Evolution of a laboratory mechanomyograph.

Mechanomyography is currently the accepted laboratory reference standard for quantitative neuromuscular blockade monitoring. Mechanomyographs are not commercially available. Previously, a mechanomyograph was built by our laboratory and used in several clinical studies. It was subsequently redesigned to improve its usability and functionality and to accommodate a wider range of hand sizes and shapes using an iterative design process. Each version of the redesigned device was initially tested for usability and functionality in the lab with the investigators as subjects without electrical stimulation. The redesigned devices were then assessed on patients undergoing elective surgery under general anesthesia without neuromuscular blocking drugs. Since the patients were not paralyzed, the expected train-of-four ratio was 1.0. The device accuracy and precision were represented by the train-of-four ratio mean and standard deviation. If issues with the device's useability or functionality were discovered, changes were made, and the redesign processes repeated. The final mechanomyograph design was used to collect 2,362 train-of-four ratios from 21 patients. The mean and standard deviation of the train-of-four ratios were 0.99 ± 0.030. Additionally, the final mechanomyograph design was easier to use and adjust than the original design and fit a wider range of hand sizes. The final design also reduced the frequency of adjustments and the time needed for adjustments, facilitating data collection during a surgical procedure.

Machine learning based analysis and detection of trend outliers for electromyographic neuromuscular monitoring.

PURPOSE: Neuromuscular monitoring is frequently plagued by artefacts, which along with the frequent unawareness of the principles of this subtype of monitoring by many clinicians, tends to lead to a cynical attitute by clinicians towards these monitors. As such, the present study aims to derive a feature set and evaluate its discriminative performance for the purpose of Train-of-Four Ratio (TOF-R) outlier analysis during continuous intraoperative EMG-based neuromuscular monitoring. METHODS: Patient data was sourced from two devices: (1) Datex-Ohmeda Electromyography (EMG) E-NMT: a dataset derived from a prospective observational trial including 136 patients (21,891 TOF-R observations), further subdivided in two based on the type of features included; and (2) TetraGraph: a clinical case repository dataset of 388 patients (97,838 TOF-R observations). The two datasets were combined to create a synthetic set, which included shared features across the two. This process led to the training of four distinct models. RESULTS: The models showed an adequate bias/variance balance, suggesting no overfitting or underfitting. Models 1 and 2 consistently outperformed the others, with the former achieving an F1 score of 0.41 (0.31, 0.50) and an average precision score (95% CI) of 0.48 (0.35, 0.60). A random forest model analysis indicated that engineered TOF-R features were proportionally more influential in model performance than basic features. CONCLUSIONS: Engineered TOF-R trend features and the resulting Cost-Sensitive Logistic Regression (CSLR) models provide useful insights and serve as a potential first step towards the automated removal of outliers for neuromuscular monitoring devices. TRIAL REGISTRATION: NCT04518761 (clinicaltrials.gov), registered on 19 August 2020.

Unilateral abnormality of initial motor-evoked potential in the upper limb detected during lumbar spine surgery: a case report.

BACKGROUND: We present a case with abnormal findings of initial motor-evoked potential (MEP) in the left upper limb after prone positioning during lumbar spine surgery. CASE PRESENTATION: A 71-year-old man with bilateral lower extremity numbness without a history of preexisting motor weakness underwent L3-5 spinal fenestration. Initial MEP monitoring after prone positioning revealed markedly prolonged latency and lower amplitude in the left abductor pollicis brevis (APB). Because the left upper limb somatosensory-evoked potentials had normal values, a position-related impending peripheral nerve injury located between the neck and the forearm was excluded. Postoperative examination revealed that MEP abnormality in the left APB was caused by carpal tunnel syndrome. CONCLUSIONS: Abnormal initial MEP from the upper limb was unexpectedly detected after prone positioning during lumbar spine surgery. The condition was caused by preexisting carpal tunnel syndrome.

Practice Guidelines for Monitoring Neuromuscular Blockade-Elements to Change to Increase the Quality of Anesthesiological Procedures and How to Improve the Acceleromyographic Method.

