Pediatric Intraoperative Electromyographic Responses at the Adductor Pollicis and Flexor Hallucis Brevis Muscles: A Prospective, Comparative Analysis.

BACKGROUND: Peripheral nerve stimulation with a train-of-four (TOF) pattern can be used intraoperatively to evaluate the depth of neuromuscular block and confirm recovery from neuromuscular blocking agents (NMBAs). Quantitative monitoring can be challenging in infants and children due to patient size, equipment technology, and limited access to monitoring sites. Although the adductor pollicis muscle is the preferred site of monitoring, the foot is an alternative when the hands are unavailable. However, there is little information on comparative evoked neuromuscular responses at those 2 sites. METHODS: Pediatric patients undergoing inpatient surgery requiring NMBA administration were studied after informed consent. Electromyographic (EMG) monitoring was performed simultaneously in each participant at the hand (ulnar nerve, adductor pollicis muscle) and the foot (posterior tibial nerve, flexor hallucis brevis muscle). RESULTS: Fifty patients with a mean age of 3.0 ± standard deviation (SD) 2.9 years were studied. The baseline first twitch amplitude (T1) of TOF at the foot (12.46 mV) was 4.47 mV higher than at the hand (P <.0001). The baseline TOF ratio (TOFR) before NMBA administration and the maximum TOFR after antagonism with sugammadex were not different at the 2 sites. The onset time until the T1 decreased to 10% or 5% of the baseline value (T1) was delayed by approximately 90 seconds (both P =.014) at the foot compared with the hand. The TOFR at the foot recovered (TOFR ≥0.9) 191 seconds later than when this threshold was achieved at the hand (P =.017). After antagonism, T1 did not return to its baseline value, a typical finding with EMG monitoring, but the fractional recovery (maximum T1 at recovery divided by the baseline T1) at the hand and foot was not different, 0.81 and 0.77, respectively (P =.68). The final TOFR achieved at recovery was approximately 100% and was not different between the 2 sites. CONCLUSIONS: Although this study in young children demonstrated the feasibility of TOF monitoring, interpretation of the depth of neuromuscular block needs to consider the delayed onset and the delayed recovery of TOFR at the foot compared to the hand. The delay in achieving these end points when monitoring the foot may impact the timing of tracheal intubation and assessment of adequate recovery of neuromuscular block to allow tracheal extubation (ie, TOFR ≥0.9).

Effect of tetanic stimulation prior to train-of-four monitoring on the time to muscle response stabilization with neuromuscular blockade with rocuronium in patients aged 60 to 80 years: A prospective randomized controlled trial.

PURPOSE: To determine the effect of tetanic stimulation on the time to achieve stabilization of the T1 height, by acceleromyography train-of-four (TOF) ratio monitoring, in patients aged 60 to 80 years. METHODS: Randomized, prospective, single-blind, controlled trial in patients aged 60 to 80 years undergoing elective surgery under general anesthesia in two university hospitals in Brazil between December 2019 and March 2022. This trial was performed in accordance with the principles of the Helsinki Declaration and the guidelines for good clinical research practice in pharmacodynamic studies of neuromuscular blocking agents II. Participants were randomly allocated by computer-generated numbers to receive tetanic stimulation (intervention group, n = 25) or not receive tetanic stimulation (control group, n = 25) to achieve T1 height stabilization on TOF ratio monitoring. The primary endpoint was to evaluate the effect of tetanic stimulation on the time to achieve stabilization of the T1 height. We also evaluated the effect on the onset time of rocuronium and time to recover from neuromuscular blockade with a single dose of rocuronium 0.6 mg.kg-1 with spontaneous recovery. RESULTS: There was no statistically significant difference between the groups in the time to T1 height stabilization (intervention: 4.3 [2.0-8.0] min; control: 5.8 [2.0-10.5] min; p = 0.202), onset time of the neuromuscular blocking agent (intervention: 1.9 [±0.7] min; control: 2.2 [±1.0] min; p = 0.219), or neuromuscular blockade recovery times to normalized TOF values of 0.7 (intervention: 106.1 [±37.2] min; control: 91.7 [±27.5] min; p = 0.295), 0.8 (intervention: 114.3 [±40.1] min; control: 97.8 [±28.9] min; p = 0.225), 0.9 (intervention: 126.5 [±44.0] min; control: 106.9 [±30.6] min; p = 0.153), and 1.0 (intervention: 138.3 [±43.4] min; control: 123.8 [±43.5] min; p = 0.425). CONCLUSION: The results of this study suggest that the recommendation to use tetanic stimulation to shorten the time to T1 height stabilization in neuromuscular monitoring did not alter the stabilization time of the T1 twitch or the pharmacodynamics of neuromuscular blockade with rocuronium in patients aged 60 to 80 years.

