Debra Morrison

Suppression of Central Sleep Apnea by Continuous Positive Airway Pressure and Transplant-Free Survival in Heart Failure A Post Hoc Analysis of the Canadian Continuous Positive Airway Pressure for Patients With Central Sleep Apnea and Heart Failure Trial (CANPAP)

Background— In the main analysis of the Canadian Continuous Positive Airway Pressure (CPAP) for Patients with Central Sleep Apnea (CSA) and Heart Failure Trial (CANPAP), CPAP had no effect on heart transplant–free survival; however, CPAP only reduced the mean apnea-hypopnea index to 19 events per hour of sleep, which remained above the trial inclusion threshold of 15. This stratified analysis of CANPAP tested the hypothesis that suppression of CSA below this threshold by CPAP would improve left ventricular ejection fraction and heart transplant–free survival. Methods and Results— Of the 258 heart failure patients with CSA in CANPAP, 110 of the 130 randomized to the control group and 100 of the 128 randomized to CPAP had sleep studies 3 months later. CPAP patients were divided post hoc into those whose apnea-hypopnea index was or was not reduced below 15 at this time (CPAP-CSA suppressed, n=57, and CPAP-CSA unsuppressed, n=43, respectively). Their changes in left ventricular ejection fraction and heart transplant–free survival were compared with those in the control group. Despite similar CPAP pressure and hours of use in the 2 groups, CPAP-CSA–suppressed subjects experienced a greater increase in left ventricular ejection fraction at 3 months (P=0.001) and significantly better transplant-free survival (hazard ratio [95% confidence interval] 0.371 [0.142 to 0.967], P=0.043) than control subjects, whereas the CPAP-CSA–unsuppressed group did not (for left ventricular ejection fraction, P=0.984, and for transplant-free survival, hazard ratio 1.463 [95% confidence interval 0.751 to 2.850], P=0.260). Conclusions— These results suggest that in heart failure patients, CPAP might improve both left ventricular ejection fraction and heart transplant–free survival if CSA is suppressed soon after its initiation.

Canadian Thoracic Society guidelines: Diagnosis and treatment of sleep disordered breathing in adults

The Canadian Thoracic Society (CTS) guidelines for the diagnosis and treatment of sleep disordered breathing in adults were developed over the past year. A one-day meeting was held in Montreal, Quebec, on October 28, 2005, just before the annual CTS meeting. The meeting was facilitated by Dr R Davies (Oxford, United Kingdom), and speakers included D Morrison (Halifax, Nova Scotia), J Kimoff (Montreal), J Fleetham (Vancouver, British Columbia), C George (London, Ontario), M Kryger (Winnipeg, Manitoba), P Hanly (Calgary, Alberta), F Hill (Saskatoon, Saskatchewan), D Bradley (Toronto, Ontario), N Ayas (Vancouver), M Fitzpatrick (Kingston, Ontario), F Series (Quebec City, Quebec), K Ferguson (London) and W Tsai (Calgary). This meeting was attended by 28 Canadian physicians with an interest in sleep disordered breathing. A draft of an Executive Summary was developed, and then reviewed and finalized by the CTS Sleep Disordered Breathing Committee at a one-day meeting in Toronto on February 17, 2006. The Committee members then individually ranked the level of evidence as: grade A – high-quality meta-analysis or single randomized clinical trial (RCT) that had a low risk of bias; grade B – high-quality systematic review of cohort studies or single cohort study with a low risk of bias or extrapolated evidence from high-quality RCTs or RCTs with a risk of bias; grade C – case-control studies or cohort studies with a risk of bias; or grade D – case series, case reports or expert opinion. The Committee members also ranked their agreement with each statement (strongly agree, agree, neutral, disagree or strongly disagree). No statement was included unless at least 90% of the Committee either strongly agreed or agreed with it.

Home mechanical ventilation: a Canadian Thoracic Society clinical practice guideline.

Increasing numbers of patients are surviving episodes of prolonged mechanical ventilation or benefitting from the recent availability of userfriendly noninvasive ventilators. Although many publications pertaining to specific aspects of home mechanical ventilation (HMV) exist, very few comprehensive guidelines that bring together all of the current literature on patients at risk for or using mechanical ventilatory support are available. The Canadian Thoracic Society HMV Guideline Committee has reviewed the available English literature on topics related to HMV in adults, and completed a detailed guideline that will help standardize and improve the assessment and management of individuals requiring noninvasive or invasive HMV. The guideline provides a disease-specific review of illnesses including amyotrophic lateral sclerosis, spinal cord injury, muscular dystrophies, myotonic dystrophy, kyphoscoliosis, post-polio syndrome, central hypoventilation syndrome, obesity hypoventilation syndrome, and chronic obstructive pulmonary disease as well as important common themes such as airway clearance and the process of transition to home. The guidelines have been extensively reviewed by international experts, allied health professionals and target audiences. They will be updated on a regular basis to incorporate any new information.

