Postoperative respiratory failure is defined as failure to wean from mechanical ventilation within 48 to 72 hours or the need for unplanned postoperative intubation. It occurs in up to 3% of the patients undergoing noncardiac surgery and is associated with increased mortality and the development of further complications such as myocardial infarction, pneumonia, renal failure, deep venous thrombosis, and pulmonary embolism. Despite advances in perioperative care, the incidence of PRF and its associated mortality have remained largely unchanged.