Complex Sleep Research Articles

Adaptive Servo‐Ventilation (ASV) therapy improves long‐term prognosis in patients with complex sleep apnea syndrome (Comp SAS) better than cheyne‐stokes respiration (CSR)‐central sleep apnea (CSA)

Adaptive Servo‐Ventilation (ASV) therapy improves long‐term prognosis in patients with complex sleep apnea syndrome (Comp SAS) better than cheyne‐stokes respiration (CSR)‐central sleep apnea (CSA)

Prevalence of adiposity and its association with sleep duration, quality, and timing among 9-12-year-old children in Guangzhou, China.

BackgroundShort sleep duration has been reported to be associated with obesity in children, but findings are not consistent. Since few studies have examined the relationship between more complex sleep characteristics and obesity, we examined the association between adiposity and self-reported sleep duration, bedtime, and sleep quality in 9–12-year-old Chinese children using multilevel mixed models.Methods5518 children aged 9–12 years were recruited from 29 randomly selected primary schools in Guangzhou, China in 2014. Standardized questionnaires were used to obtain data to estimate sleep duration on typical weekdays and weekends. Sleep quality data were collected using the Children's Sleep Habits Questionnaire (CSHQ). Trained researchers undertook measurements of weight, height, and waist circumference (WC) for all participating children. Body mass index (BMI) z-scores were derived using the World Health Organization (WHO) child growth reference, and children were classified as overweight or obese using +1 and +2 SD as cut-offs, respectively. Percentage body fat (BF%) was calculated using bioelectrical impedance.ResultsLonger sleep duration was inversely associated with BMI z-score (β = −0.16, p < 0.05), WC (β = −1.11, p < 0.05) and later bedtime was associated with higher BMI z-score (β = 0.03, p < 0.05), WC (β = 1.72, p < 0.001), and BF% (β = 0.15, p < 0.05) in multivariable multilevel mixed models, after adjustment for age, gender, physical activity, parental education level, and average monthly income. No association was seen between sleep quality and adiposity.ConclusionShorter sleep duration and later bedtime are associated with higher adiposity indices in early adolescents from southern China.

Positional Complex Sleep Apnea: Not So Complex

Complex sleep apnea (CxSA) is commonly seen during PAP therapy and it is often difficult to treat. Here we are reporting a case of positional complex sleep apnea in which CxSA was more prominent in supine position and it was treated with Bilevel PAP-S/T mode along with position therapy. This case highlights that postural therapy can be tried along with basic PAP modes in management of CxSA in setting of resource limitations before moving to costlier therapies like Adaptive servo ventilation.

1235 Complex Sleep Apnea Refractory to Positive Airway Pressure (PAP) Therapy While on Baclofen that Responded to Continuous Positive Airway Pressure (CPAP) Therapy upon Cessation of Baclofen

1235 Complex Sleep Apnea Refractory to Positive Airway Pressure (PAP) Therapy While on Baclofen that Responded to Continuous Positive Airway Pressure (CPAP) Therapy upon Cessation of Baclofen

