Postoperative High-flow Nasal Oxygenation After High-risk Surgery in the Frail Adult

High flow nasal oxygen (HFNO) in the immediate postoperative period has been demonstrated to reduce the risk of postoperative pulmonary complications (PPC) after cardiothoracic surgery. In specific groups of patients such as the obese and after upper abdominal surgery the results are contradictive. However, there is lack of evidence if HFNO in the general high-risk patient after abdominal and non-cardiac thoracic surgery can reduce the prevalence of PPC, hypoxaemia and escalation of therapy. Therefore, the investigators aim to compare the use of HFNO with conventional oxygen therapy (COT) in high-risk patients after abdominal and non-cardiac thoracic surgery regarding postoperative pulmonary complications.