A compressomyograph train of four monitoring device.

The monitoring of the neuromuscular blockade is critical for patient's safety during and after surgery. The monitoring of neuromuscular blockade often requires the use of Train of Four (TOF) technique. During a TOF test two electrodes are attached to the ulnar nerve, and a series of four electric pulses are applied. The electrical stimulation causes the thumb to twitch, and the amount of twitch varies depending on the amount of neuromuscular blockade in patient's system. Current medical devices used to assist anesthesiologists to perform TOF monitoring often require free hand movement and do not provide accurate or reliable results. The goal of this work is to design, prototype and test a new medical device that provides reliable TOF results when thumb movement is restricted. A medical device that uses a pressurized catheter balloon to detect the response thumb twitch of the TOF test is created. An analytical model, numerical study, and mechanical finger testing were employed to create an optimum design. The design is tested through a pilot human subjects study. No significant correlation is reported with subjects' properties, including hand size.

Neuromuscular end-point predictive capability of published rocuronium pharmacokinetic/pharmacodynamic models: An observational trial.

BACKGROUND: Objective neuromuscular monitoring remains the single most reliable method to ensure optimal perioperative neuromuscular management. Nevertheless, the prediction of clinical neuromuscular endpoints by means of Pharmacokinetic (PK) and Pharmacodynamic (PD) modelling has the potential to complement monitoring and improve perioperative neuromuscular management.s STUDY OBJECTIVE: The present study aims to assess the performance of published Rocuronium PK/PD models in predicting intraoperative Train-of-four (TOF) ratios when benchmarked against electromyographic TOF measurements. DESIGN: Observational trial. SETTING: Tertiary Belgian hospital, from August 2020 up to September 2021. PATIENTS AND INTERVENTIONS: Seventy-four patients undergoing general anaesthesia for elective surgery requiring the administration of rocuronium and subject to continuous EMG neuromuscular monitoring were included. PK/PD-simulated TOF ratios were plotted and synchronised with their measured electromyographic counterparts and their differences analysed by means of Predictive Error derivatives (Varvel criteria). MAIN RESULTS: Published rocuronium PK/PD models overestimated clinically registered TOF ratios. The models of Wierda, Szenohradszky, Cooper, Alvarez-Gomez and McCoy showed significant predictive consistency between themselves, displaying Median Absolute Performance Errors between 38% and 41%, and intra-individual differences (Wobble) between 14 and 15%. The Kleijn model outperformed the former with a lower Median Absolute Performance Error (16%, 95%CI [0.01; 57]) and Wobble (11%, 95%CI [0.01; 34]). All models displayed considerably wide 95% confidence intervals for all performance metrics, suggesting a significantly variable performance. CONCLUSIONS: Simulated TOF ratios based on published PK/PD models do not accurately predict real intraoperative TOF ratio dynamics. TRIAL REGISTRATION: NCT04518761 (clinicaltrials.gov), registered on 19 August 2020.

The impact of electrosurgical devices on electromyography-based neuromuscular monitoring during abdominal laparotomy: a case series.

The present study aimed to evaluate the effect of electrosurgical devices on neuromuscular monitoring using an electromyography (EMG)-based neuromuscular monitor during abdominal laparotomy. Seventeen women (aged 32-64 years) undergoing gynecological laparotomy under total intravenous general anesthesia were enrolled in the study. A TetraGraph™ was placed to stimulate the ulnar nerve and to monitor the abductor digiti minimi muscle. After device calibration, train-of-four (TOF) measurements were repeated at intervals of 20 s. Rocuronium 0.6 to 0.9 mg/kg was administered for induction, and additional doses of 0.1 to 0.2 mg/kg were administered to maintain TOF counts ≤ 2 during the surgery. The primary outcome of the study was the ratio of measurement failure. The secondary outcomes of the study were the total number of measurements, the number of measurement failures, and the most extended consecutive number of measurement failures. The data are expressed as median (range). Of the 3091 (1480-8134) measurements, the number of measurement failures was 94 (60-200), resulting in a failure ratio of 3.5% (1.4-6.5%). The most extended consecutive number of measurement failures was 8 (4-13). All attending anesthesiologists were able to maintain and reverse neuromuscular blocks under EMG guidance. This prospective observational study demonstrated that the use of EMG-based neuromuscular monitoring does not seem to be heavily affected by electrical interference during lower abdominal laparotomic surgery. Trial registration This trial was registered in the University Hospital Medical Information Network under registration number UMIN000048138 (registration date; June 23, 2022).