0508 SLEEP APNEA AND ATRIAL FIBRILLATION - PHENOTYPE AND OUTCOMES

Sleep apnea, especially central (CSA), is associated with atrial fibrillation (AF). We hypothesized that AF patients are at high risk for treatment-emergent/complex apnea, and residual disease during long-term therapy with positive airway pressure. The sleep laboratory database at the Beth Israel Deaconess Medical center and affiliated services was queried, focusing on patients with AF, to extract polysomnographic information. The BIDMC Online Medical Records was used to collect co-morbid information. Residual apnea and related information was extracted from the EnocreAnywhere database; at the BIDMC, tracking is life-long, enabling assessment of outcomes beyond 6 months. Three hundred and eighteen patients had complete clinical/polysomnographic data, and 212 were reviewed in EncoreAnywhere. Split night was 31%. Summary statistics: age 68.3 ± 11.1 years, 69.1% male, BMI 33.6 ± 8 Kg/M2, ejection fraction 53.5 ± 10.8 (22% less than 50%), hypertension 68.6%. Baseline total sleep time (TST): 181.4 ± 116.3 minutes, sleep efficiency 62.9 ± 19.3 %, N1 24.3 ± 21.5% TST, N3: 9.7 ± 13.9 % TST, RDI: 39.4 ± 21.7, AHI4% 8.2 ± 11.9, minimum saturation 81.8 ± 10 %. Titration data: TST: 242 ± 98.9 minutes, sleep efficiency 66.9 ± 19.8 %, N1: 18 ± 15.2 %, RDI 27 ± 21.6, AHI4% 5 ± 8.5, minimum saturation 85.4 ± 6.9 %. CSA was noted in 4% on baseline, and treatment-emergent/complex apnea in 30%. The mean duration of use of positive airway pressure (93% continuous) was 21 ± 3 months, mean use 4.1 ± 2.1 hours. Residual AHI-flow was 11.6 ± 7.8 / hour of use, and periodic breathing of at least 10 minutes duration on visual waveforms inspection in 76.4 %. Patients with AF have highly fragmented sleep during diagnostic and titration polysomnograms. Complex sleep apnea is common, as is residual sleep apnea and periodic breathing on waveforms. This likely reflects persistently elevated loop gain. AF patients with sleep apnea are at high risk for reduced treatment effectiveness, and may require a dedicated phenotype-driven clinical pathway for optimal management. Beth Israel Deaconess Medical Center Chief Academic Officer’s Innovation Grant.

Microbial Products and Cytokines in Sleep and Fever Regulation.

Excessive sleepiness and fever are constitutional symptoms associated with systemic infection. Although fevers have been investigated for many years, sleep responses to infectious challenge have only recently been investigated. Inoculation of animals with bacterial, viral, protozoan and fungal organisms result in complex sleep responses dependent upon the microbial agent and route of administration. The general pattern is characterized by an initial robust increase in non-rapid eye movement sleep (NREMS) followed by a period of NREMS inhibition. REMS is inhibited after infectious challenge. The sleep responses are accompanied by fever but the two responses are, in part, independent from each other. Sleep responses, like fevers, may be beneficial to host defense although this area is relatively uninvestigated. Microbial products likely responsible for sleep and fever responses include bacterial muramyl peptides and endotoxin, and viral double stranded RNA. These microbial products induce sleep and fever responses in animal models. The exact mechanism of how these structurally diverse microbial products elicit sleep and fever remain unknown; however these substances share the ability to induce cytokine production. Cytokines such as interleukin-1 (IL-1), tumor necrosis factor, acidic fibroblast growth factor (FGF), and interferon-α (IFN-α) are somnogenic whether given directly into brain or intravenously. Other cytokines lack somnogenic activity, e.g., IL-2, IL-6, IFNβ and basic FGF. The somnogenic actions of cytokines probably involve growth hormone-releasing hormone (GHRH) and nitric oxide. Anti-GHRH or inhibition of NO production inhibits normal sleep and inhibits IL-1-induced sleep. In conclusion, cytokines are likely key mediators of fever and sleep responses to infection. The microbial-cytokine altered sleep likely results from an amplification of physiological sleep mechanisms which include cytokines, several neuropeptides and neurotransmitters such as nitric oxide.

