Peri-operative management of neuromuscular blockade: A guideline from the European Society of Anaesthesiology and Intensive Care

Prolonged duration of action of suxamethonium in pregnant and postpartum patients: A registry study

BACKGROUND

Suxamethonium is hydrolysed by butyrylcholinesterase (BChE) and a low BChE activity can result in a prolonged duration of action of suxamethonium. The BChE activity is reduced during pregnancy and postpartum period by up to 33%. However, it can also be reduced by mutations in the BChE gene. In this study, we assessed BChE activity and mutations in the BChE gene in pregnant and postpartum patients with prolonged duration of action of suxamethonium. It was hypothesised that at least 30% of patients with a low BChE activity did not have a mutation in the BChE gene.

METHODS

In this registry study we focused on pregnant and postpartum patients with a history of prolonged duration of action of suxamethonium referred to the Danish Cholinesterase Research Unit (DCRU) between March 2007 and January 2023. Primary outcome was the proportion of patients without a mutation among patients with a low BChE activity. Secondary outcomes were the proportion of patients with a low BChE activity and the proportion of patients with a mutation out of the total number of patients.

RESULTS

A total of 40 patients were included and among patients with a low BChE activity, 6% (95% CI: 1%-21%) did not have a mutation. Out of the total number of included patients referred to the DCRU, 90% (95% CI: 76%-97%) had a mutation and 94% (95% CI: 80%-99%) had a low BChE activity.

CONCLUSION

Among pregnant and postpartum patients with a history of prolonged duration of action of suxamethonium and a low BChE activity, 6% did not have a mutation in the BChE gene. Our findings suggest that during pregnancy and postpartum clinically relevant prolonged duration of action of suxamethonium rarely occurs in genotypically normal patients.

The safety and efficacy of sugammadex for reversing neuromuscular blockade in younger children and infants

INTRODUCTION

Sugammadex, a novel selective antagonist of non-depolarizing neuromuscular blocking agents, has been shown to rapidly and effectively reverse moderate and deep paralysis in adults and pediatric patients over age 2, improving patient recovery and reducing the risk of postoperative complications.

AREAS COVERED

Since the use of sugammadex in patients under age 2 is not widely studied, we aim to provide an overview on the drug's application and potential use in infants and neonates. There is a limited but growing body of evidence for the safe, efficacious use of sugammadex in children under age 2. Relevant studies were identified from the most updated data including case reports, clinical trials, systematic reviews, and meta analyses.

EXPERT OPINION

The results suggest that at a dose of 2 to 4 mg/kg of sugammadex can be safely used to rapidly and effectively reverse neuromuscular blockade in neonates and infants; it is non-inferior based on incidence of adverse events compared to neostigmine. Additionally, sugammadex doses between 8 and 16 mg/kg may be used as a rescue agent for infants during 'can't intubate, can't ventilate' crisis. Overall, sugammadex offers new value in the perioperative care of patients under age 2, with further studies warranted to better understand its application and full effect in the pediatric population.

Neuromuscular blocking agent drug challenge: a literature review and protocol proposal with biological evaluation

BACKGROUND

Drug challenge is the gold standard for identifying causative agents of drug allergies. Although clinical guidelines have recently been published, they do not recommend neuromuscular blocking agent (NMBA) drug challenges. NMBA challenges are rendered difficult by the lack of homogeneity of routine allergy work-ups and the necessity of a specialised setting. Several scenarios support NMBA challenges, such as an ambiguous allergy work-up, a high suspicion of a false-positive skin test or identification of a well tolerated alternative NMBA strategy. Furthermore, routine allergy work-ups may not recognise non-IgE mechanisms, such as IgG or MRGPRX2, whereas drug challenges may reveal them. Finally, if the culprit NMBA is not identified, subsequent anaesthesia regimens will be challenging to implement, resulting in increased risk.

OBJECTIVES

This literature review discusses the indications, strategies, doses, monitoring methods, limitations, and unresolved issues related to drug challenges for NMBAs.

DESIGN

The literature review included randomised controlled trials, observational studies, reviews, case reports, series, and comments on humans.

DATA SOURCES

Studies were retrieved from databases (PubMed) and electronic libraries (OVID, EMBASE, Scopus, etc.).

ELIGIBILITY CRITERIA

All studies that referred to the NMBA challenge were included without publication date limitations.

