Comparison of supramaximal currents obtained by acceleromyography and electromyography for monitoring the adductor pollicis muscle in pediatric patients

Abstract

The aim of this study was to compare the supramaximal currents obtained simultaneously by acceleromyography (AMG) TOF-Watch^® SX and electromyography (EMG) AF-201P in pediatric patients. Patients aged 2-11 years who underwent elective surgery under general anesthesia were enrolled. AMG and EMG monitors were placed on opposite arms of the patient to stimulate the ulnar nerve and monitor the adductor pollicis muscles following the induction of general anesthesia. After the monitors were calibrated, rocuronium 0.6 mg/kg was administered. Endotracheal intubation was performed when the EMG showed a train-of-four (TOF) count of 0. The primary outcome was the supramaximal current set by each device's calibration. The secondary outcomes were the time from the administration of rocuronium to a TOF count of 0, the baseline and final TOF ratios, and the conditions surrounding intubation. The paired t test and the Wilcoxon signed-rank test were used to analyze parametric and nonparametric data. A P value < 0.05 indicated statistical significance. Clinical data from 25 pediatric patients were analyzed. The supramaximal current was significantly lower with EMG than with AMG (27.4 ± 6.1 vs. 54.2 ± 8.4 mA, p <.001). The time to a TOF count of 0 was significantly shorter with EMG than with AMG (58 [24-170] vs. 75 [26-236] seconds, p <.001). Both the baseline and final TOF ratios were significantly lower with EMG than with AMG. The ease of laryngoscopy was rated as excellent for all patients. The vocal cords were abducted in 76% of patients, and no movement to insertion of the endotracheal tube was confirmed in 96% of patients. We found that the supramaximal current was significantly lower with EMG than with AMG.