Complex sleep apnea syndrome

Complex sleep apnea syndrome (Comp-SAS) is the term used to describe a specific form of sleep disordered breathing characterized by the arise of central sleep apnea in patient with previous obstructive sleep apnea syndrome (OSAS) treated with continuous positive airway pressure devices (CPAP). The mechanisms of its occurrence are not well understood, but partly it seems to be a consequence of increased carbon dioxide elimination under positive airway pressure treatment and related improvement of pulmonary ventilation. The prevalence of Comp-SAS ranges from 5% to 20% of OSAS patient getting CPAP therapy with no significant predictors in comparison with simple obstructive sleep apnea, but more likely to happened in older males with more severe OSAS and accompanying cardiovascular pathology such as ischemic heart disease, atrial fibrillation and heart failure. In most cases of Comp-SAS, central apnea events are transient and disappear after continuous CPAP therapy use for 1 to 2 months. Novel treatment options like adaptive servo-ventilation or BiPAP-ST are available for such non-responders to CPAP but contra-indicated to patients with systolic heart failure. From the other hand, still not clear is it mandatory to treat all affected individuals with Comp-SAS if the disease is uncomplicated and patient is asymptomatic.

Prevalence and clinical correlates of flunitrazepam-related complex sleep behaviors.

Complex sleep behaviors (CSB) are often associated with the use of hypnotic drugs. This study investigated the prevalence and correlates of CSB among psychiatric patients who were given flunitrazepam. From June 2011 to May 2012, a total of 268 psychiatric outpatients who had received flunitrazepam for at least 3 months were enrolled. Data on occurrence of CSB, demographic characteristics, flunitrazepam dosage and duration of use, psychiatric diagnoses, physical illnesses, and alcohol use were collected. Logistic regression analysis was used to examine the clinical correlates of CSB. Sixty-six participants (24.6%) reported experiencing CSB. Logistic regression analysis showed that a high dosage (>2 mg/day) of flunitrazepam (odds ratio [OR] = 1.941, 95% confidence interval [CI] = 1.090-3.455, P = 0.024) and alcohol use (OR = 1.948, 95%CI = 1.023-3.709, P = 0.042) were significantly associated with the occurrence of CSB. Sex, age, duration of flunitrazepam use, psychiatric diagnoses, and physical illnesses were not significantly associated with the occurrence of CSB. CSB among flunitrazepam users should be monitored routinely, especially among those receiving a high dosage who also consume alcohol.

Pathogenesis of central and complex sleep apnoea.

Central sleep apnoea (CSA) - the temporary absence or diminution of ventilatory effort during sleep - is seen in a variety of forms including periodic breathing in infancy and healthy adults at altitude and Cheyne-Stokes respiration in heart failure. In most circumstances, the cyclic absence of effort is paradoxically a consequence of hypersensitive ventilatory chemoreflex responses to oppose changes in airflow, that is elevated loop gain, leading to overshoot/undershoot ventilatory oscillations. Considerable evidence illustrates overlap between CSA and obstructive sleep apnoea (OSA), including elevated loop gain in patients with OSA and the presence of pharyngeal narrowing during central apnoeas. Indeed, treatment of OSA, whether via continuous positive airway pressure (CPAP), tracheostomy or oral appliances, can reveal CSA, an occurrence referred to as complex sleep apnoea. Factors influencing loop gain include increased chemosensitivity (increased controller gain), reduced damping of blood gas levels (increased plant gain) and increased lung to chemoreceptor circulatory delay. Sleep-wake transitions and pharyngeal dilator muscle responses effectively raise the controller gain and therefore also contribute to total loop gain and overall instability. In some circumstances, for example apnoea of infancy and central congenital hypoventilation syndrome, central apnoeas are the consequence of ventilatory depression and defective ventilatory responses, that is low loop gain. The efficacy of available treatments for CSA can be explained in terms of their effects on loop gain, for example CPAP improves lung volume (plant gain), stimulants reduce the alveolar-inspired PCO2 difference and supplemental oxygen lowers chemosensitivity. Understanding the magnitude of loop gain and the mechanisms contributing to instability may facilitate personalized interventions for CSA.

Residual Events during Use of CPAP: Prevalence, Predictors, and Detection Accuracy.

