Answer:

Respiratory failure commonly complicates the postoperative period and is strongly associated with an increased mortality. A number of clinical prediction rules exist to predict the risk of postoperative pulmonary complications. Predisposing factors include a high American Society of Anesthesiologists (ASA) Physical Status Classification, poor functional status, and hypoalbuminemia. Lung diseases such as obstructive airways dysfunction, extrapulmonary diseases such as liver cirrhosis, congestive heart failure, renal failure, and current or former smoking status also predispose patients to respiratory failure. Additional risk factors include emergency indications for surgery, prolonged procedural time, and the requirement for large volume fluid and blood product resuscitation. Because of their effects on respiratory mechanics, thoracoabdominal surgeries, especially aortic aneurysm repair, are particularly high-risk procedures.

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