RESULTS

NMBA challenge may be considered in NMBA anaphylaxis patients with inconclusive or ambivalent IgE diagnostic work-up under controlled conditions (presence of anaesthetists and allergists with continuous monitoring in a secured environment). To illustrate its utility, a case report of a double NMBA challenge in a patient with NMBA cross-reactivity is presented, along with biological explorations to detect subclinical cellular activation, a novel aspect of this procedure.

CONCLUSION

Drug challenges could be implemented during the NMBA allergy work-up under strict safety conditions at specialised centres with close collaboration between anaesthetists and allergists. This could decrease uncertainty and contribute to defining a safer strategy for subsequent anaesthetic drug regimens.

A pharmacovigilance study of FDA adverse events for sugammadex

BACKGROUND

Sugammadex, a selective steroidal neuromuscular blocking agent reversal agent, is increasingly employed for the rapid restoration of neuromuscular function. This study aimed to conduct a comprehensive evaluation of sugammadex's safety profile.

METHODS

Adverse events (AEs) related to sugammadex reported in the FDA Adverse Event Reporting System (FAERS) database from January 2009 to September 2023 were extracted. Disproportionality analysis with four measures: reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and multi-item gamma Poisson shrinker (MGPS) were employed to detect significant AEs. We also inspected for unexpected AEs absent from the sugammadex FDA approval documentation and categorized AEs based on the latest version (26.1) of 'Important Medical Event Terms List (IME list)' developed by the EudraVigilance Expert Working Group.

RESULTS

A total of 1452 reports were linked to sugammadex. At the preferred terms (PTs) levels, 98 sugammadex-related AEs were identified, including "anaphylactic reaction", "bradycardia", "bronchospasm" and "cardiac arrest". Among them, 37 representing unexpected events were absent from official FDA labeling, and 50 AEs were recognized as IME warranting observation. Notably, 19 PTs denoted serious AEs were absent from labeling yet needing IME surveillance, including: "Kounis syndrome", "angioedema", "pulseless electrical activity" and "laryngeal edema".

CONCLUSION

The study identified unexpected and potentially life-threatening AEs associated with sugammadex, a valuable agent for rapidly reversing neuromuscular blockade. Clinicians are advised to be mindful of these potential risks, particularly in patients with allergies or existing cardiovascular or respiratory conditions.

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.

The Effect of Phonomyography Prototype for Intraoperative Neuromuscular Monitoring: A Preliminary Study

Quantitative neuromuscular monitoring, as extolled by clinical guidelines, is advocated to circumvent the complications associated with neuromuscular blockers (NMBs), such as residual neuromuscular block (rNMB). Nonetheless, the worldwide utilization of such methods remains undesirable. Phonomyography (PMG) boasts the advantages of convenience, stability, and multi-muscle recording which may be a promising monitoring method. The purpose of this preliminary study is conducting a feasibility analysis and an effectiveness evaluation of a PMG prototype under general anesthesia. A prospective observational preliminary study was conducted. Twenty-five adults who had undergone none-cardiac elective surgery were enrolled. The PMG prototype and TOF-Watch SX simultaneously recorded the pharmacodynamic properties of single bolus rocuronium at the ipsilateral adductor pollicis for each patient. For the primary outcome, the time duration to 0.9 TOF ratio of the two devices reached no statistical significance (p > 0.05). For secondary outcomes, the multi-temporal neuromuscular-monitoring measurements between the two devices also reached no statistical significance (p > 0.05). What is more, both the Spearman's and Pearson's correlation tests revealed a strong correlation across all monitoring periods between the PMG prototype and TOF-Watch SX. Additionally, Bland-Altman plots demonstrated a good agreement between the two devices. Thus, the PMG prototype was a feasible, secure, and effective neuromuscular-monitoring technique during general anesthesia and was interchangeable with TOF-Watch SX.

Effects of avoidance versus use of neuromuscular blocking agents for facilitation of tracheal intubation in children and infants

BACKGROUND

The European Society of Anesthesiology and Intensive Care recommends the use of neuromuscular blocking agents (NMBA) in adults, to facilitate tracheal intubation and reduce its associated complications. Children who undergo tracheal intubation may suffer some of the same complications, however, no consensus exists regarding the use of NMBA for tracheal intubation in the pediatric population. We will explore the existing evidence assessing the effects of avoidance versus the use of NMBA for the facilitation of tracheal intubation in children and infants.

