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.

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.

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.

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.

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.

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.

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.

Rate of residual neuromuscular block using single-dose rocuronium in general anesthesia for ENT surgery: a retrospective cohort study.

INTRODUCTION: NMB facilitates intubating conditions in general anesthesia. However, it is associated with significant residual postoperative paralysis and morbidity. OBJECTIVE: To investigate the rate of underdiagnosed residual NMB based on two TOFR criteria (< 0.91 and < 1.00). METHODS: We performed a retrospective study adhering to STROBE guidelines. We included patients undergoing ENT surgery using single-dose neuromuscular block for balanced general anesthesia from June to December 2018. We collected demographic and anthropometric data, ASA score, NMBA dose, TOFR recordings at 5, 30 and 60 min and end of the surgery, anesthesia and surgery time, and administration of reversal agent. Statistical analysis included descriptive and dispersion measures statistics, curve and cross tables for residual NMB on different TOFR criteria with sub-analysis for AR, RR, and OR in patients over 65 years old. RESULTS: We included 57 patients, mean age 41; 43 females and 14 males. Mean anesthetic and surgical time were 139.4 and 116.1 min, respectively. All the patients received rocuronium under a mean ponderal single-dose of 0.48 mg/kg. Residual NMB rates were 29.9 and 49.1% for a TOFR < 0.91 and < 1.00, respectively. Older adults had an OR of 6.08 for residual NMB. CONCLUSIONS: The rate of residual NMB was 29.9 to 49.1%, depending on the criteria used (TOFR < 0.91 and < 1.00, respectively). Patients above 65 years old had an increased risk of residual NMB (6.08 OR) and clinical symptoms related to residual NMB (11.75 OR). We recommend future research aiming to provide a specific surveillance protocol for patients above 65 years old, including shorter-action NMB, early reversal, and prolonged surveillance using the TOFR criteria of < 1.00 to identify patients at risk of residual NMB readily.

Neuromuscular block: Monitoring, reversal, and residual blockade in small animals.

Nondepolarizing neuromuscular blocking agents are used frequently during ophthalmic surgery of dogs and cats. Residual neuromuscular block (NMB)-impaired neuromuscular function at recovery from anesthesia-is a main concern when these agents are used in small animals. In humans, residual NMB reduces the ability to protect the airway (swallow and cough) and increases the incidence of hypoxia and upper airway collapse after recovery from anesthesia. In dogs, impaired neuromuscular function of the larynx can be detected even after common indicators of neuromuscular function suggest that recovery from NMB is complete. Objective monitoring of NMB is a simple, cost-effective strategy to minimize the risk of residual NMB. This review summarizes relevant aspects of monitoring and reversal of NMB, and strategies to minimize the risk of residual NMB in clinical practice of small animals.

Effect of quantitative versus qualitative neuromuscular blockade monitoring on rocuronium consumption in patients undergoing abdominal and gynecological surgery: a retrospective cohort study.

The level of neuromuscular blockade can be assessed by subjective (qualitative) and objective (quantitative) methods. This study aims to compare the dosage of the neuromuscular blocking agents (NMBA) rocuronium and the need for reversion by sugammadex between those methods. A retrospective, observational analysis was conducted. In the tactile qualitative-neuromuscular monitoring-group (tactile NMM) (n = 244), muscle contractions were assessed tactilely. In the quantitative neuromuscular monitoring-group (n = 295), contractions were accessed using an acceleromyograph. Primary endpoints were dosage of rocuronium per minute operation-time (milligram per kilogram bodyweight per minute (mg/kgBW/min)), count of repeated rocuronium administrations and use of sugammadex. Secondary endpoints were: NMM use before repeated NMBA application or extubation, time to extubation, post-operative oxygen demand. A total of n = 539 patients were included. n = 244 patients were examined with tactile NMM and 295 patients by quantitative NMM. Quantitative NMM use resulted in significantly lower rocuronium dosing (tactile NMM: 0.01 (± 0.007) mg/kgBW/min vs. quantitative NMM: 0.008 (± 0.006) mg/kgBW/min (p < 0.001)). In quantitative NMM use fewer repetitions of rocuronium application were necessary (tactile NMM: 83% (n = 202) vs. quantitative NMM: 71% (n = 208) p = 0.007). Overall, 24% (n = 58) in the tactile NMM-group, and 20% (n = 60) in the quantitative NMM-group received sugammadex ((p = 0.3), OR: 1.21 (0.81-1.82)). Significantly fewer patients in the quantitative NMM-group required oxygen-supply postoperative (quantitative NMM: 43% (n = 120)) vs. tactile NMM: 57% (n = 128)) (p = 0.002). The use of quantitative assessment of NMBA results in a lower overall dosage and requires fewer repetitions of rocuronium application. Therefore, quantitative monitoring systems should be used to monitor NMBA intraoperatively to reduce NMBA dosing, while achieving continuous neuromuscular blockade.

