Study 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
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.
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.
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.