Clinical side effects of continuous positive airway pressure in patients with obstructive sleep apnoea

CPAP is considered the gold standard treatment in OSA and is highly efficacious in controlling OSA symptoms. However, treatment effectiveness is limited because of many factors including low adherence due to side effects. This review highlights the range of side effects associated with CPAP therapy in patients with OSA. This information is important for the initiation of patients onto CPAP as well as their continued care while on treatment, given the increase in non‐medically supervised CPAP care models in use globally.     

Predicting optimal continuous positive airway pressure in Japanese patients with obstructive sleep apnoea syndrome

Background and objective: Several algorithms that predict the optimal CPAP have been developed for Caucasian patients with OSA syndrome, but these algorithms do not allow for racial differences in craniofacial anatomy. We investigated whether an equation that included data on craniofacial structure, physique and severity of OSA could more accurately predict the optimal CPAP for Japanese patients with OSA syndrome. Methods: In 170 Japanese patients with OSA syndrome, the optimal CPAP was determined by manual titration during polysomnography. An equation predicting the optimal pressure was derived from anthropometric, polysomnographic and cephalometric data. This equation was validated in another 110 Japanese patients with OSA syndrome. Results: Stepwise multiple regression analysis identified AHI, BMI, mean SaO₂ and a cephalometric parameter: the angle between a line from point B to the menton (Me) and a line from Me to the hyoid bone (H) (BMeH), as independent predictors of optimal CPAP. The following equation was constructed to predict the optimal CPAP: 27.78 + (0.041 × BMeH) + (0.141 × BMI) + (0.040 × AHI) ? (0.312 × mean SaO₂). This equation accounted for 47% of the variance in optimal pressure (R² = 0.47, P < 0.0001). The measured optimal pressure and the pressure calculated using this equation were very similar in the other 110 patients with OSA syndrome (9.5 ± 3.0 and 9.2 ± 2.1 cmH₂O, respectively). Conclusion: Optimal CPAP was more accurately predicted by combining a cephalometric parameter with BMI and polysomnographic data in Japanese patients with OSA, suggesting that craniofacial structure may be important in the pathogenesis of OSA syndrome among Asians.     

Effect of continuous positive airway pressure on ambulatory blood pressure in patients with obstructive sleep apnoea

OBJECTIVES: Previous reports on the effects of continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA) on blood pressure has shown contradictory results. Accordingly, we have investigated the effects of CPAP on blood pressure and on the potential reversal of the diagnosis of hypertension in patients with OSA evaluated repeatedly by ambulatory blood pressure monitoring. METHODS: We studied 122 patients (104 men and 18 women), 55.1+/-10.5 years of age, with diagnosis of OSA corroborated by overnight polysomnography at the clinic. Among those patients, 83 were treated with CPAP after their first evaluation, while 39 remained without CPAP for the duration of the trial. Blood pressure was measured by ambulatory monitoring at 20-min intervals during the day and at 30-min intervals at night for 48 consecutive hours, at baseline and after 2 and 4 months of intervention. RESULTS: There was a small, but not statistically significant, reduction in ambulatory blood pressure in patients treated with CPAP (0.7 and 1.5 mmHg in 24-h mean of systolic and diastolic blood pressure after 2 months of therapy; 2.0 and 2.3 mmHg after 4 months; P>0.239). The blood pressure reduction was very similar in patients with OSA followed for 4 months without CPAP (1.9 and 2.2 mmHg in 24-h mean of systolic and diastolic blood pressure, respectively; P=0.543). We found a high (77%) prevalence of hypertension among the patients participating in this study, although only 37% were receiving antihypertensive medication at the time of recruitment. The prevalence of hypertension was slightly but not significantly reduced to just 74% after 4 months of treatment with CPAP. CONCLUSIONS: The small reduction in blood pressure for consecutive profiles of ambulatory monitoring can probably be explained by the documented 'ABPM pressor effect' on patients using the ambulatory device for the first time. The high prevalence of hypertension among patients with OSA is not significantly reduced by treatment with CPAP. These results suggest that patients with OSA should always be properly evaluated for diagnosis of hypertension, and provided, if needed, with antihypertensive treatment apart from the recommended CPAP.     