Effects of rocuronium dosage on intraoperative neurophysiological monitoring in patients undergoing spinal surgery.

WHAT IS KNOWN AND OBJECTIVE: Intraoperative neurophysiological monitoring (IONM) has been widely used in clinical practice. Therefore, the influence of neuromuscular blockers essential for spinal anaesthesia on IONM is worthy of our attention, but no randomized study has evaluated the dose-response effect. This study investigated the effects of different doses of rocuronium bromide on the intraoperative monitoring of motor evoked potentials (MEPs). METHODS: We conducted a randomized, double-blind trial to assess the effects of three rocuronium bromide doses (6.0, 9.0, 12 µg·kg-1 ·min-1 ) combined with intravenous infusion of propofol 6-8 mg·kg-1 ·h-1 and remifentanil 10 µg·kg-1 ·h-1 on the amplitudes of somatosensory evoked potentials (SEPs) and MEPs at the time of the baseline recording (T1 ), before pedicle screw placement (T2 ) and before spinal canal decompression (T3 ). Secondary outcomes included measurement of neuromuscular function, the occurrence of unexpected intraoperative body movement and recovery of spontaneous breathing. RESULTS AND DISCUSSION: A total of 123 patients were enrolled, and 120 patients were ultimately analysed. No differences were observed in the amplitude of SEPs among the three groups (p > 0.05). The MEP amplitude differences at T1 , T2 and T3 in all limbs did not differ in patients receiving rocuronium at 6.0 µg·kg-1 ·min-1 and 9.0 µg·kg-1 ·min-1 (p > 0.05). However, when rocuronium was administered at 12.0 µg·kg-1 ·min-1 , MEP amplitudes at the time point T3 were significantly attenuated compared with the time points T1 and T2 in both right upper limb and left lower limb (p = 0.002, p = 0.025, respectively). In patients treated with rocuronium 6.0 µg·kg-1 ·min-1 , the incidence of unexpected body movement was significantly higher (p = 0.026), and the train-of-four count (TOF count) showed a significant increase at T2 and T3 (p < 0.001) compared to other doses. WHAT IS NEW AND CONCLUSION: Rocuronium bromide at a rate of 9.0 µg·kg-1 ·min-1 provided suitable and adequate muscle relaxation without inhibiting IONM; thus, this dose is recommended for spinal surgery.

The interest of 100 versus 200 Hz tetanic stimulations to quantify low levels of residual neuromuscular blockade with mechanomyography: a pilot study.

A more sensitive method than the train-of-four ratio seems required to detect low levels of residual neuromuscular blockade before tracheal extubation. The goal of the study was to determine the potential benefit of 5 s of 100 versus 200 Hz tetanic stimulation to quantify the residual block with mechanomyography in anesthetised patients. Twenty informed and consenting 18- to 80-year-old patients undergoing nose surgery were included. On the left hand, neuromuscular transmission was continuously monitored by acceleromyography. On the right side, a new mecanomyographic device (Isometric Thumb Force©) recorded the force of thumb adduction (N) developed during 5 s of 100- and 200 Hz tetanic stimulations of the ulnar nerve at three consecutive times: baseline before inducing the neuromuscular blockade, at the time of contralateral train-of-four ratio 0.9 recovery, and 3 min after additional sugammadex reversal. Tetanic Fade Ratios (TFR = F residual/F max) were compared between 100 and 200 Hz stimulations using Student's t test. At the time of TOF ratio 0.9 recovery, both 100 and 200 Hz TFR were significantly decreased compared to baseline (0.61 and 0.16 on average, respectively, p < 0.0001). The 200 Hz TFR was significantly lower than the 100 Hz TFR (p < 0.0001). There were no differences between baseline and post-reversal TFR. The 200 Hz TFR has the potential to better describe low levels of residual neuromuscular blockade than the TOF ratio and 100 Hz TFR and would benefit from further investigations. Retrospectively registered in the Australian and New Zealand Clinical Trials Registry ACTRN12619000273189.

