A5028082580- Obstructive Sleep Apnea Research
- Neuroscience of respiration and sleep
- Sleep and related disorders
- Sleep and Wakefulness Research
- Restless Legs Syndrome Research
- Respiratory Support and Mechanisms
- Cardiovascular and Diving-Related Complications
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Dysphagia Assessment and Management
- Genetic Associations and Epidemiology
- Tracheal and airway disorders
- High Altitude and Hypoxia
- Intensive Care Unit Cognitive Disorders
- Heart Rate Variability and Autonomic Control
- Sleep and Work-Related Fatigue
- Dialysis and Renal Disease Management
- Neonatal and fetal brain pathology
- Myeloproliferative Neoplasms: Diagnosis and Treatment
- Gastroesophageal reflux and treatments
- Genomics and Rare Diseases
- Congenital Heart Disease Studies
- Cardiovascular Disease and Adiposity
- Diet and metabolism studies
- Parkinson's Disease Mechanisms and Treatments
- EEG and Brain-Computer Interfaces
University of Calgary
2016-2025
Foothills Medical Centre
2015-2024
Allen Institute for Brain Science
2010-2024
University of British Columbia
2007-2024
GTx (United States)
2021-2022
In-Q-Tel
2021-2022
Beth Israel Deaconess Medical Center
2021
University of Saskatchewan
2020
Canadian Sleep & Circadian Network
2019-2020
Libin Cardiovascular Institute of Alberta
2010-2019
The Canadian Continuous Positive Airway Pressure for Patients with Central Sleep Apnea and Heart Failure trial tested the hypothesis that continuous positive airway pressure (CPAP) would improve survival rate without heart transplantation of patients who have central sleep apnea failure.
In the main analysis of 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, only reduced mean apnea-hypopnea index to 19 events per hour sleep, which remained above trial inclusion threshold 15. This stratified CANPAP tested hypothesis that suppression CSA below this by would improve left ventricular ejection fraction survival.Of 258 failure patients in...
Sleep apnea is common in patients with chronic renal failure and not improved by either conventional hemodialysis or peritoneal dialysis. With nocturnal hemodialysis, undergo seven nights per week at home, while sleeping. We hypothesized that would correct sleep because of its greater effectiveness.
Recent studies have challenged the traditional hypothesis that excessive environmental noise is central to etiology of sleep disruption in intensive care unit (ICU). We characterized potentially disruptive ICU stimuli and patient-care activities determined their relative contributions disruption. Furthermore, we studied effect isolation by placing healthy subjects both normal noise-reduced locations. Seven mechanically ventilated patients six were continuous 24-hour polysomnography with...
We hypothesized that mortality is higher in patients with congestive heart failure (CHF) who develop Cheyne-Stokes respiration (CSR) during sleep than CHF without CSR. Overnight polysomnography was performed on 16 male chronic, stable CHF: nine had CSR (CSR group) and seven did not (CHF group). The group a apnea-hypopnea index (AHI: 41 +/- 17 versus 6 5/hr) experienced greater disruption. There were no significant intergroup differences between age, weight, cardiac function, pulmonary...
We examined the influence of gender on polysomnographic features obstructive sleep apnea (OSA) in a retrospective study 830 patients with OSA diagnosed by overnight polysomnography (PSG). The severity was determined from apnea– hypopnea index (AHI) for total time (AHITST), and classified as mild (5 to 25 events/h), moderate (26 50 severe ( > 50/events/h). Differences during different stages were assessed comparing AHI non-rapid eye movement (NREM) (AHINREM) rapid (REM) (AHIREM) calculating...
Study Objective: To determine the effect of supplemental oxygen on Cheyne-Stokes respiration, nocturnal saturation (SaO2), and sleep in male patients with severe, stable congestive heart failure. Design: Randomized, single-blind, placebo-controlled crossover study. Setting: Patients referred from outpatient cardiology clinics two teaching hospitals. Patients: Sequential sample nine outpatients Interventions: For each patient, studies (after an adaptation night) consecutive randomized nights...
