Nocturnal hypoxemic burden during positive airway pressure treatment across different central sleep apnea etiologies.

INTRODUCTION: Nocturnal hypoxemia is associated with increased cardiovascular mortality. Here, we assess whether positive airway pressure by adaptive servo-ventilation (ASV) reduces nocturnal hypoxemic burden in patients with primary central sleep apnea (primary CSA), or heart failure related central sleep apnea (CSA-HF) and treatment emergent central sleep apnea (TECSA). METHODS: Overnight oximetry data from 328 consecutive patients who underwent ASV initiation between March 2010 and May 2018 were retrospectively analyzed. Patients were stratified into three groups: primary CSA (n = 14), CSA-HF (n = 31), TECSA (n = 129). Apnea hypopnea index (AHI) and time spent below 90% SpO2 (T90) was measured. Additionally, T90 due to acute episodic desaturations (T90Desaturation) and due to non-specific and non-cyclic drifts of SpO2 (T90Non-specific) were assessed. RESULTS: ASV reduced the AHI below 15/h in all groups. ASV treatment significantly shortened T90 in all three etiologies to a similar extent. T90Desaturation, but not T90Non-specific, was reduced by ASV across all three patient groups. AHI was identified as an independent modulator for ΔT90Desaturation upon ASV treatment (B (95% CI: -1.32 (-1.73; -0.91), p < 0.001), but not for ΔT90 or ΔT90Non-specific. Body mass index was one independent predictor of T90. CONCLUSIONS: Across different central sleep apnea etiologies, ASV reduced AHI, but nocturnal hypoxemic burden remained high due to a non-specific component of T90 not related to episodic desaturation. Whether adjunct risk factor management such as weight-loss can further reduce T90 warrants further study.

Long-term outcome with focus on pulmonary hypertension in Obesity Hypoventilation Syndrome.

INTRODUCTION: Pulmonary Hypertension (PH) is a frequent comorbidity in Obesity Hypoventilation Syndrome (OHS). OBJECTIVE: We investigated long-term outcome of OHS with a particular emphasis on PH. METHODS: In a prospective design, 64 patients with OHS and established noninvasive positive pressure ventilation (NPPV), were assessed by serum biomarkers, right heart catheterization, blood gases analysis, lung function, Epworth-Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), World Health Organization-functional class (WHO-FC) and health-related quality of life (HRQL) via the Severe Respiratory Insufficiency (SRI) questionnaire. After a planned follow-up of 5 years patients were reassessed regarding vital status, WHO-FC, ESS, SRI, PSQI, body mass index (BMI) and NPPV use. Prognostic markers were explored using univariate and multivariate Cox regression analyses. RESULTS: At the 5-year follow-up, BMI tended to decrease (P = 0.05), while WHO-FC, ESS and PSQI remained unchanged. HRQL deteriorated in terms of SRI summary score and most subdomains (P < .05 each). NPPV adherence still was high (89%), while daily NPPV use increased from 6.7 (5.1; 8.0) h/d to 8.2 (7.4; 9.0) h/d (P < .05). After a 5-year follow-up, mortality was 25.8%. In univariate regression analyses only age > 69.5 years (HR = 4.145, 95%-CI = 1.180-14.565, P = 0.016), NT-proBNP > 1256 pg/mL (HR = 5.162, 95%-CI = 1.136-23.467, P = 0.018), diffusion capacity for carbon monoxide (DLCO, %pred) (HR = 0.341, 95%-CI = 0.114-1.019, P = 0.043) and higher oxygen use during daytime (HR = 5.236, 95%-CI = 1.489-18.406, P = 0.004) predicted mortality. No independent factor predicting mortality was detected in multivariate analysis. CONCLUSION: Despite a high long-term NPPV use HRQL worsened. Age, oxygen use at baseline, DLCO (%pred) and NT-proBNP, as a surrogate parameter for PH, were related to long-term survival.

Adaptive servo-ventilation and sleep quality in treatment emergent central sleep apnea and central sleep apnea in patients with heart disease and preserved ejection fraction.

BACKGROUND: Reduced sleep quality is associated with impaired quality of life and increased mortality in patients with heart failure. The aim of this study was to observe changes in sleep fragmentation and sleep quality in patients with heart disease and preserved left ventricular ejection fraction (pEF) treated with adaptive servo-ventilation (ASV) therapy for treatment of emergent central sleep apnea (TECSA) or central sleep apnea (CSA). METHODS: 114 patients with structural heart disease and pEF introduced to ASV therapy between 2010 and 2015 were retrospectively analyzed. Patients were stratified into two groups; TECSA (n = 60) or CSA (n = 54). Changes of sleep fragmentation and sleep quality from baseline to ASV initiation were compared. RESULTS: ASV therapy leads to a significant reduction of apnea-hypopnea index (AHI) and arousal index in patients with TECSA and CSA (∆AHI: - 43 ± 21 vs. - 47 ± 22/h; ∆arousal index - 11 ± 15, vs. - 11 ± 21/h). ASV treatment leads to a significant increase in sleep efficiency in TECSA compared to CSA (∆SE: 10 ± 19 vs. 1 ± 18%, p = 0.019). Both groups had significantly longer stage N3 (N3) and rapid eye movement sleep (REM) on ASV (∆N3: 8 ± 11 vs. 9 ± 13%; ∆REM 7 ± 9 vs. 3 ± 8%; p < 0.05 for all comparisons baseline vs. ASV). CONCLUSIONS: In patients with heart disease and pEF, whose TECSA and CSA were treated with ASV, a significant reduction of AHI and arousal index as well as an increase of N3 and REM sleep was observed. Increase of sleep efficiency was significantly greater in TECSA compared to CSA. Hence, improvements of sleep quality were modestly greater in patients with TECSA compared to those with CSA.

Longitudinal comparison study of pressure relief (C-Flex) vs. CPAP in OSA patients.

BACKGROUND: Continuous positive airway pressure (CPAP) devices with the option of flexible pressure delivery (e.g., C-Flex) are thought to provide an improved degree of comfort and result in better therapeutic adherence while maintaining standard CPAP efficacy. The purpose of this study was to compare adherence and subjective measures of comfort between C-Flex and CPAP treatment. METHODS: The study was an international, multisite, single-blinded study with participants randomized to either C-Flex or CPAP. Participants completed subjective measures of sleepiness and comfort at baseline, and at 30-, 90-, and 180-day follow-ups. Additionally, compliance data were downloaded from the device at each follow-up. Repeated measures analysis of variance was used to assess the effects of treatment. RESULTS: There were 138 men and 46 women (average age of 48 +/- 9.2, average Epworth Sleepiness Scale score of 14.9 +/- 3.6, and average diagnostic apnea/hypopnea index (AHI) of 51.9 +/- 27.7). C-Flex and CPAP groups were comparable on baseline measures, achieved comparable AHI on titration, and had comparable PAP pressure requirements. C-Flex users had comparable average hours of use per night and total nights of use across the study, but had a trend (p < .07) toward achieving greater total hours of utilization. While both groups had comparable decreases in sleepiness, C-Flex users reported on visual analog scales greater comfort (64.3 vs. 57.4; p = .01). CONCLUSIONS: The results of this study demonstrated that C-Flex has comparable resolution of respiratory indices and adherence. Furthermore, C-Flex users reported greater mask comfort.