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.     

Continuous positive airway pressure is associated with a decrease in pulmonary artery pressure in patients with obstructive sleep apnoea: A meta‐analysis

Pulmonary hypertension has been recognized as being associated with obstructive sleep apnoea (OSA). Continuous positive airway pressure (CPAP) might reduce pulmonary artery pressure in OSA patients; however, evidence from clinical studies is limited and inconsistent. This meta‐analysis aims to assess whether CPAP is associated with a decrease in pulmonary artery pressure in patients with OSA. This systematic review was performed in accordance with the Meta‐analysis of Observational Studies in Epidemiology guidelines. Published studies were identified through a search in MEDLINE, EMBASE and the Cochrane library through to May 2013. Two reviewers sorted papers and extracted data. A random‐effects model was used to combine results across studies comparing pulmonary artery pressure in OSA patients before and after CPAP treatment. Six articles with 181 patients were included in this meta‐analysis, including five before‐after studies and one matched‐control study. The meta‐analysis showed that CPAP was associated with a statistically significant reduction in pulmonary artery pressure in OSA patients (standardized mean difference ?1.34, 95% confidence interval: ?2.33 to ?0.34, P = 0.009). Although this meta‐analysis has some limitations, it indicates that CPAP is associated with a decrease in pulmonary artery pressure in patients with OSA.     

Dysfunctional breathing treated with continuous positive airway pressure in newly diagnosed obstructive sleep apnoea: a prospective cohort study

A prospective cohort study investigating patients with obstructive sleep apnoea (OSA) was conducted to determine the prevalence of dysfunctional breathing and if continuous positive airway pressure (CPAP) therapy improves associated symptoms. Almost half of newly diagnosed patients with OSA had dysfunctional breathing and CPAP was not an effective treatment. Dysfunctional breathing is common in patients with OSA.     

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.     

Rapid eye movement and slow-wave sleep rebound after one night of continuous positive airway pressure for obstructive sleep apnoea

Background and objective: Rebound of slow‐wave sleep (SWS) and rapid eye movement (REM) sleep is observed in patients who are on continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA); but, neither have been objectively defined. The pressure titration study often represents the first recovery sleep period for patients with OSA. Our aim was to objectively define and identify predictors of SWS and REM sleep rebound following CPAP titration. Methods: Paired diagnostic polysomnography and pressure titration studies from 335 patients were reviewed. Results: The mean apnoea‐hypopnoea index was 40.7 ± 26.1, and minimum oxygen saturation was 76 ± 14.4%. Comparing eight incremental thresholds, a rebound of 20% in REM sleep and a 40% increase in SWS allowed the best separation of prediction models. A 20% rebound in REM sleep was predicted by REM sleep %, non‐REM arousal index (ArI) and total sleep time during diagnostic polysomnography, and male gender (R² = 35.3%). A 40% rebound in SWS was predicted by SWS %, total ArI and REM sleep % during diagnostic polysomnography, and body mass index (R² = 45.4%). Conclusions: A 40% rebound in SWS, but only a 20% rebound in REM sleep on the pressure titration study, is predicted by abnormal sleep architecture and sleep fragmentation prior to the commencement of treatment.     

Auto-titrating continuous positive airway pressure therapy in patients with chronic heart failure and obstructive sleep apnoea: a randomized placebo-controlled trial.

AIMS: Obstructive sleep apnoea (OSA) is highly prevalent in patients with chronic heart failure (CHF) and may contribute to CHF progression. We aimed to determine whether treatment of OSA with continuous positive airway pressure (CPAP) would improve subjective and objective measures of heart failure severity in patients with CHF and OSA. METHODS AND RESULTS: Twenty-six patients with stable symptomatic CHF and OSA were randomized to nocturnal auto-titrating CPAP or sham CPAP for 6 weeks each in crossover design. Study co-primary endpoints were changes in peak VO(2) and 6 min walk distance. Secondary endpoints were changes in left ventricular ejection fraction, VE/VCO(2) slope, plasma neurohormonal markers, and quality-of-life measures. Twenty-three patients completed the study protocol. Mean CPAP and sham CPAP usage were 3.5 +/- 2.5 and 3.3 +/- 2.2 h/night, respectively (P = 0.31). CPAP treatment was associated with improvements in daytime sleepiness (Epworth Sleepiness Score 7 +/- 4 vs. 8 +/- 5, P = 0.04) but not in other quality-of-life measures. There were no changes in other study endpoints. CONCLUSION: In patients with CHF and OSA, auto-titrating CPAP improves daytime sleepiness but not other subjective or objective measures of CHF severity. These data suggest that the potential therapeutic benefits of CPAP in CHF are achieved by alleviation of OSA rather than by improvement in cardiac function.     

