Comparison of a new neuromuscular transmission monitor compressomyograph with mechanomyograph

Background 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). Methods The two monitors were randomly allocated to the left or right hands of 16 patients. T 1 , first twitch of the train-of-four (TOF) expressed as percentage of control response, and the TOF ratio ( T 4 : t 1 ) were used to evaluate the neuromuscular block produced by rocuronium 0.6 mg kg −1 . Results The CMG monitor exhibited no pre-relaxation reverse fade ( T 4 > T 1 ) or T 1 exceeding 100%. There was no significant difference in mean (sd) onset time, Dur 25 (time to T 1 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 T 1 % 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. Conclusions 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.