Relationship between the duration of the preoperative smoke-free period and the incidence of postoperative pulmonary complications after pulmonary surgery

Objective: To examine the relationship between the duration of the preoperative smoke-free period and the development of postoperative pulmonary complications (PPCs) in patients who underwent pulmonary surgery, and the optimal timing of quitting smoking. Design: Retrospective cohort study. Setting: Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan. Patients: Two hundred eighty-eight consecutive patients who underwent pulmonary surgery between January 1997 and December 1998. Measurements and results: We collected information on the preoperative characteristics, intraoperative conditions, and occurrence of PPCs by reviewing the medical records. Study subjects were classified into four groups based on their smoking status. A current smoker was defined as one who smoked within 2 weeks prior to the operation. Recent smokers and ex-smokers were defined as those whose duration of abstinence from smoking was 2 to 4 weeks and > 4 weeks prior to the operation, respectively. A never-smoker was defined as one who had never smoked. The incidence of PPCs among the current smokers and recent smokers was 43.6% and 53.8%, respectively, and each was higher than that in the never-smokers (23.9%; p < 0.05). The moving average of the incidence of PPCs gradually decreased in patients whose smoke-free period was 5 to 8 weeks or longer. After controlling for sex, age, results of pulmonary function tests, and duration of surgery, the odds ratios for PPCs developing in current smokers, recent smokers, and ex-smokers in comparison with never-smokers were 2.09 (95% confidence interval [CI], 0.83 to 5.25), 2.44 (95% CI, 0.67 to 8.89), and 1.03 (95% CI, 0.47 to 2.26), respectively. Conclusions: These findings indicate that preoperative smoking abstinence of at least 4 weeks is necessary for patients who undergo pulmonary surgery, to reduce the incidence of PPCs.