Optimal pre-operative duration of Continuous Positive Airway Pressure
Research type
Research Study
Full title
Assessment of the Optimal Duration of Continuous Positive Airway Pressure (CPAP) Pre-Operatively in Patients with Newly-Diagnosed Obstructive Sleep Apnoea Syndrome Referred for Bariatric Surgery.
IRAS ID
205300
Contact name
Michael K Wood
Contact email
Sponsor organisation
Ashford and St Peter's Hospitals NHS Foundation Trust
Duration of Study in the UK
2 years, 3 months, 21 days
Research summary
Obesity is increasing pandemically. It is the greatest risk factor for Obstructive Sleep Apnoea/Hypopnoea Syndrome (OSAHS), which occurs in up to 70% of patients referred for Bariatric (weight-reduction) surgery.
OSAHS is caused by recurrent collapse of the upper airway during sleep leading to intermittent airway obstruction, despite respiratory effort. The resulting recurrent cycles of hypoxaemia (reduced blood oxygen levels) and repeated waking (“arousals”), cause fragmented sleep. Three mechanisms resulting from intermittent hypoxaemia/arousals relevant to cardiovascular consequences of OSAHS have been proposed: sympathetic activation, oxidative stress, and systemic inflammation. These are thought to be associated with increased risk of hypertension, heart attacks, heart failure, strokes, and sudden death from heart rhythm disturbances.
Patients referred for bariatric surgery are screened for OSAHS; if present they are treated with Continuous Positive Airway Pressure (CPAP), a mechanism of delivering air at continuous pressure via a face-mask to “splint open” the patient’s airway and prevent repetitive airway closure. Previous studies have demonstrated a beneficial effect of CPAP in this group of patients on such variables as blood pressure, heart function, exercise capacity and blood levels of chemicals released in OSAHS (inflammatory markers). However, the question of how long this should be used before patients are considered optimised (fit) for surgery remains unanswered.
Our feasibility study aims to assess the effect of CPAP and duration of use in patients with newly-diagnosed OSAHS on several of these variables whilst they are undergoing routine assessment for bariatric surgery, a process that lasts approximately 12 to 24 months in our Trust (Ashford and St Peter’s Hospitals NHS Foundation Trust). Patients will be studied at baseline and at pre-determined time points before surgery, then once after surgery. The majority of the tests will be performed at the Surrey Human Performance Institute, in collaboration with Surrey University.REC name
West Midlands - South Birmingham Research Ethics Committee
REC reference
17/WM/0322
Date of REC Opinion
14 Aug 2017
REC opinion
Favourable Opinion