Quantitative Neuromuscular Monitoring and Postoperative Outcomes: A Narrative Review.

Over the past five decades, quantitative neuromuscular monitoring devices have been used to examine the incidence of postoperative residual neuromuscular block in international clinical practices, and to determine their role in reducing the risk of residual neuromuscular block and associated adverse clinical outcomes. Several clinical trials and a recent meta-analysis have documented that the intraoperative application of quantitative monitoring significantly reduces the risk of residual neuromuscular blockade in the operating room and postanesthesia care unit. In addition, emerging data show that quantitative monitoring minimizes the risk of adverse clinical events, such as unplanned postoperative reintubations, hypoxemia, and postoperative episodes of airway obstruction associated with incomplete neuromuscular recovery, and may improve postoperative respiratory outcomes. Several international anesthesia societies have recommended that quantitative monitoring be performed whenever a neuromuscular blocking agent is administered. Therefore, a comprehensive review of the literature was performed to determine the potential benefits of quantitative monitoring in the perioperative setting.

Peri-operative diaphragm ultrasound as a new method of recognizing post-operative residual curarization.

BACKGROUND: This study sought to evaluate the diagnostic accuracy of peri-operative diaphragm ultrasound in assessing post-operative residual curarization (PORC). METHODS: Patients undergoing non-thoracic and non-abdominal surgery under general anaesthesia were enrolled from July 2019 to October 2019 at Peking Union Medical College Hospital. A train-of-four ratio (TOFr) lower than 0.9 was considered as the gold standard for PORC. Diaphragm ultrasound parameters included diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) during quiet breathing (QB) and deep breathing (DB). The diaphragm excursion fraction (DEF) was calculated as the DE-QB divided by the DE-DB. The diaphragm excursion difference (DED) was defined as DE-DB minus DE-QB. Receiver operating characteristic curve analysis was used to determine the cut-off values of ultrasound parameters for the prediction of PORC. RESULTS: In total, 75 patients were included, with a PORC incidence of 54.6%. The DE-DB and DED were positively correlated with the TOFr, while the DEF was negatively correlated with the TOFr. The DE-DB cut-off value for predicting PORC was 3.88 cm, with a sensitivity of 85.4% (95% confidence interval [CI]: 70.1-93.9%), specificity of 64.7% (95% CI: 46.4-79.7%), positive likelihood ratio of 2.42 (95% CI 1.5-3.9), and negative likelihood ratio of 0.23 (95% CI: 0.1-0.5). The DED cut-off value was 1.5 cm, with a specificity of 94.2% (95% CI: 80.3-99.3%), sensitivity of 63.4% (95% CI: 46.9-77.9%), positive likelihood ratio of 10.78 (95% CI: 2.8-42.2), and negative likelihood ratio of 0.39 (95% CI: 0.3-0.6). CONCLUSIONS: Peri-operative diaphragm ultrasound may be an additional method aiding the recognition of PORC, with DED having high specificity.

Effects of depth of neuromuscular blockade on the BIS-guided propofol requirement: A randomized controlled trial.