Humidified nasal continuous positive airway pressure in obstructive sleep apnoea.

Heated humidification of nasal continuous positive airway pressure (nCPAP) reduces upper airway symptoms and improves initial use in obstructive sleep apnoea syndrome (OSAS). The present study aimed to assess the effect of heated humidification of nCPAP on upper airway symptoms and initial use in obstructive sleep apnoea. This study was of a randomised, crossover design. Subjects with polysomnographically confirmed OSAS were randomised to 3 weeks nCPAP treatment with heated humidification (nCPAP-humid) or placebo humidification (nCPAP pl-humid). Objective and subjective nCPAP use, upper airway symptoms, and treatment satisfaction were compared. Thirty seven of 42 patients completed the protocol. nCPAP-humid reduced the frequency of adverse upper airway symptoms. nCPAP use over 3 weeks was greater with nCPAP-humid compared with nCPAP pl-humid. No difference was found between the treatment arms in terms of subjective treatment satisfaction or alertness. Heated humidification of nasal continuous positive airway pressure reduces upper airway symptoms and is associated with a small increase in initial use but not subjective sleepiness or treatment satisfaction. The results support the use of heated humidification as a strategy to reduce side-effects related to continuous positive airway pressure but not routine initial use.     

Endocrine effects of nasal continuous positive airway pressure in male patients with obstructive sleep apnoea

OBJECTIVE: Obstructive sleep apnoea (OSA) is a relatively common condition producing disabling somnolence and profound physiological responses to hypoxaemic episodes during sleep, including significant oscillations in blood pressure. This study aimed to provide controlled data on the interaction between OSA and endocrine axes to establish whether overrepresentation of pathology such as hypertension and hypogonadism in OSA subjects might have an endocrine basis. DESIGN, SETTING AND SUBJECTS: Parallel randomized sham placebo controlled 1-month trial of nasal continuous positive airway pressure (nCPAP) in 101 male subjects with OSA presenting to a respiratory sleep clinic. METHODS: Analysis of gonadotrophins, testosterone, sex hormone binding protein (SHBG), prolactin, cortisol, thyroid stimulating hormone (TSH), free thyroxine (free T4), insulin-like growth factor-1 (IGF-1), renin and aldosterone were performed at baseline and after 1 month's active or placebo nCPAP intervention. Quality of life questionnaire scoring was also recorded over the same time period. RESULTS: Testosterone and SHBG showed significant negative correlations with baseline OSA severity. Active treatment of OSA produced SHBG elevation and TSH reduction (P< or =0.03). Both groups showed an increase in aldosterone (P<0.001) and IGF-1 (P< or =0.03), associated with a large improvement in subjective quality of life scoring. CONCLUSIONS: These findings demonstrate significant changes in endocrine axes not previously reported in a placebo-controlled trial. OSA is a recognized reversible cause of testosterone reduction; SHBG suppression correlating to baseline OSA severity supports a diagnosis of secondary hypogonadism. Significant rises in aldosterone and IGF-1 on treatment coincide with increased physical activity and an improved quality of life score.     

Decrease in haematocrit with continuous positive airway pressure treatment in obstructive sleep apnoea patients.

