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The Avoidance of the Supine Posture During Sleep for Patients with Supine-Related Sleep Apnea
Abstract
Positional therapy is the avoidance of the supine posture during sleep for patients with supine-related sleep apnea. This therapy is mainly suitable for patients with supine-related sleep apnea (positional patients) who have most of their breathing abnormalities concentrated in the supine posture, and in whom while sleeping in the lateral postures (and sometimes in the prone posture), the amount of breathing abnormalities is significantly reduced to a nonpathological level. If a sleep apnea patient has mainly apneas and hypopneas in the supine posture, but when sleeping in the lateral positions or prone posture these breathing abnormalities disappear or are markedly reduced to a non-pathological level, it is almost intuitively obvious that this patient should avoid the supine posture during sleep. It is not clear, however, how the patient should accomplish this task during sleep. To avoid this posture during sleep, and thereafter to learn how to sleep only in the other postures (mainly the lateral posture), it becomes important to find a simple behavioral therapy.
... On the other hand, we also did not include the scope of sleep-related interventions, which may include treatments for sleep disorders and sleep-related treatments for non-sleep disorders. The former may involve surgeries, oral appliances, and sleep posture therapy for OSA [116,117], while the latter may involve night braces/splints for other musculoskeletal conditions [118,119] or sleep posture and appliances for pregnancy [120]. Future reviews might consider scoping reviews on the modeling and simulation aspects to guide the improvement of research validity from a technical perspective. ...
Biomechanical studies play an important role in understanding the pathophysiology of sleep disorders and providing insights to maintain sleep health. Computational methods facilitate a versatile platform to analyze various biomechanical factors in silico, which would otherwise be difficult through in vivo experiments. The objective of this review is to examine and map the applications of computational biomechanics to sleep-related research topics, including sleep medicine and sleep ergonomics. A systematic search was conducted on PubMed, Scopus, and Web of Science. Research gaps were identified through data synthesis on variants, outcomes, and highlighted features, as well as evidence maps on basic modeling considerations and modeling components of the eligible studies. Twenty-seven studies (n = 27) were categorized into sleep ergonomics (n = 2 on pillow; n = 3 on mattress), sleep-related breathing disorders (n = 19 on obstructive sleep apnea), and sleep-related movement disorders (n = 3 on sleep bruxism). The effects of pillow height and mattress stiffness on spinal curvature were explored. Stress on the temporomandibular joint, and therefore its disorder, was the primary focus of investigations on sleep bruxism. Using finite element morphometry and fluid-structure interaction, studies on obstructive sleep apnea investigated the effects of anatomical variations, muscle activation of the tongue and soft palate, and gravitational direction on the collapse and blockade of the upper airway, in addition to the airflow pressure distribution. Model validation has been one of the greatest hurdles, while single-subject design and surrogate techniques have led to concerns about external validity. Future research might endeavor to reconstruct patient-specific models with patient-specific loading profiles in a larger cohort. Studies on sleep ergonomics research may pave the way for determining ideal spine curvature, in addition to simulating side-lying sleep postures. Sleep bruxism studies may analyze the accumulated dental damage and wear. Research on OSA treatments using computational approaches warrants further investigation.
... As Joosten et al. commented [2], the effect of PT on OSA has been examined by a number of studies which utilized different strategies and devices for avoiding the supine posture during sleep. These data have been reviewed extensively also elsewhere [10,11]. In addition to ...
The aggravating effect of the supine body position on breathing abnormalities during sleep was recognized from the earliest studies on sleep breathing disorders. Most of the anatomical and physiological correlates of this phenomenon appear to be due to the effect of gravity on the upper airway. Although few articles have been published on this topic, it has been shown in a large population of obstructive sleep apnoea (OSA) patients that more than half of them are Positional Patients, i.e. they have at least twice as many apnoeas/hypopnoeas during sleep in the supine posture as in the lateral position. This positional phenomenon is influenced by factors such as Respiratory Disturbances Index (RDI), Body Mass Index (BMI), age and sleep stages. The sleep supine posture not only increases the frequency of the abnormal breathing events but also their severity. This sleep posture also has a detrimental effect on snoring, as well as on the optimal CPAP pressure.Positional Therapy, i.e. the avoidance of the supine posture during sleep, is a simple behavioural therapy for many mild to moderate OSA patients. Unfortunately, only a few studies, including only a few patients, have investigated this form of therapy. Although the results of these studies are promising, the lack of a reliable long-term evaluation of its efficacy is perhaps an important reason why this form of therapy has not been widely accepted. Since mild to moderate OSA patients are the majority of the OSA patients and since without treatment, a large percentage of them will develop a more severe form of the disease, a thorough evaluation with a major emphasis on the long-term effectiveness of this form of therapy is urgently needed.
Little is known regarding long-term patient compliance with the tennis ball technique (TBT), one of the original simple methods of positional therapy (i.e., avoiding the supine posture during sleep) for posture-dependent obstructive sleep apnea patients. The purpose of this study was to investigate long-term patient compliance with TBT.
A follow-up questionnaire was mailed to all patients prescribed TBT at the Adelaide Institute for Sleep Health between July 2004 and March 2008 (n = 108).
Sixty-seven patients replied to the questionnaire. Baseline demographic/clinical characteristics were not significantly different from non-respondents. Among the respondents, follow-up time was (mean +/- SD) 2.5 +/- 1.0 years. Four (6.0%) reported they were still using TBT (group A); 9 (13.4%) were no longer using TBT, claiming to have learned to avoid the supine position during sleep (group B); and 54 (80.6%) were neither using TBT nor avoiding the supine posture (group C). The main reason for ceasing TBT use in group C was that TBT was too uncomfortable (34/54 patients).
Long-term patient compliance with TBT appears to be very poor, with less than 10% of patients reporting continued use (group A) approximately 30 months after prescription. With most TBT non-compliers reporting it to be too uncomfortable, alternative forms of positional therapy appear to be needed.
The aim of this study was to evaluate demographic and polysomnographic characteristics of positional (PPJ) and non-positional obstructive (NPP) sleep apnea (OSA) patients in 2077 OSA patients diagnosed in our Sleep Disorders Unit during a period of 10 years. An OSA patient is defined as positional if he has twice as many or more breathing abnormalities (apnea and hypopneas) while he sleeps in his supine posture compared to the lateral ones. Of the 2077 OSA patients, 1118 (53.8%) were positional and 959 (46.2%) were non-positional. No age differences were found between these two groups of patients. However, NPP were heavier and thus had a higher BMI than PP. PP had fewer and Less severe breathing abnormalities during sleep compared to NPP and thus, they enjoyed better sleep quality expressed by higher percentages of stage 2, 4 and 3+4 as well as a lower amount of short arousals than NPP. Also, PP patients are less sleepy during daytime hours than NPP. During the Multiple Sleep Latency Test (MSLT), NPP fall asleep faster in every nap than PP patients. No differences between these two patient groups were found for any parameter of Periodic Limb Movement Disorders. AHI and BMI are independently but inversely related to positional dependency. As AHI and BMI increase, the Likelihood to be a positional patient decreases. NPP have breathing abnormalities in the supine and lateral postures, thus, for them without question, CPAP is the treatment of choice. Since avoiding the supine posture during sleep may significantly improve the sleep quality and daytime alertness of many positional patients, it is imperative to carry out a high-quality study to evaluate if this is a real therapeutic alternative for many positional patients.
The purpose of the study was to determine if the adverse effect of body position on obstructive sleep apnea (OSA) is worsened during rapid eye movement (REM) sleep and if patients with OSA decrease the time spent supine during REM sleep.
Overnight polysomnography from 80 sequential patients referred to Buffalo VA Sleep Lab for suspected OSA were analyzed with 20 patients in each of the following groups: normal with apnea-hypopnea indices (AHI) <5/h, mild (AHI, 5-< 15/h), moderate (AHI, 15-<30/h), and severe (AHI, >30/h). We used extended Cox models with the Anderson-Gill modification for multiple events with two time varying covariates: sleep stage and body position. Generalized estimating equations with logit link were used to take into account correlated data within each patient for the relation between sleep stage and body position.