Neuromuscular blocking agents are a crucial pharmacological element of general anesthesia. Decades of observations and scientific studies have resulted in the identification of many risks associated with the uncontrolled use of neuromuscular blocking agents during general anesthesia or an incomplete reversal of neuromuscular blockade in the postoperative period. Residual relaxation and acute postoperative respiratory depression are the most serious consequences. Cyclic recommendations have been developed by anesthesiology societies from many European countries as well as from the United States and New Zealand. The newest recommendations from the American Society of Anesthesiologists and the European Society of Anesthesiology were published in 2023. These publications contain very detailed recommendations for monitoring the dosage of skeletal muscle relaxants in the different stages of anesthesia-induction, maintenance and recovery, and the postoperative period. Additionally, there are recommendations for various special situations (for example, rapid sequence induction) and patient populations (for example, those with organ failure, obesity, etc.). The guidelines also refer to pharmacological drugs for reversing the neuromuscular transmission blockade. Despite the development of several editions of recommendations for monitoring neuromuscular blockade, observational and survey data indicate that their practical implementation is very limited. The aim of this review was to present the professional, technical, and technological factors that limit the implementation of these recommendations in order to improve the implementation of the guidelines and increase the quality of anesthesiological procedures and perioperative safety.

Tolerance to preoperative placement of electrodes for neuromuscular monitoring using the Tetragraph™.

Background: Quantitative train-of-four (TOF) monitoring has recently been shown to be feasible in infants and children using a novel electromyography (EMG)-based monitor with a pediatric-sized self-adhesive sensor. However, placement of the sensor and initiation of TOF monitoring may require additional time in the operating room (OR), delaying workflow and the time to induction of anesthesia. The current study evaluates the feasibility of placing the self-adhesive sensor in the preoperative holding area in pediatric patients before arrival to the OR. Methods: Consented pediatric patients undergoing inpatient surgery requiring the administration of NMBAs were enrolled. The EMG electrode was placed along the ulnar nerve on the volar aspect of the distal forearm to provide neurostimulation. After the induction of anesthesia, monitoring was initiated and TOF recording started before the administration of the NMBA. A Likert score (0-10) was used to assess ease of placement, tolerability of the monitor during the preoperative period, and its ability to generate a recorded response in the OR. Results: The final study cohort included 40 patients with a median age of 3.7 years. Fourteen patients (35%) pulled off the sensor before arrival to the OR and 26 patients (65%) arrived at the OR with the sensor intact and functioning. Older children were more likely to maintain the sensor until arrival to the OR compared to younger patients (median age of 5.24 versus 1 year, P = 0.0521). A median age of 3.7 years correlated with an 80% chance of arriving in the OR with the sensor intact. Application ease and tolerance of the sensor were higher in the group that maintained the sensor until OR arrival. Conclusion: In patients more than 4 years of age, placement of the self-adhesive sensor for EMG-based TOF monitoring may be feasible. However, in younger patients, additional interventions may be required to achieve a similar success rate.

Does the objective measurement of muscle strength improve the detection of postoperative residual muscle weakness?

Background and Aims: The postoperative residual neuromuscular block (PRNB) has a significant impact on patient safety and well-being, but continues to remain underestimated. Objective evaluation of handgrip strength using a force dynamometer can be useful to identify postoperative muscle weakness. Material and Methods: Thirty-two American Society of Anesthesiologists (ASA) class I and II patients who received general anesthesia were included. Patients were extubated after the train-of-four (TOR) ratio (TOFR) was >0.90 and the clinical criteria for motor power recovery were judged as adequate. The measurements of handgrip strength and peak expiratory flow rate (PEFR) were obtained at baseline, 15 min after extubation, and 1, 2, and 4 h postoperatively. The incidence of significant decline from baseline (>25%) was determined. The correlation between handgrip strength and PEFR was assessed using Spearman correlation. The time to return to baseline for muscle grip strength and PEFR was performed using Kaplan-Meier survival analysis. A P value of 0.05 was considered significant for all tests. Results: The incidence of the significant decline in handgrip strength from baseline was 100% at 15 and 60 min, 76% at 2 h, and 9.4% at 4 h. There was a strong correlation between muscle grip strength and PEFR (0.89, P < 0.001). None of the patients exhibited the potential complications of PRNB. (PRMB in abstract. It should be uniform) The mean time to return to the baseline value of muscle grip strength was 3.8 h (95% confidence interval [CI] 3.6-3.9), and the mean time to return to baseline for PEFR was 3.2 h (95% CI 2.9-3.4 h). Conclusion: Objective assessment of muscle grip strength using a force dynamometer has the potential to be a new objective metric to monitor postoperative muscle weakness.

