Perioperative UtiLisation of SupplEmental Oxygen

The World Health Organisation recommends that all patients having a general anaesthetic for surgery should be given 80% oxygen as this might reduce their risk of getting an infection after their operation. However there remains a lot of uncertainty about how much oxygen patients should be given whilst undergoing surgery. In other areas of medicine evidence is slowly emerging to suggest that giving less oxygen may be as safe or even safer than giving high amounts of oxygen (e.g. after a heart attack, patients unnecessarily given oxygen seem to do worse than those given air). The amount of oxygen currently given to patients having surgery varies widely; in a recent study of almost 400 procedures across 29 hospitals, we found values ranged from below 30% to almost 100% oxygen. The aim of this research is to explore if giving less oxygen will generate less strain on parts of the body, particularly the lungs as they are always exposed to all of the oxygen that enters the body. Participants undergoing major elective surgical procedures will be randomised to receive either 80%, 55% or 30% throughout their general anaesthetic and levels of inflammation, oxidative stress and perioperative recovery will all be measured for upto 7 days after surgery.