Relevant clinical and physiologic data are available to help guide decision making in the management of patients who are at risk for or already have postoperative pulmonary complications. Prophylactic measures should be simple and focused. Inexpensive treatment methods should be tried before resorting to more individual-intensive and expensive measures. Proper treatment of postoperative atelectasis requires adequate patient assessment and knowledge of the therapeutic options. Costs, measured in dollars as well as in patient morbidity and mortality, are substantially greater when physicians fail to recognize and treat reversible disease before elective surgery and when effective postoperative therapy is not provided in accordance with individual needs.