Ethnicity and socioeconomic status predict initial continuous positive airway pressure compliance in New Zealand adults with obstructive sleep apnoea

Background: Understanding factors that contribute to low continuous positive airway pressure (CPAP) compliance will lead to improvements in the long‐term outcome of patients with obstructive sleep apnoea (OSA) syndrome. Both cultural and socioeconomic factors are likely to be important but have not been systematically studied. Aim: To examine the effect of ethnicity and socioeconomic status on initial CPAP usage for people with OSA in New Zealand. Methods: We retrospectively collected demographic, clinical and CPAP treatment‐related data on patients undergoing a 1‐month CPAP trial for a 10‐month period. We compared objectively measured CPAP usage (by anova ) with self‐identified ethnicity; levels of socioeconomic deprivation (NZDep06 index), Epworth Sleepiness Scale (ESS) and Apnoea‐Hypopnoea Index (AHI). Results: A total of 214 patients with a mean age of 52.7 (±11.8) years, mean AHI 57.3 (±35.8) events per hour and mean ESS 13 (±5.58)/24 made up the cohort. CPAP usage which averaged 5.13 ± 2.34 h per night was significantly lower in patients of non‐European ethnicity (P = 0.019 univariate) and remained significant after socioeconomic status was added to the model (P = 0.048). Patients living in the most socioeconomically deprived areas showed significantly lower compliance with CPAP on univariate analysis (P = 0.024, NZDep06 scores 1&2, average 5.3 per night compared to score NZDep06 scores 9&10, average 4.3 h per night), but this effect was no longer significant once ethnicity was added to the model (P = 0.28). Conclusion: CPAP usage in New Zealand is affected by both ethnicity and level of socioeconomic deprivation. We recommend further research to unravel specific cultural and socioeconomic reasons for the variance reported.     

Treatment of obstructive sleep apnoea in Samoa progressively reduces daytime blood pressure over 6 months

Background and objective:   While recent meta-analyses suggest that OSA elevates daytime blood pressure (BP), most studies have included patients with mild hypertension, so CPAP treatment has only reduced BP by 2–3 mm Hg. To determine the strength of the OSA–BP relationship, this study examined the effect of CPAP in a cohort where severe OSA and under-treated hypertension coexist.
Methods:   Baseline demographic and sleep study data were recorded in 221 consecutive patients referred for sleep studies in Samoa. OSA was treated with CPAP and BP recorded for 6–7 months in 180 patients. A subgroup of 64 patients, representative of the entire group, but with regular follow-up, is also described.
Results:   OSA was diagnosed in 218/221 patients; of those who commenced CPAP, 180 returned for follow-up at least once within 7 months. Following CPAP, BP decreased by 7.1/5.9 mm Hg at 1 month and 12.9/10.5 mm Hg at 6 months ( n  = 180, P  < 0.0001). In the 64 patients with regular follow-up, those with the highest baseline BP had the greatest fall in BP with CPAP; BP in the hypertensive subgroup (32/64) decreased 21.5/13.1 mm Hg at 6 months ( P  < 0.0001).
Conclusions:   Hypertensive OSA patients can exhibit large falls in BP with CPAP at 1 month, with further significant reductions at 3 and 6 months. Overall, the fall in BP was proportional to the initial elevation of the BP with many patients achieving normal BP at 6 months.     

Pulmonary hypertension in obstructive sleep apnoea: effects of continuous positive airway pressure: a randomized, controlled cross-over study.