The hazard ratios for events in REM vs non-REM sleep was significant for the normal, mild, and moderate groups only: 1.71 (95% CI 1.4-2.08), 1.45 (95% CI 1.22-1.73), 1.28 (95% CI 1.1-1.5), respectively. The hazard ratio for events in the supine vs non-supine position was significant for the mild and moderate groups only: 1.25 (95% CI 1.02-1.52) and 1.24 (95% CI 1.04-1.47), respectively. The addition of an interaction effect between sleep stage and body position was not statistically significant for any group. The odds ratios of sleeping in supine position for REM vs non-REM sleep were 0.47 (95% CI 0.27-0.82) for moderate OSA group and 0.54 (95% CI 0.3-0.95) for severe OSA.
In summary, we found significant effects of both sleep stage and body position in mild and moderate but not severe OSA. Patients with moderate and severe OSA were less likely to spend time in the supine position during REM compared with non-rapid eye movement sleep.
It is well known that the sleeping position influences the rate of apnea-hypopnea events; however, whether events in one position may have more influence on daytime sleepiness than events in another position has not been thoroughly investigated.
We retrospectively examined the relationship between the body position-specific apnea-hypopnea index (AHI) and daily sleepiness.
We assessed the sleeping body position, the body position-specific AHI and the Epworth Sleepiness Scale (ESS) in a total of 699 patients who were referred for suspected obstructive sleep apnea-hypopnea syndrome (OSAHS) and underwent diagnostic polysomnography.
For all subjects, only the lateral position-specific AHI (L-AHI) showed a weak but significant correlation with the ESS (r = 0.102; p < 0.05). For mild-to-moderate OSAHS patients, there was no correlation between the ESS and the AHI at any position. For severe OSAHS patients, the ESS showed a closer correlation with the L-AHI (r = 0.266; p < 0.001) than with the supine position-specific AHI (S-AHI; r = 0.141; p < 0.05). In a subgroup analysis, divided into positional and non-positional severe OSAHS patients, the correlation coefficients also identified a link between the L-AHI and the ESS. Finally, a multiple linear regression analysis indicated that the ESS was better explained by the L-AHI than by the S-AHI in severe OSAHS patients.
The L-AHI is considered to have a stronger influence on daytime sleepiness than the S-AHI in Japanese patients with severe OSAHS.
In patients with obstructive sleep apnea (OSA), the severity and frequency of respiratory events is increased in the supine body posture compared with the lateral recumbent posture. The mechanism responsible is not clear but may relate to the effect of posture on upper airway shape and size. This study compared the effect of body posture on upper airway shape and size in individuals with OSA with control subjects matched for age, BMI, and gender.
11 males with OSA and 11 age- and BMI-matched male control subjects.
Anatomical optical coherence tomography was used to scan the upper airway of all subjects while awake and breathing quietly, initially when supine, and then in the lateral recumbent posture. A standard head, neck, and tongue position was maintained during scanning. Airway cross-sectional area (CSA) and anteroposterior (A-P) and lateral diameters were obtained in the oropharyngeal and velopharyngeal regions in both postures. A-P to lateral diameter ratios provided an index of regional airway shape. In equivalent postures, the ratio of A-P to lateral diameter in the velopharynx was similar in OSA and control subjects. In both groups, this ratio was significantly less for the supine than for the lateral recumbent posture. CSA was smaller in OSA subjects than in controls but was unaffected by posture.
The upper airway changes from a more transversely oriented elliptical shape when supine to a more circular shape when in the lateral recumbent posture but without altering CSA. Increased circularity decreases propensity to tube collapse and may account for the postural dependency of OSA.
To determine the effect of head posture on upper airway collapsibility and site of collapse of the passive human upper airway.
Pharyngeal critical closing pressure (Pcrit) and site of airway collapse were assessed during head flexion, extension and rotation in individuals undergoing propofol anesthesia.
Operating theatre of major teaching hospital.
Fifteen healthy volunteers (8 male), including 7 who were undergoing surgery unrelated to the head or neck.
Applied upper airway pressure was progressively decreased to induce variable degrees of inspiratory flow limitation and to define Pcrit. Upper airway and oesophageal pressure transducers identified the site of collapse. Genioglossus muscle activity (EMGgg) was assessed using intramuscular fine wire electrodes inserted percutaneously. Data from 3 subjects were excluded from analysis due to persistent EMGgg. In the neutral posture Pcrit was -0.4 +/- 4.4 cm H2O and collapsed most frequently in the velopharyngeal region. Relative to neutral, Pcrit increased to 3.7 +/- 2.9 cm H2O (P < 0.01) and decreased to -9.4 +/- 3.8 cm H2O (P < 0.01) when the head was flexed and extended, respectively but was unchanged by rotation (-2.6 +/- 3.3 cm H2O; n = 10; P = 0.44). The site of collapse varied, in no consistent pattern, with change in head posture in 5 subjects.
Head posture has a marked effect on the collapsibility and site of collapse of the passive upper airway (measured by EMGgg) indicating that controlling head posture during sleep or recovery from anesthesia may alter the propensity for airway obstruction. Further, manipulating head posture during propofol sedation may assist with identification of pharyngeal regions vulnerable to collapse during sleep and may be useful for guiding surgical intervention.
Changes in sleep posture have been shown to improve obstructive sleep apnea (OSA). To investigate the mechanisms by which this occurs we assessed upper airway stability in eight patients with severe OSA in three postures (supine, elevated to 30 degrees, and lateral). We used a specially adapted nasal continuous positive airway pressure (nCPAP) mask to measure upper airway closing pressure (UACP) and upper airway opening pressure (UAOP) during non-REM sleep. Statistical comparisons were made between postures using ANOVA for repeated measures. Elevation resulted in a less collapsible airway compared with both the supine and lateral positions (mean UACP: 30 degrees elevation -4.0 +/- 3.2 compared with supine 0.3 +/- 2.4 cm H2O, p < 0.05 and; lateral -1.1 +/- 2.2 cm H2O, p < 0.05). Supine UACP and lateral UACP were not significantly different. Elevation or lateral positioning produced a 50% reduction in mean UAOP (supine 10.4 +/- 3.5 cm H2O compared with 30 degrees elevation 5.3 +/- 2.1, p < 0.05; and lateral 5.5 +/- 2.1 cm H2O, p < 0.05). We conclude that in severely affected OSA patients upper body elevation, and to a lesser extent lateral positioning, significantly improve upper airway stability during sleep, and may allow therapeutic levels of nCPAP to be substantially reduced.
To compare anthropomorphic, nocturnal polysomnographic (PSG), and multiple sleep latency test (MSLT) data between positional (PP) and nonpositional (NPP) obstructive sleep apnea (OSA) patients.
This is a retrospective analysis of anthropomorphic, PSG, and MSLT data of a large group of OSA patients who underwent a complete PSG evaluation in our sleep disorders unit. The patients were divided in two groups: the PP group, those patients who had a supine respiratory disturbance index (RDI) that was at least two times higher than the lateral RDI, and the NPP group, those patients in whom the RDI in the supine position was less than twice that in the lateral position.
From a group of 666 consecutive OSA patients whose conditions were diagnosed in our unit from September 1990 to February 1995, 574 patients met the following criteria and were included in the study: RDI > 10; age > 20 years, and body mass index (BMI) > 20.
Of all 574 patients, 55.9% were found to be positional. No differences in height were observed but weight and BMI were significantly higher in the NPP group, these patients being on the average 6.5 kg heavier than those in the PP group. The PP group was, on average, 2 years younger than the NPP group. Nocturnal sleep quality was better preserved in the PP group. In this group, sleep efficiency and the percentages of deep sleep (stages 3 and 4) were significantly higher while the percentages of light sleep (stages 1 and 2) were significantly lower than in the NPP group. No differences for rapid eye movement (REM) sleep were found. In addition, wakefulness after sleep onset and the number of short arousals (< 15 s) were significantly lower in the PP group. Apnea index and total RDI were significantly higher and the minimal arterial oxygen saturation in REM and non-REM sleep was significantly lower in the NPP. No differences in periodic limb movements data were found between the two groups. The average MSLT was significantly shorter in the NPP group. Univariate and multivariate stepwise logistic regression analysis showed that the most dominant variable that correlates with positional dependency in OSA patients is RDI, followed by BMI which also adds a significant contribution to the prediction of positional dependency. Age, although significant, adds only a minor improvement to the prediction of this positional dependency phenomenon. A severe, obese, and older OSA patient is significantly less likely to be positional than a mild-moderate, thin, and young OSA patient. In four obese OSA patients who lost weight, a much more pronounced reduction was seen in the lateral RDI than in the supine RDI, and three of these cases who were previously NPP became PP.
In a large population of OSA patients, most were found to have at least twice as many apneas/hypopneas in the supine than in the lateral position. These so-called "positional patients" are on the average thinner and younger than "nonpositional patients." They had fewer and less severe breathing abnormalities than the NPP group. Consequently their nocturnal sleep quality was better preserved and, according to MSLT data, they were less sleepy during daytime hours. RDI was the most dominant factor that could predict the positional dependency followed by BMI and age. RDI showed a threshold effect, the prevalence of PP in those with severe RDI (RDI > or = 40) was significantly lower than in those OSA patients with mild-moderate RDI. BMI showed a major significant inverse relationship with positional dependency, while age had only a minor although significant inverse relationship with it. Body position during sleep has a profound effect on the frequency and severity of breathing abnormalities in OSA patients.
Cheyne-Stokes Respiration (CSR) is a common finding in Chronic Heart Failure and Stroke patients. The body position effect during sleep on obstructive breathing abnormalities is well known. However, the effect of body position during sleep on breathing abnormalities of central type like CSR has not been well documented.
Six sleep studies (two complete Polysomnographic (PSG) evaluations and four Pulse Oximetry recordings (PO)), were carried out in a 57-year-old female patient with a recent Cerebro Vascular Accident (CVA who had both Obstructive Sleep Apnea (OSA) and CSR.
The first PSG was carried out two months post-stroke and revealed a severe, continuous CSR pattern during Non Rapid Eye Movements (NREM) sleep (mainly with central apneas), and Obstructive Sleep Apnea (OSA) during Rapid Eye Movements (REM) sleep, independent of body position: Supine Respiratory Disturbance Index (SRDI) = 85.2 and Lateral RDI (LRDI) = 95.4. A second PSG was performed three months later after an overall clinical improvement and showed a complete disappearance of CSR during NREM sleep and OSA during REM sleep in her lateral posture (LRDI = 0), while the RDI in the supine posture was only slightly improved (SRDI = 73.2). The CSR pattern was less severe and was characterized mainly by central hypopneas. Two PO recordings between the PSG studies showed similar improvement trends. Two additional PO recordings, two and three weeks after the last PSG (the first one with the patient lying supine and the second one with the patient lying on her side throughout the night), revealed a further significant improvement in the supine posture (SRDI = 37.5).
The results of this study suggest that body posture may play a role not only in the prevalence and severity of obstructive breathing disorders, but also in CSR, a central type of breathing abnormalities during sleep.
The influence of position during sleep on central apnoeas during Cheyne-Stokes respiration has not previously been studied systematically. The current authors aimed to study the effect of body position and sleep stages on central sleep apnoeas during Cheyne-Stokes respiration.
A total of 20 consecutive patients with cardiovascular diseases and central sleep apnoea during Cheyne-Stokes respiration were investigated using nocturnal polysomnography, including a body position sensor mounted on the patient's sternum.
The mean central apnoea–hypopnoea index was significantly higher in the supine position than in nonsupine positions (41±13 versus 26±12). The central apnoea–hypopnoea index was highest in sleep stages 1 and 2, and lowest in slow-wave sleep and rapid eye movement sleep. In every sleep stage, central apnoeas and hypopnoeas were more prevalent in the supine position compared with nonsupine positions.
In conclusion, sleep in the supine body position increases the frequency of apnoeas and hypopnoeas in patients with Cheyne-Stokes respiration.
The primary aim of this study was to determine the prevalence of positional obstructive sleep apnea using a functional definition. Positional sleep apnea was defined as a total apnea-hypopnea index (AHI) > or = 5 with a > 50% reduction in the AHI between the supine and nonsupine postures, and an AHI that normalizes (AHI < 5) in the nonsupine posture. A secondary aim was to determine if positional sleep apnea can be diagnosed accurately during a split-night study.
Retrospective chart review.
Two sleep centers in Buffalo, NY, one a Veterans Affairs Western New York Healthcare System Sleep Center (VAWNY) and the other a freestanding ambulatory center (Associated Sleep Center [ASC]).
Three hundred twenty-six patients from the VAWNY, including 57 patients who underwent a split-night study and 242 patients from the ASC who underwent polysomnography.
None.
Patient characteristics and sleep study results.
Positional sleep apnea was seen in 49 of 99 patients (49.5%) with mild sleep apnea (AHI, 5 to 15/h), 14 of 72 patients (19.4%) with moderate sleep apnea (AHI, 15 to 30/h), and 5 of 77 patients (6.5%) with severe sleep apnea (AHI > 30/h). Sufficient sleep (> 15 min) in both postures was not seen in 104 of 269 patients (38.7%) and 80 of 242 overnight studies (33.1%) at the VAWNY and ASC, respectively, and was not seen in 47 of 57 split-night studies (82.5%). The percentage of studies with insufficient sleep in both postures was significantly greater for split-night studies (p < 0.0001).
Positional sleep apnea is common particularly in patients with mild disease. Positional sleep apnea cannot usually be assessed during a split-night study.
The influence of sleeping position on obstructive sleep apnea severity is well established. However, in central sleep apnea with Cheyne Stokes respiration (CSA-CSR) in which respiratory-control instability plays a major pathophysiologic role, the effect of position is less clear.
To examine the influence of position on CSA-CSR severity as well as central and mixed apnea frequency.
Polysomnograms with digitized video surveillance of 20 consecutive patients with heart failure and CSA-CSR were analyzed for total apnea-hypopnea index, mean event duration, and mean oxygen desaturation according to sleep stage and position. Position effects on mixed and central apnea index, mean apnea duration, and mean desaturation were also examined in non-rapid eye movement sleep.
Data are presented as mean +/- SEM unless otherwise indicated. Group age was 59.9 +/- 2.3 years, and total apnea-hypopnea index was 26.4 +/- 3.0 events per hour. Compared with supine position, lateral position reduced the apnea-hypopnea index in all sleep stages (Stage 1, 54.7 +/- 4.2 events per hour vs 27.2 +/- 4.1 events per hour [p < .001]; Stage 2, 43.3 +/- 6.1 events per hour vs 14.4 +/- 3.6 events per hour [p < .001]; slow-wave sleep, 15.9 +/- 6.4 events per hour vs 5.4 +/- 2.9 events per hour [p < .01]; rapid eye movement sleep, 38.0 +/- 7.3 events per hour vs 11.0 +/- 3.0 events per hour [p < .001]). Lateral position attenuated apnea and hypopnea associated desaturation (supine 4.7% +/- 0.3%, lateral 3.0% +/- 0.4%; p < .001) with no difference in event duration (supine 25.7 +/- 2.8 seconds, lateral 26.9 +/- 3.4 seconds; p = .921). Mixed apneas were longer than central (29.1 +/- 2.1 seconds and 19.3 +/- 1.1 seconds; p < .001) and produced greater desaturation (6.1% +/- 0.5% and 4.5% +/- 0.5%, p = .003). Lateral position decreased desaturation independent of apnea type (supine 5.4% +/- 0.5%, lateral 3.9% < or = 0.4%; p = .003).
