Preoperative pulmonary evaluation. Identifying patients at increased risk for complications.

During surgical procedures, multiple physiologic changes affect the pulmonary system and its defense mechanisms. The presence of basic risk factors (eg, smoking, chronic obstructive pulmonary disease, severe obesity) can affect whether these physiologic changes result in pulmonary complications or even death. Therefore, the presence of risk factors should be ascertained in all patients before abdominal or thoracic surgery. The degree of risk can be further determined preoperatively by additional evaluation, such as pulmonary function testing, newer assessment of cardiorespiratory status, history taking, and physical examination. The presence of risk factors and the type of operation to be performed should guide decisions about whether to perform a procedure or to use prophylactic measures before and after surgery. New operative techniques may allow some procedures that were prohibited in the past to be performed in high-risk patients.