 and AHI = 15, respectively. The SVM models designed based on the oxyhemoglobin desaturation index (ODI) derived from oximetry measurements provided an accuracy of 90.42-90.55%, a sensitivity of 89.36-89.87%, a specificity of 91.08-93.05%, and an area under ROC curve (AUC) of 0.953-0.957 for the diagnosis of severe OSA patients; as well as achieved an accuracy of 87.33-87.77%, a sensitivity of 87.71-88.53%, a specificity of 86.38-86.56%, and an AUC of 0.921-0.924 for the diagnosis of moderate to severe OSA patients. The predictive outcome of ODI to diagnose severe OSA patients is better than to diagnose moderate to severe OSA patients. Overnight pulse oximetry provides satisfactory diagnostic performance in detecting severe OSA patients. Home-styled oximetry may be a tool for severe OSA diagnosis.
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Elevated loop gain, consequent to hypersensitive ventilatory control, is a primary nonanatomical cause of obstructive sleep apnoea (OSA) but it is not possible to quantify this in the clinic. Here we provide a novel method to estimate loop gain in OSA patients using routine clinical polysomnography alone. We use the concept that spontaneous ventilatory fluctuations due to apnoeas/hypopnoeas (disturbance) result in opposing changes in ventilatory drive (response) as determined by loop gain (response/disturbance). Fitting a simple ventilatory control model (including chemical and arousal contributions to ventilatory drive) to the ventilatory pattern of OSA reveals the underlying loop gain. Following mathematical-model validation, we critically tested our method in patients with OSA by comparison with a standard (continuous positive airway pressure (CPAP) drop method), and by assessing its ability to detect the known reduction in loop gain with oxygen and acetazolamide. Our method quantified loop gain from baseline polysomnography (correlation versus CPAP-estimated loop gain: n=28; r=0.63, p<0.001), detected the known reduction in loop gain with oxygen (n=11; mean± sem change in loop gain (ΔLG) −0.23±0.08, p=0.02) and acetazolamide (n=11; ΔLG −0.20±0.06, p=0.005), and predicted the OSA response to loop gain-lowering therapy. We validated a means to quantify the ventilatory control contribution to OSA pathogenesis using clinical polysomnography, enabling identification of likely responders to therapies targeting ventilatory control.
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Background: Obstructive sleep apnea (OSA) has been reported to be a risk factor for cardiovascular (CV) disease. Although the apnea-hypopnea index (AHI) is the most commonly used measure of OSA, other less well studied OSA-related variables may be more pathophysiologically relevant and offer better prediction. The objective of this study was to evaluate the relationship between OSA-related variables and risk of CV events. Methods and findings: A historical cohort study was conducted using clinical database and health administrative data. Adults referred for suspected OSA who underwent diagnostic polysomnography at the sleep laboratory at St Michael's Hospital (Toronto, Canada) between 1994 and 2010 were followed through provincial health administrative data (Ontario, Canada) until May 2011 to examine the occurrence of a composite outcome (myocardial infarction, stroke, congestive heart failure, revascularization procedures, or death from any cause). Cox regression models were used to investigate the association between baseline OSA-related variables and composite outcome controlling for traditional risk factors. The results were expressed as hazard ratios (HRs) and 95% CIs; for continuous variables, HRs compare the 75th and 25th percentiles. Over a median follow-up of 68 months, 1,172 (11.5%) of 10,149 participants experienced our composite outcome. In a fully adjusted model, other than AHI OSA-related variables were significant independent predictors: time spent with oxygen saturation <90% (9 minutes versus 0; HR = 1.50, 95% CI 1.25-1.79), sleep time (4.9 versus 6.4 hours; HR = 1.20, 95% CI 1.12-1.27), awakenings (35 versus 18; HR = 1.06, 95% CI 1.02-1.10), periodic leg movements (13 versus 0/hour; HR = 1.05, 95% CI 1.03-1.07), heart rate (70 versus 56 beats per minute [bpm]; HR = 1.28, 95% CI 1.19-1.37), and daytime sleepiness (HR = 1.13, 95% CI 1.01-1.28).The main study limitation was lack of information about continuous positive airway pressure (CPAP) adherence. Conclusion: OSA-related factors other than AHI were shown as important predictors of composite CV outcome and should be considered in future studies and clinical practice.
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Purpose: This study aims to assess the association between excessive daytime sleepiness (EDS) and variables extracted from the pulse-oximetry signal obtained during overnight polysomnography. Methods: A cross-sectional design was used to study the relation between four hypoxemia variables and EDS as determined by Epworth Sleepiness Scale scores (ESSS) in 200 consecutive patients, newly diagnosed with obstructive sleep apnea (OSA), as defined by an apnea-hypopnea index (AHI)≥ 15. Hypoxemia measurements were compared between sleepy (ESSS ≥ 10) and nonsleepy (ESSS<10) patients before and after dichotomizing the cohort for each hypoxemia variable (and for AHI) such that there were 35 (165) patients in each of the corresponding higher (lower) subcohorts. The hypoxemia variables were combined into a biomarker, and its accuracy for predicting sleepiness in individual patients was evaluated. We planned to interpret prediction accuracy above 80 % as evidence that hypoxemia predicted EDS. Results: Hypoxemia was unassociated with sleepiness in OSA patients with AHI in the range of 15 to 50. In patients with AHI>50, the hypoxemia biomarker (but not individual hypoxemia variables) predicted sleepiness with 82 % accuracy. Conclusion: Nocturnal hypoxemia as determined by a polyvariable biomarker reliably predicted EDS in patients with severe OSA (AHI>50), indicating that oxygen fluctuation had a direct role in the development of EDS in patients with severe OSA.
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The definitions of respiratory events and recommendations concerning monitoring technology will continue to evolve as more knowledge is gained about the effect of using different definitions or technology on outcomes. Improved ability to predict patients who will improve symptomatically with treatment (especially in patients with "milder" obstructive sleep apnea) is clearly needed. It is hoped that this document is simply a starting point of a new process to provide a flexible and evolving set of respiratory definitions. The recommendations in this document are based predominantly on consensus. The task force attempted to carefully weigh the current evidence as well as to respond to concerns raised by the sleep community about the recommendations in the 2007 scoring manual. Many areas of uncertainty remain. No set of definitions can completely cover the wide variety of respiratory events encountered by clinicians. There is no substitute for clinical correlation of PSG findings with the clinical symptoms of the patient being evaluated.