Previous preliminary results have shown an overnight decrease in haematocrit and red cell count after the first night of treatment with nasal continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA) patients. The present study was designed to confirm these preliminary data, and to analyse the long-term effects of CPAP. The haematocrit and red cell count (RCC) were measured in 80 OSA patients on two consecutive mornings, after an untreated night and after a CPAP treatment night. The haematocrit and RCC significantly decreased with CPAP (from 44.0 +/- 0.5 to 42.4 +/- 0.4%, p less than 0.0001 and from 4.769 +/- 0.051 to 4.597 +/- 0.052 x 10(12) red cells.l-1, p less than 0.0001, respectively). Neither the decrease in haematocrit nor the decrease in RCC were correlated with the decrease in urine volume or flow which occurred with CPAP. Thirty five of these patients remained untreated for 45 +/- 4 days, before home treatment with CPAP was initiated. The haematocrit and RCC had returned to values close to those before initial treatment and decreased again after the first treatment night. Twenty one of the patients were re-evaluated after at least one year of home treatment with CPAP, again on two consecutive nights either with CPAP or untreated. The follow-up, post-CPAP haematocrit and RCC were slightly and nonsignificantly higher than after the baseline CPAP night, but still lower than after the baseline untreated night (p less than 0.02). After the untreated follow-up night, no significant change in haematocrit was observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Treatment of obstructive sleep apnoea with nasal continuous positive airway pressure in stroke.

The prevalence of obstructive sleep apnoea (OSA) following stroke is high and OSA is associated with increased morbidity, mortality and poor functional outcome. Nasal continuous positive airway pressure (nCPAP) is the treatment of choice for OSA, but its effects in stroke patients are unknown. The effectiveness and acceptance of treatment with nCPAP in 105 stroke patients with OSA, admitted to rehabilitation was prospectively investigated. Subjective wellbeing was measured with a visual analogue scale in 41 patients and 24-h blood pressure was determined in 16 patients before and after 10 days of treatment. Differences were compared between patients who did and did not accept treatment. There was an 80% reduction of respiratory events with concomitant increase in oxygen saturation and improvement in sleep architecture. No serious side-effects were noticed. Seventy-four patients (70.5%) continued treatment at home. Nonacceptance was associated with a lower functional status, as measured by the Barthel Index, and the presence of aphasia. Ten days after initiation of nCPAP, compliant users showed a clear improvement in wellbeing (differences in visual analogue scale (deltaVAS) mean+/-SD 26+/-26 mm) versus noncompliant patients (deltaVAS 2+/-25 mm, p=0.021). Only the compliant group had a reduction in mean nocturnal blood pressure (deltaBP; -8+/-7.3 mmHg versus 0.8+/-8.4 mmHg, p=0.037). Stroke patients with obstructive sleep apnoea can be treated effectively with nasal continuous positive airway pressure and show a similar improvement and primary acceptance to obstructive sleep apnoea patients without stroke. Continuous positive airway pressure acceptance is associated with improved wellbeing and decreased nocturnal blood pressure.     

Continuous positive airway pressure in heart failure patients with obstructive sleep apnoea

Background: The aim of the study was to study the effect of 6 months of continuous positive airway pressure (CPAP) in community heart failure (HF) patients with obstructive sleep apnoea (OSA). Methods: Clinically stable outpatients with HF and OSA (left ventricular ejection fraction (LVEF) <45%, apnoea/hypopnoea index >15/h, n = 19) treated with CPAP and a control group (LVEF <45%, apnoea/hypopnoea index <10/h, n = 7) were compared at baseline and at 6 months by Minnesota heart failure score, Epworth sleepiness score, shuttle walk distance, brain natriuretic peptide, urinary catecholamines and echocardiographic indices using paired t‐test, McNemar’s tests and effect sizes. Results: In HF patients with OSA, CPAP improved LVEF (35.9 ± 6.1% to 40.6 ± 8.0%, P = 0.015), decreased LV end‐systolic volume (152 ± 74 to 135 ± 62 cm³, P = 0.03), systolic blood pressure (P = 0.04) and sleepiness (Epworth sleepiness score 8.8 ± 4.8 to 6.3 ± 3.2, P = 0.01), whereas walk distance, catecholamines, brain natriuretic peptide levels and symptoms were unchanged. These outcomes did not change in the HF control group. Conclusion: In community HF patients with OSA, CPAP therapy over 6 months improved LVEF, systolic blood pressure and sleepiness, but not sympathetic activation, brain natriuretic peptide or exercise levels. Acceptance was relatively low, potentially limiting therapeutic effectiveness.     