The response to chemical stimuli (chemical responsiveness) and the increases in respiratory drive required for arousal (arousal threshold) opening airway without (effective recruitment are important determinants of ventilatory instability and, hence, severity obstructive apnea. We measured these variables 21 apnea patients (apnea-hypopnea index 91 +/- 24 h(-1)) while on continuous-positive-airway pressure. During sleep, pressure was intermittently reduced (dial down) induce severe hypopneas....
Rationale: Periodic occlusion of the upper airway in patients with obstructive sleep apnea leads to chronic intermittent hypoxia, which increases acute hypoxic ventilatory response (AHVR). Animal studies suggest that oxidative stress may modulate AHVR by increasing carotid body sensitivity hypoxia. This has not been shown humans.Objectives: To determine whether 4 days exposure hypoxia and strength association between AHVR.Methods: After two normoxic control (Day −4 Day 0), 10 young healthy...
Intermittent hypoxia (IH) is believed to contribute the pathogenesis of hypertension in obstructive sleep apnea through mechanisms that include activation renin-angiotensin system. The objective this study was assess role type I angiotensin II receptor mediating an increase arterial pressure associated with a single 6-hour IH exposure. Using double-blind, placebo-controlled, randomized, crossover design, we exposed 9 healthy male subjects sham IH, placebo medication, and antagonist losartan....
The Canadian Thoracic Society (CTS) guidelines for the diagnosis and treatment of sleep disordered breathing in adults were developed over past year. A one-day meeting was held Montreal, Quebec, on October 28, 2005, just before annual CTS meeting. facilitated by Dr R Davies (Oxford, United Kingdom), speakers included D Morrison (Halifax, Nova Scotia), J Kimoff (Montreal), Fleetham (Vancouver, British Columbia), C George (London, Ontario), M Kryger (Winnipeg, Manitoba), P Hanly (Calgary,...
To develop and validate an algorithm that provides a continuous estimate of sleep depth from the electroencephalogram (EEG).Retrospective analysis polysomnograms.Research laboratory.114 patients who underwent clinical polysomnography in centers at University Manitoba (n = 58) Calgary 56).None.Power spectrum EEG was determined 3-second epochs divided into delta, theta, alpha-sigma, beta frequency bands. The range powers each band 10 aliquots. patterns were assigned 4-digit number reflects...
The visual appearance of cortical arousals varies considerably, from barely meeting scoring criteria to very intense arousals. Arousal sleep is associated with an increase in heart rate (HR). Our objective was quantify the intensity manner using time and frequency characteristics electroencephalogram (EEG) determine whether HR response arousal correlates so determined.
Study Objectives:Certain respiratory control characteristics determine whether patients with collapsible upper airway develop stable or unstable breathing during sleep, thereby influencing the severity of obstructive apnea (OSA). These include arousal threshold (TA), response to transient hypoxia and hypercapnia (Dynamic Response) increase in drive required for arousal-free opening (TER). We wished these are inherent acquired untreated OSA.
Background Although obstructive sleep apnea (OSA) is more common in patients with kidney disease, whether nocturnal hypoxia affects function unknown. Methods We studied all adult subjects referred for diagnostic testing of between July 2005 and December 31 2007 who had serial measurement their function. Nocturnal was defined as oxygen saturation (SaO2) below 90% ≥12% the monitoring time. The primary outcome, accelerated loss function, a decline estimated glomerular filtration rate (eGFR) ≥4...
To determine the reasons for inter-scorer variability in sleep staging of polysomnograms (PSGs).Fifty-six PSGs were scored (5-stage scoring) by 2 experienced technologists, (first manual, M1). Months later, technologists edited their own scoring (second M2) based upon feedback from investigators that highlighted differences between scoring. The then with an automatic system (Auto) and them, epoch-by-epoch (Edited-Auto). This resulted 6 different manual scores each PSG. Epochs classified as...