Intubating conditions would be excellent and hemodynamic variables would be relatively stable during rapid- sequence anesthesia induction if tracheal intubation was performed at a proper time. The purpose of this study was to identify the ideal intubation time after rocuronium with either thiopental or propofol.

113 patients, ASA physical status I or II, were randomly divided into four groups. Patients in group TR60 (thiopental-rocuronium) and in group PR60 (propofol-rocuronium) were intubated within 60 s, while groups TR90 and PR90 were intubated within 90 s after the administration of rocuronium. Intubating conditions were graded by an experienced anesthesiologist, and hemodynamic variables were noted just before induction (baseline), immediate after induction, immediate after intubation, and 5 min after intubation.

Clinically acceptable intubating conditions (good or excellent) were not statistically different among the four groups. However, 55 and 64% of patients in groups TR90 and PR90, respectively, had excellent intubating conditions compared to only 39 and 38% in groups TR60 and PR60 (P < 0.05). Mean arterial pressure and rate pressure product (RPP) immediately after intubation were relatively stable in groups TR90 and PR90 compared to those in groups TR60 and PR60 (P < 0.05).

The intubation time after rocuronium, rather than the choice of induction agent, is the deciding factor affecting intubating conditions and hemodynamic variables during rapid-sequence anesthesia induction. Ninety seconds after the administration of rocuronium with either thiopental or propofol might be an ideal intubation time.