Short-Term Preoperative Smoking Cessation and Postoperative Complications
June 1, 2002 4 minutes read
Short-Term Preoperative Smoking Cessation and Postoperative Complications
Abstract & Commentary
Synopsis: This study of a 6-week smoking cessation intervention prior to hip or knee replacement produced a preoperative quit rate of 64% and a significantly lower incidence of postoperative complications, primarily wound infections.
Source: Möller AM, et al. Lancet. 2002;359:114-117.
This randomized clinical trial from 3 university hospitals in Denmark sought to determine the effect of a short-term preoperative smoking cessation regimen on the incidence and effect of complications following hip and knee replacement. Current smokers scheduled for one of these procedures were invited to participate in the study, and those who consented were randomized to a 6-week preoperative smoking cessation intervention or a nonintervention control. Intervention patients met weekly with a project nurse trained in smoking cessation. They were offered the options of stopping completely or reducing cigarette use by 50%. In addition to counseling, the patients in this group received free nicotine replacement therapy. Postoperative complications were assessed by an assessor masked to the intervention, and patients were observed from the onset of surgery to hospital discharge.
A total of 120 out of 166 patients screened for the study agreed to participate. The intervention and control groups were evenly matched in terms of demographics, comorbidities, preoperative laboratory results, pulmonary function, intraoperative factors, and smoking habits. Both groups smoked an average of 15 cigarettes per day and had average past exposures of about 36 pack-years. Chronic cardiopulmonary disease was known to be present in 10-15% of the patients. Of the 60 patients randomized to smoking cessation, 4 had surgery cancelled or postponed and 56 completed the intervention: 36 stopped smoking, 14 cut down, and 6 did not change their smoking habits. Among the 60 control patients, 8 had their surgery cancelled or postponed; 4 of the remaining 52 stopped smoking, and 48 continued smoking.
The overall postoperative complication rate was 52% in the control group and 18% in the smoking cessation group (P = 0.0003). By complication category, only wound-related complications were significantly more frequent in the control patients: 16 (31%) vs. 3 (5%); P = 0.001. Wound infections accounted for the majority of these. There were trends suggesting more cardiovascular insufficiency (5 vs 0 patients; P = 0.08) and an increased requirement for secondary surgery (8 vs 2 patients; P = 0.07) in the control patients, but these differences did not meet Möller and colleagues’ a priori thresholds for significance. The reduction in complication rate was observed only among intervention patients who stopped smoking preoperatively; patients who only reduced their cigarette consumption were indistinguishable from the control group. Length of hospital stay (13 vs 11 days, in control and intervention groups, respectively) was not different (P = 0.41).
Comment by David J. Pierson, MD
In this study, a 6-week smoking cessation intervention prior to hip or knee replacement was associated with a preoperative quit rate of 64% and a significantly lower incidence of postoperative wound infections. Möller et al postulate that the latter was due to elimination of adverse effects of smoking on wound healing, including vasoconstriction, abnormal collagen formation, and impaired immune function. The presence of these things in smokers has been suggested by a variety of experimental studies. Regardless of the mechanisms for the differences observed in this study, the authors conclude that short-term smoking cessation has important benefits, and recommend that their intervention regimen be widely adopted.
Everybody "knows" that people should stop smoking before elective surgery. However, unlike the situation with long-term effects of smoking cessation, actual proof of the beneficial effects of short-term abstinence from smoking has been hard to come by.1,2 This study provides much-needed support for preoperative smoking cessation but falls short of the proof that is needed in this area. Although Möller et al used a rigorous study design, it is uncertain whether the person performing the "blinded" daily assessments for complications throughout the patients’ hospital courses could truly be unaware of whether they were continuing to smoke. How the various complications were defined is not stated in the paper, and the clinical effect of the observed complications is uncertain in the absence of any difference in hospital stays. A postoperative complication rate of 52% of the control patients is extremely high. In addition, although it is not a criticism of the study, getting nearly two thirds of long-term smokers to quit altogether during the 6 weeks prior to scheduled surgery (confirmed by exhaled carbon monoxide monitoring) is a degree of success that most programs could only dream of. Thus, this study is an important step in the right direction, but whether these results could be achieved in clinical practice remains to be seen.
Dr. Pierson is Professor of Medicine, University of Washington, Medical Director Respiratory Care, Harborview Medical Center, Seattle.
References
1. Tobin MJ, et al. Respir Care. 1984;29(6):641-649.
2. Warner MA, et al. Anesthesiology. 1984;60:380-383.
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