Tracheal intubation with rocuronium using the "timing principle"

Abstract

We compared the endotracheal intubating conditions after rocuronium, using the "timing principle," with those after succinylcholine. The timing principle entails administration of a single bolus dose of nondepolarizing muscle relaxant, followed by an induction drug at the onset of clinical weakness. Forty-five patients were randomly assigned to three groups. Patients allocated to Groups 1 and 2 received rocuronium 0.6 mg/kg. At the onset of clinical weakness (onset of ptosis), anesthesia was induced with thiopental 4-6 mg/kg; intubation was accomplished after 45 s in Group 1 and after 60 s in Group 2. Patients in Group 3 received vecuronium (0.01 mg/kg) 3 min before the administration of thiopental and succinylcholine 1.5 mg/kg, and their tracheas were intubated 60 s later by a blind anesthesiologist. Intubating conditions were assessed according to a grading scale and were either good (5 patients in Groups 1 and 2, 4 patients in Group 3) or excellent (10 patients in Groups 1 + 2, 11 patients in Group 3) in all patients. Patients were interviewed postoperatively, and all were satisfied with the induction of anesthesia. We conclude that rocuronium 0.6 mg/kg provides good to excellent intubating conditions 45 and 60 s after the induction of anesthesia using the timing principle.

Implications: We compared the ease with which a breathing tube could be placed in patients using three techniques. The standard technique (succinylcholine) was compared with two others in which a muscle-relaxing drug (rocuronium) was administered just before the anesthetic drug (so-called timing principle). No difference among the techniques was observed.