Vigilance: the behavioral impact of quantitative monitoring on administration and antagonism of neuromuscular blocking agents.

PURPOSE: The aim of this study was to determine whether use of acceleromyography (1) changes dosing of neuromuscular blocking agents (NMBAs), and (2) increases the time between neostigmine administration and extubation, when compared with subjective assessment of neuromuscular blockade. METHODS: For this retrospective study, data were collected from patient electronic medical records. Patients were included if they had received an NMBA as part of a general anesthetic in 2013 and 2014. Data were analyzed by category of monitoring device: quantitative monitor (acceleromyograph [AMG]) or subjective device (peripheral nerve stimulator [PNS]). Outcomes measured were the total dose of NMBA administered and, the timing of the last dose of NMBA and anticholinesterase relative to tracheal extubation. RESULTS: Results from multivariate models showed that use of acceleromyography was not associated with a change in the total dose of NMBA administered. In contrast, the number of times any monitor was used, as determined by the frequency with which the train-of-four count (TOFC) was recorded, correlated with the administration of greater amounts of rocuronium (P < 0.01) and vecuronium (P < 0.01). The use of acceleromyography did not prolong the time interval between neostigmine administration and tracheal extubation. The number of times any monitor was used during an anesthetic was associated with a decrease in this time interval. The interval decreased an average of 2.7 min each successive time the TOFC was recorded (P < 0.01). CONCLUSIONS: The data presented provides insight about the behavioral engineering inherent to the practice of anesthesiology. Introduction of neuromuscular blockade assessment appeared to increase provider vigilance in dosing of NMBAs-regardless of assessment method. The frequency of intraoperative monitoring (quantitative or subjective) was associated with an increased total dose of NMBA administered and decreased time interval between the last dose of neostigmine and extubation.

Effects of age on sugammadex reversal of neuromuscular blockade induced by rocuronium in Chinese children: a prospective pilot trial.

BACKGROUND: Sugammadex reverses neuromuscular blockade induced by steroidal relaxants. We compared the recovery for neuromuscular blockade reversal with sugammadex in children aged 1-12 years. METHODS: From August 2019 to August 2020, patients who received 2.0 mg·kg- 1 sugammadex for neuromuscular blockade reversal after surgery were recruited. The primary outcome was the time for the train-of-four ratio (TOFR) to recover to 0.9; secondary outcomes included the incidence of the TOFR < 0.9, extubation time, length of stay at the post-anesthesia care unit, and adverse events. Hemodynamic parameters before and 5 min after sugammadex administration and vital signs in the recovery room were also recorded. RESULTS: Eighty-six children were recruited (1 to < 3 years, n = 23; 3 to < 5 years, n = 33; 5 to ≤12 years, n = 30). Intergroup differences in the recovery of the TOFR to 0.9 were not statistically significant (F = 0.691, p = 0.504). Recurrence of the TOFR < 0.9 was not observed in any group. Five minutes after sugammadex administration, the heart rates of patients aged 3 to < 5 and 5 to ≤12 years were significantly lower than those at baseline (p < 0.05). Extubation time was similar in patients aged 1 to ≤12 years. Length of stay and end-tidal capnography at the post-anesthesia care unit as well as adverse events did not differ significantly. CONCLUSION: A moderate (TOF count two) rocuronium-induced neuromuscular blockade can be effectively and similarly reversed with sugammadex 2 mg·kg- 1 in Chinese children aged 1-12 years. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR1900023715 (June 8, 2019).

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.

Exploratory Outlier Detection for Acceleromyographic Neuromuscular Monitoring: Machine Learning Approach.