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Purpose Newly developed algorithms putatively derive measures of sleep, wakefulness, and respiratory disturbance index (RDI) through detailed analysis of heart rate variability (HRV). Here, we establish levels of agreement for one such algorithm through comparative analysis of HRV-derived values of sleep–wake architecture and RDI with those calculated from manually scored polysomnographic (PSG) recordings. Methods Archived PSG data collected from 234 subjects who participated in a 3-day, 2-night study characterizing polysomnographic traits of chronic fatigue syndrome were scored manually. The electrocardiogram and pulse oximetry channels were scored separately with a novel scoring algorithm to derive values for wakefulness, sleep architecture, and RDI. Results Four hundred fifty-four whole-night PSG recordings were acquired, of which, 410 were technically acceptable. Comparative analyses demonstrated no difference for total minutes of sleep, wake, NREM, REM, nor sleep efficiency generated through manual scoring with those derived through HRV analyses. When NREM sleep was further partitioned into slow-wave sleep (stages 3–4) and light sleep (stages 1–2), values calculated through manual scoring differed significantly from those derived through HRV analyses. Levels of agreement between RDIs derived through the two methods revealed an R = 0.89. The Bland–Altman approach for determining levels of agreement between RDIs generated through manual scoring with those derived through HRV analysis revealed a mean difference of −0.7 ± 8.8 (mean ± two standard deviations). Conclusion We found no difference between values of wakefulness, sleep, NREM, REM sleep, and RDI calculated from manually scored PSG recordings with those derived through analyses of HRV.
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Background: It has been suggested that sleep-disordered breathing (SDB) is a risk factor for diabetes, but long-term follow-up studies are lacking. The aim of this community-based study was to analyze the influence of SDB on glucose metabolism after > 10 years. Methods: Men without diabetes (N = 141; mean age, 57.5 years) were investigated at baseline, including whole-night respiratory monitoring. After a mean period of 11 years and 4 months, they were followed up with an interview, anthropometric measurements, and blood sampling. Insulin resistance was quantified using the homeostasis model assessment of insulin resistance (HOMA-IR). ΔHOMA-IR was calculated as (HOMA-IR at follow-up − HOMA-IR at baseline). An oral glucose tolerance test was performed on 113 men to calculate the insulin sensitivity index. Results: The mean apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) at baseline were 4.7 and 3.3, respectively. At follow-up, 23 men had diabetes. An ODI > 5 was a predictor of developing diabetes (OR, 4.4; 95% CI, 1.1-18.1, after adjusting for age, BMI, and hypertension at baseline and ΔBMI and years with CPAP during follow-up). The ODI was inversely related to the insulin sensitivity index at follow-up (r = −0.27, P = .003). A deterioration in HOMA-IR was significantly related to all variables of SDB (AHI, AHI > 5; ODI, ODI > 5; minimum arterial oxygen saturation), even when adjusting for confounders. When excluding the variable years with CPAP from the multivariate model, all associations weakened. Conclusions: SDB is independently related to the development of insulin resistance and, thereby, the risk of manifest diabetes mellitus.
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To quantify sources of night-to-night variability. This project was conducted in 285 middle-aged African American, Caucasian, and Chinese women from the Study of Women's Health Across the Nation (SWAN) Sleep Study living in Chicago, the Detroit area, Oakland, and Pittsburgh. The study used 3 repeated nights of in-home polysomnography (PSG) measures. Night 1 data included assessment of sleep staging, sleep apnea, and periodic limb movements, while Nights 2 and 3 focused on sleep staging. Mean total sleep time (TST) increased substantially from 365 minutes on Night 1 to 391 minutes and 380 minutes, respectively, on Nights 2 and 3. Mean percent sleep efficiency (SE%) for the 3 nights were 83%, 85%, and 85%, respectively. Night 1 sleep values were significantly different than Nights 2 and 3 measures except for S2 (%), S1 (min), and Delta (S3+4)%. Nights 2 and 3 differences in variability were negligible. Obesity, past smoking, and financial strain measures were associated with greater Night 1 vs. Night 2 or Night 3 differences. We concluded that there was significant Night 1 vs. Nights 2 and 3 variability and, though relatively modest, it was sufficient to bias estimates of association. Additionally, personal characteristics including smoking, obesity, and financial strain increased night-to-night variability. This reports adds new information about between and within person sources of variation with in-home PSG and identifies elements that are essential in the design and planning of future sleep studies of multi-ethnic groups in social and physiological transition states such as the menopause.
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In 2003, the QUADAS tool for systematic reviews of diagnostic accuracy studies was developed. Experience, anecdotal reports, and feedback suggested areas for improvement; therefore, QUADAS-2 was developed. This tool comprises 4 domains: patient selection, index test, reference standard, and flow and timing. Each domain is assessed in terms of risk of bias, and the first 3 domains are also assessed in terms of concerns regarding applicability. Signalling questions are included to help judge risk of bias. The QUADAS-2 tool is applied in 4 phases: summarize the review question, tailor the tool and produce review-specific guidance, construct a flow diagram for the primary study, and judge bias and applicability. This tool will allow for more transparent rating of bias and applicability of primary diagnostic accuracy studies.
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One of the most important caveats of ambulatory devices is the inability to record and stage sleep. We assessed an algorithm determining 4 different stages: wake, light sleep, deep sleep, and REM sleep using signals derived from the portable monitor Watch-PAT100 (PAT recorder). Participants (38 normal subjects and 189 patients with obstructive sleep apnea [OSA]) underwent simultaneous overnight recordings with polysomnography (PSG) and the PAT recorder in a study originally designed to assess the accuracy of the PAT recorder in diagnosing OSA. Light/deep sleep and REM sleep from the PAT recorder recording were automatically scored based on features extracted from time series of peripheral arterial tone amplitudes and inter pulse periods. The PSG scored sleep stages 1 and 2 were classified as light sleep for epoch-by-epoch comparisons. The overall agreement in detecting light/deep and REM sleep were 88.6% ± 5.9% and 88.7% ± 5.5%, respectively. There was a good agreement between PSG and the PAT recorder in quantifying sleep efficiency (78.4% ± 9.9% vs. 78.8% ± 13.4%), REM latency (237 ± 148 vs. 225 ± 159 epochs), and REM percentage (14.4% ± 6.5% vs. 19.3% ± 8.7%). OSA severity did not affect the sensitivity and specificity of the algorithm. The Cohen κ coefficient for detecting all sleep stages: sleep from wake, REM from NREM sleep, and deep from light sleep were 0.48, 0.55, 0.59, and 0.46, respectively. Analysis of autonomic signals from the PAT recorder can detect sleep stages with moderate agreement to more standard techniques in normal subjects and OSA patients. This novel algorithm may provide insights on sleep and sleep architecture when applying the PAT recorder for OSA diagnosis.
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Obstructive sleep apnea (OSA) may lead to life-threatening problems if it is left undiagnosed. Polysomnography is the "gold standard" for OSA diagnosis; however, it is expensive and not widely available. The objective of this systematic review is to identify and evaluate the available questionnaires for screening OSA. We carried out a literature search through MEDLINE, EMBASE, and CINAHL to identify eligible studies. The methodological validity of each study was assessed using the Cochrane Methods Group's guideline. Ten studies (n = 1,484 patients) met the inclusion criteria. The Berlin questionnaire was the most common questionnaire (four studies) followed by the Wisconsin sleep questionnaire (two studies). Four studies were conducted exclusively on "sleep-disorder patients", and six studies were conducted on "patients without history of sleep disorders". For the first group, pooled sensitivity was 72.0% (95% confidence interval [CI]: 66.0-78.0%; I(2) = 23.0%) and pooled specificity was 61.0% (95% CI: 55.0-67.0%; I(2) = 43.8%). For the second group, pooled sensitivity was 77.0% (95% CI: 73.0-80.0%; I(2) = 78.1%) and pooled specificity was 53.0% (95% CI: 50-57%; I(2) = 88.8%). The risk of verification bias could not be eliminated in eight studies due to insufficient reporting. Studies on snoring, tiredness, observed apnea, and high blood pressure (STOP) and STOP including body mass index, age, neck circumference, gender (Bang) questionnaires had the highest methodological quality. The existing evidence regarding the accuracy of OSA questionnaires is associated with promising but inconsistent results. This inconsistency could be due to studies with heterogeneous design (population, questionnaire type, validity). STOP and STOP-Bang questionnaires for screening of OSA in the surgical population are suggested due to their higher methodological quality and easy-to-use features.
