Hemodynamic and pharmacodynamic comparison of doxacurium and pipecuronium with pancuronium during induction of cardiac anesthesia: Does the benefit justify the cost?

We compared the pharmacodynamic effects and hospital costs of three long- acting neuromuscular blocking drugs in a prospective, randomized, double- blind manner. Each neuromuscular blocking drug was administered with fentanyl (50 μg/kg) for intravenous induction of anesthesia for coronary artery bypass surgery. Each patient received twice the 95% effective dose (ED₉₅) of either pancuronium (0.14 mg/kg, n = 10), pipecuronium (0.10 mg/kg, n = 10), or doxacurium (0.05 mg/kg, n = 10). Hemodynamic measurements were recorded at baseline, 5 min after completion of anesthetic induction, immediately after endotracheal intubation, and 5 min after intubation. Only small hemodynamic differences between neuromuscular blocking drugs were observed. Doxacurium (but not pancuronium or pipecuronium) significantly decreased mean arterial blood pressure (from 94 ± 4 mm Hg before induction to 83 ± 3 mm Hg 5 min after intubation); nevertheless, there were no significant between-group differences at any time. Pancuronium increased heart rate (from 68 ± 4 beats/min before induction to 76 ± 5 beats/min 5 min after intubation); however, pancuronium differed significantly from doxacurium and pipecuronium only 5 min after induction and 5 min after intubation. Central venous pressure, pulmonary artery occlusion pressure, cardiac index, and systemic and pulmonary vascular resistance indices did not change. Electrocardiographic abnormalities were observed in two pipecuronium patients: ST segment depression in one and premature ventricular contractions in another. No other electrocardiographic changes were observed. There were no significant between-group differences in the need for hemodynamic interventions. The time from muscle relaxant administration to 95% twitch depression was significantly longer for doxacurium (530 ± 49 s) than for either pancuronium (264 ± 31 s) or pipecuronium (234 ± 23 s). The cost to a 70-kg patient of twice the ED₉₅ dose was: pancuronium, $1.69; pipecuronium, $22.88; and doxacurium, $19.60. We conclude that whereas doxacurium and pipecuronium may be less likely than pancuronium to increase heart rate during induction of anesthesia, these two neuromuscular blocking drugs are no less likely to produce hemodynamic aberrations requiring drug interventions and are considerably more expensive.