Try our beta test site
IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more...

Unrecognised Obstructive Sleep Apnea Study (OSA)

This study is currently recruiting participants. (see Contacts and Locations)
Verified May 2016 by University Health Network, Toronto
Information provided by (Responsible Party):
Dr. Frances Chung, University Health Network, Toronto Identifier:
First received: December 12, 2011
Last updated: May 25, 2016
Last verified: May 2016

December 12, 2011
May 25, 2016
July 2011
December 2017   (Final data collection date for primary outcome measure)
primary outcome of this study is postoperative vascular event within 30 days after surgery [ Time Frame: 30 days ]
Same as current
Complete list of historical versions of study NCT01494181 on Archive Site
Not Provided
Not Provided
Not Provided
Not Provided
Unrecognised Obstructive Sleep Apnea Study
Postoperative Vascular Events in Unrecognised Obstructive Sleep Apnea

Plan of investigation:

This is an observational cohort study to determine the effect of OSA, independent of other risk factors, on postoperative vascular events. The study is conceived, designed and will be conducted, and analyzed independent to any company. There is no commercial sponsorship.

The potential study subjects will be approached by study coordinator at preoperative clinic. If the patient is interested in participating the study, he/she will be screened and consented. Undetected or untreated OSA will be established by STOP-Bang questionnaire and subsequent overnight PSG by using Apnea Link Plus which is level ( 2 ) at patient's home.The following data will be recorded: including age, gender, history of coronary artery disease, prior revascularization, cerebrovascular disease, peripheral vascular disease, critical aortic valvular stenosis, congestive heart failure, atrial fibrillation, diabetes treated with insulin or an oral diabetic drug, hypertension, hypercholesterolemia treated with drug therapy, tobacco use, renal insufficiency and the type of surgery. For all study patients, the nocturnal blood oxygen saturation will be monitored by a pulse oximeter (PULSOX 300i) for first 3 nights postoperatively.During their stay in hospital, patients will be followed daily, and outcomes will be recorded, until discharge.. ECG will be measured preoperatively and repeated on day 1 to 3 after surgery. Venous blood will be collected 6-12 hours and on the first 3 days after surgery for measuring cTnT concentration.If patient's ECG is abnormal and/or patient is positive for troponin test, treating physician will be contacted for further treatment. Patient will be contacted 30 days after surgery by phone to ascertain if they have experienced any adverse out come.
Time Perspective: Prospective
Not Provided
Not Provided
Non-Probability Sample
Surgical patient
Obstructive Sleep Apnea
Not Provided
Not Provided
Chan MT, Wang CY, Seet E, Tam S, Lai HY, Walker S, Short TG, Halliwell R, Chung F; POSA Investigators.. Postoperative vascular complications in unrecognised Obstructive Sleep apnoea (POSA) study protocol: an observational cohort study in moderate-to-high risk patients undergoing non-cardiac surgery. BMJ Open. 2014 Jan 9;4(1):e004097. doi: 10.1136/bmjopen-2013-004097.

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
December 2017
December 2017   (Final data collection date for primary outcome measure)

Patients Inclusion & Exclusion Criteria:

Inclusion criteria:

Ethics Committee approval and informed consent will be obtained. We plan to study patients at moderate-to-high risk for postoperative vascular complications because our data from other trials suggested that the incidence of OSA in these patients is higher than the general population. We will include patients who are:

  1. adult males and females, age ≥ 45 years, undergoing elective non-cardiac surgery that is expected to require a postoperative hospital stay of more than 3 nights, and
  2. at increased risk for postoperative vascular events, defined as having at least one of the following risk factors (a) high-risk surgery (intra-peritoneal, intra-thoracic or supra-inguinal vascular surgery); (b) history of ischemic heart disease; (c) history of congestive heart failure; (d) history of cerebrovascular disease (d) diabetes requiring insulin therapy (e) serum creatinine > 175 µmol/L.

Exclusion criteria:

Patients will be excluded if:

  1. they have a previous diagnosis of OSA or any sleep-related breathing disorder and on treatment
  2. they are unwilling or physically unavailable for PSG on any night before surgery;
  3. their surgery included tonsillectomy, septoplasty, uvuloplasty, pharyngoplasty, tracheostomy, or prolonged (> 48 hrs) postoperative mechanical ventilation of the lungs is anticipated. It is because these procedures/interventions are likely to cure or at least modify the severity of OSA.
Sexes Eligible for Study: All
45 Years and older   (Adult, Senior)
Contact: Dr. Frances Chung, MBBS, FRCPC 4166035800 ext 5433
Contact: Sohail Iqbal, MD 4167908307
Canada,   Hong Kong,   Malaysia,   Singapore
Version Nov 14, 2011
Not Provided
Not Provided
Not Provided
Dr. Frances Chung, University Health Network, Toronto
University Health Network, Toronto
Not Provided
Principal Investigator: Frances Chung, MBBS, FRCPC University Health Network, Toronto
University Health Network, Toronto
May 2016

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP