Transient hypoxemia during sleep in chronic obstructive pulmonary disease is not a sleep apnea syndrome.
ABSTRACT We measured ear oxygen saturation (SaO2), chest wall movement, and oronasal air flow, and took electroencephalographic tracings during nocturnal sleep in 20 healthy subjects and 20 similarly aged patients with chronic obstructive pulmonary disease (COPD), none of whom was obese. Thirteen of the patients with COPD were persistently hypoxemic and hypercapnic when awake ("blue and bloated", Type B); the remaining 7 maintained relatively normal arterial gas tensions when awake despite equally severe airways obstruction ("pink and puffing", Type A). Hypoxemic episodes (HE) (SaO2 falls of greater than 10%) occurred during sleep in all the blue bloaters but in only 3 of 7 pink puffers and 3 of 20 normal subjects. However, the maximal change in arterial oxygen tension (PaO2) (calculated from SaO2 values assuming normal pH) was similar in all 3 groups, averaging 24 mmHg. Furthermore, the cumulative duration of apnea and hypopnea was the same in each group. Only one patient COPD had more than 2 apneas per night, and obstructive apnea was seen only in the healthy subjects. Sleep apnea syndromes thus appear to be rare in nonobese patients with COPD. Of the 40 HE in patients with COPD, 29 occurred during periods of hypoventilation. In 10 blue bloaters whose arterial blood was sampled during sleep, the measured fall in PaO2 during the HE (mean, 11.2 mmHg) was greater than the rise in PaCO2 (mean, 4.2 mmHg). Although these changes in arterial gas tensions could be produced by an increase in ventilation-perfusion imbalance during the HE, it is suggested that unsteady-state gas exchange during transient hypoventilation could provide an alternative explanation.
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ABSTRACT: OBJECTIVES: The objective of the study was to find the prevalence of sleep-related disturbances in patients of Eisenmenger syndrome. DESIGN: Prospective observational study. SETTING: Tertiary care referral centre in North India. PARTICIPANTS: The study included 25 patients with Eisenmenger syndrome (mean age 25.2±9.6 years, 18 men) and 12 patients with cyanotic congenital heart disease with pulmonary stenosis physiology (mean age 20.5±8.5 years, 8 men) as controls. INTERVENTIONS: All the patients underwent an overnight comprehensive polysomnogram study and pulmonary function testing. MAIN OUTCOME MEASURE: Oxygen desaturation index, which is the number of oxygen drops per hour. RESULTS: The patients and controls had significant nocturnal hypoxaemia in the absence of apnoea and hypopnoea. The mean oxygen drop index in Eisenmenger syndrome group was 9.0±6.2 and in the control group was 8.0±5.9 (p=0.63). The apnoea-hypopnoea index was 3.37±5.0 in the Eisenmenger syndrome group and was 2.1±3.6 in the control group. Patients with >10 oxygen drops per hour had significantly higher haemoglobin (17.2±1.3% vs 14.4±1.5%, p<0.001) than those with oxygen drops less than 10. CONCLUSIONS: Eisenmenger syndrome patients have significant nocturnal hypoxaemia unrelated to hypopnoea and apnoea. Nocturnal desaturation occurred more frequently in patients with greater haemoglobin values.BMJ Open 01/2013; 3(3). · 1.58 Impact Factor
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ABSTRACT: Background: While point measurement of resting arterial partial pressure of oxygen (PaO2) is the traditional gold-standard for assessment of oxygenation in chronic obstructive pulmonary disease (COPD), 24-h oximetry may identify further patients with clinically significant hypoxaemia. We aimed to describe the relationship between these two parameters and identify other correlated variables.Methods: All patients registered with the Barwon Health Hospital Admission Risk Program from 1 March to 31 October 2008 for the diagnosis of COPD were identified. The main inclusion criteria were obstructive spirometry, clinical stability and moderate resting hypoxaemia (PaO2 56–70 mmHg). All patients underwent 24-h oximetry, arterial blood gas, spirometry, anthropometry and telephone questionnaire, and 23 patients also completed polysomnography.Results: Inclusion criteria were met in 35 of 287 patients. Mean recording time was 23.5 h, representing 97% of intended oximetry time. Nineteen patients (54%) spent greater than 30% of recorded oximetry time below 90%. There was a moderate inverse correlation between time below 90% saturations and PaO2 (r=−0.40, P= 0.02), with body mass index (BMI) the only other independent predictor of the primary outcome identified (r= 0.39, P= 0.02). Correlations were similar for waking hours considered separately. However, for sleeping oximetry, BMI and age were the only independent predictors of time below 90%. Polysomnography demonstrated a high prevalence of rapid eye movement-related hypoventilation and obstructive sleep apnoea syndrome.Conclusions: Many patients with moderate hypoxaemia on resting PaO2 desaturate significantly on ambulatory oximetry. The correlation between PaO2 and proportion of saturations below 90% is moderate and similar to BMI, but this pattern does not hold during sleeping hours.Internal Medicine Journal 03/2012; 42(4):387 - 394. · 1.82 Impact Factor
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ABSTRACT: The use of domiciliary noninvasive positive pressure ventilation (NPPV) in stable chronic obstructive pulmonary disease (COPD) with chronic hypercapnic respiratory failure has yielded variable effects on survival, quality of life, and dyspnea. We hypothesized that use of NPPV in stable COPD and partial pressure of carbon dioxide (PaCO2) <52 mmHg might result in improvement in quality of life and dyspnea. Thirty patients with stable COPD (forced expiratory volume in the first second <50% predicted and PaCO2 <52 mmHg) were prospectively randomized to receive domiciliary NPPV (bilevel positive airway pressure, 15/5 cm H2O) or usual therapy for 6 months. Measurements were made at baseline, 6 weeks, 3 months, and 6 months. Primary outcomes were quality of life as assessed by the Chronic Respiratory Disease Questionnaire (CRQ), and dyspnea as measured by the Transitional Dyspnea Index (TDI). Fifteen subjects in the NPPV arm and 12 controls completed all the study visits. At 6 weeks and 3 months, the NPPV arm showed significant improvement in TDI total score. However, this effect persisted only in the TDI-Task at 6 months (P=0.03). NPPV use was associated with a small improvement in the CRQ-Mastery domain (0.6 versus -0.1, P=0.04). The arterial partial pressure of oxygen (PaO2) in the control arm worsened over the period of the study, whereas it remained stable in the NPPV arm (change -7.2 mmHg versus +2.1 mmHg, respectively, P=0.02). NPPV resulted in a small improvement in quality of life indices in stable COPD patients with PaCO2 <52 mmHg. Future larger studies will clarify the role of NPPV in this stable subgroup of patients with COPD.International Journal of COPD 01/2013; 8:581-9.