Lateral position attenuates severity of CSA-CSR. This effect is independent of postural effects on the upper airway and is likely to be due to changes in pulmonary oxygen stores. Further studies are required to investigate mechanisms involved.
A 'Positioner' preventing sleeping on the back can effectively reduce obstructive sleep apnea (OSA), but not always snoring for patients with long-term OSA. By preference, the device should be used for younger snorers without OSA as a training tool to avoid sleeping on the back. Instructions and support by a nurse are necessary for compliance.
Snoring is a progressive condition with a prevalence of 25-30% among the adult male population. Long-term snoring seems to be the basis for apneas caused by vibration damage to the pharyngeal tissue. Patients with OSA often have more apneas in the supine position than in the lateral position. Preventing sleeping on the back is a way to treat OSA. The aim of this study was to evaluate the efficacy and comfort of a recently developed Positioner.
A total of 23 patients diagnosed with positional sleep apnea (AHI>15 in supine position and AHI<5 in lateral position), were included. The Positioner--a soft vest, attached to a board placed under the pillow, makes it impossible for the patient to sleep on his back. It was fitted and tried out individually. Patients answered sleep questionnaires and kept sleep diaries before beginning use. After 3 months, a new sleep study was done while using the Positioner and new questionnaires were filled out.
Eighteen patients (5 women and 13 men) completed the study. The rest could not tolerate being strapped into the Positioner. Of those participating, 61% demonstrated a decrease of AHI to<10 using the Positioner. The Epworth Sleepiness Scale (ESS) decreased from a mean of 12.3 to 10.2. Half of the patients snored more frequently with the Positioner. The evaluation of comfort showed that minor adjustments are desirable.
This study was performed to evaluate the efficacy of positional therapy using a recently developed vest-type device to treat snoring in positional-dependent snorers. Seventeen (60.7%) of the 28 subjects were diagnosed as position-dependent snorers with or without mild obstructive sleep apnea through laboratory nocturnal polysomnography and were included in a pre- and post-treatment comparative parallel study. The mean total snoring rate (from 36.7 ± 20.6% to 15.7 ± 16.2%, P < 0.0001) and snoring rate in the supine position (from 45.8 ± 22.8% to 25.4 ± 20.6%, P < 0.0001) decreased significantly with use of the vest. The mean percent change of total snoring rate between baseline and with the positional device was significant (63.5 ± 22.5%, P < 0.0001). Of the 17 subjects, 15 (88.2%) decreased their snoring rate more than 50% without subjective adverse effects. There were no significant differences in sleep efficiency, arousal index, and wake after sleep onset while sleeping with the vest-type positional device. In conclusion, positional therapy using the recently developed vest-type device is effective at decreasing snoring without subjective and objective adverse effects in position-dependent snorers with or without mild obstructive sleep apnea.
Background:
Approximately half of obstructive sleep apnea (OSA) patients are positional (i.e., the majority of their breathing abnormalities during sleep appear in the supine posture). Little information exists as to whether avoiding the supine posture during sleep (positional therapy) is a valuable form of therapy for these patients.
Aim:
To assess the use of positional therapy (by the tennis ball technique [TBT]) during a 6 month period in 78 consecutive positional OSA patients.
Methods:
Demographic, polysomnographic, and self-reported questionnaire data on the use of the TBT were analyzed.
Results:
Of the 50 patients who returned the questionnaire, 19 (38%) (group A) said they were still using the TBT, and 12 (24%) (group B) said they used it initially and stopped using it within a few months but were still avoiding the supine position during sleep. Nineteen patients (38%) (group C) stopped using the TBT within a few months but did not learn how to avoid the sleep supine posture. Patients still using the TBT showed a significant improvement in their self-reported sleep quality (P < .005) and daytime alertness (P < .046) and a decrease in snoring loudness (P < .001). Patients of groups A and B were older than patients who did not comply with this therapy (P < .001). The main reason for patients stopping the use of the TBT in group C was that using it was uncomfortable.
Conclusions:
Positional therapy appears to be a valuable form of therapy mainly for some older aged positional OSA patients.
We hypothesized that positional therapy would be equivalent to continuous positive airway pressure (CPAP) at normalizing the apnea-hypopnea index (AHI) in patients with positional obstructive sleep apnea (OSA).
Thirty-eight patients (25 men, 49 +/- 12 years of age, body mass index 31 +/- 5 kg/m2) with positional OSA (nonsupine AHI <5 events/h) identified on a baseline polysomnogram were studied. Patients were randomly assigned to a night with a positional device (PD) and a night on CPAP (10 +/- 3 cm H2O).
Positional therapy was equivalent to CPAP at normalizing the AHI to less than 5 events per hour (92% and 97%, respectively [p = 0.16]). The AHI decreased from a median of 11 events per hour (interquartile range 9-15, range 6-26) to 2 (1-4, 0-8) and 0 events per hour (0-2, 0-7) with the PD and CPAP, respectively; the difference between treatments was significant (p < 0.001). The percentage of total sleep time in the supine position decreased from 40% (23%-67%, 7%-82%) to 0% (0%-0%, 0%-27%) with the PD (p < 0.001) but was unchanged with CPAP (51% [36%-69%, 0%-100%]). The lowest SaO2 increased with the PD and CPAP therapy, from 85% (83%-89%, 76%-93%) to 89% (86%-9%1, 78%-95%) and 89% (87%-91%, 81%-95%), respectively (p < 0.001). The total sleep time was unchanged with the PD, but decreased with CPAP, from 338 (303-374, 159-449) minutes to 334 (287-366, 194-397) and 319 (266-343, 170-386) minutes, respectively (p = 0.02). Sleep efficiency, spontaneous arousal index, and sleep architecture were unchanged with both therapies.
Positional therapy is equivalent to CPAP at normalizing the AHI in patients with positional OSA, with similar effects on sleep quality and nocturnal oxygenation.
The present study determines the influence of sleeping position on central sleep apnea (CSA) in patients with heart failure (HF).
The apnea/hypopnea index (AHI) during different body positions while asleep was examined by cardiorespiratory polygraphy in 71 patients with HF (ejection fraction <45%).
Twenty-five of the patients having predominantly CSA (central apnea index 10/h) with a lower obstructive apnea index (<5/h) were assigned to groups with positional (lateral to supine ratio of AHI <50%, n=12) or non-positional (ratio > or = 50%, n=13) CSA. In the non-positional group the BNP level was higher, the ejection fraction was lower and the trans-tricuspid pressure gradient was higher than in the positional group. Multiple regression analysis revealed more advanced age (p=0.006), log(10)BNP (p=0.017) and lung-to-finger circulation time (p=0.020) as independent factors of the degree of positional CSA. Intensive treatment for HF changed CSA from non-positional to positional in all eight patients tested. Single night of positional therapy reduced CSA (p<0.05) and BNP level (p=0.07) in seven positional patients.
As cardiac dysfunction progresses, severity of CSA also increases and positional CSA becomes position-independent. Positional therapy could decrease CSA, thereby having a valuable effect on HF.
Cheyne-Stokes respirations occur in 40% of patients with heart failure. Orthopnea is a cardinal symptom of heart failure and may affect the patient's sleeping angle. The objective of this study was to assess the respiratory and hemodynamic response to sleeping angle in a group of subjects with stable heart failure.
Twenty-five patients underwent overnight polysomnography with simultaneous and continuous impedance cardiographic monitoring. Sleeping polysomnographic and impedance cardiographic data were recorded.
The study was conducted in a sleep center.
All 25 patients had clinically stable heart failure and left ventricular ejection fractions < 40%.
The patients slept at 0 degrees, 15 degrees, 30 degrees, and 45 degrees in random order.
