An observational study comparing the performance of TOF-Cuff with TOF-Scan monitoring during anaesthetic induction in clinical routine.

INTRODUCTION: Neuromuscular monitoring by acceleromyography assesses the effects of non-depolarising neuromuscular blocking agents used during anaesthesia induction to optimise intubation conditions. A new type of neuromuscular monitor, TOF-Cuff, integrates electrode stimulation into a blood pressure monitoring cuff. Comparisons of this device with TOF-Scan, considered a clinical standard acceleromyography device, have not been published. MATERIAL AND METHODS: This prospective, observational study was approved by the Ethics Committee East Switzerland (BASEC-nr. 2016-02044), and patients' consent was obtained before inclusion. The study's aim was to compare TOF-Cuff with TOF-Scan by measuring the duration from the administration of a neuromuscular blocking agent to a train-of-four (TOF) ratio of 0%. After anaesthesia induction, atracurium was administered (0.5 mg kg-1) and TOF ratios were recorded every 15 seconds using the two devices simultaneously. Patients were grouped according to body mass index (< or ≥ 30 kg m-2). RESULTS: Twenty-five non-obese and twenty-five obese patients were included. In non-obese patients, bias was -3 s (± 21.2; limits of agreement -44.7 to 38.4; P = 0.702). In obese patients, bias was -20 s (± 35.0; limits of agreement -88.6 to 48.6; P = 0.0139). Large intra-individual differences of up to 60 seconds were detected even in non-obese patients. CONCLUSIONS: A significant systematic difference in the time to reach a TOF ratio of 0% was found when using the two devices in obese patients. In non-obese and obese patients, there were large intra-individual and clinically relevant differences. The two devices cannot be used interchangeably.

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®, 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® and acceleromyometry (TOF-Scan®). Included were 26 adults with body mass index <35 kg/m2. TOF-Scan® and TOF-Cuff® 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® was 140.4 s (±34.3), and 132.7 s (±32.5) for TOF-Cuff®, 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® was faster and 60 s when the TOF-Scan® was faster. CONCLUSIONS: No statistically significant systematic difference was found between TOF-Scan® and TOF-Cuff®. However, there was high variability and wide limits of agreement. The two devices cannot be used interchangeably.

Neuromuscular monitoring using TOF-Cuff® versus TOF-Scan®: an observational study under clinical anesthesia conditions.

BACKGROUND: Anesthesia guidelines advise objective neuromuscular monitoring. Acceleromyography, the standard technique used in clinical practice, is commonly used with the train-of-four (TOF) nerve stimulation pattern. Objective of this study was to compare the performance of two devices, TOF-Scan® and TOF-Cuff®. METHODS: This prospective, controlled observational study included patients undergoing surgery in general anesthesia with the need of neuromuscular blockade. Both neuromuscular monitoring devices were simultaneously placed on individual patients. Atracurium (0.5 mg/kg) was administered once. Main outcome measure was return time to TOF ratio ≥90%, secondary outcomes were time to TOF-ratio of 0% (during induction) and time to recovery to TOF-count of two. Results from the two devices were compared by Bland-Altman plots and one-sample t-test (P<0.05). RESULTS: Mean time to recovery to TOF ratio 90% was 79.6±13.6 min for TOF-Scan® and 70.8±12.8 min for TOF-Cuff® (P<0.001; mean bias 8.9 min, 95% CI: 5.8-12.0). Mean time to TOF-ratio 0% was 164.6±38.8 s for TOF-Scan® and 145.5±44.6 s for TOF-Cuff® (P<0.001; mean bias 19.1 s, 95% CI: 10.0-28.2). Mean time to recovery to TOF count two was 52.8±12.5 min for TOF-Scan® and 45.5±11.1 min for TOF-Cuff® (P<0.001; mean bias 7.3 min, 95% CI: 4.3-10.2). CONCLUSIONS: TOF-Cuff® consistently recorded the endpoints earlier than TOF-Scan®. Despite large intra-individual variations found with both devices, these results could be meaningful in a clinical setting.

Placement of TOF-Cuff® on the lower leg for neuromuscular and blood pressure monitoring during anesthetic induction for shoulder surgeries.

PURPOSE: The aim of this study was to compare two devices for neuromuscular monitoring during anesthetic induction. TOF-Cuff® was installed on the lower leg stimulating the tibial nerve, while the more conventional TOF-Scan® was installed over the ulnar nerve at the wrist. Methods Twenty adult patients were enrolled in this prospective, controlled study. Train-of-four (TOF) was recorded every 15 s until TOF ratio of 0%. Mean arterial blood pressure (MAP) was assessed with TOF-Cuff® and with standard anesthesia monitoring from the brachial artery. MAP was measured before and after anesthetic induction. Time to TOF ratio = 0% was compared with one-sample t test and Bland-Altman plots. Results Patients received 0.53 ± 0.09 mg atracurium per kg body weight intravenously. Mean time to TOF ratio = 0% was 150.8 s (± 43.7) for TOF-Scan®, and 174.4 s (± 42.7) for TOF-Cuff® (p = 0.1356). Bias was - 15.9 (95% confidence interval - 37.5 to 5.6) with 95% limits of agreement of - 95.2 to 63.3. Twenty-five percent of the patients had a technical issue with a TOF-Cuff® measurement. For MAP, mean difference was 1.4 (95% confidence interval - 2.4 to 5.2) with 95% limits of agreement of - 22.7 to 25.5. Conclusion The time from administration of a common dose of atracurium to a TOF ratio of 0% assessed with TOF-Cuff® stimulating the tibial nerve compared to TOF-Scan® stimulating the ulnar nerve showed large limits of agreement in Bland-Altman analysis. There was a high failure rate with TOF-Cuff® measurements on the lower leg.