BACKGROUND: Deep neuromuscular blockade is considered beneficial for improving the surgical space condition during laparoscopic surgery. Adequacy of the surgical space condition may affect the anesthetists' decision regarding titration of depth of anesthesia. We investigated whether deep neuromuscular blockade reduces the propofol requirement under bispectral index monitoring compared to moderate neuromuscular blockade. METHODS: Adult patients undergoing elective laparoscopic colorectal surgery were randomly allocated to a moderate or deep group. A train-of-four count of 1-2 in the moderate group, and a post-tetanic count of 1-2 in the deep group, were maintained by continuous infusion of rocuronium. The induction and maintenance of anesthesia were achieved by target-controlled infusion of propofol and remifentanil. The dose of propofol was adjusted to maintain the bispectral index in the range of 40-50. The remifentanil dose was titrated to maintain the systolic blood pressure to within 20% of the ward values. RESULTS: A total of 82 patients were included in the analyses. The mean±SD dose of propofol was 7.54 ±â€Š1.66 and 7.42 ±â€Š1.01 mg·kg-1·h-1 in the moderate and deep groups, respectively (P = .104). The mean±SD dose of remifentanil was 4.84 ±â€Š1.74 and 4.79 ±â€Š1.77 µg kg-1 h-1 in the moderate and deep groups, respectively (P = .688). In comparison to the moderate group, the deep group showed significantly lower rates of intraoperative patient movement (42.9% vs 22.5%, respectively, P = .050) and additional neuromuscular blocking agent administration (76% vs 53%, respectively, P = .007). Postoperative complications, including pulmonary complications, wound problems and reoperation, were not different between the two groups. CONCLUSION: Deep neuromuscular blockade did not reduce the bispectral index-guided propofol requirement compared to moderate neuromuscular blockade during laparoscopic colon surgery, despite reducing movement of the patient and the requirement for a rescue neuromuscular blocking agent. TRIAL REGISTRATION: Clinicaltrials.gov (NCT03890406).

Effects of deep neuromuscular block with low-pressure pneumoperitoneum on respiratory mechanics and biotrauma in a steep Trendelenburg position.

We hypothesized that deep neuromuscular blockade (NMB) with low-pressure pneumoperitoneum (PP) would improve respiratory mechanics and reduce biotrauma compared to moderate NMB with high-pressure PP in a steep Trendelenburg position. Seventy-four women undergoing robotic gynecologic surgery were randomly assigned to two equal groups. Moderate NMB group was maintained with a train of four count of 1-2 and PP at 12 mmHg. Deep NMB group was maintained with a post-tetanic count of 1-2 and PP at 8 mmHg. Inflammatory cytokines were measured at baseline, at the end of PP, and 24 h after surgery. Interleukin-6 increased significantly from baseline at the end of PP and 24 h after the surgery in moderate NMB group but not in deep NMB group (Pgroup*time = 0.036). The peak inspiratory, driving, and mean airway pressures were significantly higher in moderate NMB group than in deep NMB group at 15 min and 60 min after PP (Pgroup*time = 0.002, 0.003, and 0.048, respectively). In conclusion, deep NMB with low-pressure PP significantly suppressed the increase in interleukin-6 developed after PP, by significantly improving the respiratory mechanics compared to moderate NMB with high-pressure PP during robotic surgery.

Changes in countermovement jump performance and subjective readiness-to-train scores following a simulated soccer match.

The study investigated whether countermovement jump (CMJ) metrics and subjective responses to a readiness-to-train questionnaire (RTT-Q) tracked simulated match-induced acute fatigue. This was a randomized cross-over repeated measures study. Participants were assigned into one of two groups; CONTROL or LIST. The LIST group performed the Loughborough Intermittent Shuttle Run (LIST), which was designed to simulate the demands of a soccer match. The CONTROL performed light physical activity at an intensity of <65% of maximal heart rate. Each group performed three CMJ's and completed an RTT-Q before (PRE), and again at 24 and 48 h after the LIST and/or CONTROL interventions. At 24 h there were significant differences in RTT-Q answers between the Pre and 24 h for the LIST group for questions; "Do you feel physically strong today?" and "Do you have muscle soreness today?" (p = 0.02 and 0.0008, respectively). The questions "Do you feel mentally strong today?" and "Do you have muscle soreness today?" (p = 0.02 and p = 0.0001 respectively) were the only questions that had a significant difference between Pre and 48 h for the LIST group. None of the CMJ metrics (LIST or CONTROL) changed significantly at any stage of the experiment. Although fatigue was detected by changes in the RTT-Q at 24 and 48 h after the LIST, none of the CMJ metrics changed. These findings suggest that subjective measures are more sensitive to low-level fatigue than objective measures, thus effective monitoring should include both.

