Damage to the ciliated cells of the tracheobronchial tree and incidence of postoperative pulmonary complications were measured ured by point-scoring systems in 202 patients who breathed dry and humidified anesthetic gases for 225+/-78 min. The incidence of postoperative pulmonary complications decreased as the humidity of administered anesthetic gases increased from 0 to 32.5 mg H2O/1. A similar relationship was found between the amount of inhaled moisture and the damage to the ciliated epithelium of the tracheobronchial tree. These results appear to indicate that a high inspired humidity is beneficial for operations on normothermic patients, and that cellular damage caused by dryness is a possible contributory factor in the production of the pulmonary atelectasis that follows stoppage of the mucociliary transport system in the immediate postoperative period.
(C) 1979 American Society of Anesthesiologists, Inc.