Neuromuscular monitoring during modified rapid sequence induction: A comparison of TOF-Cuff® and TOF-Scan®

Background: Acceleromyometry is the clinical standard for quantitative neuromuscular monitoring, mostly using the stimulation pattern train-of-four (TOF). TOF-Cuff (R), a recently introduced neuromuscular monitor with stimulating electrodes integrated within a blood pressure cuff, assesses the muscular response in the upper arm. Methods: The time from administration of a neuromuscular blocking agent to TOF-ratio 0% during modified rapid sequence induction was compared between TOF-Cuff (R)' and acceleromyometry (TOF-Scan (R)). Included were 26 adults with body mass index <35 kg/m(2). TOF-Scan (R) and TOF-Cuff (R) were simultaneously fitted on patients' opposite arms. The mean difference to TOF-ratio 0% was compared using the one sample t-test (p < 0.05) and Bland-Altman plots. Results: After anesthesia induction, atracurium 0.9 mg/kg (+/- 0.08) i.v. was administered. The mean time to TOF ratio 0% for TOF-Scan (R) was 140.4 s (+/- 34.3), and 132.7 s (+/- 32.5) for TOF-Cuff (R), with a mean difference of 5.4 (95% CI: -9.9 to 20.7, p = 0.472). The maximum difference between the two modalities was 135 s when the TOF-Cuff (R) was faster and 60 s when the TOF-Scan (R) was faster. Conclusions: No statistically significant systematic difference was found between TOF-Scan (R) and TOFCuff (R). However, there was high variability and wide limits of agreement. The two devices cannot be used interchangeably. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of College of Emergency Nursing Australasia.