To assess the frequency, severity, and determinants of residual respiratory events during continuous positive airway therapy (CPAP) for obstructive sleep apnea (OSA) as determined by device output. Subjects were consecutive OSA patients at an American Academy of Sleep Medicine accredited multidisciplinary sleep center. Inclusion criteria included CPAP use for a minimum of 3 months, and a minimum nightly use of 4 hours. Compliance metrics and waveform data from 217 subjects were analyzed retrospectively. Events were scored manually when there was a clear reduction of amplitude (≥ 30%) or flow-limitation with 2-3 larger recovery breaths. Automatically detected versus manually scored events were subjected to statistical analyses included Bland-Altman plots, correlation coefficients, and logistic regression exploring predictors of residual events. The mean patient age was 54.7 ± 14.2 years; 63% were males. All patients had a primary diagnosis of obstructive sleep apnea, 26% defined as complex sleep apnea. Residual flow measurement based apnea-hypopnea index (AHIFLOW) > 5, 10, and 15/h was seen in 32.3%, 9.7%, and 1.8% vs. 60.8%, 23%, and 7.8% of subjects based on automated vs. manual scoring of waveform data. Automatically detected versus manually scored average AHIFLOW was 4.4 ± 3.8 vs. 7.3 ± 5.1 per hour. In a logistic regression analysis, the only predictors for a manual AHIFLOW > 5/h were the absolute central apnea index (CAI), (odds ratio [OR]: 1.5, p: 0.01, CI: 1.1-2.0), or using a CAI threshold of 5/h of sleep (OR: 5.0, p: < 0.001, CI: 2.2-13.8). For AHIFLOW > 10/h, the OR was 1.14, p: 0.03 (CI: 1.1-1.3) per every CAI unit of 1/hour. Residual respiratory events are common during CPAP treatment, may be missed by automated device detection and predicted by a high central apnea index on the baseline diagnostic study. Direct visualization of flow data is generally available and improves detection.

PT656. Prevalence and Clinical Correlates of Flunitrazepam-Related Complex Sleep Behaviors

PT656. Prevalence and Clinical Correlates of Flunitrazepam-Related Complex Sleep Behaviors

Insomnia Characterization: From Hypnogram to Graph Spectral Theory.

To quantify and differentiate control and insomnia sleep onset patterns through biomedical signal processing of overnight polysomnograms. The approach consisted of three tandem modules: 1) biosignal processing module, which used state-space time-varying autoregressive moving average (TVARMA) processes with recursive particle filter, 2) hypnogram generation module that implemented a fuzzy inference system (FIS), and 3) insomnia characterization module that discriminated between control and subjects with insomnia using a logistic regression model trained with a set of similarity measures ( d1, d2 , d3, d4). The study employed sleep onset periods from 16 control and 16 subjects with insomnia. State-spaced TVARMA processes with recursive particle filtering provided resilience to nonlinear, nonstationary, and non-Gaussian conditions of biosignals. FIS managed automated sleep scoring robust to intersubjects' and interraters' variability. The similarity distances quantified in a scalar measure the transitions amongst sleep onset stages, computed from expert and automated hypnograms. A statistical set of unpaired two-tailed t -tests suggested that distances d1 , d2, and d3 had larger statistical significance ( ) to characterize sleeping patterns. The logistic regression model classified control and subjects with insomnia with sensitivity 87 % , specificity 75 %, and accuracy 81 %. Our approach can perform a supportive role in either biosignal processing, sleep staging, insomnia characterization, or all the previous, coping with time-consuming procedures and massive data volumes of standard protocols. The introduction of graph spectral theory and logistic regression for the diagnosis of insomnia represents a novel concept, attempting to describe complex sleep dynamics throughout transitions networks and scalar measures.

