Effect of smoking on induction of anaesthesia with sevoflurane

Abstract

Inhalational induction with sevoflurane has been shown to be a viable alternative to intravenous induction; however, studies have focused mainly on healthy patients or volunteers. Airway complications in patients with potential airway irritability have not been studied. Sixty smokers undergoing general anaesthesia were randomly assigned to one of three groups: group 1, vital capacity breathing with 8% sevoflurane; group 2, tidal breathing with 8% sevoflurane; and group 3, tidal breathing with step-up of sevoflurane (sevoflurane concentration increased by increments of 2% every 10 s until 8%). Step-up induction was significantly slower to induce loss of consciousness than a vital capacity breath or tidal breathing at 8% (p < 0.05). Step-up induction produced more complications than tidal breathing at 8% (p = 0.05). All patients had acceptable induction of anaesthesia with no patient having an oxygen saturation below 96% at any time. Blood pressure and heart rate decreased gradually over time in all groups (p < 0.001), but there were no significant differences between groups. Patient satisfaction with the techniques was high with 59 of 60 patients willing to have the same technique again. Inhalational induction with sevoflurane can be used safely as an induction technique in smokers. In common with other patient groups, use of a high initial concentration reduces induction time without causing additional airway or cardiovascular complications.