Predictors of prognosis in type 1 myotonic dystrophy (DM1): longitudinal 18-years experience from a single center.

The aim of the study was to identify possible predictors of neurological worsening and need of non-invasive ventilation (NIV) in individuals affected by myotonic dystrophy type 1 (DM1), the most common form of adult-onset muscular dystrophy. METHODS: A retrospective observational cohort study was undertaken. Thirty-three patients with genetic diagnosis of DM1 were followed at our Neuromuscular unit in Modena. Abnormal trinucleotide repeat (CTG) expansion of dystrophy protein kinase gene (MDPK) on chromosome 19q 13.3 was the prerequisite for inclusion. The number of CTG repeats was determined. All the participants were older than 14 at the time of enrolment, therefore they could be included into the juvenile or adult form of the disease. Participants were neurologically evaluated every 6-8 months up to 18 years. Neurological impairment was assessed by Muscular Impairment Rating (MIRS), Medical Research Council (MRC), and modified Rankin (mRS) scales. The independent variables considered for prognosis were age at first evaluation, duration of the disease, CTG repeat number, gender, and presence of cardiac and vascular morbidities.Male patients were 51.5% and female patients 48.5%. Sixteen patients were younger than the mean age of 30.1 years, while the remaining 17 were up to 65. Twelve subjects (36.4%) underwent NIV before the end of follow-up. Muscle force and disability scores showed statistically significant deterioration (p < 0.001) during follow-up. The worsening was significantly higher among patients carrying higher number of CTG repeats and of younger age. The presence of cardio-vascular involvement has significant impact on neurological and respiratory progression.Neurological worsening is predicted by CTG expansion size, young age and presence of cardio-vascular morbidities.

Efecto de las técnicas neuromusculares y de jones en pacientes bruxistas con cefaleas tensionales episódicas y crónicas / No disponible

INTRODUCCIÓN: El bruxismo es una disfunción temporomandibular que tensa los músculos de la masticación, especialmente los músculos temporales y maseteros, y que a su vez puede causar cefaleas tensionales episódicas o crónicas. OBJETIVOS: Valorar el efecto de las técnicas neuromusculares y de Jones aplicadas sobre el músculo temporal en la amplitud de la apertura vertical de la boca, el umbral del dolor a la presión y la extensión craneocervical, en pacientes bruxistas con cefaleas tensionales episódicas y crónicas. MATERIAL Y MÉTODOS: Estudio experimental, tipo ensayo clínico aleatorizado y doble ciego. Se realizaron con cada paciente tres sesiones de osteopatía. La muestra estuvo formada por 52 pacientes diagnosticados de bruxismo y cefaleas tensionales episódicas y crónicas, a los que se aplicó las técnicas neuromuscular y técnica de Jones en el músculo temporal (grupo experimental), o una intervención control (contacto occipital). Se llevaron a cabo mediciones antes de hacer la intervención, inmediatamente después de realizar las técnicas y tres días después de realizar las técnicas con algometría de los puntos gatillos de la musculatura temporal, inclinometría para el movimiento craneocervical, así como mediciones de la apertura vertical de la boca con pie del rey. RESULTADOS: El grupo experimental obtuvo mejoras significativas en la apertura vertical de la boca (p < 0,001), en el umbral del dolor a la presión sobre el punto seleccionado del músculo temporal (p < 0,001) y en la en extensión craneocervical (p < 0,001). CONCLUSIONES: Las técnicas neuromusculares y de Jones aplicadas sobre el músculo temporal en pacientes bruxistas con cefaleas tensionales son útiles de cara a obtener mejoras en aspectos de interés en patologías álgicas diversas a nivel craneocervical

No disponible

Rapid prototyping of soft bioelectronic implants for use as neuromuscular interfaces.

