Performance of acceleromyography with a short and light TOF-tube compared with mechanomyography: A clinical comparison

BACKGROUNDDisturbances in the thumbʼs movement interfere with the functioning of acceleromyography in many clinical settings. The short and light (SL) train-of-four (TOF)-Tube is a new version of a rigid tubular device that was designed to protect the thumb from external disturbances during surgery, even when the hand is not accessible by the anaesthesiologist. OBJECTIVETo compare the precision and performance of acceleromyography performed with the aid of the SL TOF-Tube (AMGTT) with standard isometric mechanomyography (MMG). DESIGNSimultaneous arm-to-arm comparison of both methods in the same anaesthetised patient. SETTINGA monocentric study, performed from September 2007 to June 2008. PATIENTSNineteen ASA I to II patients scheduled to undergo lower limb orthopaedic surgery under general anaesthesia. INTERVENTIONNeuromuscular transmission monitoring during baseline, onset and spontaneous recovery of rocuronium-induced neuromuscular block. MAIN OUTCOME MEASURESInitial baseline and repeatability coefficients were assessed during 10 consecutive measurements of the first twitch height (T1) and TOF T4/T1 ratio and compared using a z test. The spontaneous recoveries of defined blockade levels (onset, T1 25% of initial calibration and TOF ratio 0.9) were compared in terms of duration and intensity. Agreement between both techniques was assessed by the Bland–Altman method. RESULTSThe mean ± SD control TOF ratios were 98 ± 1% (MMG) and 103 ± 2% (AMGTT). The repeatability coefficients were higher (P