Cytology of respiratory epithelium as a predictor of respiratory complications after operation.

A study of 111 patients undergoing elective surgery under general endotracheal anesthesia has shown that the pulmonary complication rate after operation is minimal in nonsmokers (7.9 percent) and that it rises steadily as smoking habit increases, reaching 43 percent in very heavy smokers. Peak expiratory flow rate and timed vital capacity (FEV1) were unaffected before operation except in very heavy smokers. The morphologic integrity of the ciliated tracheobronchial epithelial cells seen in smears obtained within ten minutes of the onset of anesthesia and quantitated by a scoring system, deteriorates progressively with increasing smoking habit and constitutes the most sensitive index for the prediction of diminished resistance to the stress of anesthesia and operation and of incipient chronic obstructive lung disease in smokers.