Cisatracurium infusion for neuromuscular blockade in the pediatric intensive care unit: A dose-finding study

OBJECTIVE: To evaluate the safety and efficacy of cisatracurium besylate, a neuromuscular blocking agent in infants zero to 2 yrs of age. DESIGN: An open-label study to evaluate efficacy and safety of cisatracurium as a continuous infusion in infants. SETTING: A tertiary pediatric intensive care unit. PATIENTS: Eleven children, 0-2 yrs of age, requiring prolonged neuromuscular blockade. INTERVENTIONS: Cisatracurium besylate, 0.1 mg/kg, was administered as an intravenous bolus dose and repeated if necessary until a >90% neuromuscular blockade, as determined by train-of-four response, was achieved. Patients were allowed to recover to 90% blockade (I/IV twitch) after the initial bolus and were administered continuous infusion at 2 &mgr;g/kg/min. The continuous infusion rate was adjusted to maintain a train-of-four response of 0-I/IV, with an increase in the rate preceded by a bolus dose of cisatracurium besylate. An electromyographic monitor was used to measure recovery at the end of infusion, when possible. Heart rate and blood pressure were recorded after the initial bolus dose and after changes in infusion rates. Blood samples were drawn at steady-state during cisatracurium infusion at several different times during the study and at the end of infusion for measurement of plasma cisatracurium and laudanosine concentrations. MEASUREMENTS AND MAIN RESULTS: The mean infusion rate of cisatracurium besylate required to maintain train-of-four response of 0-I/iv was 5.4 +/- 3.0 &mgr;g/kg/min. The mean total duration of infusion was 64.5 +/- 36 hrs. Ten percent and complete neuromuscular recovery occurred at 26.6 +/- 10.4 and 74.8 +/- 32 mins, respectively, after discontinuation of infusion. Mean cisatracurium and laudanosine concentrations were 342.5 +/- 169 and 163.3 +/- 116 ng/mL, respectively. Four (37%) patients had undetectable (<5 ng/mL) cisatracurium concentrations at the time of 100% neuromuscular recovery (train-of-four response of IV/IV or no fade at 50 mA on the electromyogram). No significant hemodynamic changes were observed during treatment with cisatracurium besylate (p <.05). CONCLUSIONS: A longer period of recovery from neuromuscular blockade was observed compared with reports of older children. Recovery from neuromuscular blockade after long-term use was not associated with any adverse events in the immediate postinfusion period. Cisatracurium besylate is a safe and effective neuromuscular blocking agent for children 0-2 yrs of age.