Clinical assessment of long-term infusion of vecuronium in pediatric intensive care

Abstract

Objective: To assess clinically the efficacy of vecuronium in providing prolonged muscle relaxation in children and to study the mean effective dose and its relation to patient age and duration of infusion. Design: Prospective, observational study. Setting: Pediatric intensive care unit (PICU) of a university tertiary care center. Patients: All pediatric patients consecutively admitted to our PICU between September 1998 and June 1999 requiring neuromuscular blockade for a period longer than 24 hours were included. Those with impairment of renal, liver and/or neuromuscular function were excluded from the study. Vecuronium infusion was adjusted according to clinically effective neuromuscular degree of blockade assessed by means of peripheral nerve stimulation in train-of-four (TOF) modality. Measurements and main results: Twenty patients were studied. Initial infusion rate was 0.09±0.01 mg/kg/hour. Duration of infusion ranged between 1 and 24 days. Mean infusion rate was 0.11±0.03 mg/kg/hour. Mean infusion rate of patients < 2 years (0.085±0.016 mg/kg/hour) was significantly lower (p < 0.001) than in older patients (0.133±0.030 mg/kg/hour). A significant positive correlation between age and mean infusion rate was detected (r = 0.62, p = 0.034). No correlation between mean doses and time of infusion was found. The most frequent adverse effect detected was peripheral edema (20%), always in patients ≤ 6 months old. Persistent quadriplegic myopathy was detected in a 13-year-old boy with status asthmaticus simultaneously treated with high doses of methylprednisolone. Conclusions: The clinically effective mean dose of vecuronium infusion varies according to age; the mean effective dose in children aged less than 2 years is a 36% minor than older patients'. When used for prolonged time, vecuronium infusion rate should be adjusted according to bedside neuromuscular function monitoring with peripheral nerve stimulation in TOF mode, in order to optimize degree of blockade and avoid overdosing and development of tolerance. The most frequent adverse effect in infants was peripheral edema.