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To compare apnea-hypopnea indices (AHIs) derived using 3 standard hypopnea definitions published by the American Academy of Sleep Medicine (AASM); and to examine the impact of hypopnea definition differences on the measured prevalence of obstructive sleep apnea (OSA). Retrospective review of previously scored in-laboratory polysomnography (PSG). Two tertiary-hospital clinical sleep laboratories. 328 consecutive patients investigated for OSA during a 3-month period. N/A. AHIs were originally calculated using previous AASM hypopnea scoring criteria (AHI(Chicago)), requiring either >50% airflow reduction or a lesser airflow reduction with associated >3% oxygen desaturation or arousal. AHIs using the "recommended" (AHI(Rec)) and the "alternative" (AHI(Alt)) hypopnea definitions of the AASM Manual for Scoring of Sleep and Associated Events were then derived in separate passes of the previously scored data. In this process, hypopneas that did not satisfy the stricter hypopnea definition criteria were removed. For AHI(Rec), hypopneas were required to have > or =30% airflow reduction and > or =4% desaturation; and for AHI(Alt), hypopneas were required to have > or =50% airflow reduction and > or =3% desaturation or arousal. The median AHI(Rec) was approximately 30% of the median AHI(Chicago), whereas the median AHI(Alt), was approximately 60% of the AHI(Chicago), with large, AHI-dependent, patient-specific differences observed. Equivalent cut-points for AHI(Rec) and AHI(Alt), compared to AHI(Chicago) cut-points of 5, 15, and 30/h were established with receiver operator curves (ROC). These cut-points were also approximately 30% of AHI(Chicago) using AHI(Rec) and 60% of AHI(Chicago) using AHI(Alt). Failure to adjust cut-points for the new criteria would result in approximately 40% of patients previously classifled as positive for OSA using AHI(Chicago) being negative using AHI(Rec) and 25% being negative using AHI(Alt). This study demonstrates that using different published standard hypopnea definitions leads to marked differences in AHI. These results provide insight to clinicians and researchers in interpreting results obtained using different published standard hypopnea definitions, and they suggest that consideration should be given to revising the current scoring recommendations to include a single standardized hypopnea definition.
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When conducting a treatment intervention study, it is assumed that a level of reliability can be obtained from the measurement tool such that the outcome can be reasonably assessed. Investigate the reliability of laboratory polysomnography, the gold standard for assessment of treatment outcomes for obstructive sleep apnea, at a 1-month interval. In a clinical trial of 118 patients recruited to assess the effects of a pharmaceutical treatment intervention, a subset of 20 patients designated as placebo controls completed two polysomnography studies, one at baseline and one at least one month later. The correlation between the overall Apnea/Hypopnea indices from the two polysomnography (PSG) studies was poor (r = 0.44) and the results were biased, with a mean increase of seven events per hour on night 2. Twenty-five percent of the subjects had an increase greater than 20 events/hour on night 2 and only 45% of participants had a night-to-night difference of < or =5 events/hour. The correlation between overall apnea indexes for nights 1 and 2 (r = 0.61) was improved, compared to the overall apnea/hypopnea indexes. The correlation in sleep efficiency across the two nights was relatively week (r = 0.52) but significant. The correlations between nights 1 and 2 for the percentage of time supine (r = 0.70) and the supine apnea-hypopnea index (AHI) (r = 0.69) were similar and highly significant. The correlation for the non-supine AHI was only 0.25 In this study, the reliability of a single-night PSG in measuring treatment outcome was compromised as a result of the large night-to-night variability of subjects' obstructive sleep apnea (OSA). Studies employing the AHI as an outcome need to be adequately powered with respect to the inherent night-to-night variability in the measurement. When assessing treatment intervention outcomes, there may be benefit from the acquisition and averaging of multiple nights of data in order to mitigate the inherent night-to-night variability of OSA and improve the accuracy of the outcome assessment.
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To comprehensively evaluate the ability and reliability of the representative previously proposed oxyhemoglobin indexes derived automatically for predicting the severity of obstructive sleep apnea hypopnea syndrome (OSAHS). Patients with a diagnosis of OSAHS by standard polysomnography were recruited from China Medical University Hospital Centre. There were 257 patients in the learning set and 279 patients in the validation set. The presence of OSAHS was defined as apnea-hypopnea index (AHI) > 5/h. Three kinds of oxyhemoglobin indexes, including the oxyhemoglobin desaturation index (ODI), time-domain index, and frequency-domain index, were used. Degrees of severity were AHI > 15/h and AHI > 30/h, representing moderate and severe OSAHS. A total of 28 oxyhemoglobin indexes were tested in our study. Among the three kinds of indexes, ODI had a better diagnostic performance than the time-domain and frequency-domain indexes, with the results coincident in the validation set and learning set. For predicting the severity of OSAHS with AHI > 15/h or > 30/h, the ODI clinically had the higher correlation with AHI than time-domain and frequency-domain indexes, with sensitivity/specificity achieving 84.0%/84.3% in AHI > 15/h and 87.8%/96.6% in AHI > 30/h, respectively. Based on the smaller SEE of the AHI, the ODI had a significantly smaller SEE than the time-domain and frequency-domain indexes. The ODI index provided a high level of diagnostic sensitivity and specificity at different degrees of OSAHS severity.
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We examined the effects of arousal- and desaturation-based scoring criteria on the apnea-hypopnea index (AHI) and on the measured prevalence of obstructive sleep apnea (OSA). Ninety-four randomly selected patients underwent overnight polysomnography. Studies were scored according to three different criteria for hypopnea, as defined by a >= 10 s discernible reduction in thoracoabdominal movement associated with: (1) >= 4% decrease in oxygen saturation (SaO2) (Type A); (2) either a >= 4% decrease in SaO2 or an arousal (Type B); or (3) electroencephalographically based arousal alone (Type C). Excellent correlation existed between AHI-A, AHI-B, and the oxygen desaturation index (ODI) (r > 0.98). AHI-A and AHI-B differed by only 2.04 +/- 1.72/h (2 SD). AHI-A and AHI-B differed from the ODI by 1.04 +/- 4.07/h and 3.07 +/- 4.30/h, respectively. Despite these small differences, use of the Type B rather than Type A definition resulted in an extra case of OSA being diagnosed for every 14 to 31 patients tested, depending on the definition of OSA (AHI: >= 5, 10, 15, or 20/h). The addition of arousal-based scoring criteria for hypopnea causes only small changes in the AHI, but if OSA is defined solely by an AHI value, the measured prevalence of OSA will increase.