Sleep apnea in Chiari I malformation

A 36-year-old non-obese woman consulted her physician for recent excessive daytime sleepiness (EDS) with Epworth sleepiness scale (ESS) at 13/24, morning headache and heavy snoring. Polysomnography revealed moderate mixed sleep apnea syndrome with an Apnoea–Hypopnoea Index (AHI) of 23/h (Figure 1). Despite adequate continuous positive airway pressure (CPAP) therapy, the patient reported an aggravation of EDS and headache. A second polysomnography with CPAP, conclude to moderate complex sleep apnea syndrome by revealing the persistence of numerous central sleep apnea (AHI of 21/h) but no evidence of obstructive events. The patient reported a sensation of unrefreshing sleep and EDS (ESS at 17/24) with no symptoms suggesting cardiac failure, periodic limb movement disorder or narcolepsy. Physical examination, including neurologic and cardiac examinations, was normal. Routine blood tests, arterial blood gas analysis and echocardiography were performed and showed no significant abnormalities.

Advanced Positive Airway Pressure Modalities

Auto-adjusting positive airway pressure (PAP) devices are increasingly becoming the first line treatment for obstructive sleep apnea (OSA). More complex sleep- disordered breathing such as Cheyne-Stokes respirations and central sleep apnea related to heart failure as well as complex sleep-disordered breathing related to chronic hypoventilation syndromes may require the use of advanced positive airway pressure modalities such as automated servo ventilation (ASV) and volume targeted pressure limited ventilation. Identifying patients with complex sleep-disordered breathing that will benefit from treatment with advanced modalities re- mains an area of active investigation. A recent and surprising development found ASV to be associated with an increased risk of sudden cardiac death when used to treat central sleep apnea in patients with symptomatic systolic heart failure and an ejection fraction less than 45 %. The optimal treatment of central sleep apnea in heart failure and the role of ASV are currently in question. The following chapter is intended to provide the clinician with a description of newer PAP modal- ities; a review of evidence supported indications for use as well as provide a framework for managing patients with ad- vanced positive airway pressure therapy.

Clinical Use of Loop Gain Measures to Determine Continuous Positive Airway Pressure Efficacy in Patients with Complex Sleep Apnea. A Pilot Study.

Measures of unstable ventilatory control (loop gain) can be obtained directly from the periodic breathing duty ratio on polysomnography in patients with Cheyne-Stokes respiration/central sleep apnea and can predict the efficacy of continuous positive airway pressure (CPAP) therapy. In this pilot study, we aimed to determine if this measure could also be applied to patients with complex sleep apnea (predominant obstructive sleep apnea, with worsening or emergent central apneas on CPAP). We hypothesized that loop gain was higher in patients whose central events persisted 1 month later despite CPAP treatment versus those whose events resolved over time. We calculated the duty ratio of the periodic central apneas remaining on the CPAP titration (or second half of the split night) while patients were on optimal CPAP with the airway open (obstructive apnea index < 1/h). Loop gain was calculated by the formula: LG = 2π/[(2πDR - sin(2πDR)]. Patients were followed on CPAP for 1 month. Post-treatment apnea-hypopnea index and compliance data were recorded from smart cards. Thirty-two patients with complex sleep apnea were identified, and 17 patients had full data sets. Eight patients continued to have a total of more than five events per hour (11.8 ± 0.5/h) (nonresponders). The remaining nine patients had an apnea-hypopnea index less than 5/h (2.2 ± 0.4/h) (responders). Loop gain was higher in the nonresponders versus responders (2.0 ± 0.1 vs. 1.7 ± 0.2, P = 0.026). Loop gain and the residual apnea-hypopnea index 1 month after CPAP were associated (r = 0.48, P = 0.02). CPAP compliance was similar between groups. In this pilot study, loop gain was higher for patients with complex sleep apnea in whom central apneas persisted after 1 month of CPAP therapy (nonresponders). Loop gain measurement may enable an a priori determination of those who need alternative modes of positive airway pressure.

Complex sleep apnea at auto-titrating CPAP initiation: prevalence, significance and predictive factors.