METHODS

This protocol follows the preferred reporting items for systematic reviews and meta-analyses protocols recommendations. We will include all randomized controlled clinical trials assessing the effects of avoidance versus the use of NMBA for facilitation of tracheal intubation (oral or nasal) using direct laryngoscopy or video laryngoscopy in pediatric participants (<18 years). Our primary outcome is incidence of difficult tracheal intubation. Secondary outcomes include incidence of serious adverse events, failed intubation, events of upper airway discomfort or injury, and difficult laryngoscopy. We will conduct a thorough database search to identify relevant trials, including CENTRAL, MEDLINE, EMBASE, BIOSIS, Web of Science, CINAHL, and trial registries. Two review authors will independently handle the screening of literature and data extraction. Each trial will be evaluated for major sources of bias with the "classic risk of bias tool" used in the Cochrane Collaboration tool from 2011. We will use Review manager (RevMan) or R with the meta package to perform the meta-analysis. We will perform a trial sequential analysis on the meta-analysis of our primary outcome, providing an estimate of statistical reliability. Two review authors will independently assess the quality of the body of evidence using the grading of recommendations assessment, development, and evaluation (GRADE) approach. We will use GRADEpro software to conduct the GRADE assessments and to create "Summary of the findings" tables.

The Use of Muscle Relaxants After Chemotherapy and Radiotherapy

Introduction

Patients after chemotherapy and radiotherapy while being operated can suffer from different systemic problems, which may complicate the anesthetic management. Some interactions between muscle relaxants and chemotherapeutics can occur.

Aim

This article aims to present the use of muscle relaxants in cancer patients who have undergone chemotherapy and radiotherapy.

Material and Methods

Our work is based on the available literature and the authors' experience.

Conclusion

Based on our observations and a thorough examination of the medical literature, it is advisable to exercise significant caution when employing muscle relaxants in individuals undergoing chemotherapy and radiotherapy. All muscle relaxants can behave differently after chemotherapy and radiotherapy, and for this reason, practitioners should familiarize themselves with the pharmacodynamics and pharmacokinetics of their chosen muscle relaxant.

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.

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.

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.

Under-dosing and over-dosing of neuromuscular blocking drugs and reversal agents: beware of the risks

The phenomena of residual curarisation and recurarisation after the use of long-acting non-depolarising neuromuscular blocking drugs such as tubocurarine and pancuronium were well recognised 60 years ago. But the incidence seemed to decline with the introduction of atracurium and vecuronium. However, recently there have been an increasing number of reports of residual and recurrent neuromuscular block. Some of these reports are a result of inappropriate doses of rocuronium, sugammadex or both, together with inadequate neuromuscular monitoring. We urge clinicians to review their practice to ensure the highest standards of clinical care when using neuromuscular blocking drugs and reversal agents. This includes the use of quantitative neuromuscular monitoring whenever neuromuscular blocking drugs are administered.

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.

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.

Cardiac Arrest in the Post-anesthesia Care Unit (PACU): Postoperative Recurrence of Neuromuscular Block After Sugammadex Reversal

Sugammadex has transformed clinical practice by enabling the rapid reversal of rocuronium-induced neuromuscular block (NMB) at any depth. We present a case of cardiac arrest following postoperative recurarization despite the sugammadex-induced transient reversal of NMB. Despite its proven clinical reliability, this case highlights the often overlooked aspects that must be considered when using this drug. An 84-year-old male patient was scheduled for a laparoscopic partial gastrectomy for gastric cancer. At the end of the procedure, reversal of NMB was evidenced by an acceleromyographic train-of-four (TOF) ratio of ≥0.9 following sugammadex administration. In the post-anesthesia care unit (PACU), pulseless electrical activity was perceived, with a regression of TOF count to 1. After providing successful advanced cardiac life support, additional sugammadex administration led to uneventful extubation. When the concentration of free rocuronium decreases in the central compartment following sugammadex administration, redistribution of rocuronium from the peripheral to the central and effect-site compartments may cause recurarization. Special care is required in cases involving obese and elderly patients as well as those with renal impairment or hypothermia. To provide effective and predictable reversal of NMB, proper use of sugammadex should be pursued, including adequate dosing and monitoring.

From Brobdingnag to Lilliput: Gulliver's travels in airway management guidelines

Neonatal airway management comes with exclusive anatomical, physiological, and environmental complexities, and probably higher incidences of accidents and complications. No dedicated airway management guidelines were available until the recently published first joint guideline released by a task force supported by the European Society of Anaesthesiology and Intensive Care and the British Journal of Anaesthesia and focused on airway management in children under 1 yr of age. The guideline offers a series of recommendations based on meticulous methodology including multiple Delphi rounds to complement the sparse and scarce available evidence. Getting back from Brobdingnag, the land of giants with many guidelines available, this guideline represents a foundational cornerstone in the land of Lilliput.