Canadian Thoracic Society 2011 guideline update: Diagnosis and treatment of sleep disordered breathing

The Canadian Thoracic Society (CTS) published an executive summary of guidelines for the diagnosis and treatment of sleep disordered breathing in 2006⁄2007. These guidelines were developed during several meetings by a group of experts with evidence grading based on committee consensus. These guidelines were well received and the majority of the recommendations remain unchanged. The CTS embarked on a more rigorous process for the 2011 guideline update, and addressed eight areas that were believed to be controversial or in which new data emerged. The CTS Sleep Disordered Breathing Committee posed specific questions for each area. The recommendations regarding maximum assessment wait times, portable monitoring, treatment of asymptomatic adult obstructive sleep apnea patients, treatment with conventional continuous positive airway pressure compared with automatic continuous positive airway pressure, and treatment of central sleep apnea syndrome in heart failure patients replace the recommendations in the 2006⁄2007 guidelines. The recommendations on bariatric surgery, complex sleep apnea and optimum positive airway pressure technologies are new topics, which were not covered in the 2006⁄2007 guidelines.

Canadian Sleep Society/Canadian Thoracic Society position paper on the use of portable monitoring for the diagnosis of obstructive sleep apnea/hypopnea in adults

The present position paper on the use of portable monitoring (PM) as a diagnostic tool for obstructive sleep apnea⁄hypopnea (OSAH) in adults was based on consensus and expert opinion regarding best practice standards from stakeholders across Canada. These recommendations were prepared to guide appropriate clinical use of this new technology and to ensure that quality assurance standards are adhered to. Clinical guidelines for the use of PM for the diagnosis and management of OSAH as an alternative to in-laboratory polysomnography published by the American Academy of Sleep Medicine Portable Monitoring Task Force were used to tailor our recommendations to address the following: indications; methodology including physician involvement, physician and technical staff qualifications, and follow-up requirements; technical considerations; quality assurance; and conflict of interest guidelines. When used appropriately under the supervision of a physician with training in sleep medicine, and in conjunction with a comprehensive sleep evaluation, PM may expedite treatment when there is a high clinical suspicion of OSAH.

Design of the effect of adaptive servo-ventilation on survival and cardiovascular hospital admissions in patients with heart failure and sleep apnoea: the ADVENT-HF trial

Both types of sleep‐disordered breathing (SDB), obstructive and central sleep apnoea (OSA and CSA, respectively), are common in patients with heart failure and reduced ejection fraction (HFrEF). In such patients, SDB is associated with increased cardiovascular morbidity and mortality but it remains uncertain whether treating SDB by adaptive servo‐ventilation (ASV) in such patients reduces morbidity and mortality.

Obstructive sleep apnea and driving: A Canadian Thoracic Society and Canadian Sleep Society position paper

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 drivers 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.

Directives de la Société Canadienne de Thoracologie: Diagnostic et Traitement des Troubles Respiratoires du Sommeil de L’Adulte

Comité des troubles respiratoires du sommeil de la SCT Correspondence : John Fleetham, Respiratory Medicine, 7th Floor, Diamond Health Care Centre, 2775 Laurel Street, Vancouver (Colombie-Britannique) V5Z 1M9. Téléphone 604-875-5653, télécopie 604-875-5587, courriel John.Fleetham@vch.ca La version anglaise a été publiée dans le Can Respir J 2006;13(7):387-92 Les directives de la Société canadienne de thoracologie (SCT) concernant le diagnostic et le traitement des troubles respiratoires du sommeil de l’adulte ont été élaborées au cours de l’année écoulée. Une réunion d’un jour s’est tenue à Montréal (Québec) le 28 octobre 2005, juste avant le congrès annuel de la SCT. Cette rencontre a été animée par le docteur R Davies (Oxford, Royaume-Uni), avec des présentations par D Morrison (Halifax, Nouvelle-Écosse), J Kimoff (Montréal), J Fleetham (Vancouver, Colombie-Britannique), C George (London, Ontario), M Kryger (Winnipeg, Manitoba), P Hanly (Calgary, Alberta), F Hill (Saskatoon, Saskatchewan), D Bradley (Toronto, Ontario), N Ayas (Vancouver), M Fitzpatrick (Kingston, Ontario), F Sériès (Québec, Québec), K Ferguson (London) et W Tsai (Calgary). Vingt-huit médecins canadiens s’intéressant aux troubles respiratoires du sommeil y ont pris part. Une ébauche de résumé a été élaborée, puis révisée et finalisée par le Comité des troubles respiratoires du sommeil de la SCT lors d’une journée de réunion à Toronto, le 17 février 2006. Les membres du Comité ont ensuite classé les niveaux de preuve comme suit : niveau A – méta-analyse de qualité ou essai clinique randomisé (ECR) unique comportant un faible risque de biais; niveau B – analyse méthodique de qualité d’études de cohortes, étude de cohortes unique comportant un faible risque de biais ou preuves extrapolées à partir d’ECR de qualité ou d’ECR comportant un risque de biais; niveau C – études cas-témoins ou études de cohortes comportant un risque de biais; ou niveau D – séries de cas, exposés de cas ou rapports d’experts. Les membres du Comité ont également indiqué leur opinion concernant chaque déclaration (tout à fait d’accord, d’accord, neutre, pas d’accord ou pas du tout d’accord). Seules les déclarations avec lesquelles au moins 90 % des membres du comité étaient tout à fait d’accord ou d’accord ont été incluses.

