1. Home
  2. keyboard_arrow_right
  3. Closed
  4. keyboard_arrow_right
  5. PRISM
A controlled trial of continuous positive airway pressure (CPAP) to prevent respiratory complications and improve survival following major abdominal surgery


The aim of the PRISM study is to determine whether early postoperative continuous positive airway pressure (CPAP) reduces the incidence of subsequent respiratory complications and improves one-year survival following major intra-peritoneal surgery.


Far from being replaced by new drug therapies, surgical treatments are offered to more patients than ever before. In particular, older patients with serious medical problems are more likely to undergo surgery today than 20 years ago. In a technical sense, surgery and anaesthesia are very safe, yet high-risk patients frequently develop medical complications, especially following major abdominal surgery. These complications have a lasting human and financial cost which may be avoidable. Surgery and anaesthesia have a number of harmful effects on the lungs, and respiratory complications, such as pneumonia, are amongst the most important in terms of frequency and severity. However, current standard treatments like physiotherapy and supplemental oxygen do not always prevent complications from developing.

Several, small clinical trials have shown that continuous positive airways pressure (CPAP) can reduce respiratory complications after major abdominal surgery. CPAP is a method of supporting breathing using slightly pressurised air, usually delivered using a tightfitting facemask. This can make it easier for patients to breathe, and may help them recover more quickly from the effects of surgery and anaesthesia, so avoiding complications such as pneumonia. CPAP has been widely used for many years in the treatment of patients with various types of breathing problems and can be delivered safely on hospital wards or even in the patient’s home. However, a lack of robust evidence from largescale clinical trials has prevented the routine use of CPAP for patients after abdominal surgery.

We aim to recruit 4,800 patients into an international, randomised controlled trial to determine whether CPAP immediately after major abdominal surgery can reduce the number of patients who develop serious respiratory complications.

Chief investigator

Chief investigator

Prof Rupert Pearse

Principal investigator

Principal investigator

Dr Tonny Veenith
Current recruitment number