Association between continuous positive airway pressure and circulating omentin levels in patients with obstructive sleep apnoea

Purpose

Inflammation and oxidative stress play important roles in the pathogenesis of obstructive sleep apnoea syndrome (OSAS). Omentin is expressed in visceral adipose tissue and is associated with the inflammatory response. The aim of this study was to assess the relationship between OSAS and omentin based on a comparison of its serum levels at baseline and after 3 months of continuous positive airway pressure (CPAP) therapy.

Methods

Ninety-six newly diagnosed OSAS patients and 31 non-apnoeic controls were enrolled in this study. Blood samples were obtained in the morning after polysomnography. Within the OSAS group, 30 patients were started on CPAP therapy and then reassessed clinically, including a blood test for serum omentin and other biochemical analysis, at 3 months.

Results

Serum omentin levels were significantly lower in the OSAS group than in the control group (27.7?±?7.6 and 42.5?±?5.2 ng/mL, P?<?0.001). In the subgroup analysis, omentin concentrations were significantly lower in patients with severe OSAS than in those with mild/moderate OSAS (P?<?0.001). Circulating omentin levels were significantly correlated with the apnoea–hypopnoea index (AHI), mean SaO₂, oxygen desaturation index, and serum C-reactive protein levels. Treatment with CPAP resulted in a significant increase in circulating omentin levels after 3 months, from 22.7?±?1.4 to 41.2?±?3.3 ng/mL (P?<?0.001).

Conclusions

OSAS is associated with low serum omentin levels, and these levels can be reversed by effective CPAP treatment.

     

Nasal continuous positive airway pressure: influence on digital volume pulse in obstructive sleep apnoea patients

Obstructive sleep apnoea (OSA) is linked to increased cardiovascular risk. This risk can be reduced by nasal continuous positive airway pressure (nCPAP) treatment. As OSA is associated with an increase of several vasoconstrictive factors, we investigated whether nCPAP influences the digital volume pulse wave. We performed digital photoplethysmography during sleep at night in 94 consecutive patients who underwent polysomnography and 29 patients treated with nCPAP. Digital volume pulse waves were obtained independently of an investigator and were quantified using an algorithm for continuous automated analysis. In patients with OSA and an apnoea/hypopnoea index (AHI) of >10 events · h(-1), a significant vasoconstriction was observed during the night (p<0.0001 by Friedman's test). A significant positive correlation existed between vasoconstriction and AHI (Spearman correlation, r = 0.27; p<0.01; n = 94) and the arousal index (Spearman correlation, r = 0.21; p < 0.05; n = 94). After 6 months of nCPAP treatment, the AHI was significantly reduced from 27 ± 3 events · h(-1) to 4 ± 2 events · h(-1) (each n = 29; p<0.001) and vasoconstriction during the night was significantly reduced from 10 ± 3% to 3 ± 1% (p<0.01). We show changes in the reflective index during the night consistent with vasoconstriction in patients with OSA, which are significantly reduced after 6 months of nCPAP treatment.     

Falls in blood pressure in patients with obstructive sleep apnoea after long-term nasal continuous positive airway pressure treatment

