The influence of smoking on postoperative nausea and vomiting

Abstract

In response to a letter from Dr Dolenska (Anaesthesia 1997; 52: 1021), Koivuranta et al. (Anaesthesia 1998; 53: 413) defend the findings of their survey [1] that postoperative nausea and vomiting (PONV) is less common in both male and female smokers compared with nonsmokers. We have made some similar observations in recent unpublished work investigating PONV in day-case arthroscopy patients. Our patients underwent a standardised anaesthetic and were exposed to either isoflurane or desflurane. We found a significant incidence of nausea in the desflurane group. Analysis of these 76 patients, utilising a Chi-squared test, showed nonsmokers to be at a significantly higher risk of nausea than smoking patients (Table 1). Further statistical analysis of our results was performed with a Chi-squared test, with Yates' correction for continuity, for the smaller single sex samples (54 male and 22 female patients). There appeared to be statistical significance for the group as a whole and male patients (p < 0.05). However, for female patients, the association of smoking protecting against nausea was not significant (p < 0.1). This may be due to both sample size and a female predisposition to PONV. There is other support for the observation that smoking protects from PONV [2]. Koivuranta et al. speculate that smokers are more tolerant to anaesthetic gases and other toxins than nonsmokers and consequently have a lower incidence of PONV. We think it is unlikely that any action of inhaled nicotine should protect from PONV, but postulate that one of the many other complex component chemicals within cigarette smoke may have an anti-emetic effect. Further research should clarify the effect of smoking on PONV in all categories of patient. The prospect of identifying the anti-emetic mechanism of smoking may have exciting implications for our understanding and future treatment of postoperative nausea and vomiting.