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Using spectral analysis of oximetry data, we prospectively evaluated the validity of this methodology in patients clinically suspected of suffering from obstructive sleep apnoea (OSA). A total of 233 outpatients were studied. Nocturnal oximetry was performed simultaneously with conventional polysomnography for all participants. The power density of oxygen saturation was analysed using Fast-Fourier transformation of the oximetric signal. Nocturnal oximetry test results were considered as abnormal (suspicion of OSA) if a peak in the spectrum between the period boundaries 30 and 70 s was observed. A normal test result was defined as the absence of the 30-70 s peak from the spectrum. Single-blind evaluation was performed by three independent observers, and agreement of two or more of these was considered definitive. The peak amplitude and the ratio of the area enclosed in the 30-70 s peak to the total area of the spectrum (r(S)) were measured. The presence of a peak has a sensitivity of 78%, a specificity of 89%, a positive predictive value of 89% and a negative predictive value of 78%. Apnoea-hypopnoea indexes were correlated significantly with peak amplitude (r=0.74; P<0.001) and with r(S) (r=0.69; P<0.001). For a peak amplitude threshold of 0.7%(2), the sensitivity was 94% and the specificity was 65% for OSA diagnosis. Using a threshold for r(S) of 0.15, the sensitivity was 91% and the specificity was 67%. Thus the spectral analysis of nocturnal oximetry and identification of a peak at 30-70 s could be useful as a diagnostic technique for OSA subjects.
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Polysomnography (PSG) is currently the "gold standard" for the diagnosis of the sleep apnoea hypopnoea syndrome (SAHS). Nocturnal oximetry (NO) has been used with contradictory results. A prospective study was performed to determine the accuracy of NO as a diagnostic tool and to evaluate the reduction in the number of PSGs if the diagnosis of SAHS had been established by this method. Two hundred and seventy five patients with a clinical suspicion of SAHS were admitted to undergo, in the same night, full PSG and NO. Desaturation was defined as a fall in the haemoglobin saturation level (SaO(2)) to lower than 4% from the baseline level and an oxygen desaturation index per hour (ODI) was obtained in each patient with three cut off points: >/= 5 (ODI-5), >/= 10 (ODI-10), and >/= 15 (ODI-15). SAHS was diagnosed in 216 patients (194 men). After withdrawing patients with abnormal lung function (forced expiratory volume in one second (FEV(1)) lower than 80% predicted), sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV) of NO were: ODI-5 (80%, 89%, 97%, 48%); ODI-10 (71%, 93%, 97%, 42%); ODI-15 (63%, 96%, 99%, 38%). The accuracy for each ODI was 0.81, 0.75, and 0.70, respectively. If NO had been considered as a diagnostic tool and PSG had been performed only in patients with a negative NO (false negative and true negative) and those with a positive NO and abnormal pulmonary function tests, 135/275 (ODI-5), 156/275 (ODI-10), and 170/275 (ODI-15) PSGs would have been performed, a reduction of 140, 119, and 105, respectively. Nocturnal oximetry in patients with suspected SAHS and normal spirometric values permits the institution of therapeutic measures in most patients.
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To determine the value of home oximetry as a screening test in patients with moderate to severe symptoms of obstructive sleep apnea (OSA). Retrospective, observational study. The Sleep Unit of a tertiary referral, university hospital. 116 patients referred for evaluation of moderate to severe symptoms of OSA in which both home oximetry and polysomnography (PSG) were performed. NA. Three numerical oximetry indices were evaluated: average of desaturations > or =4% and average of resaturations > or =3% per hour of analysis time (DI4% and RI3%, respectively); and cumulative percentages of time spent at saturations below 90% (CT90%). A qualitative assessment was also performed. Oximetry indices were compared with apnea/hypopnea index (AHI) by simple linear regression and Bland-Altman analyses. Optimal cut-off points, in terms of sensitivity and specificity, for the oximetry indices were searched using ROC analysis, at an AHI threshold of > or =10. The correlation between AHI and the desaturation indices was r = 0.50 for CT90%, r = 0.60 for DI4%, and r = 0.58 for RI3%. No bias was found between PSG and oximetry indices in Bland-Altman plots. Neither the numerical indices nor the qualitative analysis achieved an adequate (>0.8) area under the ROC curve. A CT90% <0.79 excluded OSA with 84% sensitivity. A DI4% > or =31.4 or a RI3% > or =40.5 diagnosed OSA with 97% specificity. Using these values, 38% of the patients would have been correctly classified by oximetry alone, 10% would have been incorrectly classified, and 50% could not have been classified with certainty. Eleven (15%) OSA patients would have been missed by oximetry. Correlation between home oximetry and PSG was not high. Oximetry was more useful to confirm than to exclude OSA in our study. Qualitative assessment was not better than numerical analysis. The greatest value of oximetry in this setting seems to be as a tool to rapidly recognize and treat more severe OSA patients in waiting list for PSG.
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Sleep constitutes an important biological function and occupies a large part of peoples' life. Sleep, is necessary to allow human body to carry out all normal functions and get a normal life. The deprivation of sleep and his general disorders, tend to become one of the moderns' man major problems. The modern lifestyle is the reason why more and more people are suffering from sleep disorders and mainly from breathing disorders during sleep, which can be sometimes very dangerous. Due to lack of time and lack of rest, people often do not enjoy the sleep they needed for their revitalization. The purpose of this retrospective study is to explore the during the sleep respiratory disorders.