OBJECTIVES: Effective treatment of obstructive sleep apnoea (OSA) with nasal continuous positive airway pressure (nCPAP) lowers blood pressure (BP). The long-term effects of nCPAP treatment on BP in OSA patients are not well known. The time period of such treatment sufficient to lower BP in OSA patients is also not known. We investigated compliance with long-term nCPAP therapy and its effects on BP. METHODS: This observational study involved 66 OSA patients [59 men, seven women; mean age, 51 (48-54) years; body mass index (BMI), 28.7 (27.7-29.7) kg/m; apnoea and hypopnoea, 50.3 (45.6-55.0)/h; 95% confidence intervals]. BP and BMI were measured before the study and at two checkpoints after usage of nCPAP [620 (552-688) and 1071 (1000-1143) days]. RESULTS: The different times between the first and second checkpoints for detecting objective compliance were 17 (4-30) min (P = 0.003). Diastolic BP decreased by 5.9 (3.1-8.7) mmHg after 600 days nCPAP treatment and by 4.6 (2.0-7.2) mmHg after 1000 days (P = 0.0006). Systolic BP and BMI did not change significantly. Usage of nCPAP treatment for a daily average of 3 h was needed to achieve a significant decrease in diastolic BP [7.4 (4.3-10.6) mmHg, P < 0.0001]. Diastolic BP of normotensive OSA patients did not change significantly by nCPAP treatment, but that of hypertensive OSA patients decreased significantly within 1 month-3 years of nCPAP treatment whether or not medication was used. CONCLUSIONS: In patients with severe OSA, the use of nCPAP for a daily average of 3 h would be sufficient to decrease the diastolic BP of hypertensive OSA patients.     

Reverse atrial electrical remodelling induced by continuous positive airway pressure in patients with severe obstructive sleep apnoea

Background

Obstructive sleep apnoea (OSA) is associated with cardiovascular morbidity and mortality, including atrial arrhythmias. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA; its impact on atrial electrical remodelling has not been fully investigated. Signal-averaged p-wave (SAPW) duration is an accepted marker for atrial electrical remodelling.

Objective

The objective of this study is to determine whether CPAP induces reverse atrial electrical remodelling in patients with severe OSA.

Methods

Consecutive patients attending the Sleep Disorder Clinic at Kingston General Hospital underwent full polysomnography. OSA-negative controls and severe OSA were defined as apnoea–hypopnea index (AHI)?<?5 events/hour and AHI?≥?30 events/hour, respectively. SAPW duration was determined at baseline and after 4–6 weeks of CPAP in severe OSA patients or without intervention controls.

Results

Nineteen severe OSA patients and 10 controls were included in the analysis. Mean AHI and minimum oxygen saturation were 41.4?±?10.1 events/hour and 80.5?±?6.5 % in severe OSA patients and 2.8?±?1.2 events/hour and 91.4?±?2.1 % in controls. At baseline, severe OSA patients had a greater SAPW duration than controls (131.9?±?10.4 vs 122.8?±?10.5 ms; p?=?0.02). After CPAP, there was a significant reduction of SAPW duration in severe OSA patients (131.9?±?10.4 to 126.2?±?8.8 ms; p?<?0.001), while SAPW duration did not change after 4–6 weeks in controls.

Conclusion

CPAP induced reverse atrial electrical remodelling in patients with severe OSA as represented by a significant reduction in SAPW duration.     

Efficacy of daytime continuous positive airway pressure titration in severe obstructive sleep apnoea.

The aim of this study was to evaluate manual nasal continuous positive airway pressure (nCPAP) titration during daytime polysomnography compared with conventional overnight titration for patients with severe obstructive sleep apnoea. Thirty-two patients who underwent daytime titration were retrospectively matched (for age, sex, body mass index and apnoea/hypopnoea index (AHI)) to a group titrated overnight during the same period. Successful titration was defined as the identification of the nCPAP level (effective nCPAP (Peff)) required to eliminate respiratory events during all sleep stages. After 3 months of therapy on nCPAP at Peff, nCPAP utilization history was obtained and a group of patients underwent a repeat polysomnogram (PSG) and completed a follow-up Epworth Sleepiness Scale (ESS) score. Initial titration was successful in 91% of daytime patients and 91% of overnight patients. The success of daytime titration was not related to diagnostic AHI or ESS score. Subjective nCPAP utilization was statistically similar in both groups. On the follow-up PSG, there were no significant differences between daytime (n=11) and overnight (n=11) patients in measures of sleep quality or respiratory disturbance. Both groups demonstrated similar and significant improvements in ESS score. These findings suggest that the effective nasal continuous positive airway pressure can be accurately established during daytime titration in a substantial proportion of severe, symptomatic obstructive sleep apnoea patients.     

