Evaluation of different induction techniques for tracheal intubation.

Conditions for tracheal intubation and the hemodynamic changes associated with different intravenous anesthetic induction techniques were studied in seventy-two ASA I patients randomly assigned to one of six groups (G). Anesthesia was induced with I.V. propofol 2.5 in G 1, 3, 5 or with thiopental 5 mg/kg (G2, 4, 6). In G 1-4, the standard sequence of administering muscle relaxant was used. G 1 and 2 received succinylcholine 1 mg/kg after induction, and one min later laryngoscopy and orotracheal intubation attempted. G3 and 4 received 0.5 mg/kg atracurium and intubation attempted 3 min later. In G 5 and G 6 the "timing principle" was used; atracurium 0.5 mg/kg was given first followed by propofol and thiopental, and one minute after the induction agent intubation attempted. There was no statistically significant difference in the intubating conditions between the six groups of patients studied. Similar to succinylcholine timing technique with atracurium and propofol or thiopental reliably provided excellent or good intubating conditions in two minutes.