Coadministration of intravenous calcium along with neostigmine for rapid neuromuscular blockade recovery: A systematic review and meta-analysis.

Postoperative residual curarization (PORC) and the impact of the coadministration of intravenous calcium along with an acetylcholinesterase inhibitor on it are not well addressed. Extensive electronic database screening was done until October 7, 2022 after enlisting the protocol of this systematic review in PROSPERO (CRD42021274879). Randomized controlled trials (RCTs) evaluating the impact of intravenous calcium and neostigmine coadministration on neuromuscular recovery were included in this meta-analysis. Our search retrieved four RCTs with a total of 266 patients. The application of calcium shortened the neuromuscular recovery time (SMD = -2.13, 95% confidence interval [CI]: -2.66 to -1.59, I2 = 66%) and reduced the risk of PORC at 5 min (odds ratio [OR] = 0.21, 95% CI: 0.10-0.46, I2 = 0%), with an improved train-of-four (TOF) ratio at 5 min (mean difference [MD] = 9.28, 95% CI: 4-14.57, I2 = 66%). However, neither significant reduction in PORC at 10 min (OR = 0.41, 95% CI: 0.15-1.09, I2 = 0%) nor a better TOF ratio was associated with coadministration of calcium (MD = 0.40, 95% CI: -1.3-2.11). Coadministration of calcium along with neostigmine during the early period of neuromuscular blockade reversal can be used to enhance neuromuscular recovery.

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.

Onset and duration of action of escalating doses of atracurium in anesthetized healthy goats.

OBJECTIVE: The aim of this study was to describe the onset and duration of action of escalating doses of atracurium in healthy, anesthetized goats. STUDY DESIGN: Randomized, blinded, triple crossover study. Animals A total of eight (five males and three females) healthy goats weighing 42.7-123.5 kg and aged from 11 months to 8 years. METHODS: Goats were anesthetized three times with propofol and anesthesia was maintained with isoflurane. One of three doses of atracurium was administered intravenously 30 minutes after induction: 0.25 mg kg-1 (AT25), 0.5 mg kg-1 (AT50) or 0.75 mg kg-1 (AT75). Acceleromyographic train-of-four ratio (TOFR) followed by train-of-four counts (TOFC) were recorded at 30 second intervals after atracurium administration to determine blockade onset (TOFC = 0). The TOFR followed by TOFC were recorded at 5 minute intervals until return to pre-atracurium baseline (TOFR = 1.0). Normally distributed data were analyzed with repeated measures anova and a Tukey multiple comparison test. Data not normally distributed were analyzed with a Friedman test and a Dunn's multiple comparison test. RESULTS: For AT50 and AT75, 100% of goats achieved TOFC = 0 after atracurium administration. For AT25, however, 87.5% of goats achieved TOFC = 0 after atracurium administration. The onset time was shorter for AT75 [1.5 (0.5-1.5) minutes; median (range)] than for AT25 [2 (1-4) minutes] (p = 0.048). The duration of action [from onset time to complete reversal (TOFR = 1.0)] was significantly shorter for AT25 (52 ± 12 minutes, mean ± SD) than for AT50 (77 ± 18 minutes) (p < 0.001) and AT75 (85 ± 16 minutes) (p < 0.001). There was no significant difference in duration between AT50 and AT75 (p = 0.238). CONCLUSIONS AND CLINICAL RELEVANCE: Doses of 0.5 and 0.75 mg kg-1 atracurium may produce complete neuromuscular blockade in healthy, anesthetized goats.

