Lack of effect of nicotine on replanted rabbit ears.

Abstract

Many published papers have noted peripheral vasoconstrictive effects of cigarette smoking. In fact, smoking even a single cigarette can significantly reduce digital blood flow.' Smoking cigarettes on a chronic basis has been indicted as an etiologic factor in chronic ulcers of the extremities. We have witnessed the healing of a chronic finger-tip ulcer following abstinence from a three-pack-per-day cigarette habit in one patient? We have also demonstrated a temporary delay in wound healing in excised wounds on the ears of rabbits compared with a control groupP Although there is little that has been published on this, many surgeons have noted the deleterious effects of cigarette smoking after microvascular procedures, particularly replantation. More than 500 compounds have been isolated from the particulate and gaseous phases of tobacco smoke. Nicotine has been suspected as being the major villain in vasoconstriction. To test our hypothesis that nicotine ingestion could effect the survival of replants, we performed the following experiment in the Microsurgical Research Unit a t the University of Toronto. One ear on each of 20 male New Zealand white rabbits was severed and replanted. Ten of these rabbits served as controls. The remaining ten rabbits received megaphysiologic doses of nicotine (2 mg/kg) subcutaneously twice daily for five preoperative and ten postoperative days. Some of the rabbits treated with the nicotine demonstrated convulsive reactions to the injections, however, each rabbit postoperatively developed good capillary refill in the replanted ear within an hour and all of the replanted ears survived in both the control and the treated group alike. Our results were surprising and unexpected. We are not ready to advocate cigarette smoking in patients undergoing replantation based on this one experiment as we do not feel we have perfected our model, and we are planning a better model to continue our investigations. We wish to report the negative result of our present endeavor to spare other investigators the time and effort we have entered into this study. Until an improved model can be developed that more closely approximates the actual situation of cigarette smoking in humans, clinical observations should certainly take precedence over findings in this experimental study.