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This editorial refers to ‘Nocturnal hypoxaemia is associated with increased mortality in stable heart failure patients’[†][1], by O. Oldenburg et al ., on page 1695. Oldenburg and colleagues, in this issue of the journal, confirm that abnormalities of breathing during sleep are very common in patients with heart failure and reduced ejection fraction (HFREF).1 In a cohort of 963 patients with chronic stable HFREF, they report that 58% had moderate or severe sleep-disordered breathing (SDB), as defined by an apnoea–hypopnea index (AHI) of at least 15 episodes per hour of recording time using unattended in-hospital polygraphy. Over a median follow-up of almost 7.5 years, half of the cohort died, and those with moderate to severe SDB (AHI ≥15) had a higher mortality. After correction for baseline covariates, this association was no longer present. However, another measure of SDB, i.e. the time the patients spent with hypoxaemia (arterial oxygen saturation <90%), was highly significantly associated with mortality, even after adjustment for baseline covariates, with an increase in all-cause mortality of 16% [95% confidence interval (CI) 9–24%] per hour spent below 90% oxygen saturation during sleep ( P < 0.001). They argue that nocturnal hypoxaemic ‘burden’ may be an important target for the treatment of SDB, and that AHI, the classical descriptor of the severity of SDB, may be less useful for this patient group. Hypoxaemia of ≥22 min duration appeared to be the best discriminator between those who died subsequently and those who did not. That breathing can be disordered during sleep is undisputed. The most common form in the general population, and in those with cardiac disease, is obstructive sleep apnoea (OSA), where … [1]: #fn-2
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Study objective: To characterize the association among apnea-hypopnea indices (AHIs) determined using three common metrics for defining hypopnea, and to develop a model to calibrate between these AHIs. Design: Cross-sectional analysis of Sleep Heart Health Study Data. Setting: Community-based. Participants: There were 6,441 men and women age 40 y or older. Measurement and results: Three separate AHIs have been calculated, using all apneas (defined as a decrease in airflow greater than 90% from baseline for ≥ 10 sec) plus hypopneas (defined as a decrease in airflow or chest wall or abdominal excursion greater than 30% from baseline, but not meeting apnea definitions) associated with either: (1) a 4% or greater fall in oxyhemoglobin saturation - AHI4; (2) a 3% or greater fall in oxyhemoglobin saturation - AHI3; or (3) a 3% or greater fall in oxyhemoglobin saturation or an event-related arousal - AHI3a. Median values were 5.4, 9.7, and 13.4 for AHI4, AHI3, and AHI3a, respectively (P < 0.0001). Penalized spline regression models were used to compare AHI values across the three metrics and to calculate prediction intervals. Comparison of regression models demonstrates divergence in AHI scores among the three methods at low AHI values and gradual convergence at higher levels of AHI. Conclusions: The three methods of scoring hypopneas yielded significantly different estimates of AHI, although the relative difference is reduced in severe disease. The regression models presented will enable clinicians and researchers to more appropriately compare AHI values obtained using differing metrics for hypopnea.
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Background: Reducing the need for diagnostic sleep studies for obstructive sleep apnea (OSA) would reduce direct and opportunity costs while expediting time to treatment for this common and morbid disorder. We sought to determine if an established sleep apnea screening questionnaire (STOP-BANG) and wrist-worn overnight oximetry data could provide high positive predictive value for the presence of OSA. Methods: We conducted a prospective observational study of consecutive unattended sleep study patients at a single facility. Patients were referred for sleep testing after chart review by a sleep physician. We assessed area under the receiver-operating characteristic curve (ROC AUC) and positive predictive value (PPV) of STOP-BANG score and oxygen desaturation index (ODI) for a respiratory disturbance index (RDI) ≥15/h. Results: Among 234 test patients, 65 % had an RDI ≥15/h. STOP-BANG had poor ability to discriminate these patients (ROC AUC 0.62). ODI added significant diagnostic information to the STOP-BANG score, increasing the ROC AUC to 0.86. Having the ODI, the STOP-BANG score no longer contributed significant diagnostic information, and the ODI alone discriminated as well as the combination (ROC AUC 0.86). Forty nine percent had an ODI ≥7/h, which had PPV of 92 % (95 % confidence interval (CI), 86 to 96 %). In the validation sample of 1,196 consecutive patients, ODI ≥ 7/h had a PPV of 97 % (95 % CI, 95 to 97 %). Conclusions: Among patients with a high prevalence of OSA, high ODI is common and its presence has high PPV for OSA. These data suggest that overnight oximetry prior to sleep testing could significantly reduce the number of patients requiring sleep studies, thereby reducing costs and time to treatment.
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In 2003, the QUADAS tool for systematic reviews of diagnostic accuracy studies was developed. Experience, anecdotal reports, and feedback suggested areas for improvement; therefore, QUADAS-2 was developed. This tool comprises 4 domains: patient selection, index test, reference standard, and flow and timing. Each domain is assessed in terms of risk of bias, and the first 3 domains are also assessed in terms of concerns regarding applicability. Signalling questions are included to help judge risk of bias. The QUADAS-2 tool is applied in 4 phases: summarize the review question, tailor the tool and produce review-specific guidance, construct a flow diagram for the primary study, and judge bias and applicability. This tool will allow for more transparent rating of bias and applicability of primary diagnostic accuracy studies.
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Obstructive sleep apnoea is a common disease that is now more widely recognised because of the rise in prevalence and the increasingly compelling data that shows major neurocognitive and cardiovascular sequelae. At the same time, the clinical practice of sleep medicine is changing rapidly, with novel diagnostics and treatments that have established a home-based (rather than laboratory-based) management approach. We review the most recent insights and discoveries in obstructive sleep apnoea, with a focus on diagnostics and therapeutics. As will be discussed, management of obstructive sleep apnoea could soon transition from a so-called one size fits all approach to an individualised approach. Copyright © 2015 Elsevier Ltd. All rights reserved.
Article
Recently, there has been a debate about the rules used to score hypopnea events. The purpose of this study was to examine the effect of different oxygen desaturation threshold (ODT) levels on the apnea-hypopnea index (AHI) and on a recently introduced parameter, adjusted AHI. Adjusted AHI incorporates the severity of individual breathing cessation events. We also aimed to clarify the impact of the different ODT levels on the current classification of obstructive sleep apnea (OSA) severity. Ambulatory polygraphic recordings of 68 patients (19 F/49 M, median age 53.2 years, AHI ≥5) were analyzed retrospectively. Hypopneas were defined as ≥30 % drop in airflow for ≥10 s associated with ≥2 % oxygen desaturation (ODT2%), and after that, using stricter ODT criteria (ODT3%-ODT8%). Compared to ODT4%, the ODT3% resulted in 5.6 events/h higher median conventional AHI, but only 1.5 events/h higher median adjusted AHI. A significant rearrangement of patients between the clinical severity categories took place when using different ODTs. When assessing with ODT3% instead of ODT4%, the portion of the patients with moderate or severe OSA (AHI ≥15) raised from 29.4 to 73.5 % using conventional AHI, but only marginally, i.e., from 73.5 to 77.9 %, using the adjusted AHI. The conventional AHI was found to be susceptible even to minor changes in ODT level which may lead to substantial variability in AHI-based classification of disease severity. Since the adjusted AHI comprises information on severity of individual breathing cessations, it reduces the variability related to ODT levels used in hypopnea scoring and can increase the accuracy of estimation of OSA severity.
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OSA is a common chronic disorder that is associated with significant morbidity and mortality including cardiovascular, metabolic, and neurocognitive disease and increased cancer-related deaths. OSA is characterized by recurrent episodes of apneas and hypopneas associated with repetitive episodes of intermittent hypoxemia, intrathoracic pressure changes, and arousals. Intermittent hypoxemia (IH) is now being recognized as a potential major factor contributing to the pathogenesis of OSA-related comorbidities. OSA-related high-frequency IH is characterized by cycles of hypoxemia with reoxygenation that is distinctly different than sustained low-frequency hypoxia and contributes to ischemia-reperfusion injury. Data from both animal and human studies support mechanistic links between IH and its adverse impact at the tissue level. IH promotes oxidative stress by increased production of reactive oxygen species and angiogenesis, increased sympathetic activation with BP elevation, and systemic and vascular inflammation with endothelial dysfunction that contributes to diverse multiorgan chronic morbidity and mortality affecting cardiovascular disease, metabolic dysfunction, cognitive decline, and progression of cancer. Data from observational studies in large population groups also support the role for hypoxia in the pathogenesis of OSA comorbidity. Treatment with CPAP to reverse OSA-related symptoms and comorbidities has been shown to provide variable benefit in some but not all patient groups. Early treatment with CPAP makes intuitive sense to promote maximal functional recovery and minimize residual injury. More studies are needed to determine the interacting effects of IH and obesity, differential effects of both short-term and long-term hypoxemia, and the effect of CPAP treatment.