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 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.

Propofol TCI or sevoflurane anesthesia without muscle relaxant for thoracoscopic thymectomy in myasthenia gravis patients: a prospective, observational study

BACKGROUND

Myasthenia gravis (MG) patients interact unpredictably with anesthetic agents, including neuromuscular blocking agents. Here, we investigate the effectiveness of general anesthesia without muscle relaxants using either propofol via target-controlled infusion systems (TCI) or sevoflurane in MG patients undergoing thoracoscopic thymectomy.

METHODS

This prospective, open-label, observational study was conducted in a university hospital. We included 90 myasthenic patients undergoing thoracoscopic thymectomy with general anesthesia. Patients received induction and maintenance anesthesia with propofol TCI (group P, n = 45) or induction with propofol 2-3 mg.kg-1 and maintenance anesthesia with sevoflurane (group S, n = 45). In both groups, the procedure was performed under the guidance of entropy with sufentanil but not a muscle relaxant. Intubation conditions, hemodynamic changes, respiratory function, neuromuscular transmission, arterial blood gas, and complications were evaluated.

RESULTS

All patients achieved good intubation conditions. Hemodynamic instability was more frequent in group S than in group P, mostly in the induction stage, and was controllable. The reduction in the intraoperative train-of-four ratio from baseline at 30 min, 60 min, and 90 min in group S was 10.3%, 14.2%, and 14.3%, respectively, significantly higher than that in group P (6.8%, 7.2%, and 8.4%, respectively), which completely recovered at the end of the surgery. All patients were extubated in the operating room without complications. No other significant differences between the groups were observed.

CONCLUSIONS

Anesthesia with propofol TCI or sevoflurane without muscle relaxants in MG patients offered safe and effective conditions for thoracoscopic thymectomy. Sevoflurane achieved higher levels of intraoperative muscular relaxation than propofol TCI. Postoperative neuromuscular function was not affected by these anesthetics.

Educating anaesthetists on neuromuscular monitoring: the challenges continue

The need to introduce guidelines on neuromuscular monitoring emphasising the use of quantitative techniques that record the train-of-four ratio is now recognised by an increasing number of national anaesthetic societies in the Western world. But the challenge of convincing individual anaesthetists to adopt and use this practice routinely remains. For >10 yr, it has been recognised that all staff in anaesthetic departments need to have regular training in modern neuromuscular monitoring techniques. We discuss a publication in this journal that describes the challenges of setting up multicentre training in Spain to expand the use of quantitative neuromuscular monitoring and their short-term results.

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.

Deep versus moderate neuromuscular blockade during total hip arthroplasty to improve postoperative quality of recovery and immune function: protocol for a randomised controlled study

INTRODUCTION

There is accumulating evidence that deep neuromuscular blockade (NMB) improves intraoperative surgical conditions during laparoscopic surgery. Studies investigating the effects of deep NMB in open surgery are scarce. In theory, by limiting surgical damage through deeper muscle relaxation, postoperative inflammation and concomitant immune suppression can be reduced. Therefore, this study will investigate the effects of deep NMB during total hip arthroplasty, which demands a relatively large exposure of the hip joint through and in between muscles.

METHODS AND ANALYSIS

This study is a monocentre blinded randomised controlled trial in 100 patients undergoing total hip arthroplasty under general anaesthesia. Patients will be randomised in a 1:1 fashion to an intervention group of intraoperative deep NMB (a post-tetanic count of 1-2) or a control group receiving moderate NMB (a train-of-four count of 1-2). NMB will be achieved by continuous or bolus administration of rocuronium, respectively. The primary endpoint is the quality of recovery at postoperative day 1 measured by the Quality of Recovery-40 Questionnaire, analysed by Analysis of Variance. The secondary endpoint is postoperative innate immune function, measured by ex vivo production capacity of tumour necrosis factor and interleukin-1β on endotoxin stimulation of whole blood.

ETHICS AND DISSEMINATION

Ethical approval for this study was granted by the Medical Ethics Committee 'METC Oost-Nederland' (reference number 2022-15754). Informed consent will be obtained prior to study participation. Study results will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov Registry (NCT05562999) and EudraCT Registry (2022-002451-19).

