AS/3® neuromuscular transmission module (M-NMT) vs. mechanomyography for neuromuscular block monitoring

Abstract

GRAZ-01-6 Introduction: The AS/3® (Datex-Ohmeda, Finland) neuromuscular transmission module (M-NMT) is a piezoelectric motion sensor for monitoring neuromuscular block. We compared this monitor with the Relaxometer mechanomyograph (MMG). Methods: The two monitors were alternately attached to the left or right hands of 20 patients given rocuronium 0.6 mg kg−1 (2 × ED95). T1, first twitch of the train-of-four (TOF) and the TOF ratio (T4:T1) were used to evaluate the neuromuscular block. Results: There was no significant difference in the mean ± SD (min) onset time and time to 0.8 TOF ratio recovery, measured by the M-NMT (1.5 ± 0.3, 49.4 ± 8.1) compared to the MMG (1.8 ± 0.6, 50.9 ± 9.9). However, the time to T1 25% recovery was significantly longer when monitored by the M-NMT (25.6 ± 8) compared to the MMG (20.2 ± 6.3). According to a Bland and Altman analysis, the TOF ratio bias (the difference between the two monitors) was −0.031 and the limits of agreement (bias ± 1.96 SD) were −0.281 and +0.22 (Fig. 1).FigureConclusions: The M-NMT module could accurately point the time to tracheal intubation as well as full recovery from neuromuscular block. However, it was less accurate in detecting the time to rocuronium repeat dose administration. M-NMT has the advantages of being incorporated in the anaesthesia monitor, its quick-fit sensor is small, simple to set up, and does not require a rigid support to the arm. Thus the M-NMT is a reliable clinical monitor in everyday anaesthesia practice.