None listed
Conditions
Brief summary
The study purpose is to evaluate the effect of 3 months CPAP treatment on exercise capacity of OSA patients. The study hypothesis is that exercise capacity of Chinese patients with moderate to severe OSA regardless of obesity status will be improved after CPAP treatment. Cardiopulmonary exercise test will be used to estimate the exercise capacity while polysomnography will be used for OSA diagnosis. Cardiopulmonary exercise test (CPET) is a safe investigation that has been used as a prognostic assessment in heart disease. In the past decade, there has been a growing interest in applying CPET on evaluation of exercise capacity and cardiovascular risk in OSA patients. Several studies showed that OSA patients had lower peak oxygen consumption rate (V’O2 in ml/min/kg), greater diastolic blood pressure at maximal exercise and reduced heart rate recovery than control group and these findings are linked to increased cardiovascular risk. Continuous positive airway pressure (CPAP) is a treatment of OSA that was found to improve maximal exercise response by increasing peak V’O2, heart rate recovery and blood pressure recovery. It was therefore postulated that CPAP treatment could reduce cardiovascular risk in OSA patients. Nevertheless, majority of these studies were done on obese Caucasian population and few are on Chinese ethnicity or non-obese OSA patients. The obesity definitions are different between Caucasian and Chinese population and previous studies results may not be totally applicable to Chinese patients with OSA. In obese population, the total body weight that was used in previous studies may be inaccurate compared with fat free mass (FFM) which is important especially during exercise test. FFM may provide a better estimation. Besides, one meta-analysis found that non-obese OSA patients (BMI <30 kg/m2) had higher degree of peak V’O2 reduction than obese OSA patients and therefore evaluating CPAP effect on this group of patients is valuable.
Interventions
Recruited subjects with moderate and severe obstructive sleep apnea (OSA) first receive investigations including polysomnography, cardiopulmonary exercise test, spirometry, echocardiography, blood test and chest X ray. Afterwards, they will receive three months continuous positive airway pressure (CPAP) treatment which is a standard management (Not experimental/new treatment). Participants would have received continuous positive airway pressure treatment regardless of their involvement in the st
Recruited subjects with moderate and severe obstructive sleep apnea (OSA) first receive investigations including polysomnography, cardiopulmonary exercise test, spirometry, echocardiography, blood test and chest X ray. Afterwards, they will receive three months continuous positive airway pressure (CPAP) treatment which is a standard management (Not experimental/new treatment). Participants would have received continuous positive airway pressure treatment regardless of their involvement in the study. After three months treatment, they will receive their second cardiopulmonary exercise test. CPAP titration may be performed in the sleep laboratory or in home settings. For in-laboratory PAP titration, an attended titration using a Philips Respironics DreamStation Auto CPAP or a Resmed Airsense 10 Autoset for autotitration under polysomnography (PSG) guidance will be performed. PAP pressure that can abolish respiratory events during supine REM sleep with good leakage control will be set as the treatment pressure. For home PAP titration, a Resmed Airsense 10 Autoset will be used for one week. Telemonitoring and daily phone contact will be conducted by trained nurses to optimize PAP usage and to perform trouble-shooting if needed. At the end of titration period, average 95% pressure with AHI less than 5/hr, good oxygen saturation and acceptable leakage will be set as the treatment pressure. If patient failed to achieve good control during home PAP titration, in-laboratory PAP titration till be arranged. Patients will be allowed to use fixed CPAP or autoCPAP according to their preferences after titration. The planned CPAP treatment would be every night over a period of at least 4 hours during sleep for a total duration of 3 months. Two sessions will be conducted as follow-up. The first session is a 30-minute face-to-face follow up conducted by respiratory nurses 6 weeks after CPAP titration to assess the following: whether patient has started PAP treatment; treatment compliance (An acceptable compliance will be defined as more than 4hr usage per night and 5-7 nights per week); treatment efficacy (Good treatment efficacy will be defined as average AHI < 5 per hour). If patient’s PAP machine cannot generate compliance report, an overnight oximetry will be performed. Good treatment efficacy will be defined as oxygen desaturation index (ODI) < 5 per hour. Trouble-shooting will be performed if patient cannot achieve good treatment compliance and efficacy. The second session is also a face-to-face appointment conducted by respiratory physicians and respiratory nurses 6 weeks after the first session to reassess parameters aforementioned. The second CPET will be arranged for participants that can achieve good treatment compliance and efficacy with CPAP.
Sponsors
Cheng Hei Shun
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
a) Chinese patients b) 18 – 70 years old c) Newly diagnosed with moderate to severe OSA confirmed by polysomnography (PSG)
Exclusion criteria
a) Pre-existing known pulmonary/cardiac diseases b) Left ventricular ejection fraction (LVEF) <50% or significant valvular disease detected in echocardiogram c) Ethnicity other than Chinese d) Invalid informed consent e) Previously or currently on OSA treatment (CPAP/Oral appliance/Surgical treatment) f) Sleep disorder other than OSA (e.g. central sleep apnea) g) Obesity hypoventilation syndrome h) Contraindication to CPAP treatment i) Contraindication to cardiopulmonary exercise test j) Known thyroid/renal/hepatic/neurological disease k) Known musculoskeletal disorder l) Mentally incapable m) Anaemia n) Peripheral vascular disease o) Alcohol/substance abuse p) Current medication including sedatives/sympathomimetics q) Acute respiratory/cardiovascular event within six weeks of cardiopulmonary exercise test
Outcome results
None listed