Lay summary
More than 280,000 surgeries are performed in New Zealand every year. The amount of oxygen given to patients during and after major operations may affect their risk of post-operative complications. Given the large number of operations being performed, establishing the optimal approach to oxygen therapy in patients undergoing major surgery is a public health priority. The Hospital Operating Theatre- Randomised OXygen trial (HOT-ROX) is a 1760-participant randomised controlled trial (RCT). It will establish whether careful titration of oxygen improves outcomes compared with using oxygen liberally for patients having major surgery. Before proceeding with HOT-ROX, this feasibility study is being conducted to evaluate a range of issues including protocol compliance, recruitment rate feasibility, protocol safety, and ease of protocol implementation.