Article
Intermittent hypoxia and unstable breathing are key features of obstructive sleep apnoea (OSA), the most common pathological problem of breathing in sleep. Unstable ventilatory control is characterised by high loop gain (LG), and likely contributes to cyclical airway obstruction by promoting airway collapse during periods of low ventilatory drive. Potential new strategies to treat OSA include manipulations designed to lower LG. However, the contribution of inherent versus induced LG abnormalities in OSA remains unclear. Hence, a better understanding of the mechanisms causing high LG in OSA is needed to guide the design of LG based treatments. OSA patients exhibit abnormal chemoreflex control which contributes to increased LG. These abnormalities have been shown to normalise after continuous positive airway pressure treatment, suggesting induced rather than inherent trait abnormalities. Experimental intermittent hypoxia, mimicking OSA, increases hypoxic chemosensitivity and induces long term facilitation; a sustained increase in ventilatory neural output which outlasts the original stimulus. These neuroplastic changes induce the same abnormalities in chemoreflex control as seen in OSA patients. This review outlines the evidence to support that a key component of high LG in OSA is induced by intermittent hypoxia, and is reversed by simply preventing this inducing stimulus. Copyright © 2014 Elsevier Ltd. All rights reserved.
Article
While polysomnography remains the current gold standard in sleep investigation, guidelines for single night versus consecutive recordings in a sleep laboratory have been disputed mainly because of two phenomena: the first-night effect and night-to-night variability. One hundred and twenty nine subjects, that underwent two consecutive nights of polysomnographic recording in a general University Hospital's sleep lab, were divided into four groups: sleep-related breathing disorders (SRBD), insomnia, movement and behavioral disorders and a healthy control (HC) group based on their complaints at admission and sleep study results. Sleep parameters of both consecutive two nights were compared and analyzed. All groups showed a significant first-night effect. However the latter seemed more pronounced in the insomnia group. Furthermore, a clinically significant intra-patient night-to-night variability was found for the apnea-hypopnea index in the SRBD-group. Due to the observed first-night effect among any subject group and the potential impact of night-to-night variability of the apnea-hypopnea index, we conclude that the clinical assessment of sleep disorders should be similar in every patient. Hence, the present study underlines the importance of two consecutive nights of polysomnographic recording as a potential reference standard for the execution of sleep investigations.
Article
The electroencephalographic records from 43 subjects who slept for four consecutive nights in a laboratory environment were studied in an effort to describe the First Night Effect. These records showed that the first night of laboratory sleep contains more awake periods and less Stage I-rapid eye movement sleep. There is a delay in the onset of Stages IV and I-REM and the sleep is more changeable. These effects rapidly adapt out by the second night of sleep.
Article
It is impractical to perform polysomnography (PSG) in all surgical patients suspected of having sleep disordered breathing (SDB). We investigated the role of nocturnal oximetry in diagnosing SDB in surgical patients. All patients 18 years and older who visited the preoperative clinics for scheduled inpatient surgery were approached for study participation. Patients expected to have abnormal electroencephalographic findings were excluded. All patients underwent an overnight PSG at home with a portable device and a pulse oximeter. The PSG recordings were scored by a certified sleep technologist. The oximetry recordings were processed electronically. Four hundred seventy-five patients completed the study: 217 males and 258 females, aged 60 ± 11 years, and body mass index 31 ± 7 kg/m(2). The apnea-hypopnea index (AHI), the average number of episodes of apnea and hypopnea per hour of sleep, was 9.1 (2.8 to 21.4) [median (interquartile range)] and 64% patients had AHI >5. There was a significant correlation between oxygen desaturation index (ODI, hourly average number of desaturation episodes) and cumulative time percentage with SpO(2) <90% (CT90) from nocturnal oximetry, with the parameters measuring sleep breathing disorders from PSG. Compared to CT90, ODI had a stronger correlation and was a better predictor for AHI. The area under receiver operator characteristics curve for ODI to predict AHI >5, AHI >15, and AHI >30 was 0.908 (CI: 0.880 to 0.936), 0.931 (CI: 0.090 to 0.952), and 0.958 (CI: 0.937 to 0.979), respectively. The cutoff value based on the maximal accuracy for ODI to predict AHI >5, AHI >15, and AHI >30 was ODI >5, ODI >15, and ODI >30. The accuracy was 86% (CI: 83%-88%), 86% (CI: 83%-89%), and 94% (CI: 92%-96%), respectively. The ODI >10 demonstrated a sensitivity of 93% and a specificity of 75% to detect moderate and severe SDB. ODI from a high-resolution nocturnal oximeter is a sensitive and specific tool to detect undiagnosed SDB in surgical patients.
Article
This study examined changes in sleep parameters between the laboratory and the home setting before and after laboratory monitoring in depressed insomniacs undergoing treatment. This study was a post hoc analysis of a double-blind, randomized, placebo-controlled clinical trial performed with 60 depressed, insomniac outpatients. Patients underwent actigraphic monitoring along with sleep diaries over a continuous 2-week period. After one week of baseline monitoring, subjects spent one night in the laboratory with concurrent actigraphic and PSG monitoring with sleep diaries. Actigraphic monitoring and sleep diaries were continued for another week at home, along with initiation of open-label fluoxetine (FLX). Actigraphically recorded laboratory sleep during the night in the laboratory was found to be improved relative to actigraphically recorded sleep at home, with less wake time and greater sleep time and sleep efficiency occurring in the laboratory. In contrast, sleep diaries indicated a slight worsening of sleep in the laboratory compared to home, with significantly more awakenings in the laboratory compared to the week at home before and after the laboratory night. The differences between objective and subjective sleep measurements seen in depressed insomniacs may be influenced by the monitoring setting and measurement modality. ClinicalTrials.gov Identifier: NCT00247624.
Article
Obstructive sleep apnea syndrome (OSA) alters sleep quality and is associated with sleepiness and decreased cognitive functioning. It has therefore always been recognized as a major public health issue with potential societal consequences: accidents, increased morbidity, and cognitive deficits impairing work efficiency. The number of patients diagnosed and treated for OSA has increased drastically in the last few years. In response to this epidemic, health authorities have encouraged studies investigating how patients cope with OSA and also its diagnosis, comparing ambulatory to hospital-based polysomnography. Based on epidemiological knowledge, this review aims to carefully describe the possible links between sleep apnea and public health concerns along with identifying the certitudes and missing data concerning the consequences of sleep apnea on accidents, work, economics and health-related quality of life.
