Anesthesiologists are likely to encounter many patients who smoke cigarettes over their career. Smoking is an independent risk factor for surgical complications, even after accounting for its contribution to such chronic diseases as Chronic Obstructive Pulmonary Disease (COPD) and heart disease. One meta-analysis found relative risks: 2.15 for wound-related complications in smokers compared to non-smokers, 1.73 for pulmonary complications, and 1.60 for admission to the ICU. Smoking accounts for approximately $10 billion in postoperative costs annually in the United States.
Cigarette smoking accelerates atherosclerosis via endothelial injury, oxidative damage, increased thrombosis and a worsened lipid profile. Smoking also increases sympathetic tone, elevating heart rate, blood pressure, and contractility. Despite increasing coronary flow in healthy subjects, nicotine can decrease coronary perfusion in those with preexisting Coronary Artery Disease due to coronary vasoconstriction. Oxygen delivery to tissues is decreased due to elevated carboxyhemoglobin levels, which can exceed 10%.
Smoking cessation in patients with coronary disease can decrease risk of all-cause mortality by 1/3. It is difficult to define how long an abstinence is necessary to achieve this benefit, but it is estimated to be on the order of several months. However even brief periods of abstinence (days) can decrease carbon monoxide levels and improve autonomic instability.
Many of smoking’s pulmonary manifestations are irreversible, however several weeks of cessation can improve cough and wheezing. While mucus production can increase over the first couple weeks of abstinence, mucociliary clearance is partially improved after one week. Complications such as respiratory failure, laryngospasm and other induction-related airway events, bronchospasm, pneumonia, and unanticipated ICU admission are decreased after 8 weeks of cessation in several observational studies, with full benefit after 12 weeks. Some individual complications such as laryngospasm may be decreased after only a few days, as upper airway sensitivity to chemical irritants takes only a short time to return to normal upon smoking cessation.
Wound infections, dehiscence, and bone nonunion associated with smoking may return to non-smoking levels after a few weeks, though the exact duration of abstinence necessary requires further study.
Anesthesia providers are in a unique position to counsel patients preoperatively on the benefits of smoking cessation. The longer the duration of abstinence the more substantial the benefits, however even cessation in the days leading up to surgery is beneficial in decreasing intra- and postoperative complications.
References
Nolan MB, Warner DO. Perioperative tobacco use treatments: putting them into practice. BMJ 2017;358:j3340
Warner DO. Perioperative abstinence from cigarettes: physiologic and clinical consequences. Anesthesiology 2006;358:356-67.