New advances in clinical application of neostigmine: no longer focusing solely on increasing skeletal muscle strength

Neostigmine is a clinical cholinesterase inhibitor, that is, commonly used to enhance the function of the cholinergic neuromuscular junction. Recent studies have shown that neostigmine regulates the immune-inflammatory response through the cholinergic anti-inflammatory pathway, affecting perioperative neurocognitive function. This article reviews the relevant research evidence over the past 20 years, intending to provide new perspectives and strategies for the clinical application of neostigmine.

Consensus Guidelines for Perioperative Care for Emergency Laparotomy Enhanced Recovery After Surgery (ERAS®) Society Recommendations Part 2-Emergency Laparotomy: Intra- and Postoperative Care

BACKGROUND

This is Part 2 of the first consensus guidelines for optimal care of patients undergoing emergency laparotomy (EL) using an Enhanced Recovery After Surgery (ERAS) approach. This paper addresses intra- and postoperative aspects of care.

METHODS

Experts in aspects of management of high-risk and emergency general surgical patients were invited to contribute by the International ERAS® Society. PubMed, Cochrane, Embase, and Medline database searches were performed for ERAS elements and relevant specific topics. Studies on each item were selected with particular attention to randomized clinical trials, systematic reviews, meta-analyses, and large cohort studies and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Recommendations were made on the best level of evidence, or extrapolation from studies on elective patients when appropriate. A modified Delphi method was used to validate final recommendations. Some ERAS® components covered in other guideline papers are outlined only briefly, with the bulk of the text focusing on key areas pertaining specifically to EL.

RESULTS

Twenty-three components of intraoperative and postoperative care were defined. Consensus was reached after three rounds of a modified Delphi Process.

CONCLUSIONS

These guidelines are based on best available evidence for an ERAS® approach to patients undergoing EL. These guidelines are not exhaustive but pull together evidence on important components of care for this high-risk patient population. As much of the evidence is extrapolated from elective surgery or emergency general surgery (not specifically laparotomy), many of the components need further evaluation in future studies.

Evaluation of a Protocol for the Management of Maintenance and Reversal of Rocuronium Block Using Neostigmine or Sugammadex

BACKGROUND

Postoperative residual neuromuscular blockade (PRNB) is defined as an adductor pollicis train-of-four ratio (TOFR) <0.9. It is a common postoperative complication when nondepolarizing muscle relaxants are either not reversed or reversed with neostigmine. PRNB has been reported in 25% to 58% of patients who receive intermediate-acting nondepolarizing muscle relaxants, and it is associated with increased morbidity and decreased patient satisfaction. We conducted a prospective descriptive cohort study during the implementation of a practice guideline that included the selective use of sugammadex or neostigmine. The primary study aim of this pragmatic study was to estimate the incidence of PRNB at arrival to the postanesthesia care unit (PACU) when the practice guideline is followed.

METHODS

We enrolled patients undergoing orthopedic or abdominal surgery requiring neuromuscular blockade. Rocuronium administration was guided by surgical requirements and based on ideal body weight, with dose reductions for women and/or age >55 years. Only qualitative monitoring was available to the anesthesia providers, and selection of sugammadex or neostigmine was guided by tactile assessments of the response to train-of-four (TOF) stimulation by a peripheral nerve stimulator. Neostigmine was administered if no fade was detected in the TOF response at the thumb. Deeper blocks were reversed with sugammadex. The prespecified primary and secondary end points were the incidence of PRNB at arrival to the PACU, defined as a normalized TOFR (nTOFR) < 0.9, and severe PRNB, defined as nTOFR <0.7 on arrival to the PACU. Anesthesia providers were blinded to all quantitative measurements made by research staff.

RESULTS

Analysis included 163 patients, and 145 underwent orthopedic and 18 abdominal surgeries. Of the 163 patients, 92 (56%) were reversed with neostigmine and 71 (44%) with sugammadex. The overall incidence of PRNB at PACU arrival was 5 of 163 or 3% (95% confidence interval [CI], 1-7). The incidence of severe PRNB in PACU was 1% (95% CI, 0-4). Three of the 5 subjects with PRNB had TOFR <0.4 at time of reversal but were given neostigmine since anesthesia providers detected no fade by qualitative assessment.

CONCLUSIONS

The use of a protocol that specifies rocuronium dosing and selective use of sugammadex versus neostigmine based on qualitative assessment of TOF count and fade allowed us to achieve an incidence of PRNB of 3% (95% CI, 1-7) at PACU arrival. Quantitative monitoring may be needed to further reduce this incidence.