Article
Clinic-based observational studies in men have reported that obstructive sleep apnea is associated with an increased incidence of coronary heart disease. The objective of this study was to assess the relation of obstructive sleep apnea to incident coronary heart disease and heart failure in a general community sample of adult men and women. A total of 1927 men and 2495 women > or =40 years of age and free of coronary heart disease and heart failure at the time of baseline polysomnography were followed up for a median of 8.7 years in this prospective longitudinal epidemiological study. After adjustment for multiple risk factors, obstructive sleep apnea was a significant predictor of incident coronary heart disease (myocardial infarction, revascularization procedure, or coronary heart disease death) only in men < or =70 years of age (adjusted hazard ratio 1.10 [95% confidence interval 1.00 to 1.21] per 10-unit increase in apnea-hypopnea index [AHI]) but not in older men or in women of any age. Among men 40 to 70 years old, those with AHI > or =30 were 68% more likely to develop coronary heart disease than those with AHI <5. Obstructive sleep apnea predicted incident heart failure in men but not in women (adjusted hazard ratio 1.13 [95% confidence interval 1.02 to 1.26] per 10-unit increase in AHI). Men with AHI > or =30 were 58% more likely to develop heart failure than those with AHI <5. Obstructive sleep apnea is associated with an increased risk of incident heart failure in community-dwelling middle-aged and older men; its association with incident coronary heart disease in this sample is equivocal.
The objective of this study is to test whether there is a difference between the polysomnographic (PSG) values of Apnea-hypopnea index (AHI), minimal oxygen saturation (SpO(2)), oxygen desaturation index (ODI) and arousal index recorded on two consecutive nights (so-called "first night effect") in patients with sleep-disordered breathing (SDB) and concomitant upper airway pathology. Retrospective case-control study of polysomnographical recordings of 130 patients (112 males, 18 females, age range 23-80 years) with SDB and upper airway pathology who were tested on two consecutive nights in a hospital sleep laboratory was conducted. Only patients with upper airway pathology without other medical conditions causing SDB were included. AHI, minimal SpO(2), ODI and arousal index values of the first night were compared to those of the second night using Wilcoxon's test. There were no significant statistical differences between AHI, SpO(2), ODI and arousal index values (P = 0.130, P = 0.640, P = 0.052, and P = 0.692, respectively) between the two nights. However, 15% of the patients showed significant variability in the AHI between the two recordings and in 6% of the patients, a diagnosis of severe OSA (AHI > 10/h) would have been missed if only one night of sleep study had been performed. In general, one night of sleep study is sufficient to lead to a clear diagnosis of severe OSA in patients with sleep-disordered breathing and upper airway pathology but may still not diagnose 6% of the patients with severe OSA. Additionally, 15% of the patients showed a significant variability in the AHI between the two nights.
Article
Screening for obstructive sleep apnea (OSA) is recommended as part of the preoperative assessment of obese patients scheduled for bariatric surgery. The objective of this study was to compare the sensitivity of oximetry alone versus portable polygraphy in the preoperative screening for OSA. Polygraphy (type III portable monitor) and oximetry data recorded as part of the preoperative assessment before bariatric surgery from 68 consecutive patients were reviewed. We compared the sensitivity of 3% or 4% desaturation index (oximetry alone) with the apnea-hypopnea index (AHI; polygraphy) to diagnose OSA and classify the patients as normal (<10 events per hour), mild to moderate (10-30 events per hour), or severe (>30 events per hour). Using AHI, the prevalence of OSA (AHI > 10 per hour) was 57.4%: 16.2% of the patients were classified as severe, 41.2% as mild to moderate, and 42.6% as normal. Using 3% desaturation index, 22.1% were classified as severe, 47.1% as mild to moderate, and 30.9% as normal. With 4% desaturation index, 17.6% were classified as severe, 32.4% as mild, and 50% as normal. Overall, 3% desaturation index compared to AHI yielded a 95% negative predictive value to rule out OSA (AHI > 10 per hour) and a 100% sensitivity (0.73 positive predictive value) to detect severe OSA (AHI > 30 per hour). Using oximetry with 3% desaturation index as a screening tool for OSA could allow us to rule out significant OSA in almost a third of the patients and to detect patients with severe OSA. This cheap and widely available technique could accelerate preoperative work-up of these patients.
Article
Sympathetic activity varies continuously across sleep stages. During rapid eye movement sleep, sympathetic tone increases substantially but is highly variable. Microarousals are associated with momentary bursts of sympathetic activity. Abnormal respiratory events progressively elevate sympathetic activity in proportion to the severity of oxyhemoglobin desaturation. These phenomena imply that cardiovascular markers of sympathetic activity such as peripheral arterial tone (PAT) and pulse transit time could be indirect tools for diagnosing sleep disordered breathing and characterizing sleep structure and fragmentation. Measurement of variations in PAT coupled with pulse rate accelerations and desaturations in oximetry can be used to diagnose sleep apnea. Good agreement between both manually and automatically analyzed PAT recordings and polysomnography has been demonstrated during in-laboratory or at-home studies. Numerous validation studies against esophageal pressure have demonstrated that pulse transit time is the best noninvasive method for measurement of respiratory effort. Pulse transit time and PAT are sensitive techniques for arousal recognition, particularly in children and infants. There are specific sleep stage-dependent PAT patterns that allow for the recognition of rapid eye movement sleep and, in the case of nonrapid eye movement sleep, the separation of lighter stages from deeper, slow wave sleep. Elevated nocturnal sympathetic activity as documented by PAT attenuations is linked with chronically elevated blood pressure in humans. Cardiovascular markers of autonomic control during sleep permit not only the diagnosis of obstructive sleep apnea and estimation of sleep structure but are also linked with the prevalence of daytime hypertension.
Article
The purpose of this meta-analysis is to compare clinical screening tests for obstructive sleep apnea and establish an evidence base for their preoperative use. Diagnostic odds ratios were used as summary measures of accuracy, and false-negative rates were used as measures of missed diagnosis with each screening test in this review. Metaregression revealed that clinical models, logarithmic equations, combined techniques, cephalometry, and morphometry are significant characteristics, whereas body mass index, history of hypertension, and nocturnal choking are significant test elements associated with higher diagnostic accuracy. Test accuracy in repeated validation studies of the same screening test is variable, suggesting an underlying heterogeneity in either the clinical presentation of obstructive sleep apnea or the measured clinical elements of these models. Based on the false-negative rates, it is likely that most of the clinical screening tests will miss a significant proportion of patients with obstructive sleep apnea.
Article
Obstructive sleep apnoea (OSA) is a common disorder in which repetitive apnoeas expose the cardiovascular system to cycles of hypoxia, exaggerated negative intrathoracic pressure, and arousals. These noxious stimuli can, in turn, depress myocardial contractility, activate the sympathetic nervous system, raise blood pressure, heart rate, and myocardial wall stress, depress parasympathetic activity, provoke oxidative stress and systemic inflammation, activate platelets, and impair vascular endothelial function. Epidemiological studies have shown significant independent associations between OSA and hypertension, coronary artery disease, arrhythmias, heart failure, and stroke. In randomised trials, treating OSA with continuous positive airway pressure lowered blood pressure, attenuated signs of early atherosclerosis, and, in patients with heart failure, improved cardiac function. Current data therefore suggest that OSA increases the risk of developing cardiovascular diseases, and that its treatment has the potential to diminish such risk. However, large-scale randomised trials are needed to determine, definitively, whether treating OSA improves cardiovascular outcomes.
