Prevention of Respiratory Insufficiency after Surgical Management (PRISM) trial: report of the protocol for a pragmatic randomised controlled trial of Continuous Positive Airway Pressure (CPAP) to prevent respiratory complications and improve survival following major abdominal surgery.
BACKGROUND: Over 300 million patients undergo surgery worldwide each year. Postoperative morbidity - particularly respiratory complications - are most frequent and severe among high-risk patients undergoing major abdominal surgery. However, standard treatments, like physiotherapy or supplemental oxygen, often fail to prevent these. Preliminary research suggests that prophylactic continuous positive airways pressure (CPAP) can reduce the risk of postoperative respiratory complications. However, without evidence from a large clinical effectiveness trial, CPAP has not become routine care. This trial aims to determine whether early postoperative CPAP reduces the incidence of respiratory complications and improves one-year survival following major intra-peritoneal surgery. METHODS: This is an international multi-centre randomised controlled trial with open study group allocation. The participants are aged 50 years and over undergoing major elective intra-peritoneal surgery. The intervention is CPAP for at least four hours, started within four hours of the end of surgery. The primary outcome is a composite of pneumonia, re-intubation, or death within 30 days of randomization. RESULTS: All participants with a recorded outcome will be analysed on an intention-to-treat basis. The primary analysis will use a mixed-effects logistic regression model, which includes centre as a random-intercept, and will be adjusted for the minimisation factors and other pre-specified covariates. TRIAL REGISTRATION: ISRCTN 56012545. CONCLUSION: This is the first proposed clinical effectiveness trial of postoperative CPAP to prevent respiratory complications of which we are aware. The large sample size and multi-centre international design will make the result generalisable to a variety of healthcare settings.