AIMS: We tested the hypothesis that: (i) obstructive sleep apnoea (OSA) by itself originates pulmonary hypertension (PH); and (ii) the application of continuous positive airway pressure (CPAP) can reduce pulmonary pressure. METHODS AND RESULTS: In this randomized and cross-over trial, 23 middle-aged OSA (apnoea-hypopnoea index, 44.1 +/- 29.3 h(-1)) and otherwise healthy patients and 10 control subjects were included. OSA patients randomly received either sham or effective CPAP for 12 weeks. Echocardiographic parameters, blood pressure recordings, and urinary catecholamine levels were obtained at baseline and after both treatment modalities. At baseline, OSA patients had higher pulmonary artery systolic pressure than control subjects (29.8 +/- 8.8 vs. 23.4 +/- 4.1 mmHg, respectively, P = 0.036). Ten out of 23 patients [43%, (95% CI: 23-64%)] and none of the control subjects had PH at baseline (P = 0.012). Two patients were removed from the study because of inadequate CPAP compliance. Effective CPAP induced a significant reduction in the values for pulmonary systolic pressure (from 28.9 +/- 8.6 to 24.0 +/- 5.8 mmHg, P < 0.0001). The reduction was greatest in patients with either PH or left ventricular diastolic dysfunction at baseline. CONCLUSION: Severe OSA is independently associated with PH in direct relationship with disease severity and presence of diastolic dysfunction. Application of CPAP reduces pulmonary systolic pressure levels.     

Obstructive sleep apnoea and cardiovascular disease

Obstructive sleep apnoea (OSA) leads to both acute and chronic physiological effects on the cardiovascular system. There is now a large amount of evidence showing that OSA is independently associated with a wide spectrum of clinical cardiovascular disease (CVD). Evidence for a causative effect of OSA is strongest for hypertension, but is weaker for other cardiovascular disorders. Large prospective trials are ongoing and when results become available the link between OSA and CVD is likely to be strengthened. Treatment of OSA with continuous positive airway pressure has been shown to improve blood pressure, particularly in those with hypertension, and also left ventricular ejection fraction in those with congestive heart failure. Given the high prevalence of OSA in the community and its effects on the cardiovascular system, symptoms of this disorder should be sought in patients being investigated or treated for CVD.     

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.     

Airline policies for passengers with obstructive sleep apnoea who require in‐flight continuous positive airways pressure

Background and objective: The aim of this study was to investigate the current policies of Australian and New Zealand airlines on the use of in‐flight CPAP by passengers with OSA. Methods: A survey was conducted of 53 commercial airlines servicing international routes. Information was obtained from airline call centres and websites. The policies, approval schemes and costs associated with in‐flight use of CPAP were documented for individual airlines. Results: Of the 53 airlines contacted, 28 (53%) were able to support passengers requiring in‐flight CPAP. All these airlines required passengers to bring their own machines, and allowed the use of battery‐operated machines. Six airlines (21%) allowed passengers to plug their machines into the aircraft power supply. The majority of airlines (19, 68%) did not charge passengers for the use of CPAP, while 9 (32%) were unsure of their charging policies. Many airlines only permitted certain models of CPAP machine or battery types. Conclusions: Many airlines are unaware of CPAP. Those who are, have relatively consistent policies concerning the use of in‐flight CPAP.     

Routine use of humidification with nasal continuous positive airway pressure

Background: Heated humidification can reduce nasal symptoms caused by continuous positive airway pressure (CPAP) treatment, but its routine use has not been studied over the medium term in a randomized controlled trial. The aim of this study is to determine if heated humidification would reduce nasal symptoms and improve adherence with CPAP treatment in all patients with sleep apnoea irrespective of whether they had nasal symptoms initially. Methods: A randomized, parallel group design. Patients were treated for 3 months with a Fisher & Paykel HC201 pump with built‐in heated humidification, or with the heater disabled and without water. Adherence was measured with a timer built into the pumps. Nasal symptoms were measured with a 10‐cm visual analogue scale. Results: There were 25 in the humidification group and 29 in the non‐humidification group. After 12 weeks mean (standard deviation) adherence with CPAP was 4.7 (2.4) and 4.5 (2.2) hours per night respectively. Nasal symptoms that were reduced were nose blocked* 6 (12), 18 (26); sneezing* 4 (8), 15 (25); dry nose* 8 (12), 24 (33); stuffy nose* 7 (14), 22(31); dry mouth* 13 (18), 33(36); and runny nose* 6 (17), 14 (29). Parameters marked with an asterisk ‘*’ had P < 0.05 with t‐tests. Conclusion: The routine use of heated humidification with CPAP in all patients with sleep apnoea reduced nasal symptoms, but did not improve adherence.