A randomized cross-over study of auto-continuous positive airway pressure versus fixed-continuous positive airway pressure in patients with obstructive sleep apnoea

Background and objectives:   To compare the efficacy of auto-CPAP (AutoSet Spirit, ResMed) versus fixed-CPAP (S6 Elite, ResMed) in improving daytime sleepiness, health status, objective compliance and the ultimate treatment preference in patients with severe OSA.
Methods:   The study recruited 43 subjects aged 18–65 years with newly diagnosed severe OSA (AHI >30/h). Patients were initially treated with either auto-CPAP or fixed-CPAP for 2 months and then crossed over after a washout period of 1 week for another 2 months.
Results:   The study was completed by 41 patients. Results are presented as mean (SE). Use of auto-CPAP in the first and the second month was significantly higher than that of fixed-CPAP [129.7 (9.9) and 130.5 (10.7) h vs 115.2 (9.5) and 113.2 (9.4) h, P  = 0.04 and 0.01], whereas mean hourly use per night was 4.3 and 4.4 h versus 3.8 and 3.7 h, respectively. The Epworth sleepiness scores improved after 1 month in both treatments (13.4 to 8.5 and 8.2, P  < 0.01 for both). The Sleep apnoea quality of life index improved in the first month in both compared with baseline [4.6 (0.2) to 5.0 (0.2) for auto-CPAP and 4.9 (0.2) for fixed-CPAP, P  = 0.01 and 0.04, respectively], with no difference between the two treatments. Nine and 30 patients preferred auto-CPAP and fixed-CPAP, respectively, at the end of the trial, whereas 14 and 25 patients would have chosen the same treatments if cost had not been a consideration.
Conclusions:   Auto-CPAP and fixed-CPAP were equally effective in improving symptoms and health status in patients with severe OSA. Usage was higher with auto-CPAP, but more patients ultimately chose fixed-CPAP.     

Association between continuous positive airway pressure and changes in serum leptin in patients with obstructive sleep apnoea: a meta-analysis

Purpose

The role of leptin in the development of obstructive sleep apnoea (OSA) has been identified. However, the effects of OSA treatment using continuous positive airway pressure (CPAP) on serum leptin levels remain controversial. To address this issue, a meta-analysis was conducted to evaluate the effects of CPAP therapy on serum leptin levels in OSA.

Methods

A comprehensive literature search was performed to identify studies that focused on the effects of CPAP therapy (treatment duration, ≥4 weeks) on the serum leptin levels of OSA patients. Standardised mean difference (SMD) was used to analyse the summary estimates for CPAP therapy.

Results

Fifteen studies involving 427 patients were included in the meta-analysis. Results indicate that the overall SMD of the leptin levels before and after CPAP therapy was 0.137 (95 % confidence interval (CI) 0.002 to 0.272); test for overall effect z?=?1.99 (P?=?0.046). Sources of heterogeneity were not found by subgroup and meta-regression analyses. Subgroup analyses showed that differences in OSA severity, baseline body mass index, compliance, CPAP duration and leptin assay did not affect the effectiveness of CPAP therapy.

Conclusions

The evidence for the use of CPAP therapy on decrease of leptin levels in OSA patients is low, and stronger evidence is needed.     

Effects of nasal continuous positive airway pressure on pulmonary haemodynamics and tissue oxygenation in patients with obstructive sleep apnoea

We investigated the acute effects of nasal continuous positive airway pressure (CPAP) on pulmonary haemodynamics and tissue oxygenation in eight men with obstructive sleep apnoea (OSA) by means of right heart catheterization. They were tested at four dosage levels of nasal CPAP: 0, 5, 10, and 15 cmH2O. Nasal CPAP significantly reduced the cardiac index at the 10 and 15 cmH2O doses. The mean pulmonary artery pressure was significantly elevated with 10 and 15 cmH2O, and pulmonary capillary wedge pressure was significantly increased with 15 cmH2O of nasal CPAP. Pulmonary vascular resistance was significantly increased with 10 cmH2O of nasal CPAP. The 5 cmH2O dose of nasal CPAP did not affect significantly these parameters. Mixed venous oxygen tension was unchanged at any pressure. We conclude that tissue oxygenation was maintained in the OSA patients during administration of nasal CPAP, even though a high CPAP clearly affected pulmonary haemodynamics.     