Sugammadex for reversal of moderate-to-deep rocuronium block in a clinical setting: A retrospective report of 10 dogs.

OBJECTIVE: To compare recovery times of sugammadex with spontaneous recovery from rocuronium-induced neuromuscular block (NMB) in dogs. STUDY DESIGN: Retrospective, unmatchedcase-control study. ANIMALS: A total of 10 dogs administered sugammadex and 10 dogs recovering spontaneously from rocuronium-induced NMB. METHODS: Files of dogs administered rocuronium between March and August 2023 were inspected. The train-of-four (TOF) count at the time of sugammadex administration and the time between administration and TOF ratio >90% (recovery time) were recorded. The recovery time for those not administered reversal agents was considered from the first TOF value >0 until TOF ratio >90%. The dose of sugammadex and the cumulative dose of rocuronium were recorded. Rocuronium doses and recovery times were compared using Mann-Whitney tests. The coefficient of determination (R2) between the cumulative rocuronium dose and sugammadex dose and the recovery time were calculated. RESULTS: Dogs in the sugammadex and spontaneous recovery groups were administered intravenously (IV) 0.76 (0.4-2.6) and 0.61 (0.3-2.9) mg kg-1 of rocuronium, respectively (p = 0.325). Recovery time after 3.9 (2.9-5.5) mg kg-1 of sugammadex IV was 1 (1-3) minutes and was 20 (10-35) min for spontaneous recovery (p < 0.0001). The R2 for rocuronium and sugammadex doses and recovery times were 0.19 (p = 0.2) and 0.012 (p = 0.758). CONCLUSIONS AND CLINICAL RELEVANCE: Sugammadex 2.9-5.5 mg kg-1 reversed moderate (TOF count 1-3) or deep (TOF count 0) rocuronium-induced NMB within 3 minutes, substantially faster than spontaneous recovery.

Comparative performance of stimpod electromyography with mechanomyography for quantitative neuromuscular blockade monitoring.

PURPOSE: The purpose of this study was to compare the Stimpod electromyograph neuromuscular blockade monitor to mechanomyography, which is widely considered to be the reference standard. METHODS: The Stimpod electromyograph was used with its designated electrode array on the same hand as the mechanomyograph. Pairs of train-of-four measurements were recorded every 0.5-2 min. When the train-of-four count was zero on the electromyograph monitor, pairs of post tetanic count measurements were recorded every 2.5 min, instead of train-of-four measurements. Measurements were recorded from immediately after induction of anesthesia until just before emergence. Stimulation current was set to 60 mA with a duration of 200 microsec. The mechanomyography recording system recorded each twitch waveform for analysis. High resolution electromyograph waveforms were also recorded using a datalogger accessory provided by the manufacturer, facilitating inspection of individual waveforms. The administration of neuromuscular blocking drugs was left up to the discretion of the anesthesia care team. RESULTS: Twenty-three patients contributed 1,088 data pairs suitable for analysis. Bland-Altman analysis of 415 pairs of train-of-four ratios showed a bias of 0.028 and limits of agreement of -0.18 and 0.24. Two hundred seventy-three train-of-four count data pairs were compared by Cohen's quadratically weighted kappa which was calculated to be 0.44, indicating moderate agreement. Three hundred thirty-eight post tetanic count data pairs were compared by Cohen's quadradically weighted kappa which was calculated to be 0.80, indicating substantial agreement. CONCLUSION: The electromyograph produced results that were comparable to the mechanomyograph.

The depth of neuromuscular blockade is not related to chest wall elastance and respiratory mechanics in moderate to severe acute respiratory distress syndrome patients. A prospective cohort study.

