Postoperative pulmonary complications contribute significantly to overall perioperative morbidity and mortality. In a study of patients undergoing elective abdominal surgery, as an example, pulmonary complications occurred significantly more often than cardiac complications and were associated with significantly longer hospital stays . The National Surgical Quality Improvement Program (NSQIP) also found that postoperative pulmonary complications were the most costly of major postoperative medical complications (including cardiac, thromboembolic, and infectious) and resulted in the longest length of stay .
The field of preoperative pulmonary evaluation is increasingly driven by evidence-based medicine, rather than expert opinion. As the impact of pulmonary complications following surgery has become increasingly apparent, estimation of their risk should be a standard element of all preoperative medical evaluations.
The definition of postoperative pulmonary complications, pertinent anesthetic physiology, identification of patient and procedure-related risk factors, and the role of preoperative pulmonary function testing and pulmonary risk indices will be reviewed here. Strategies for reducing postoperative pulmonary complications and the evaluation of candidates for lung resection surgery are discussed separately. (See "Strategies to reduce postoperative pulmonary complications" and "Preoperative evaluation for lung resection".)
DEFINITION OF POSTOPERATIVE PULMONARY COMPLICATIONS
The reported frequency of postoperative pulmonary complications in the literature varies from 2 to 70 percent. This wide range is due in part to patient selection and procedure-related risk factors, although differing definitions for postoperative complications account for much of the variability and make comparison of reported incidences across different studies difficult.
One broad definition of postoperative pulmonary complications includes all patients with fever and either pulmonary signs, symptoms (eg, productive cough, rhonchi, or diminished breath sounds), or changes on chest x-ray (eg, atelectasis, consolidation, or incomplete expansion) [3,4]. However, many such liberally defined postoperative complications are of no clinical relevance.