Long-term treatment with continuous positive airway pressure improves quality of life in obstructive sleep apnoea syndrome.

Continuous positive airway pressure (CPAP) is an established treatment of obstructive sleep apnoea syndrome (OSAS). While it is known that CPAP reverses the pathological breathing pattern and improves daytime sleepiness, there are no sufficient data on the long-term influence of CPAP on quality of life in patients with OSAS. Thirty-nine patients with polysomnographically verified OSAS (apnoea/hypopnoea index (AHI): (mean+/-SD) 46.8+/-21.8 events x h(-1)) were prospectively studied. All patients answered three quality of life measures (Complaint List, Nottingham Health Profile Part 1 (NHP), and Verbal Analogue-Scale "quality of life") prior to the initiation of CPAP therapy. After a mean of 9 months they were re-evaluated by polysomnography, and completed the questionnaires once again. As expected, CPAP was effective in treating the sleep-related breathing disorder. AHI decreased significantly from (mean+/-SD) 46.8+/-21.8 events x h(-1) to 3.3+/-6.3 events x h(-1), and minimum oxygen saturation increased from 77.1+/-9.3% to 89.9+/-3.4%, while body mass index did not change significantly (31.3+/-5.4 versus 30.8+/-4.8 kg x m(-2)). During long-term treatment with CPAP the Complaint List revealed a significant improvement of the extent of subjective impairment due to physical and general complaints (26.4+/-9.9 versus 20.4+/-11.1), and NHP a significant improvement of emotional reactions (19.8+/-21.7 versus 11.1+/-14.0) and energy (50.8+/-36.6 versus 32.1+/-36.7), but not of pain, physical mobility, sleep, social isolation, and quality of life as assessed by the It is concluded that long-term continuous positive airway pressure therapy is effective in improving not only pathological breathing patterns but also parameters that estimate quality of life in patients with obstructive sleep apnoea syndrome.     

Effect of continuous positive airway pressure vs placebo continuous positive airway pressure on sleep quality in obstructive sleep apnea

STUDY OBJECTIVES: Continuous positive airway pressure (CPAP) therapy has become the treatment of choice for obstructive sleep apnea (OSA). However, the efficacy of CPAP therapy has not been evaluated against a suitable control. We investigated the effectiveness of CPAP therapy in improving sleep quality in patients with OSA. We hypothesized that CPAP improves sleep quality. PATIENTS: Forty-eight CPAP-naive OSA patients were evaluated. None were receiving antihypertensive medications, and none had major medical illnesses. DESIGN: Patients were randomized to receive either CPAP or placebo CPAP (CPAP at an ineffective pressure) for 7 days in a double-blind fashion. Forty-one patients completed the protocol. Sleep quality variables, arousals, sleep arterial oxygen saturation (SaO(2)), and respiratory disturbance index (RDI) were assessed at baseline, after 1 day of treatment, and after 7 days of treatment. Repeated measures analysis of variance was used to evaluate the effects of treatment, time, and the interaction of the two. RESULTS: As expected, CPAP lowered RDI and number of arousals, and increased SaO(2) over time (p = 0.001). Contrary to expectations, both CPAP and placebo CPAP had comparable effects on sleep quality as assessed by sleep architecture, sleep efficiency, total sleep time, and wake after sleep onset time. CONCLUSIONS: This study confirms the effectiveness of CPAP in lowering the number of arousals and the RDI, and in raising SaO(2). However, our data suggest that short-term CPAP is no different than placebo in improving sleep architecture. Further evaluation of the effectiveness of CPAP using a suitable placebo CPAP in prospective randomized studies is needed