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Central sleep apnea is common among patients who have heart failure and increases the risk of death in this setting. In the Canadian Continuous Positive Airway Pressure trial, continuous positive airway pressure (CPAP) therapy administered to patients with heart failure was found to reduce the severity of central sleep apnea and increase the left ventricular ejection fraction, but did not improve survival. Continuous positive airway pressure therapy administered to patients with heart failure was found to reduce the severity of central sleep apnea and increase the left ventricular ejection fraction but did not improve survival. Central sleep apnea, which is present in approximately 25 to 40 percent of patients with chronic heart failure, 1 – 3 results from cyclic hyperventilation and falls in the partial pressure of arterial carbon dioxide below the apnea threshold. 4 The condition affects cardiovascular function adversely by causing tissue hypoxia, arousals from sleep, and activation of the sympathetic nervous system, and it independently increases the risk of death. 1 , 5 , 6 In short-term, single-center randomized trials lasting one to three months involving small numbers of patients who had central sleep apnea and chronic heart failure, continuous positive airway pressure (CPAP) attenuated the central sleep . . .

During sleep, the brain cycles regularly between wakefulness, nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. Nonrapid eye movement sleep is subdivided into four stages: stage I, a transitional stage between wake and sleep; stage II, which makes up most of the sleep period; and stages III and IV, which typically occur in the first half of the night and during which more profound stimulus is required to wake the sleeper. Parasomnias occur when transitions between these stages are blurred (commonly between stages III/IV and the awake state), causing behaviours that lack the complete awareness and mentation associated with wakefulness.1 It is not cost-effective to obtain a polysomnogram for patients with NREM parasomnia, except to exclude other causes of additional sleep instability (e.g., obstructive sleep apnea, periodic limb movement disorder, narcolepsy). Because one of the ICSD diagnostic criteria for REM sleep behaviour disorder requires the demonstration of REM sleep without atonia,1 polysomnography is needed to confirm this diagnosis and to rule out comorbid sleep disorders, such as obstructive sleep apnea or periodic limb movement disorder, which are more prevalent in adults and may need to be a focus of management. Rapid eye movement sleep behaviour disorder is characterized by activity in REM sleep causing injury or sleep disruption. Polysomnography is required to confirm the associated electromyographic abnormalities. In REM sleep behaviour disorder, there is a loss of REM atonia with excessive muscle tone, twitches on electromyography, and movements that often appear to be dream enactment, potentially causing injury to the sleeper or bed partner. Episodes usually occur about once a week, but may be as often as four times nightly over consecutive nights. In contrast to all NREM parasomnias, the sleeper awakens rapidly without confusion and often with good recall of a dream that corresponds with the enacted behaviours that can include talking, laughing, swearing, shouting, reaching, grabbing, flailing, punching, hitting or running.5

Objective This study was designed to assess the sensitivity and specificity of a portable sleep apnea recording device ( ApneaLink ™) using standard polysomnography (PSG) as a reference and to evaluate the possibility of using the ApneaLink ™ as a case selection technique for patients with suspected obstructive sleep apnea (OSA). Materials and methods Fifty patients (mean age 48.7 ± 12.6 years, 32 males) were recruited during a 4-week period. A simultaneous recording of both the standard in-laboratory PSG and an ambulatory level 4 sleep monitor ( ApneaLink ™) was performed during an overnight study for each patient. PSG sleep and respiratory events were scored manually according to standard criteria. ApneaLink ™ data were analyzed either with the automated computerized algorithm provided by the manufacturer following the American Academy of Sleep Medicine standards (default setting DFAL) or The University of British Columbia Hospital sleep laboratory standards (alternative setting, ATAL). The ApneaLink respiratory disturbance indices (RDI), PSG apnea–hypopnea indices (AHI), and PSG oxygen desaturation index (ODI) were compared. Results The mean PSG-AHI was 30.0 ± 25.8 events per hour. The means of DFAL-RDI and ATAL-RDI were 23.8 ± 21.9 events per hour and 29.5 ± 22.2 events per hour, respectively. Intraclass correlation coefficients were 0.958 between PSG-AHI and DFAL-RDI and 0.966 between PSG-AHI and ATAL-RDI. Receiver operator characteristic curves were constructed using a variety of PSG-AHI cutoff values (5, 10, 15, 20, and 30 events per hour). Optimal combinations of sensitivity and specificity for the various cutoffs were 97.7/66.7, 95.0/90.0, 87.5/88.9, 88.0/88.0, and 88.2/93.9, respectively for the default setting. The ApneaLink ™ demonstrated the best agreement with laboratory PSG data at cutoffs of AHI ≥ 10. There were no significant differences among PSG-AHI, DFAL-RDI, and ATAL-RDI when all subjects were considered as one group. ODI at 2%, 3%, and 4% desaturation levels showed significant differences ( p  < 0.05) compared with PSG-AHI, DFAL-RDI, and ATAL-RDI for the entire group. Conclusion The ApneaLink ™ is an ambulatory sleep monitor that can detect OSA and/or hypopnea with acceptable reliability. The screening and diagnostic capability needs to be verified by further evaluation and manual scoring of the ApneaLink ™. It could be a better choice than traditional oximetry in terms of recording respiratory events, although severity may be under- or overestimated.

