The influence of anesthesia and postoperative analgesic management of lung function.

General anesthesia itself may influence postoperative lung function. It leads to a depression of the functional residual capacity, which, in combination with surgical trauma and postoperative pain, can provoke insufficient breathing, retention of bronchial secretions, and atelectasis. Regional anesthesia has no influence on lung function. After upper abdominal or thoracic surgery, postoperative epidural analgesia causes a significant increase of lung function as compared with systemic analgesia. The combination of regional anesthesia and general anesthesia intraoperatively appears to reduce lung function much less than general anesthesia alone.