BACKGROUND: Data concerning the depth of neuromuscular blockade (NMB) required for effective relaxation of the respiratory muscles in ARDS are scarce. We hypothesised that complete versus partial NMB can modify respiratory mechanics. METHOD: Prospective study to compare the respiratory mechanics of ARDS patients according to the NMB depth. Each patient was analysed at two times: deep NMB (facial train of four count (TOFC) = 0) and intermediate NMB (TOFC >0). The primary endpoint was the comparison of chest wall elastance (ELCW) according to the NMB level. RESULTS: 33 ARDS patients were analysed. There was no statistical difference between the ELCW at TOFC = 0 compared to TOFC >0: 7 cmH2O/l [5.7-9.5] versus 7 cmH2O/l [5.3-10.8] (p = 0.36). The depth of NMB did not modify the expiratory nor inspiratory oesophageal pressure (Pesexp = 8 cmH2O [5-9.5] at TOFC = 0 versus 7 cmH2O [5-10] at TOFC >0; (p = 0.16) and Pesinsp = 10 cmH2O [8.2-13] at TOFC = 0 versus 10 cmH2O [8-13] at TOFC >0; (p = 0.12)). CONCLUSION: In ARDS, the relaxation of the respiratory muscles seems to be independent of the NMB level.

Comparison of Fixed Dosing vs Train of Four Titration of Cisatracurium in COVID-19 ARDS Patients.

Background: Early neuromuscular blockade with cisatracurium has been associated with improved outcomes in moderate-severe acute respiratory distress syndrome (ARDS). Previous studies have demonstrated increased drug utilization without benefits in oxygenation using fixed dose cisatracurium compared to train-of-four (TOF) titration. Objective: We sought to compare a novel, lower fixed dose cisatracurium protocol to TOF titration evaluating the impact on PaO2:FiO2 ratio (P/F). Methods: We conducted a single-center retrospective cohort study comparing fixed dose cisatracurium to TOF titration. We included patients aged 18-89 treated for COVID-19 ARDS with a baseline P/F≤200 who received a cisatracurium infusion for ≥12 h. The primary outcome was change in P/F at 48 h from baseline. Secondary outcomes included change in P/F at 24 h and 7 days, need for mechanical ventilation at day 28, and cisatracurium utilization. Results: Analyses included 125 patients (fixed dose = 65, TOF = 60). Severe ARDS was common with a baseline median P/F of 73.7 vs 79.5, P = .133. The change in P/F at 48 h was larger in the TOF cohort in the adjusted analysis (24.9 vs 70.8, P < .005). The rate and total cumulative dose of cisatracurium were higher in the fixed dose cohort (5 vs 3 mcg/kg/min, P < .001; 1034 vs 612 mg, P < .001) despite similar infusion durations (44.1 h vs 48.5 h, P = .642). Conclusions: Patients in the TOF cisatracurium cohort had improved P/F at 48 h compared to the fixed dose cohort, while also using only 60% of the cumulative dose. Future directions should include analysis of the implications of increased cisatracurium exposure on patient outcomes.

Validation of a convolutional neural network that reliably identifies electromyographic compound motor action potentials following train-of-four stimulation: an algorithm development experimental study.

Background: International guidelines recommend quantitative neuromuscular monitoring when administering neuromuscular blocking agents. The train-of-four count is important for determining the depth of block and appropriate reversal agents and doses. However, identifying valid compound motor action potentials (cMAPs) during surgery can be challenging because of low-amplitude signals and an inability to observe motor responses. A convolutional neural network (CNN) to classify cMAPs as valid or not might improve the accuracy of such determinations. Methods: We modified a high-accuracy CNN originally developed to identify handwritten numbers. For training, we used digitised electromyograph waveforms (TetraGraph) from a previous study of 29 patients and tuned the model parameters using leave-one-out cross-validation. External validation used a dataset of 19 patients from another study with the same neuromuscular block monitor but with different patient, surgical, and protocol characteristics. All patients underwent ulnar nerve stimulation at the wrist and the surface electromyogram was recorded from the adductor pollicis muscle. Results: The tuned CNN performed highly on the validation dataset, with an accuracy of 0.9997 (99% confidence interval 0.9994-0.9999) and F1 score=0.9998. Performance was equally good for classifying the four individual responses in the train-of-four sequence. The calibration plot showed excellent agreement between the predicted probabilities and the actual prevalence of valid cMAPs. Ten-fold cross-validation using all data showed similar high performance. Conclusions: The CNN distinguished valid cMAPs from artifacts after ulnar nerve stimulation at the wrist with >99.5% accuracy. Incorporation of such a process within quantitative electromyographic neuromuscular block monitors is feasible.