Seventeen patients had Cheyne-Stokes apneas (index > 5/h) and 23 patients had hypopneas (index > 5/h). The hypopnea index showed no response to sleeping angle. The Cheyne-Stokes apnea index decreased with increasing sleeping angle (P < 0.001). This effect was seen only during supine sleep and non-rapid eye movement sleep and was absent in non-supine sleep, rapid eye movement sleep, and during periods of wakefulness. Thoracic fluid content index and left ventricular hemodynamics measured by impedance cardiography showed no response to sleeping angle.
Changing the heart failure patient's sleeping angle from 0 degrees to 45 degrees results in a significant decrease in Cheyne-Stokes apneas. This decrease occurs on a constant base of hypopneas. The changes in Cheyne-Stokes apneas are not related to changes in lung congestion and left ventricular hemodynamics.
To investigate the effect of sleep position on surgical outcomes in obstructive sleep apnea (OSA).
Retrospective review of 69 consecutive patients.
Preoperative and postoperative polysomnographic data and Epworth sleepiness scale were obtained. Patients were categorized into success, response, no response, and failure groups according to apnea-hypopnea index (AHI) after uvulopalatopharyngoplasty. Proportions of supine or lateral position and AHI of each position were evaluated. Position-corrected AHI was developed in order to eliminate the effect of sleep position.
Preoperative proportion of supine position in the failure group (n = 26) was 41.3 percent, which was the lowest among four groups (P = 0.010), and increased to 60.8 percent postoperatively (P = 0.028). Twenty-two (84.6%) among the failure group had supine position dependency. Regrouped by position-corrected AHI, 15 patients moved into different groups. Postoperative AHI showed positive correlation with increased supine position when BMI was controlled (r = 0.515, P = 0.006).
Without appropriate correction based on the change of sleep position, the fluctuation of sleep position in each polysomnography might confound surgical outcomes in OSA patients. Thus, it is a substantial issue how to control or reflect the positional effect on AHI when treatment results are evaluated.
It is generally considered that patients with obstructive sleep apnea syndrome (OSAS) at increased perioperative risk should be placed in nonsupine positions throughout the recovery process; however, not all patients with OSAS show positional dependence. The authors hypothesized that morphological differences exist in three-dimensional (3D) soft tissue and craniofacial structures of the pharyngeal airway between positional and nonpositional OSAS.
The subjects of the study were body mass index-matched, age-matched, and apnea hypopnea index-matched positional (n = 10) and nonpositional (n = 10) Japanese OSAS patients and body mass index-matched Japanese control subjects (n = 10). Pharyngeal magnetic resonance imaging and cephalometric radiography were performed during wakefulness.
The patients with positional OSAS had a smaller volume of the pharyngeal lateral wall soft tissues, larger maxilla-nasion-mandible angle, and smaller lower facial height than the nonpositional OSAS and the control subjects. The patients with positional OSAS showed a significantly steeper sella-nasion-mandible angle and smaller craniofacial volume than the control subjects. There were no significant differences in tongue volume and 3D pharyngeal anatomical balance between positional and nonpositional OSAS. Multivariate stepwise regression for positional dependence showed that the dominant determinant was the volume of the lateral pharyngeal wall, followed by lower facial height and maxilla-nasion-mandible angle.
Patients with positional OSAS have wider airways in the lateral parts, lower facial height, and more backward position of the lower jaw, which may explain differences in the maintenance of pharyngeal airway patency in the lateral sleep position.
A lateral position (LP) during sleep is effective in reducing sleep disorder symptoms in mild or moderate sleep apnea patients. However, the effect of head and shoulder posture in LP on reducing sleep disorders has not been reported. In this study, effective sleeping positions and a combination of sleep position determinants were evaluated with respect to their ability to reduce snoring and apnea. The positions evaluated included the following: cervical vertebrae support with head tilting (CVS-HT), scapula support (SS), and LP. A central composite design was applied for response surface analysis (RSA). Sixteen patients with mild or moderate positional sleep apnea and snoring who underwent polysomnography for two nights were evaluated. Based on an estimated RSA equation, LP (with a rotation of at least 30 degrees) had the most dominant effect [P = 0.0057 for snoring rate, P = 0.0319 for apnea-hypopnea index (AHI)]. In addition, the LP was found to interact with CVS-HT (P = 0.0423) for snoring rate and CVS-HT (P = 0.0310) and SS (P = 0.0265) for AHI. The optimal sleep position reduced mild snoring by more than 80% (i.e. snoring rate in the supine position was <20%) and the snoring rate was approximately zero with a 40 degrees rotation. To achieve at least 80% reduction of AHI, LP and SS should be >30 degrees and/or 20 mm respectively. To determine an effective sleep position, CVS-HT and SS, as well as the degree of the LP, should be concurrently considered in patients with positional sleep apnea or snoring.
Avoidance of sleep in the supine position is recommended in the management of position-dependent OSA hypopnoea syndrome (OSAHS). Our aim was to evaluate the efficacy of a thoracic anti-supine band (TASB), designed to mimic the so-called 'tennis ball technique', compared with nasal CPAP (nCPAP).
Twenty adults with mild to moderately severe position-dependent OSAHS (mean AHI +/- SD) 22.7 +/- 12.0/H (range 6.0-51.2); AHI supine, 59.6 +/- 27.5/H, were included in a randomized cross-over trial. Portable sleep studies were undertaken at baseline and after 1 month on each treatment. A successful treatment outcome was defined as AHI <or= 10/H.
Mean AHI was 12.0 +/- 14.5/H with the TASB and 4.9 +/- 3.9/H with nCPAP (P = 0.02; 95% confidence interval for the difference: -13.1 to -1.0). With the TASB, treatment 'success' was achieved in 13/18 subjects, whereas 'success' was achieved in 16/18 subjects using nCPAP (P = 0.004). In the two subjects with baseline AHI < 10/H, AHI remained below 10 for both therapies. The TASB successfully reduced time spent in the supine position. Mean percentage supine sleep time was 6.3 +/- 5.9% with the TASB, and 35.4 +/- 34.1% with nCPAP (P < 0.001). No significant differences in sleep efficiency or subjective responses were observed between treatments.
Control of body position during sleep using an anti-supine device mimicking the so-called 'tennis ball technique' provides benefit in the management of position-dependent OSAHS in subjects who meet strict inclusion criteria. The overall improvement is, however, less than for nCPAP.
Sixty male patients all with apnea plus hypopnea indices (A + HI) above 12.5, who met a criterion of positionality by having two or more times the rate of these events during supine sleep in comparison to their lateral sleep rate, were randomly assigned to one of four treatments for 8 weeks. All were restudied for two nights, one with and one without treatment devices. On treatment more than half the patients in each group reduced their A + HI to within normal limits and a third remained WNL without the use of devices. Half of those trained to sleep in the lateral position with the help of an alarm maintained this learning without the alarm as did half of those who were encouraged to learn this sleep posture on their own. There is an additive effect for the positional patient from wearing a tongue retaining device (TRD) if they continue to sleep in the supine position. Factors associated with successful treatment include overall severity, severity in the lateral position, weight, weight change, nasal patency and motivation to help their condition.
To determine whether the adoption of a more upright sleep posture would improve breathing and gas exchange in patients with obstructive sleep apnea syndrome (OSAS), 13 male patients with OSAS were studied during an all-night polysomnographic study while lying supine or sitting at a 60-degree angle. In the upright posture, the frequency of obstructive apnea was decreased (lying, 48.9 +/- 5.4/h; sitting, 19.6 +/- 6.9/h; p less than 0.0005) and arterial oxyhemoglobulin saturation (Sao2) was increased (nREM; mean lying, 90.6 +/- 0.8%; mean sitting, 92.1 +/- 0.5%, p less than 0.005; minimum lying, 64.8 +/- 3.2%, minimum sitting, 80.8 +/- 2.1%, p less than 0.005). In approximately half the patients studied, obstructive sleep apnea was essentially abolished by the postural intervention. These patients were more obese and had lower Pao2 and higher Paco2 values awake than the remaining patients in whom the response was either incomplete or absent. Arousal from sleep was less frequent in the upright posture, but sleep efficiency and overall sleep architecture were unchanged. This simple maneuver may be useful for treating some patients with OSAS.
