Comparison of a new neuromuscular transmission monitor compressomyograph with mechanomyograph

Abstract

We developed a new neuromuscular transmission monitor, the compressomyograph (CMG, European patent number: EP 06018557.6, US patent number: US 60/824.541). This is the first preliminary report comparing neuromuscular block monitored by CMG and the Relaxometer mechanomyograph (MMG). The two monitors were randomly allocated to the left or right hands of 16 patients. T1, first twitch of the train-of-four (TOF) expressed as percentage of control response, and the TOF ratio (T4:t1) were used to evaluate the neuromuscular block produced by rocuronium 0.6 mg kg(-1). The CMG monitor exhibited no pre-relaxation reverse fade (T4>T1) or T1 exceeding 100%. There was no significant difference in mean (SD) onset time, Dur(25) (time to T1 25% recovery), or Dur(0.9) (time to 0.9 TOF ratio recovery) measured by the CMG [2.4 (0.9), 22.6 (4.1), 43.1 (10.3) min, respectively] compared with MMG [2.1 (0.9), 22.9 (3.3), 43.3 (10.0) min, respectively]. According to Bland and Altman analysis, the bias (upper and lower limits of agreement) for T1% was -0.3% (+13.4% and -13.8%) and for TOF ratio was -0.009 (+0.068 and -0.085). CMG showed 100% sensitivity and 75% specificity in indicating full relaxation for tracheal intubation, and 80% sensitivity with 86% specificity in predicting MMG 0.9 TOF ratio. The CMG could be a reliable clinical monitor in the daily anaesthesia practice that does not require time to set up or rigid support of the arm.