Neuromuscular interfaces are required to translate bioelectronic technologies for application in clinical medicine. Here, by leveraging the robotically controlled ink-jet deposition of low-viscosity conductive inks, extrusion of insulating silicone pastes and in situ activation of electrode surfaces via cold-air plasma, we show that soft biocompatible materials can be rapidly printed for the on-demand prototyping of customized electrode arrays well adjusted to specific anatomical environments, functions and experimental models. We also show, with the monitoring and activation of neuronal pathways in the brain, spinal cord and neuromuscular system of cats, rats and zebrafish, that the printed bioelectronic interfaces allow for long-term integration and functional stability. This technology might enable personalized bioelectronics for neuroprosthetic applications.

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.

An Implantable System For Chronic In Vivo Electromyography.

Electromyography (EMG) measures the muscle response to electrical stimulation or spontaneous activity of motor units and plays an important role in assessing neuromuscular function. Chronic recording of EMG activity reflecting a muscle's reinnervation status after nerve injury has been limited, due to the invasive nature of traditional EMG recording techniques. In this regard, an implantable system is designed for long-term, in vivo EMG recording and nerve stimulation. It has been applied and tested in a study on reinnervation of laryngeal muscles. This system consists of 1) two bipolar electrode nerve cuffs and leads for stimulating each of two nerves: the recurrent laryngeal nerve (RLN) and internal branch of the superior laryngeal nerve (SLN); 2) two EMG recording electrodes and leads for each of the two laryngeal muscles: posterior cricoarytenoid (PCA) muscle and thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex; and 3) a skin receptacle interfacing all implanted lead terminals to an external recording preamplifier and stimulator using a connection cable. The wire leads are Teflon-coated, multi-filament, type 316 stainless steel. They are coiled and can stretch during body movement of the awake animal to prevent lead breakage and electrode migration. This system is implanted during an aseptic surgery. Afterwards, baseline EMG recordings are performed before the RLN is transected in the second surgery to study muscle reinnervation. Throughout the study, multiple physiological sessions are conducted in the anesthetized animal to obtain evoked and spontaneous EMG activity that reflects the reinnervation status of laryngeal muscles. The system is compact, free of infection over the course of the study, and highly durable. This implantable system can provide a reliable platform for research in which long-term recording or nerve stimulation is required in an anesthetized or freely moving animal.

A retrospective observational study of neuromuscular monitoring practice in 30,430 cases from six Danish hospitals.

Timely application of objective neuromuscular monitoring can avoid residual neuromuscular blockade. We assessed the frequency of objective neuromuscular monitoring with acceleromyography and the last recorded train-of-four ratio in a cohort of Danish patients. We extracted data from all patients receiving general anaesthesia from November 2014 to November 2016 at six hospitals in the Zealand Region of Denmark. Acceleromyography was available in all operating rooms and data were recorded automatically. The primary outcome measure was acceleromyography use in patients receiving neuromuscular blocking agents, divided into non-depolarising agents and succinylcholine only. The dataset included 76,743 cases, of which 30,430 received a neuromuscular blocking drug. Non-depolarising drugs were used in 16,525 (54%) and succinylcholine as the sole drug in 13,905 (46%) cases. Acceleromyography was used in 14,463 (88%) patients who received a non-depolarising neuromuscular blocking drug and in 4224 (30%) receiving succinylcholine alone. Acceleromyography use varied between the departments from 58% to 99% for non-depolarising drugs and from 3% to 79% for succinylcholine alone. The median (IQR [range]) of the last recorded train-of-four ratio before tracheal extubation was 0.97 (0.90-1.06 [0.01-2.20]) when non-depolarising drugs were used, and was less than 0.9 in 22% of cases. The OR for oxygen desaturation was higher with the use of succinylcholine [2.51 (95%CI 2.33-2.70) p < 0.001] and non-depolarising drugs [2.57 (95%CI 2.32-2.84) p < 0.001] as compared with cases where no neuromuscular blockade drug was used. In conclusion, acceleromyography was almost always used in cases where non-depolarising neuromuscular blocking drugs were used, but a train-of-four ratio of 0.9 was not always achieved. Monitoring was used in less than 30% of cases where succinylcholine was the sole drug used.

