Does the choice of intravenous induction drug affect intubation conditions after a fast-onset neuromuscular blocker?

STUDY OBJECTIVES: To compare intubation conditions and hemodynamic effects resulting from thiopental-rapacuronium, propofol-rapacuronium, and etomidate-rapacuronium intravenous (IV) induction.

DESIGN: Randomized, blinded study.

SETTING: Operating suites of a large university-affiliated medical center.

PATIENTS: 60 ASA physical status I and II adult patients without airway abnormalities, who were scheduled for elective surgery requiring endotracheal intubation. Patients were randomly allocated to receive IV thiopental sodium 5 mg/kg (Group 1), propofol 2 mg/kg (Group 2), or etomidate 0.3 mg/kg (Group 3) followed by rapacuronium 1.5 mg/kg. Fifty seconds later, an anesthesiologist, who had no knowledge of the induction drug used, entered the operating room and attempted laryngoscopy and intubation.

MEASUREMENTS: Intubation conditions were graded as excellent, good, poor, or impossible according to Good Clinical Research Practice criteria. Arterial blood pressure and heart rate changes accompanying both induction techniques were also monitored and recorded.

MAIN RESULTS: All patients were intubated within 55 to 70 seconds. Clinically acceptable intubation conditions were not statistically different among the three groups. Moderate tachycardia after induction was seen in all three groups, and blood pressure was significantly lower in Group 2 than in Groups 1 or 3.

CONCLUSIONS: Clinically acceptable intubation conditions are similar after either thiopental, propofol, or etomidate when a fast-onset neuromuscular blocking drug (rapacuronium 1.5 mg/kg) is used to facilitate tracheal intubation.