Article
To evaluate prospectively the validity of home oximetry for case finding in patients clinically suspected of having the sleep apnea hypopnea syndrome (SAHS). Blinded comparison of home oximetry and polysomnographic nocturnal recordings. Sleep clinic of a tertiary referral center. A total of 240 outpatients referred because of reported sleep disturbances or daytime hypersomnia compatible with the diagnosis of SAHS. All participants had nocturnal home oximetry followed by a conventional polysomnographic study. The two recordings were interpreted blindly. Home oximetry test results were classified as abnormal (suspicion of sleep-related breathing abnormalities) in the presence of repetitive, short-duration arterial oxyhemoglobin saturation. (SaO2) fluctuations without any absolute or relative decrease in the SaO2 threshold. The diagnosis of SAHS was confirmed when the apnea-plus-hypopnea index was greater than 10. Based on the results of the polysomnographic sleep study, 110 patients had SAHS (apnea-plus-hypopnea index, 38.1 +/- 2.5/h; mean +/- SE). Home oximetry test results were interpreted as abnormal in 176 patients (this included 108 patients with SAHS and 68 without SAHS) and were read as normal in 62 patients without SAHS and in 2 with SAHS. Home oximetry testing had a sensitivity of 108/110 or 98.2% (95% Cl, 93.6% to 99.8%); a specificity of 62/130 or 47.7% (Cl, 38.8% to 56.6%); a positive predictive value of 108/176 or 61.4%; and a negative predictive value of 62/64 or 96.9%. A negative home oximetry test result is helpful in ruling out the diagnosis of SAHS in patients clinically suspected of having this syndrome, because a negative test result reduced the probability from 54.1% to 3.1% in our patients. However, a positive oximetry test increased the probability from 46% to 61.4% in our group of patients.
In order to determine whether measurement of arterial oxygen saturation (SaO2) could identify patients with obstructive sleep apnea (OSA), 98 consecutive patients referred for assessment of snoring and/or daytime somnolence were assessed clinically and then underwent both unsupervised oximetry in their homes and formal polysomnography. Clinical assessment identified patients with an apnea+hypopnea index (AHI) > or = 15 events per hour with a sensitivity of 79% and a specificity of 50%. Home oximetry analyzed by counting the number of arterial oxygen desaturations recorded was inferior to clinical assessment. For desaturations of 2% or more from baseline, desaturation index (DI) > or = 15 per hour identified patients with AHI > or = 15 with sensitivity 65% and specificity 74%; for 3% desaturations, sensitivity was 51% and specificity 90%; and for 4% desaturations, sensitivity was 40% and specificity 98%. From the oximetry data, the percentage of time spent at SaO2 below 90% (CT90) was also calculated. CT90 > or = 1% identified patients with AHI > or = 15 with sensitivity 93% and specificity 51%; for patients with AHI > or = 15 ultimately given nasal continuous positive airway pressure (CPAP), the sensitivity of a CT90 > or = 1% was 100%. We concluded that home oximetry with CT90 < 1% practically excludes clinically significant OSA. Conversely, home oximetry with DI > or = 15 for 4% desaturations makes OSA likely: the positive predictive value for OSA is 83% if the pretest probability of OSA is 30% and over 90% if the pretest probability is at least 50%.
Article
The cost and inconvenience of polysomnography make simplified techniques of screening desirable in the strategy of diagnosis of sleep apnea syndrome (SAS). We have evaluated, in a prospective study of 301 consecutive patients referred for suspected sleep disorders, an index (delta index) that detects apneic events by quantifying arterial oxygen saturation (SaO2) variability. Regional sleep laboratory taking referrals from general practitioners and specialists. Classic polysomnography was the gold standard, with 15 apneas plus hypopneas per hour (RDI) being used as a threshold for definition of obstructive sleep apnea (OSA). Oximetry was recorded over the same night. Signal variability was quantified as a function of time, using digital processing of oximetric data. Sensitivity, specificity, and positive and negative predictive values of oximetry testing were calculated. A receiver operating characteristic (ROC) curve was constructed representing the comparative courses of sensitivity and 1-specificity at different thresholds of delta index. Three hundred one patients were included (age, 56 +/- 12 years). Their RDI was 30 +/- 24. For a delta threshold at 0.6, the sensitivity of oximetry for the diagnosis of OSA was 98% and the specificity was 46%. The positive and negative predictive values for diagnosing SAS were 77% and 94%, respectively. The three false-negative cases had a relatively high awake SaO2 (97 vs 93.9 +/- 2.8%), a moderate RDI (23.3 +/- 1.6), and were less obese than the other patients (body mass index: 25 +/- 3 vs 33 +/- 8). The 58 false-positive cases had an RDI of 8 +/- 4, an awake SaO2 of 93.1 +/- 3.6 vs 94.1 +/- 2.6 for the rest of the population (p = 0.01). Finally, the false-positive cases had more airways obstruction (FEV1/VC = 72 +/- 13 vs 77 +/- 15%; p = 0.026). Using a delta value of 0.8 leads to a sensitivity of 90% with 19 false-negative cases but with a higher specificity of 75%. A nocturnal oximetry test with a delta index below 0.6 is helpful in ruling out the diagnosis of SAS in patients being screened for this condition, as this yielded only three negative test results in 301 screening procedures.
Article
Between January 1994 and July 1997, 793 patients suspected of having sleep-disordered breathing had unattended overnight oximetry in their homes followed by laboratory polysomnography. From the oximetry data we extracted cumulative percentage time at SaO2 < 90% (CT90) and a saturation variability index (delta Index, the sum of the differences between successive readings divided by the number of readings - 1). CT90 was weakly correlated with polysomnographic apnea/hypopnea index (AHI). (Spearman rho = 0.36, P < 0.0001) and with delta Index (rho = 0.71, P < 0.0001). delta Index was more closely correlated with AHI (rho = 0.59, P < 0.0001). In a multivariate model, only delta Index was significantly related to AHI, the relationship being AHI = 18.8 delta Index + 7.7. The 95% CI for the coefficient were 16.2, 21.4, and for the constant were 5.8, 9.7. The sensitivity of a delta Index cut-off of 0.4 for the detection of AHI > or = 15 was 88%, for detection of AHI > or = 20 was 90% and for the detection of AHI > or = 25 was 91%. The specificity of delta Index > or = 0.4 for AHI > or = 15 was 40%. In 113 further patients, oximetry was performed simultaneously with laboratory polysomnography. Under these circumstances delta Index was more closely correlated with AHI (rho = 0.74, P < 0.0001), as was CT90 (rho = 0.58, P < 0.0001). Sensitivity of delta Index > or = 0.4 for detection of AHI > or = 15 was not improved at 88%, but specificity was better at 70%. We concluded that oximetry using a saturation variability index is sensitive but nonspecific for the detection of obstructive sleep apnea, and that few false negative but a significant proportion of false positive results arise from night-to-night variability.