Objectives The aim of this study is to better understand patients’ perspectives and preferences about treatment with continuous positive airway pressure (CPAP) and oral appliance (OA) devices for obstructive sleep apnea. Methods The current study used qualitative analysis of four focus group sessions with current CPAP and OA users. Twenty-two participants with OSA who currently use either CPAP or OA participated in the sessions at the University of British Columbia. Results Five topics from the focus group sessions were descriptively analyzed using NVivo software: goals and expectations of treatment, benefits of treatment for bed partners, side effects and inconveniences of CPAP, side effects and inconveniences of OA, and factors impacting treatment choice. In order of most to least frequently mentioned, patients expressed six expectations of treatment: improved health, apnea elimination, improved sleep, reduced fatigue, reduced snoring, and bed-partner benefits. The most to least mentioned factors impacting treatment choice were device effectiveness, transportability, embarrassment, and cost. Conclusions This qualitative study showed that many factors impact patients’ experience with their treatment device and that their treatment needs are not only physical but also relate to their lifestyle. This preliminary study provides treatment characteristics and attributes necessary to develop a quantitative questionnaire study, to assist in the selection of therapy, weighing the relative importance of patient and OSA treatment characteristics on treatment preference and adherence. Matching therapy to patient preferences may help identify the most appropriate treatment, and this may achieve greater likelihood of adherence.

Untreated obstructive sleep apnea (OSA) increases healthcare utilization and is associated with reduced work performance and occupational injuries. The economic burden related to untreated OSA is substantial, accounting for billions of dollars per year. Furthermore, therapy of OSA is an extremely cost-efficient use of healthcare resources, comparing highly favorably with other commonly funded medical therapies. Governments, transportation agencies, industry, and insurance companies need to be better informed concerning the economic impact of untreated OSA and the benefits of therapy.

Swallowing is an important physiological response that protects the airway. Although aspiration during sleep may cause aspiration pneumonia, the mechanisms responsible have not yet been elucidated. We evaluated the coordination between respiration and swallowing by infusing water into the pharynx of healthy young adults during each sleep stage. Seven normal subjects participated in the study. During polysomnography recordings, to elicit a swallow we injected distilled water into the pharynx during the awake state and each sleep stage through a nasal catheter. We assessed swallow latency, swallow apnea time, the respiratory phase during a swallow, the number of swallows, and coughing. A total number of 79 swallows were recorded. The median swallow latency was significantly higher in stage 2 (10.05 s) and stage 3 (44.17 s) when compared to awake state (4.99 s). The swallow latency in stage 3 showed a very wide interquartile range. In two subjects, the result was predominantly prolonged compared to the other subjects. There was no significant difference in the swallow apnea time between sleep stages. The presence of inspiration after swallowing, repetitive swallowing, and coughing after swallowing was more frequent during sleep than when awake. This study suggests that the coordination between respiration and swallowing as a defense mechanism against aspiration was impaired during sleep. Our results supported physiologically the fact that healthy adult individuals aspirate pharyngeal secretions during sleep.

BACKGROUND: An estimated 5.4 million Canadian adults have been diagnosed with sleep apnea or are at high risk of experiencing obstructive sleep apnea (OSA). There are no recent Canadian data regarding access to and predictors of referral for diagnostic testing in these populations. METHODS: The Sleep Apnea Rapid Response survey sampled 8647 Canadian adults and captured information about risk, testing, diagnosis and treatment of sleep apnea. Predictors of sleep laboratory test referrals were assessed using log‐linked binomial regression modelling. Information regarding sleep testing facilities was updated at the provincial and regional levels. RESULTS: Approximately 76.8% (95% CI 70.1% to 83.6%) of adult Canadians with sleep apnea and 5.1% (95% CI 3.4% to 6.7%) of those at high risk for OSA reported being referred to a sleep laboratory. Significant predictors of sleep laboratory referral in the general population were male sex, middle age, overweight or obese, a chronic condition, having a regular medical doctor and reporting symptoms of sleep apnea. Region of residence was also a predictor of reported sleep laboratory referral, with individuals from Ontario being more likely to report being referred to a sleep laboratory versus individuals from other regions. CONCLUSION: Individuals reporting risk factors and symptoms associated with OSA were more likely to report a sleep laboratory testing referral compared with those without risk factors or symptoms. However, Canada’s diagnostic sleep laboratory testing capacity varies across regions and is believed to be inadequate given the number of individuals at high risk for OSA who did not report testing referral.

