Comparison of Train of Four Measurements with Kinemyography NMT DATEX and Accelerography TOFscan

Introduction: This study was designed to compare the Datex neuromuscular transmission (NMT) kinemyography (NMTK) device with the TOFscan (TS) accelerometer during the onset and recovery of neuromuscular blockade. Patients and methods: This prospective study included adult patients who were scheduled to undergo elective surgery with general anesthesia and orotracheal intubation. The TS accelerometer was randomly placed at the adductor pollicis on one hand, and the NMTK was placed on the opposite arm. Anesthesia was initiated with remifentanil target-controlled infusion (TCI) and 2.0–3.0 mg/kg of propofol. Thereafter, 0.5 mg/kg of atracurium or 0.6 mg/kg of rocuronium was injected. If needed, additional neuromuscular blocking agents were administered to facilitate surgery. First, we recorded the train of four (TOF) response at the onset of neuromuscular blockade to reach a TOF count of 0. Second, we recorded the TOF response at the recovery of neuromuscular blockade to obtain a T4/T1 90% by both TS and NMTK. Results: There were 32 patients, aged 38–83 years, with the American Society of Anesthesiologists (ASA) Physical Status Classification I–III included and analyzed. Surgery was abdominal, gynecologic, or head and neck. The Bland and Altman analysis for obtaining zero responses during the onset showed a bias (mean) of 2.7 s (delay) of TS in comparison to NMTK, with an upper/lower limit of agreement of [104; −109 s] and a bias of 36 s of TS in comparison to NMTK, with an upper/lower limit of agreement of [−21.8, −23.1 min] during recovery (T4/T1 > 90%). Conclusions: Under the conditions of the present study, the two devices are not interchangeable. Clinical decisions for deep neuromuscular blockade should be made cautiously, as both devices appear less accurate with significant variability.