BACKGROUND: Perioperative quantitative monitoring of neuromuscular function in patients receiving neuromuscular blockers has become internationally recognized as an absolute and core necessity in modern anesthesia care. Because of their kinetic nature, artifactual recordings of acceleromyography-based neuromuscular monitoring devices are not unusual. These generate a great deal of cynicism among anesthesiologists, constituting an obstacle toward their widespread adoption. Through outlier analysis techniques, monitoring devices can learn to detect and flag signal abnormalities. Outlier analysis (or anomaly detection) refers to the problem of finding patterns in data that do not conform to expected behavior. OBJECTIVE: This study was motivated by the development of a smartphone app intended for neuromuscular monitoring based on combined accelerometric and angular hand movement data. During the paired comparison stage of this app against existing acceleromyography monitoring devices, it was noted that the results from both devices did not always concur. This study aims to engineer a set of features that enable the detection of outliers in the form of erroneous train-of-four (TOF) measurements from an acceleromyographic-based device. These features are tested for their potential in the detection of erroneous TOF measurements by developing an outlier detection algorithm. METHODS: A data set encompassing 533 high-sensitivity TOF measurements from 35 patients was created based on a multicentric open label trial of a purpose-built accelero- and gyroscopic-based neuromuscular monitoring app. A basic set of features was extracted based on raw data while a second set of features was purpose engineered based on TOF pattern characteristics. Two cost-sensitive logistic regression (CSLR) models were deployed to evaluate the performance of these features. The final output of the developed models was a binary classification, indicating if a TOF measurement was an outlier or not. RESULTS: A total of 7 basic features were extracted based on raw data, while another 8 features were engineered based on TOF pattern characteristics. The model training and testing were based on separate data sets: one with 319 measurements (18 outliers) and a second with 214 measurements (12 outliers). The F1 score (95% CI) was 0.86 (0.48-0.97) for the CSLR model with engineered features, significantly larger than the CSLR model with the basic features (0.29 [0.17-0.53]; P<.001). CONCLUSIONS: The set of engineered features and their corresponding incorporation in an outlier detection algorithm have the potential to increase overall neuromuscular monitoring data consistency. Integrating outlier flagging algorithms within neuromuscular monitors could potentially reduce overall acceleromyography-based reliability issues. TRIAL REGISTRATION: ClinicalTrials.gov NCT03605225; https://clinicaltrials.gov/ct2/show/NCT03605225.

Train-of-four monitoring with the twitchview monitor electctromyograph compared to the GE NMT electromyograph and manual palpation.

The purpose of this study was to compare train-of-four count and ratio measurements with the GE electromyograph to the TwitchView electromyograph, that was previously validated against mechanomography, and to palpation of train-of-four count. Electrodes for both monitors were applied to the same arm of patients undergoing an unrestricted general anesthetic. Train-of-four measurements were performed with both monitors approximately every 5 min. In a subset of patients, thumb twitch was palpated by one of the investigators. Eleven patients contributed 807 pairs of train-of-four counts or ratios. A subset of 5 patients also contributed palpated train-of-four counts. Bland-Altman analysis of the train-of-four ratio found a bias of 0.24 in the direction of a larger ratio with the GE monitor. For 72% of data pairs, the GE monitor train-of-four ratios were larger. For 59% of data pairs, the GE monitor train-of-four counts were larger (p < 0.0001). For 11% of data pairs, the GE monitor train-of-four count was 4 when the Twitchview monitor count was zero. When manual palpation of train-of-four count was compared to train-of-four count determined by the monitors, 70% of data pairs were identical between palpation and TwitchView train-of-four count, while 30% of data pairs were identical between palpation and GE train-of-four count. For 7% of data pairs, the GE monitor train-of-four count was 4 when the palpation count was 0. The GE electromyograph may overestimate the train-of-four count and ratio. The GE electromyograph frequently reported 4 twitches when none were actually present due to misinterpretation of artifacts.

A modified train-of-four ratio to assess recovery from depolarizing neuromuscular blockade after succinylcholine, a prospective observational study.