Individuals with obstructive sleep apnea (OSA) experience sleep fragmentation and poor sleep quality that results in daytime sleepiness, which impairs performance during driving and leads to an increased risk for collisions. Not surprisingly, observational studies have shown that patients with OSA experience a two- to 10-fold higher risk for collision compared with healthy controls. Although treatment would clearly mitigate these risks, there is no current Canadian position on driving and OSA. This article, the first Canadian position statement addressing the issue, provides an overview of provincial regulations and proposes recommendations with regard to driving in patients with OSA. Untreated patients with obstructive sleep apnea (OSA) are at increased risk for motor vehicle collisions; however, it is unclear how this should be translated into fitness-to-drive recommendations. Accordingly, the Canadian Thoracic Society (CTS) Sleep Disordered Breathing Clinical Assembly and the Canadian Sleep Society (CSS) assembled a CTS-CSS working group to propose recommendations with regard to driving in patients with OSA. Recommendations for assessing fitness to drive in noncommercial drivers: 1. Severity of OSA alone is not a reliable predictor of collision risk and, therefore, should not be used in isolation to assess fitness to drive; 2. The severity of sleep apnea should be considered in the context of other factors to assess fitness to drive; 3. The decision to restrict driving is ultimately made by the motor vehicle licensing authority; however, they should take into account the information and recommendations provided by the sleep medicine physician and should follow provincial guidelines; 4. For patients prescribed continuous positive airway pressure (CPAP) therapy, objective CPAP compliance should be documented. Efficacy should also be documented in terms of reversing the symptoms and improvement in sleep apnea based on physiological monitoring; 5. For patients treated with surgery or an oral appliance, verification of adequate sleep apnea treatment should be obtained; and 6. A driver diagnosed with OSA may be recertified as fit to drive based on assessment of symptoms and demonstrating compliance with treatment. The assessment should be aligned with the provincial driver’s license renewal period. Commercial vehicles: Assessment of fitness to drive should be more stringent for patients operating commercial vehicles. In general, the CTS-CSS working group was in agreement with the Medical Expert Panel recommendations to the Federal Motor Carrier Safety Administration in the United States; these recommendations were adapted for Canadian practitioners.

Purpose The aims of this study were to determine the frequencies of swallowing and swallowing associated with arousals during sleep in patients with obstructive sleep apnea (OSA) and to determine whether these were associated with the severity of OSA and differed according to the preceding breathing route. Methods Standard audio-video polysomnography including an evaluation of swallowing-related elevation of the thyroid cartilage and breathing route (i.e., nasal or oronasal) was undertaken in an academic sleep laboratory. Fifty-six patients were analyzed (13 non-OSA patients, 17 mild, 10 moderate, and 16 severe OSA). Results The frequency of swallowing per hour of sleep was significantly higher in the severe OSA patients when compared to mild OSA patients (mild OSA, 3.1/h and severe OSA, 8.4/h). This was mainly due to the significantly higher frequency of swallowing associated with a respiratory event-related arousal in the severe OSA patients when compared to non- and mild OSA patients (non-OSA, 0.6/h; mild OSA, 1.0/h; severe OSA, 6.0/h), especially when swallowing was preceded by oronasal breathing (non-OSA, 0.2/h; mild OSA, 0.4/h; severe OSA, 4.2/h). Conclusions Swallowing frequency during sleep can increase with increasing OSA severity in most OSA patients. These events are predominately associated with respiratory event-related arousals and are more frequent when preceded by oronasal breathing. The observed swallowing under high ventilatory needs may compromise the maintenance of the pharynx as a conduit for airflow in OSA patients.

Background Previous, largely uncontrolled studies demonstrated the substantial effects of continuous positive airway pressure ventilation (CPAP) on a variety of physiologic and biochemical markers known to be risk factors for cardiovascular disease in patients with obstructive sleep apnea (OSA). In this pilot crossover study, we assessed (1) the feasibility of using CPAP in a group of minimally symptomatic patients with OSA, assessed through patient compliance and (2) CPAP therapy's effect on biomarkers in these patients. Methods We studied patients with minimal daytime sleepiness who were referred to the University of British Columbia's Hospital Sleep Clinic with suspected OSA and an apnea-hypopnea index (AHI) > 15 events/h. Patients were randomized to either CPAP or no therapy for 4 weeks followed by a washout of 4 weeks, and then a crossover to the other intervention. Fasting morning blood and urine, 24-h blood pressure (BP) measurements, and endothelial function (peak flow-mediated dilation to nitroglycerin-mediated dilation ratio) were assessed before and after each study intervention. Results Nine adult male and four female patients were studied. Mean (SD) age was 55 (7) years, mean AHI = 27.9/h, mean Epworth Sleepiness Score = 6.8 (11/13 had a score < 10), and mean BMI = 31.1 kg/m². Mean compliance with CPAP therapy was 5.53 h/night. Compared to no therapy, potential improvements were observed with CPAP for urinary microalbumin, norepinephrine, and epinephrine to creatinine ratios (decreased by 3.51 mg/mmol, 1.70 nmol/mmol, and 0.95 nmol/mmol, respectively); 24-h BP (systolic decreased by 3.60 mmHg, diastolic by 0.70 mmHg); homeostasis model for insulin resistance score (decreased by 1.11); and endothelial function (increased by 7.4%). However, none of the above differences was significant (p > 0.10). Conclusion In this pilot study there were potential improvements in a variety of cardiovascular biomarkers with CPAP. CPAP compliance was reasonably good even though patients were not particularly sleepy. Accordingly, larger randomized controlled trials in this area appear feasible and warranted.