Obstructive sleep apnea (OSA) patients may develop central respiratory events under continuous positive airway pressure (CPAP), referred to as complex sleep apnea (CompSA). We aimed to assess prevalence and predictive factors of complex apnea and to evaluate treatment response to CPAP. Within a retrospective cohort study, we assessed clinical data of OSA patients, attending the sleep lab during a 15-months period. Included participants underwent two consecutive polysomnographies; baseline diagnosis and treatment trial. Complex apnea patients, defined by a central apnea index ≥ 5 per hour during pressure auto-titration, were compared to remainders. Among 263 included patients, the prevalence of complex apnea was 9.1%. The mean apnea hypopnea index only dropped from 52.7 to 39.9 per hour in CompSA patients, while it improved from 40.9 to 7.3 in patients without CompSA. Although a decreased sleep-fragmentation under CPAP was observable in both groups, the enhancement of Non-REM sleep was superior in patients without CompSA. The CompSA patients showed higher median apnea-hypopnea, mixed apnea and central apnea indices at baseline and displayed higher rates of comorbid heart failure and obstructive pulmonary disease, but no higher severity of associated daytime fatigue and sleepiness symptoms. Despite evidenced partial improvement of obstructive events, nocturnal hypoxemia and sleep fragmentation, the occurrence of complex apnea presented here as a clear therapeutic failure of auto-titrating CPAP and was associated with heart failure, COPD and higher central and mixed apnea indices at baseline.

Clinical, polysomnographic, and CPAP titration features of obstructive sleep apnea: Mixed versus purely obstructive type

PurposeTo determine whether obstructive sleep apnea syndrome (OSAS) patients with mixed sleep apnea (MSA) have different clinical, polysomnographic, and continuous positive airway pressure (CPAP) titration findings compared to OSAS patients without MSA. MethodsWe retrospectively reviewed the records of OSAS patients who had undergone CPAP titration and categorized them into pure-OSA and mixed-OSA groups. Demographic features, daytime sleepiness, and apnea severity were compared between the two groups using univariate and multivariate analyses. CPAP titration findings were also compared between the two groups. ResultsOne hundred and ninety-five subjects (n=126 pure-OSA; n=69 mixed-OSA) were included in the analysis. Compared to the pure-OSA group, the mixed-OSA group had a higher percentage of males (p=0.003) and a higher body mass index (p=0.044), Epworth Sleepiness Scale score (p=0.028), and apnea–hypopnea index (AHI) (p<0.001). In logistic regression analysis, older age, male sex, and higher body mass index were independently associated with mixed-OSA before PSG study. When using AHI as a covariable, the higher AHI with older age, male sex, and daytime sleepiness was independently related to mixed-OSA. The mixed-OSA group had a higher percentage of patients with complex sleep apnea, a lower percentage of patients with optimal titration, and a higher titrated pressure than the pure-OSA group. ConclusionsSevere OSA, older age, male sex, obesity, and daytime sleepiness were related to mixed-OSA. Complex sleep apnea, less optimal titration, and a higher titrated CPAP were also associated with MSA in OSAS patients.

The state of Veterans Affairs sleep medicine programs: 2012 inventory results.

The Veterans Health Administration (VHA) represents one of the largest integrated health-care systems in the country. In 2012, the Veterans Affairs Sleep Network (VASN) sought to identify available sleep resources at VA medical centers (VAMCs) across the country through a national sleep inventory. The sleep inventory was administered at the annual 2012 VA Sleep Practitioners meeting and by email to sleep contacts at each VAMC. National prosthetics contacts were used to identify personnel at VAMCs without established sleep programs. Follow-up emails and telephone calls were made through March 2013. One hundred eleven VA medical centers were included for analysis. Thirty-nine programs did not respond, and 10 were considered "satellites," referring all sleep services to a larger neighboring VAMC. Sleep programs were stratified based on extent of services offered (i.e., in-lab and home testing, sleep specialty clinics, cognitive behavioral therapy for insomnia (CBT-i)): 28 % were complex sleep programs (CSPs), 46 % were intermediate (ISPs), 9 % were standard (SSPs), and 17 % offered no formal sleep services. Overall, 138,175 clinic visits and 90,904 sleep testing encounters were provided in fiscal year 2011 by 112.1 physicians and clinical psychologists, 100.4 sleep technologists, and 115.3 respiratory therapists. More than half of all programs had home testing and CBT-i programs, and 26 % utilized sleep telehealth. The 2012 VA sleep inventory suggests considerable variability in sleep services within the VA. Demand for sleep services is high, with programs using home testing, sleep telehealth, and a growing number of mid-level providers to improve access to care.

