Spontaneous Recovery of Neuromuscular Function after Atracurium in Pediatric Patients

Spontaneous recovery of neuromuscular function after a bolus dose of 0.40 mg/kg atracurium was assessed in 60 newborn to adolescent patients during balanced anesthesia. Each patient was allowed to recover spontaneously until complete recovery of the single twitch (T1) response and the train-of-four ratio measured from the hypothenar muscle evoked compound EMG. The recovery times of T1 from the onset of relaxation to 10% recovery and to 100% recovery were significantly longer in patients under 10 kg of body weight than in the heavier patients (25 and 56 min vs 19 and 45 min, respectively, P < 0.01). The rate of recovery, calculated as the recovery index (time between 25% recovery and 75% recovery of T1), was significantly longer in patients under 2 months of age than in older infants or children and adolescents. Atracurium remains, nevertheless, a relaxant of intermediate duration of action even in small infants.