[Anesthesia induction for laryngeal mask insertion--comparison among sevoflurane, isoflurane and propofol]

We compared the patient's response to laryngeal mask (LM) insertion and hemodynamics among three anesthesia induction methods; S group used sevoflurane and slowly increased to 5% in 50% nitrous oxide; I group used isoflurane and slowly increased to 3% in 50% nitrous oxide; and P group used 2.5 mg.kg-1 propofol with 0.2 microgram.kg-1 fentanyl. Thirty patients, 35 to 65 years, for elective mastectomy were the subjects of study in each of the three groups. Preanesthetic medication was composed of i.m. injection of 0.5 mg atropine and 5 mg midazolam 30 min. prior to the induction. The number of patients with difficult insertion or demonstrating body movement or gagging in each group was in the order of P group > I group > S group. Blood pressure (BP), heart rate (HR) and rate pressure product (RPP) in the P group were significantly lower than those in the other two groups. I group showed significant increase in BP, HR and RPP. It was concluded that sevoflurane enabled the most smooth insertion of LM among the three methods of anesthesia with the least hemodynamic change.