Shortened time to neuromuscular recovery with lower doses of rocuronium in elderly patients.

INTRODUCTION: The effect of neuromuscular blocking agents may be reversed by administration of neostigmine, when two twitches are present using train-of-four (TOF) stimulation. However, in elderly patients, limited data are available about when to administer neostigmine. We hypothesised that time to two twitches after TOF (TOF-2) was shorter after rocuronium 0.6 mg/kg than after rocuronium 0.9 mg/kg. Also, we hypothesised that time to TOF-2 would be shorter after rocuronium 0.3 mg/kg than after rocuronium 0.6 mg/kg. METHODS: This was a secondary analysis of 50 elderly patients > 80 years; 16 patients received rocuronium 0.6 mg/kg, another 16 patients received rocuronium 0.9 mg/kg; and, finally, 18 patients received rocuronium 0.3 mg/kg. Patients received total intravenous anaesthesia, and neuromuscular block was monitored with acceleromyography. RESULTS: Time to TOF-2 was shorter after rocuronium 0.6 mg/kg than after rocuronium 0.9 mg/kg: 37 min. versus 59 min. (difference: 22 min. (95% confidence intervals (CI): 10 to 33 min.), p = 0.0007). Time to TOF-2 after rocuronium 0.3 mg/kg was shorter than after rocuronium 0.6 mg/kg: 19 min. versus 37 min. (difference: 18 min. (95% CI: 11 to 25 min.), p = 0.00006). However, only 33% of the patients receiving 0.3 mg/kg obtained full effect i.e. TOF-0. CONCLUSION: Time to TOF-2 was shorter after rocuronium 0.6 mg/kg than after 0.9 mg/kg and shorter after rocuronium 0.3 mg/kg than after 0.6 mg/kg. FUNDING: This work was supported by departmental sources. TRIAL REGISTRATION: This study was a secondary analysis of two clinical trials. CLINICALTRIALS: gov (NCT04512313), (NCT03857750).

Relationship between muscle mass ratio and rocuronium dose required for maintaining deep neuromuscular blockade: A prospective observational study.

BACKGROUND: Deep neuromuscular blockade (NMB) has benefits in various surgical procedures, however, precise quantitative neuromuscular monitoring is crucial for its proper maintenance and recovery. Neuromuscular blocking agent dosage relies on actual body weight (ABW), but this varies among individuals. Therefore, this study hypothesizes that there is a correlation between the rocuronium requirement for deep NMB and muscle mass ratio measured by bioelectric impedance analysis. METHODS: Ninety adult female patients undergoing laparoscopic operation were enrolled in this study. Muscle and fat masses were assessed using a body composition analyser. Deep NMB, defined as a post-tetanic count of 1-2, was maintained through the continuous infusion of rocuronium. The primary outcome involves determining the correlation between the rocuronium dose required for deep NMB and the muscle mass ratio. Conversely, secondary outcomes included assessing the relationship between the rocuronium dose for deep NMB and fat mass ratio, and ABW. Additionally, we investigated their relationship with rocuronium onset time and profound blockade duration. RESULTS: No relationship was observed between the muscle mass ratio and rocuronium dose required for maintaining deep NMB (r = 0.059 [95% CI = 0.153-0.267], p = 0.586). Fat mass ratio and ABW showed no correlation with the rocuronium dose, whereas rocuronium onset time was positively correlated with muscle mass ratio (r = 0.327) and negatively correlated with fat mass ratio (r = -0.302), respectively. Profound blockade duration showed no correlation with any of the assessed variables. CONCLUSIONS: No correlation was detected between muscle mass ratio and the rocuronium dose required to achieve deep NMB.

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.

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.