Accelerometry for Detection of Residual Neuromuscular Blockade

Overview

We have compared two techniques of neuromuscular blockade monitoring, accelerometry and electromyography (ACC vs EMG). Neuromusculartransmission was measured using both EMG and ACC in 20 ASA I – III patients undergoing elect ive craniotomy in general anaesthesia longer thentwo hours. After suxamethonium administration (Ł 100 mg) to facilitate tracheal intubation, neuromuscular block was maintained by repeated bolusesof vecuronium (1 – 4 mg). Stimulation pattern consisted of TOF supramaximal stimuli (ulnar nerve) every 20 seconds, muscle response of the adductorpollicis was observed. 1218 paired measurements of TOF were obtained (TOFEMG and TOFACC). The average difference in TOF-ratio between EMGand ACC values showed bias of 0,3 % with standard deviation ± 8.7 %. The limits of agreement (range in which 95 % of the differences between pairedmeasurements are expected to lie) were from –17 to +17 %. The sensitivity of accelerometry to detect recovery from neuromuscular block (criterionof adequate recovery was TOF-ratio ł 70 %) reached 87 %, specificity 96 %. Both measurement techniques provided reliable information of degreeof neuromuscular block. Under the study conditions described, accelerometry (although it was not as accurate as electromyography) was able to detectresidual neuromuscular blockade.

Key words:
neuromuscular block – monitoring – acceleromyography – electromyography – neuromuscular blocking agents – vecuronium