postoperative respiratory failure

there is no signle cause of postoperative respiratory insufficiency but a number of factors have been identified for example obesity, advanced age, preexisting disease, surgical procedure and its duration, intraoperative hypercapnia, anaesthetic patients undergoing thymectomy.the importance of orderly preoperative pulmonary program is emphasized.diagnosis of respiratory failure in based on recognition of a condition which may predispose to it, clinical evidence of hypxoaemia with or without hypercapnia and arterial blood gas analysis.