Ten male patients selected as having sleep apnea predominantly of the obstructive type associated with the supine sleep position on their evaluation night were trained for 1 additional night to avoid the back sleep position by wearing a gravity-activated position monitor/alarm on the chest. This device emitted an auditory signal if the patient remained supine for more than 15 s. The number of apneic events was significantly reduced, as were the number of episodes of significant O2 desaturation. While wearing the alarm, the apnea index of seven patients remained within or near normal limits. On a follow-up night, with only instructions to maintain the lateral decubitus posture, five patients remained significantly improved. Sleep position training may be appropriate as a single or interim treatment for a significant number of sleep apnea patients who have position-related obstruction.
In a patient showing a typical pickwickian syndrome a study was made of respiratory functions and arterial gasometry, with polygraphic registrations carried out during the day and at night in an attempt to evaluate sleep, respiration, blood oxyhaemoglobin and CO2 concentration of the expiratory air.It was demonstrated that, at the onset of an authentic pickwickian syndrome, the symptomatology may be confined to obesity and diurnal drowsing episodes of the type described by Dickens in his novel. This means that the permanent alveolar hypoventilation regarded by some authors as an indispensable feature of the syndrome,In the patient under discussion, the numerous episodes of diurnal slumber which characterized his condition and occurred while the blood oxyhaemoglobin saturation and alveolar CO2 concentration were entirely normal, cannot be explained on the basis of hypoxia and hypercapnia as suggested by a majority of authors. One must resort to other hypotheses, bearing in mind that the one does not necessarily exclude the other.A first hypothesis suggests that the subject drowses during the day as a result of a primary disturbance of centres in the brain stem which regulate wakefulness and sleep by a mechanism not yet understood. According to this hypothesis, we are confronted with some sort of narcolepsy.A second hypothesis holds that the subject drowses during the day because he does not sleep sufficiently at night as a result of an exaggeration of the physiological phenomenon of hypnic hypoventilation. Nocturnal polygraphic registrations disclosed respiratory pauses which occurred in the initial phase of sleep, quite apart from hypotonia of the muscles of the floor of the mouth, so rapid and pronounced that the tongue moves back and causes the obstructive apnoea responsible for a hypoxia which arouses the subject, who returns to sleep after a short while. The cyclic repetition of arousal and slumber reduces nocturnal sleep to 2–3 h a night. This loss of nocturnal sleep is held responsible for the diurnal somnolence. Unfortunately the subject's diurnal sleep is disturbed even more than his nocturnal sleep because the slightest slumber immediately produces episodes of central or obstructive apnoea.Regardless of the respective values of these two hypotheses, the authors are convinced that the majority of individuals suffering from the pickwickian syndrome drowse during the day and sleep badly at night because of a primary disturbance in the wakefulness-sleep regulation which as such is based on their obesity. This affords an obvious explanation of the established fact that the only way to suppress hypnic disturbances in pickwickian patients is to have them lose weight.
Thirty male patients evaluated sequentially for sleep apnea syndrome by all-night clinical polysomnography were compared for apnea plus hypopnea index (A + HI) during the time in the side versus time in the back sleep posture. For 24 subjects of this sample, who occupied both major body positions during the evaluation night, the apnea index was found to be twice as high during the time spent sleeping on their backs as it was when they slept in the side position. This difference is reliable and inversely related to obesity. Five patients meeting diagnostic criteria for sleep apnea on an all-night basis fell within normal limits while in the side sleep position. This suggests sleep position adjustment may be a viable treatment for some nonobese sleep apnea patients.
Fast-CT scanning was used to study the effects of changes in body position on upper airway (UA) size and shape in 11 awake subjects with obstructive sleep apnea (OSA). Six patients with position (P)-dependent OSA were compared with five patients with nonposition (NP)-dependent OSA. Scans were repeated in the prone (PRN), right side (RS), and supine (SUP) body positions at both functional residual capacity and end-inspiratory tidal volume. Significant group, group by position, and borderline group by respiration effects were detected for minimum but not mean UA dimension data. Significant differences between groups were noted in minimum cross-sectional area and minimum lateral distance but not in minimum anteroposterior distance in the RS and SUP positions. Turning from the PRN to the RS or SUP position tended to decrease UA size in the NP group by decreasing the lateral distance, while the opposite effect was found in the P group. The results indicate that changes in body position during wakefulness affect the lateral but not the anteroposterior dimensions of the UA, and the UA behaves differently in patients with NP and P OSA in response to changes in body position.
Limited data have suggested that sleep-disordered breathing, a condition of repeated episodes of apnea and hypopnea during sleep, is prevalent among adults. Data from the Wisconsin Sleep Cohort Study, a longitudinal study of the natural history of cardiopulmonary disorders of sleep, were used to estimate the prevalence of undiagnosed sleep-disordered breathing among adults and address its importance to the public health.
A random sample of 602 employed men and women 30 to 60 years old were studied by overnight polysomnography to determine the frequency of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea score). We measured the age- and sex-specific prevalence of sleep-disordered breathing in this group using three cutoff points for the apnea-hypopnea score (> or = 5, > or = 10, and > or = 15); we used logistic regression to investigate risk factors.
The estimated prevalence of sleep-disordered breathing, defined as an apnea-hypopnea score of 5 or higher, was 9 percent for women and 24 percent for men. We estimated that 2 percent of women and 4 percent of men in the middle-aged work force meet the minimal diagnostic criteria for the sleep apnea syndrome (an apnea-hypopnea score of 5 or higher and daytime hypersomnolence). Male sex and obesity were strongly associated with the presence of sleep-disordered breathing. Habitual snorers, both men and women, tended to have a higher prevalence of apnea-hypopnea scores of 15 or higher.
The prevalence of undiagnosed sleep-disordered breathing is high among men and is much higher than previously suspected among women. Undiagnosed sleep-disordered breathing is associated with daytime hypersomnolence.
The aim of this study was to compare the relative efficacy of continuous positive airway pressure (CPAP) and positional treatment in the management of positional obstructive sleep apnea (OSA), using objective outcome measures.
A prospective, randomized, single blind crossover comparison of CPAP and positional treatment for 2 weeks each.
A university teaching hospital.
Thirteen patients with positional OSA, aged (mean+/-SD) 51+/-9 years, with an apnea-hypopnea index (AHI) of 17+/-8.
(1) Daily Epworth Sleepiness Scale scores; (2) overnight polysomnography, an objective assessment of sleep quality and AHI; (3) maintenance of wakefulness testing; (4) psychometric test battery; (5) mood scales; (6) quality-of-life questionnaires; and (7) individual patient's treatment preference.
Positional treatment was highly effective in reducing time spent supine (median, 0; range, 0 to 32 min). The AHI was lower (mean difference, 6.1; 95% confidence interval [CI], 2 to 10.2; p = 0.007), and the minimum oxygen saturation was higher (4%; 95% CI, 1% to 8%; p = 0.02) on CPAP as compared with positional treatment. There was no significant difference, however, in sleep architecture, Epworth Sleepiness Scale scores, maintenance of wakefulness testing sleep latency, psychometric test performance, mood scales, or quality-of-life measures.
Positional treatment and CPAP have similar efficacy in the treatment of patients with positional OSA.