Analysis of hospital discharge data to characterize obstructive sleep apnea and its management in adult patients hospitalized in Canada: 2006 to 2007

BACKGROUND Diagnosed obstructive sleep apnea (OSA) affects 2% to 7% of middle-age persons worldwide and represents a substantial health care burden. The gold standard for treating OSA in adults is continuous positive airway pressure (CPAP) therapy. Compliance with this treatment is especially important in OSA patients experiencing concomitant acute and chronic disease or illness, and those undergoing procedures associated with sedation, analgesia and anesthesia. OBJECTIVE To describe the clinical characteristics and management of hospitalized OSA patients in Canada. METHODS Using the Canadian Institute for Health Informations hospital Discharge Abstract Database (fiscal year 2006⁄2007), a retrospective cohort study of all acute care patients discharged with a diagnosis that included OSA was performed. RESULTS An examination of the discharge data of 2,400,245 acute care hospital abstracts identified 8823 cases of OSA. The mean age of OSA patients was 45.7 years and 66.5% were men. The most common comorbidities in the adult OSA population were obesity, cardiovascular disease, type 2 diabetes mellitus and chronic obstructive pulmonary disease. In adult OSA patients, the reported surgical intervention rate using uvulopalatopharyngoplasty (9.6%) was much higher than interventional CPAP therapy (4.8%). CONCLUSIONS Only a small percentage of hospitalized OSA patients were documented as having received CPAP therapy during their stay. Issues relating to the accuracy, specificity and completeness of the Canadian Institute for Health Informations hospital Discharge Abstract Database specific to OSA and its management were identified. Practices pertaining to the reporting, coding and management of hospitalized adult OSA patients warrant further investigation and research.

Distinct Patterns of Hyperpnea During Cheyne-Stokes Respiration: Implication for Cardiac Function in Patients With Heart Failure

STUDY OBJECTIVES In heart failure (HF), we observed two patterns of hyperpnea during Cheyne-Stokes respiration with central sleep apnea (CSR-CSA): a positive pattern where end-expiratory lung volume remains at or above functional residual capacity, and a negative pattern where it falls below functional residual capacity. We hypothesized the negative pattern is associated with worse HF. METHODS Patients with HF underwent polysomnography. During CSR-CSA, hyperpnea, apnea-hyperpnea cycle, and lung to finger circulation times (LFCT) were measured. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentration and left ventricular ejection fraction (LVEF) were assessed. RESULTS Of 33 patients with CSR-CSA (31 men, mean age 68 years), 9 had a negative hyperpnea pattern. There was no difference in age, body mass index, and apnea-hypopnea index between groups. Patients with a negative pattern had longer hyperpnea time (39.5 ± 6.4 versus 25.8 ± 5.9 seconds, P < .01), longer cycle time (67.8 ± 15.9 versus 51.7 ± 9.9 seconds, P < .01), higher NT-proBNP concentrations (2740 [6769] versus 570 [864] pg/ml, P = .01), and worse New York Heart Association class (P = .02) than those with a positive pattern. LFCT and LVEF did not differ between groups. CONCLUSIONS Patients with HF and a negative CSR-CSA pattern have evidence of worse cardiac function than those with a positive pattern. Greater positive expiratory pressure during hyperpnea is likely generated during the negative pattern and might support stroke volume in patients with worse cardiac function. COMMENTARY A commentary on this article appears in this issue on page 1227. CLINICAL TRIAL REGISTRATION The trial is registered with Current Controlled Trials (www.controlled-trials.com; ISRCTN67500535) and Clinical Trials (www.clinicaltrials.gov; NCT01128816).