Prediction of postoperative hypoxemia in smokers and non-smokers

Age, weight, spirometric variables, peak expiratory flow and airway closure assessments were correlated to postoperative gas exchange in 40 cholecystectomized subjects grouped according to smoking history. Pao2 was significantly lower in the smoking group both pre- and postoperatively, but the decrease in Pao2 following operation was of the same magnitude irrespective of smoking history. In non-smokers, the preoperative relationship between expiratory reserve volume and closing volume (ERV-CV) showed the highest correlation to postoperative alveolar-arterial oxygen difference P(A-a)o2 (r = -0.88, P less than 0.001) and to the increase of P(A-a)o2 following operation (r = -0.67, P less than 0.001), whereas age was found to be the best preoperative predictor of postoperative gas exchange in smokers.