Objectives: To determine continuous positive airway pressure (CPAP) treatment compliance and reversal of excessive daytime sleepiness in patients with mild OSA.Background: CPAP therapy is the most widely accepted and used intervention in patients with a diagnosis of obstructive sleep apnea (OSA). There are, however, no widely accepted protocols to help guide the rational use of CPAP therapy. Patients with mild OSA (respiratory event index (REI) >5 or </=25) represent a subset of the OSA population where CPAP implementation needs to be evaluated.Methods: This is a retrospective study of 740 consecutive patients evaluated for sleep apnea in 1996. Mild OSA was documented in 241 patients, of whom, 41 opted for CPAP therapy. Implementation of CPAP treatment included an education session and an overnight clinical polysomnography (CPSG) for titration purposes. Patients returned for follow-ups after 1 week and 1 year of CPAP use. During each appointment, compliance and response to treatment were evaluated.Results: Of the initial 41 patients nine were lost to follow-up, 16 discontinued CPAP use during the first week, and 16 were still using CPAP after 1 year. For the 16 still using CPAP after one year, hours of use the first week was correlated to hours of use the first year (r=0.81). Patients using CPAP more than 4 h/night experienced a marked improvement in daytime sleepiness after 1 year (P<0.01).Conclusions: Patients with mild OSA showed a high rate of CPAP discontinuation. Those patients who manifested good compliance during the first week of treatment continued using CPAP for the entire first year. These patients experienced improved alertness during the day. A 1 week trial on CPAP therapy is warranted to identify patients who benefit from this form of therapy.
To compare the severity of sleep apneic events occurring in the supine posture vs the severity of sleep apneic events occurring in the lateral posture in patients with severe obstructive sleep apnea (OSA).
A retrospective analysis of apneic event variables in a group of 30 OSA patients who underwent a complete polysomnographic evaluation in our sleep disorders unit.
Thirty patients with severe OSA (respiratory disturbance index [RDI] = 70.1+/-18.2) who were nonpositional patients (NPP), ie, in whom the ratio of the supine RDI to the lateral RDI is < 2 (supine RDI = 85.7+/-11.7, lateral RDI = 64.8+/-17.3), and who had > or =30 apneic events in the lateral position and 30 apneic events in the supine position during sleep stage 2 were included in the study.
For the 30 apneic events in each body position, the following variables were evaluated: apnea duration (ApDur), minimum desaturation (MinDes), Delta desaturation (Delta-Des), duration of arousal (DurArous), maximum snoring loudness (MaxSL), and Delta heart rate (Delta-HR). In addition, three other variables assessed as a ratio of ApDur (Rate-D = Delta-Des/ApDur, R-HR =Delta-HR/ApDur, and R-Arous = DurArous/ApDur) were also calculated.
For all variables evaluated, apneic events occurring in the supine posture were significantly more severe than those apneic events occurring in the lateral posture during sleep stage 2. ApDur of both body postures correlated significantly with DurArous, Delta-HR, and MaxSL, but not with Delta-Des and MinDes. ApDur correlated linearly with DurArous for both postures. The slopes of the two regression lines were similar (p = 0.578) but the regression line intercept for the supine apneas was significantly higher than that of lateral apneas (p<0.0001). In addition, the average number of supine apneic events that did not end with an arousal was smaller than the average number of lateral apneic events not ending with an arousal (4.4+/-6.0 vs. 10.5+/-6.7, respectively; p< 0.0001). Also, only 4 of 900 (0.44%) apneic events analyzed in the lateral posture ended with an awakening (> 15 s), whereas in the supine posture, there were 37 (4.1%) such events (p<0.001).
These results show that even in patients with severe OSA who have a high number of apneic events in the supine and lateral posture, the apneic events occurring in the supine position are more severe than those occurring while sleeping in the lateral position. Thus, it is not only the number of apneic events that worsen in the supine sleep position but, probably no less important, the nature of the apneic events themselves.
This study was carried out to test the hypothesis that changes in head/body position induce changes in upper-airway dimensions. Contiguous images were obtained by means of magnetic resonance imaging in normal awake subjects during nasal breathing. A statistical analysis was made on 5 consecutive slices, including the most constricted sites in both the retropalatal and retroglossal regions. Dimensional changes in the upper airway in association with changes in head/body position were evaluated. In the retropalatal region, there was a significant decrease in the lateral dimension in the lateral recumbent position compared with that in the supine position. The cross-sectional area in the retroglossal region was significantly increased in both the "supine with the head rotated" and "lateral recumbent" positions. This change was accompanied by significant volumetric changes in the retroglossal region. Thus, sleeping with the head rotated may be effective for improving upper-airway obstruction.
We examined the effects of cervical position on the Obstructive Sleep Apnea Syndrome (OSAS) through the use of a custom-designed cervical pillow which promoted neck extension. Twelve subjects with OSAS were recruited from a tertiary sleep disorder clinic population. Of the twelve subjects, three had mild cases of OSAS, four had moderate cases, and the remaining five had severe cases. The subjects used their usual pillows during two consecutive recorded baseline nights in our laboratory. The subjects then used the cervical pillow for five days at home, and returned for two consecutive recorded nights at our laboratory while using the cervical pillow. During the nights in our laboratory, the subjects completed questionnaires, were videotaped to record head and body position, and had their breathing parameters recorded during sleep. Subjects with mild OSAS cases had a non-significant improvement in the severity of their snoring and a significant improvement in their respiratory disturbance index with the cervical pillow, while subjects with moderate OSAS cases showed no improvement in these parameters. Subjects with severe OSAS cases showed slight improvement in some measures of their abnormal respiratory events during the experimental period.
The objective of this study was to assess whether cervical positioning could improve mild to moderate cases of the obstructive sleep apnea syndrome (OSAS). Eighteen subjects recruited from a tertiary sleep disorders clinic population with mild to moderate cases of OSAS were evaluated using a custom-fitted cervical pillow designed to increase upper airway caliber by promoting head extension. The subjects used their usual pillows during two consecutive recorded baseline nights in our laboratory. They then used the cervical pillow for 5 days at home and returned for 2 consecutive recorded nights at our laboratory to use the cervical pillow. During the nights in our laboratory, the subjects completed questionnaires, were videotaped to record head and body position, and had full polysomnography. The subjects had a significant trend toward improvement in their respiratory disturbance indices with use of the cervical pillow, despite spending more time in the supine position and having similar amounts of REM sleep in the baseline and experimental conditions. They also had nonsignificant trends toward improvements in their sleep efficiency and subjective depth of their sleep as well as significantly fewer arousals and awakenings in the experimental compared with the baseline condition. We propose that cervical positioning (i.e., head extension) with a custom-fitted cervical pillow provides a simple, noninvasive, and comfortable means of reducing sleep-disordered breathing in patients with mild to moderate OSAS.
Reduction of nocturnal obstructive events during lateral position in patients with obstructive sleep apnea was previously reported. However, little information is available regarding mechanisms of the improvement and the precise pharyngeal site influenced by the lateral position. The authors tested the hypothesis that structural properties of the passive pharynx change by changing the body position from supine to lateral.
Total muscle paralysis was induced with general anesthesia in eight patients with obstructive sleep apnea, eliminating neuromuscular factors contributing to pharyngeal patency. The cross-sectional area of the pharynx was measured endoscopically at different static airway pressures. Comparison of static pressure-area plot between the positions allowed assessment of the influence of the position change on the mechanical properties of the pharynx.
The static pressure-area curves of the lateral position were above those of the supine position, with increasing maximum cross-sectional area and decreasing the closing pressure at both retropalatal and retroglossal airways.
Lateral position structurally improves maintenance of the passive pharyngeal airway in patients with obstructive sleep apnea.
Prevention of the supine position has for decades been a well known treatment option in positional obstructive sleep apnea. It was the aim of this study to test the efficacy of a recently patented commercially available supine position preventing vest.
The vest is made of linen tissue with a half cylindrical piece of hard foam in its dorsal part. 12 male patients slightly overweight (body mass index 26.5 +/- 2.6 kg/m(2)) and 55.8 +/- 11.6 years old were investigated polysomnographically prospectively.