Prevalence of central sleep apnea during continous positive airway pressure (CPAP) titration in subjects with obstructive sleep apnea syndrome at an altitude of 2640 m

BackgroundThe occurrence of central apneas when applying positive pressure (CPAP) to patients with obstructive sleep apnea syndrome (OSAS) is called complex sleep apnea (CompSA). This causes poor adherence to CPAP and persistence of symptoms. In Bogota, a city located at an altitude of 2640 m above sea level, chronic hypoxemia can generate certain instability of the respiratory system during sleep which could increase the presence of central apnea. The aim was to establish the prevalence of central apnea (central apnea index >5/h) in adults with moderate or severe OSAS during CPAP titration, and the factors associated with this. MethodPatients over 18 years old with OSAS were referred to the Fundacion Neumologica Colombiana Sleep Center, from January 2008 to June 2010. Polysomnogram (PSG) for CPAP titration was performed according to the American Academy of Sleep Medicine criteria. The prevalence was calculated and the clinical and baseline PSG factors associated with the CompSA were analyzed. ResultsWe included 988 patients, 58% men. CompSA prevalence was 11.6%. Factors associated with CompSA were: central apneas in the baseline PSG (OR: 5.34 [3.49–8.16]), history of heart failure (OR: 2.53 [1.58–4.07]), and male sex (OR: 1.68 [1.06–2.69]). ConclusionThe prevalence of complex sleep apnea in Bogota (11.6%) was intermediate compared to the reported in lower altitudes. The factors associated with the development of CompSA were male sex, heart failure, and the presence of central apnea in the baseline PSG.

P296 Effectiveness Of Adaptive Servo Ventilation In The Treatment Of Central Sleep Apnea

Background Adaptive Servo Ventilation (ASV) was developed to treat Central Sleep Apnea in patients with heart failure, which is usually associated with a low or normal PaCO2. The aim of ASV is to stabilise rather than increase overall ventilation. Evidence is limited regarding the use of ASV not only in heart failure patients but central sleep apnea of other aetiologies. The current study therefore explored this therapy in a regional sleep centre in the UK. Method A retrospective review of the outcomes of 42 patients who were treated with ASV between January 2012 and December 2013, either following conventional positive airway pressure (PAP) or as an initial therapy. Measurements included the Apnea Hypopnea Index (AHI), compliance (measured by hours of machine use/night) and subjective sleep quality, pre and post ASV. Results All patients demonstrated evidence of central sleep apnea with a reduced or normal transcutaneous CO2 during daytime spontaneous ventilation. Seven patients (16%) met the criteria for complex sleep apnea. 16 (38%) had evidence of heart failure whilst opioids were in use in six patients (14%). The majority of patients, (n = 36, 86%), were on PAP prior to ASV (mean duration 2.4 years), 22 patients (53%) were on Bi-level and 14 (33%) were on CPAP. Six patients (14%) had ASV as an initial therapy. The mean AHI improved from 31.7/h (range 2–84/h) to 5.1/h (Range 0–50/h) with ASV [Figure 1]. Compliance improved from 5.2 h/night to 6.4 h/night with ASV. 22 patients (52%) reported a subjective improvement in their sleep quality using ASV. Conclusion ASV appeared superior to traditional PAP in improving AHI, compliance and sleep quality for patients with central sleep apnea of various aetiologies.