Succinylcholine is still used in clinical practice. Its duration is highly variable and neuromuscular monitoring is recommended to assess its recovery. Unfortunately, depolarizing neuromuscular block cannot be evaluated by train-of-four (TOF) as no fade occurs. Only single twitch (ST) allows to monitor depolarizing block. The TOFScan monitor proposes a modified TOF ratio (T4/Tref) not referring to fade within a TOF series. We hypothesized that the T4/Tref allows to assess recovery from succinylcholine. This observational study aims to compare recovery from depolarizing block simultaneously assessed with T4/Tref and ST. After Ethics Committee approval and written informed consent 45 patients receiving a single dose of succinylcholine were included. ST recovery, measured with TOF-Watch SX, and T4/Tref recovery, measured by TOFScan, were assessed simultaneously. Difference between measurements was compared using Mann-Whitney U test and overall concordance with the intraclass correlation coefficient (ICC). The ICC was 0.85 [95% CI 0.82-0.87]. The first T4/Tref ratio ≥ 90% was 97% [95% CI 93-101%] the corresponding ST value was 91% [95% CI 87-97%]. The first T4/Tref ratio ≥ 100% was 103% [95% CI 102-107%], the corresponding ST value was 104% [95% CI 100-106%]; median [95% confidence interval of the median]. Time to recovery to 90% and 100% of baseline did not differ between ST or T4/Tref. It was10.0 [8.0-13.0] min vs 10.0 [8.0-12.0] min, P = 0.307 and 10.0 [9.0-15.0] min vs 10.0 [8.0-15.0] min, P = 0.546; respectively; median [IQR]. Agreement between both parameters was excellent. The T4/Tref can be used accurately to measure recovery from depolarizing neuromuscular block.

[Feasibility of Perioperative Diaphragmatic Ultrasound in Assessment of Residual Neuromuscular Blockade].

Objective To evaluate the relationship between diaphragmatic ultrasound and postoperative residual neuromuscular blockade(PRNB). Methods The patients undergoing non-thoracic and abdominal surgery under general anesthesia from August to October in 2019 were randomly enrolled from Peking Union Medical College Hospital.Diaphragmatic ultrasound was acquired pre-operation and post extubation.A 4-15 MHz probe was used to measure diaphragmatic thickness at the intersection point of 8-9 intercostal space with right anterior axillary line at the end of inspiration and expiration during quiet breathing and deep breathing(DB),and the diaphragmatic thickness fraction(DTF)was calculated.A 1-5 MHz probe was used to measure diaphragmatic excursion(DE)at the intersection point of right costal margin with midaxillary line during quiet breathing and DB.Train of four ratio(TOFr)was recorded for neuromuscular monitoring.TOFr,observer assessment of alertness and sedation score at extubation,Aldrete score at postanesthesia care unit,and postoperative pulmonary complication were recorded. Results The PRNB rate was 54.7%.The DTF-DB [31.3(21.1,45.0)vs.38.5(26.6,53.9),P=0.045] and DE-DB(2.9±1.4 vs.4.1±1.0,P<0.001)in PRNB group was lower than those in the group without PRNB.DTF-DB(r=0.351,P=0.002)and DE-DB(r=0.580,P<0.001)were correlated with TOFr. Conclusion Perioperative diaphragmatic ultrasound may be helpful for the diagnosis of PRNB.

Forty years of neuromuscular monitoring and postoperative residual curarisation: a meta-analysis and evaluation of confidence in network meta-analysis.

BACKGROUND: The reported incidence of postoperative residual curarisation (PORC) is still unacceptably high. The capacity of intraoperative neuromuscular monitoring (NMM) to reduce the incidence of PORC has yet to be established from pooled clinical studies. We conducted a meta-analysis of data from 1979 to 2019 to reanalyse this relationship. METHODS: English language, peer-reviewed, and operation room adult anaesthesia setting articles published between 1979 and 2019 were searched for on PubMed, Cochrane Central Register of Controlled Trials, ISI-WoK, and Scopus. The primary outcome was PORC incidence as defined by an at- or post-extubation train-of-four ratio (TOFR) of lower than 0.7, 0.9, or 1.0. Additional collected variables included the duration of action of neuromuscular blocking agents (NMBAs) used, sugammadex or neostigmine use, and the technique of anaesthesia maintenance. RESULTS: Fifty-three studies (109 study arms, 12 664 patients) were included. The pooled PORC incidence associated with the use of intermediate duration NMBAs and quantitative NMM was 0.115 (95% confidence interval [CI], 0.057-0.188). This was significantly lower than the PORC rate for both qualitative NMM (0.306; 95% CI, 0.09-0.411) and no NMM (0.331; 95% CI, 0.234-0.435). Anaesthesia type did not significantly affect PORC incidence. Sugammadex use was associated with lower PORC rates. The GRADE global level of evidence was very low and the refined assessment of the network meta-analysis by means of a confidence in network meta-analysis raised concerns on within- and across-study bias. CONCLUSIONS: Quantitative NMM outperforms both subjective and no NMM monitoring in reducing PORC as defined by a TOFR of <0.9.