The pretherapeutical respiratory-disturbance index (RDI) was 26.7+/-11.9/h increasing to 39.3+/-16.1/h in the supine position. When using the vest, patients no longer slept on their back and the RDI dropped to 7.6 +/- 5.1/h (p < 0.005). Total sleep time at an oxygen saturation below 90 % was reduced from 11.7 +/- 11.3 % to 1.5 +/- 2.1 %. 9 patients (75 %) were cured (RDI < 10/h and RDI reduction > 50 %), 2 patients (17 %) improved (RDI reduction > 50 %) and only the oldest patient (76 years old) remained unchanged. Even though snoring decreased from 180 +/- 125 minutes to 110 +/- 52 minutes, an increase was observed in 30 % of the patients. Sleep quality and structure did not change considerably.
The supine position prevention vest is a safe and simple treatment alternative of high efficacy in positional sleep apnea. As a complete remission cannot be predicted, polygraphic or polysomnographic controls are necessary.
We report a 38-year-old man with obstructive sleep apnea whose sleep-disordered breathing was substantially reduced by sleep in the supine, "knees-up" position, relative to his sleep in the customary supine, "knees-down" position. No obvious anatomic or pathophysiologic alterations explained this phenomenon. The effect was reproducible in the patient 4 years later. Potential mechanisms underlying such improvement, including alterations in upper airway/lung volume dependence and venous supply to upper airway vasculature, are discussed. This manipulation could be an important adjunctive treatment for a subset of obstructive sleep apnea patients demonstrating such an effect.
This study aimed to evaluate the effectiveness of elevated posture in the management of obstructive sleep apnea (OSA). Fourteen subjects presenting with mild-moderate OSA, (apnea-hypopnea index [AHI] 10 to 60/h), were included in a randomized crossover investigation. A shoulder-head elevation pillow (SHEP) was compared with nasal continuous positive airway pressure (nCPAP) therapy. Treatment success was defined as AHI<or=10/h and partial success as AHI>10<16/h. Four subjects achieved treatment success with the SHEP and three achieved partial success. The remaining seven subjects were treatment failures. In contrast, success was achieved with nCPAP in 12 subjects. One subject achieved partial success and one was a treatment failure. With the SHEP, the mean AHI decreased from 27+/-12/h to 21+/-17/h. With nCPAP, the mean AHI was 5+/-3/h; (p=0.008 for the difference between treatments). Although somewhat variable, these data provide evidence that elevated posture during sleep is helpful in the management of OSA in some individuals. Results support the use of elevated posture as second-line therapy in the management of OSA. However, no relationships could be identified between baseline data, including the identification of positional OSA, and objective outcomes that might predict patients who are likely to benefit from treatment in an elevated position.
We previously reported a case of a middle-aged man whose obstructive sleep apnea (OSA) was virtually eliminated when he slept in the supine "knees up" position. In this study, we attempt to replicate this phenomenon in a group of volunteers with previously diagnosed OSA. Results indicated no significant improvement in OSA when sleeping supine knees up. Examination of distribution of within subjects' change [calculated as Respiratory Disturbance Index (RDI) in the "knees down" position vs RDI in the knees up position] indicated a trend for improvement in the latter (p=0.12, two-tailed probability). These results suggest that knee position is unlikely to be a robust intervention for OSA though they allow for the possibility that some patients may have a moderation of their condition by such a manipulation.
We analyzed the role of sleep position in obstructive sleep apnea syndrome (OSAS). The polysomnograms of 120 patients with sleep apnea syndrome were analyzed. We associated the apnea hypopnea index (AHI) of the supine position with the AHI of the other positions. Patients were stratified in a group of positional patients (PP) (AHI supine >or= 2 x AHI other positions) and a group of non-positional patients (NPP). In 55.8% of our patients, OSAS was position dependent. PP patients were significantly (6.7 years) younger. BMI and AHI were higher in the NPP group, but the difference was not significant. Level of obstruction in the upper airway (retropalatinal vs retrolingual vs both levels) as assessed by sleep endoscopy was not significantly different between the two groups. Total sleep time (TST) was equal in both groups, but the average time in supine position was 37 min longer in the PP group. This study confirms the finding that in more than 50% of patients, OSAS is position dependent. Apart from age, no patient characteristics were found indicating the position dependency. Overall AHI does not identify positional OSAS.
Background:
Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent episodes of a complete or partial collapse of the upper airway during sleep. Traditionally, the disease is diagnosed by overnight polysomnography. Studies have shown correlation between parameters of cephalometry and severity of sleep apnea. We wish to determine the variable of craniofacial dimensions in the upper airway that contribute to OSA, and to investigate the significance of craniofacial measurements in positional and non-positional sleep apnea patients.
Methods:
From July 2002 to June 2006, we studied 84 males and 15 females who came to the sleep center because of daytime sleepiness. All the participants underwent overnight polysomnography and lateral cephalograms, performed by an experienced technician.
Results:
Craniofacial measurements of gnathion-gonion, anterior superior hyoid to mandibular plane (MP-H), posterior nasal spine (PNS) to the velum tip (SPL), widest point of the soft palate (SPW), and the product of PNS to the velum tip and widest point of the soft palate (product of soft palate (SPP)=SPL x SPW) were positively related to the apnea/hypopnea index (AHI). The velum tip to the pharyngeal wall parallel to the Frankfurt horizontal (PAS) was negatively related to the AHI. We further divided the study subjects into 4 groups according to AHI value (group 1, AHI<5; group 2, 5 <or= AHI<15; group 3, 15 <or= AHI<30; group 4, AHI >or=30). Age, body mass index (BMI), neck circumference (NC), distances of PAS, SPL, SPW, SPP and angle of sella-nasion-infradentale (SNB) were significantly different depending on the degree of severity of sleep-disordered breathing (SDB). Patients who were older, with a high BMI and longer MP-H distance, had more daytime sleepiness (Epworth sleepiness scale, ESS). Furthermore, lower AHI values and longer PAS measurements were found in the positional sleep apnea group when compared to the non-positional sleep apnea group. After adjusting for confounding factors of age, BMI and NC, we found that BMI, MP-H distance and PAS measurement were correlated with severity of OSA.
Conclusions:
Cephalometry could be a useful and inexpensive clinical tool to evaluate Chinese patients with OSA. MP-H and PAS should be measured in Chinese patients with OSA. MP-H was correlated with ESS. The PAS measurement was narrower in non-positional OSA patients compared to positional OSA patients.
The aim of this study was to clarify the interaction of lateral and supine sleeping positions with upper airway morphology in patients with obstructive sleep apnea syndrome (OSAS).
Thirty-one patients with OSAS, whose apnea/hypopnea index (AHI: number of episodes of apnea or hypopnea per hour) was over 15, were enrolled in this study. Subjects were divided in two groups according to positional effects on their AHI. In six patients, a lateral posture decreased the AHI by 50% and more (responders); in the remaining 25, lateral positioning decreased the AHI by less than 50% or even increased the AHI (nonresponders). AHI and body mass index (BMI) of the responders tended to be lower and their mean age was younger than those of nonresponders, but these differences were not statistically significant. We compared the upper airway morphology between the responders and the nonresponders regarding the tonsil size, tongue position (modified Mallanpati grade, reflecting the space between the tongue and soft palate) and the width of the fauces and retroglossal space. In addition, we compared nasal resistance between the groups using active rhinomanometry.
The width of the fauces was significantly greater (P=0.041) among the responders than among the nonresponders. However, the other parameters were not consistently different between the two, and these differences were not statistically significant either.
The distance between the fauces was the sole morphological feature to distinguish the responders and the nonresponders to the positional therapy in patients with OSAS. Lateral positioning during sleep might be a recommended sleep hygiene for OSAS patients with wide fauces.
Home modification of sleep position for sleep apnea control
- R Cartwright
R. Cartwright, Home modification of sleep position for sleep apnea control, in: L Miles,
R. Broughton, (Eds.), Clinical Evaluation and Physiological Monitoring in the Home and
Work Environment, Raven Press, Palo Alto, 1990, pp. 123–129.
Editor's note, Patient's wife cures his snoring
Editor's note, Patient's wife cures his snoring, Chest 85 (1984) 582.