Saturday, June 22, 2013
Smoking and Surgery Don’t Mix
Even routine operations are riskier for smokers.
Smokers who are scheduling a medical operation might want to think seriously about quitting, once they hear the results of a new review of the impact of smoking on surgical outcomes.
A scheduled operation is the perfect incentive for smokers to quit smoking. The fact that smokers have poorer post-surgical outcomes, with longer healing times and more complications, is not a new finding. But the study by researchers from the University of California in San Francisco, and Yale University School of Medicine, published in the Journal of Neurosurgery, spells out the surgicial risks for smokers in graphic detail.
The systematic effects of nicotine and carbon monoxide in the blood of cigarette smokers result in tissue hypoxia, which is a lack of adequate blood supply caused by a shortage of oxygen. When carbon monoxide floods the bloodstream in high concentrations, as it does in smokers, it is capable of binding with hemoglobin and thus lowering the oxygen-carrying capacity of the blood. A cascade of physiological reactions then lead to the possibility of low coagulation levels, vasoconstriction, spasms, and blood clots.
Wound Healing and Infection
If the circulatory system is dysfunctional, healing will be impaired. “In addition,” the researchers say, “tobacco may stimulate a stress response mediated by enhanced fibroblast activity, resulting in decreased cell migration and increased cell adhesion. The net consequence is inappropriate connective tissue deposition at the surgical site, delayed wound healing, and increased risks of wound infection.”
In their review of the neurosurgical literature, the researchers found higher blood loss for smokers particularly following surgery for certain kinds of tumors and for lumbar spine injuries. Smoking causes “permanent structural changes of vessels such as vessel wall thickening,” and there is evidence that smoking is linked to “larger and more vascularized tumors, which may further contribute to intraoperative blood loss during resection.”
Even smokers who don’t have any chronic conditions associated with smoking are at increased risk during and after surgery. Oxidative damage from smoke can cause “mucosal damage, goblet cell hyperplasia, ciliary dysfunction, and impaired bronchial function,” all of which impedes the ability to expel mucus, which increases the bacterial load, which alters the respiratory immune response, and which ultimately leads to higher rates of postoperative pneumonia in smokers.
The authors of the review note that the evidence is particularly strong in certain specialties: Cranial surgery, spine surgery, plastic surgery, and orthopedic surgery. One randomized clinical trial showed that a 4-week smoking cessation program lead to a 50 relative risk reduction for postoperative complications. Another study showed significant improvement in wound healing when patients abstained from smoking for 6 to 8 weeks prior to surgery. And a third trial of smokers cited in the study showed a major decrease in complications following surgery for the repair of acute bone fractures in patients who quit before surgery.
The authors close by suggesting that the seriousness of surgery can be used to create a “teachable moment” for patients who smoke. Other studies show consistently that “patients tend to be more likely to quit smoking after hospitalization for serious illness.” All of this makes the act of scheduling surgery a perfect point of contact with smokers in medical settings. Clinicians can neutrally lay out the facts of the matter, in a way that truly brings home the health consequences of tobacco.
Lau D., Berger M.S., Khullar D. & Maa J. (2013). The impact of smoking on neurosurgical outcomes, Journal of Neurosurgery, 1-8. DOI: 10.3171/2013.5.JNS122287
Graphics Credit: http://www.ontarioanesthesiologists.ca/