Neuromuscular Blockade Monitoring: Having It but Knowing When Not to Trust It.

Butyrylcholinesterase (BChE) is an enzyme involved in the degradation of depolarizing and non-depolarizing neuromuscular blocking agents (NMBA), such as succinylcholine and mivacurium, respectively. Its deficiency is inherited or acquired, and results in paralysis of skeletal muscles after NMBA administration. We report a case of a 32-year-old pregnant woman proposed for cesarean section. General anesthesia (GA) was induced using propofol and succinylcholine. The surgical procedure was uneventful but after 40 minutes, there was no reversal of neuromuscular block (NMB). Other differential diagnoses were excluded and a deficit of BChe was assumed. When the train-of-four ratio (TOFr) achieved 40%, neostigmine/atropine led to the slow recovery of NMB up to TOFr 88%. The patient was extubated, but ventilation proved ineffective, so GA was induced and the patient was reintubated. A new measurement found a TOFr of 60%. Sedation and ventilatory support were maintained until the complete reversal of NMB (4 hours after succinylcholine). Prolonged block is a rare but serious complication of the use of succinylcholine in patients with BChE deficiency. This report not only highlights the importance of intraoperative NMB monitoring in homozygotic patients for atypical cholinesterase but also raises awareness for its careful interpretation.

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.

Intraoperative electromyographic monitoring in children using a novel pediatric sensor.

Background: Train-of-four (TOF) monitoring is essential in optimizing perioperative outcomes as a means to assess the depth of neuromuscular blockade and confirm recovery following the administration of neuromuscular blocking agents (NMBAs). Quantitative TOF monitoring has been limited in infants and children primarily due to lack of effective equipment. The current study evaluates a novel electromyography (EMG)-based TOF monitor with a recently developed pediatric-sized self-adhesive sensor in infants and children. Methods: Consented pediatric patients undergoing inpatient surgery requiring the administration of NMBAs were enrolled. The EMG electrode was placed along the ulnar nerve on the volar aspect of the distal forearm. The muscle action potentials from the adductor pollicis muscle were recorded throughout surgery at 20-second intervals. Data from the monitor's built-in memory card were later retrieved and analyzed. Results: The final study cohort included 51 patients who ranged in age from 0.2 to 7.9 years and in weight from 4.2 to 36.0 kilograms. Thirty patients weighed less than 15 kgs. Supramaximal stimulus current intensity (mA) at a pulse width of 200 µsec was 30 mA in 8%; 40 mA in 29%; 50 mA in 16%; and 60 mA in 20% of the patients. Supramaximal stimulus current intensity (mA) at a pulse width of 300 µsec was 50 mA in 4%; 60 mA in 24%. The muscle action potential baseline amplitude was 8.7 ± 3.3 mV and recovered to 7.2 ± 3.7 mV after antagonism of neuromuscular blockade. The average baseline TOF ratio was 100 ± 3% and recovered to 98 ± 7% after antagonism of neuromuscular blockade. No technical issues were noted with application of the sensor or subsequent use of the monitor. Conclusion: Neuromuscular monitoring can be performed intraoperatively in pediatric patients who are less than 8 years of age using a novel commercially available EMG-based monitor with a recently developed pediatric sensor. The novel sensor allows use of an EMG-based monitor in infants and children in whom acceleromyography or subjective (visual) observation of the TOF response may not be feasible. Automatic detection of neuromuscular stimulating parameters (supramaximal current intensity level, baseline amplitude of the muscle action potential) was feasible in pediatric patients of all sizes including those weighing less than 15 kilograms or when there was limited access to the extremity being monitored.