Single breath vital capacity induction of anesthesia with 8% sevoflurane versus intravenous propofol for laryngeal tube insertion in adults

Objective: To compare the conditions for laryngeal tube airway insertion obtained by the inhalation of 8% sevoflurane using a vital capacity breath (VCB) technique with propofol intravenous induction. Methods: We carried out a prospective, randomized, single blind study at King Abdullah University Hospital, Irbid, Jordan from September 2005 to April 2006. Involved in this study were 80 adult (ASA physical status I and II) patients aged 26-70 years undergoing elective surgery under general anesthesia. The patients were randomized into 2 groups. An independent observer noted the time to loss of consciousness, the presence of adverse events, time to successful laryngeal tube placement and the number of attempts needed until a successful laryngeal tube insertion. Results: With the single VCB method, sevoflurane produced a loss of consciousness faster than propofol did (51.6 +/- 4.4 versus 59.7 +/- 4.9 seconds, p < 0.001). The insertion of laryngeal tube was faster in the propofol group (77.2 +/- 20.2 versus 122.2 +/- 33.3 seconds, p < 0.001) and required fewer attempts (1.2 +/- 0.4 versus 1.6 +/- 0.7, p < 0.02). The overall incidence of complications during the induction of anesthesia as well as during the laryngeal tube insertion, especially apnea (42% versus 0%; p < 0.001), was more frequent in the propofol group (82.5% versus 27.5%; p < 0.001). Conclusion: We conclude that vital capacity breath induction with sevoflurane produces a faster loss of consciousness and fewer side effects than propofol and efficient for laryngeal tube insertion, but takes slightly longer than propofol due to the prolonged jaw tightness.