Barriers and aids to routine neuromuscular monitoring and consistent reversal practice-A qualitative study.

BACKGROUND: Neuromuscular monitoring is recommended whenever a neuromuscular blocking agent is administered, but surveys have demonstrated inconsistent monitoring practices. Using qualitative methods, we aimed to explore barriers and aids to routine neuromuscular monitoring and consistent reversal practice. METHODS: Focus group interviews were conducted to obtain insights into the thoughts and attitudes of individual anaesthetists, as well as the influence of colleagues and department culture. Interviews were conducted at five Danish and one US hospital. Data were analysed using template analysis. RESULTS: Danish anaesthetists used objective neuromuscular monitoring when administering a non-depolarizing relaxant, but had challenges with calibrating the monitor and sometimes interpreting measurements. Residents from the US institution used subjective neuromuscular monitoring, objective neuromuscular monitoring was generally not available and most had not used it. Danish anaesthetists used neuromuscular monitoring to assess readiness for extubation, whereas US residents used subjective neuromuscular monitoring, clinical tests like 5-second head lift and ventilatory parameters. The residents described a lack of consensus between senior anaesthesiologists in reversal practice and monitoring use. Barriers to consistent and correct neuromuscular monitoring identified included unreliable equipment, time pressure, need for training, misconceptions about pharmacokinetics of neuromuscular blocking agents and residual block, lack of standards and guidelines and departmental culture. CONCLUSION: Using qualitative methods, we found that though Danish anaesthetists generally apply objective neuromuscular monitoring routinely and residents at the US institution often apply subjective neuromuscular monitoring, barriers to consistent and correct use still exist.

Multimodality Intraoperative Neurophysiological Monitoring (IONM) During Shoulder Surgeries.

Introduction: The purpose of this study is to identify the advancing role of Intraoperative Neurophysiological Monitoring (IONM) in detecting and preventing nerve injuries during shoulder surgery procedures. Methods: We performed a retrospective analysis of IONM data from ten shoulder procedures. The patients consisted of nine females and one male with ages ranging from 67 to 81 years (median: 74 years). IONM modalities utilized were bilateral Somatosensory Evoked Potentials (SSEP), Transcranial Motor Evoked Potentials (TCeMEP), ipsilateral Electromyogram (EMG) from upper extremity muscles and Train of four (TOF) recordings. Results: A decrease in signals was noted in three patients (30%). Only upper SSEP amplitude decreased in one patient; both upper extremity SSEP and TCeMEP decreased in two patients. Only one patient had poor baseline radial nerve SSEP that improved during the surgery. We performed spontaneous EMG (s-EMG) in all ten patients and successfully recorded triggered (t-EMG) in seven patients (71.4%). In one patient, SSEP and TCeMEP did not improve, and the patient woke up with deficits. Conclusions: In this small series, we were able to identify real-time impending nerve injury. The use of IONM alerted and may have prevented intraoperative nerve injury in 30% of the patients in this series. In one patient, SSEP and TCeMEP did not recover even after the intervention due to severe blood loss. The patient woke up with sensory and motor deficits. The utilization of multimodality IONM can be helpful due to signal changes, therefore minimizing the frequency of nerve injury and deficits.

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.