Intraoperative Monitoring of Neuromuscular Blockade

There is a global trend of new guidelines highly recommending quantitative neuromuscular monitoring in the operating room. In fact, it is almost certain that quantitatively monitoring the depth of intraoperative muscle paralysis may permit the rational use of muscle relaxants and avoid some of the major related complications, namely postoperative pulmonary complications. A specific culture related to this issue is necessary to integrate quantitative monitoring of muscle relaxants as part of a major monitoring entity in anesthetized patients. For this purpose, it is necessary to fully understand the physiology, pharmacology and concept of monitoring as well as the choice of pharmacological reversal, including the introduction of sugammadex a decade ago.

Management of Muscle Relaxation With Rocuronium and Reversal With Neostigmine or Sugammadex Guided by Quantitative Neuromuscular Monitoring

BACKGROUND

The optimal pharmacological reversal strategy for neuromuscular blockade remains undefined even in the setting of strong recommendations for quantitative neuromuscular monitoring by several national and international anesthesiology societies. We evaluated a protocol for managing rocuronium blockade and reversal, using quantitative monitoring to guide choice of reversal agent and to confirm full reversal before extubation.

METHODS

We conducted a prospective cohort study and enrolled 200 patients scheduled for elective surgery involving the intraoperative use of rocuronium. Providers were asked to adhere to a protocol that was similar to local practice recommendations for neuromusculalr block reversal that had been used for >2 years; the protocol added quantitative monitoring that had not previously been routinely used at our institution. In this study, providers used electromyography-based quantitative monitoring. Pharmacological reversal was accomplished with neostigmine if the train-of-four (TOF) ratio was 0.40 to 0.89 and with sugammadex for deeper levels of blockade. The primary end point was the incidence of postoperative residual neuromuscular blockade (PRNB), defined as TOF ratio <0.9 at time of extubation. We further evaluated the difference in pharmacy costs had all patients been treated with sugammadex.

RESULTS

A total of 189 patients completed the study: 66 patients (35%) were reversed with neostigmine, 90 patients (48%) with sugammadex, and 33 (17%) patients recovered spontaneously without pharmacological reversal. The overall incidence of residual paralysis was 0% (95% CI, 0-1.9). The total acquisition cost for all reversal drugs was United States dollar (USD) 11,358 (USD 60 per patient) while the cost would have been USD 19,312 (USD 103 per patient, 70% higher) if sugammadex had been used in all patients.

CONCLUSIONS

A protocol that includes quantitative monitoring to guide reversal with neostigmine or sugammadex and to confirm TOF ratio ≥0.9 before extubation resulted in the complete prevention of PRNB. With current pricing of drugs, the selective use of sugammadex reduced the total cost of reversal drugs compared to the projected cost associated with routine use of sugammadex for all patients.

Postoperative oxygenation assessed by SpO2/FiO2 ratio and respiratory complications after reversal of neuromuscular block with Sugammadex or neostigmine: A retrospective cohort study

STUDY OBJECTIVE

Residual neuromuscular block may lead to postoperative muscle weakness, inadequate oxygenation, and other pulmonary complications. Sugammadex may provide more rapid and effective restoration of neuromuscular function than neostigmine. We therefore tested the primary hypothesis that noncardiac surgical patients given sugammadex oxygenate better during initial recovery than those given neostigmine. Secondarily, we tested the hypothesis that patients given sugammadex have fewer pulmonary complications during hospitalization.

DESIGN

Retrospective cohort analysis.

SETTING

Postoperative recovery area of a tertiary care hospital.

PATIENTS

Adults who had non-cardiothoracic surgery and were given either neostigmine or sugammadex.

INTERVENTIONS

None.

MEASUREMENTS

The primary outcome was the lowest SpO₂/FiO₂ ratio in the post-anesthesia care unit. The secondary outcome was a composite of pulmonary complications.

MAIN RESULTS

Among 71,457 cases, 10,708 (15%) were given sugammadex and 60,749 (85%) received neostigmine. After propensity weighting, the mean minimum SpO₂/FiO₂ ratio was 301 ± 77 (SD) in patients given sugammadex and 303 ± 71 in those given neostigmine, yielding an estimated difference in means of -3.5 (95% confidence interval: -5.3, -1.7; P = 0.0002). 4.4% of patients given sugammadex and 3.6% of patients given neostigmine had postoperative pulmonary complications (P = 0.0005, number-needed-to-be-exposed =136; 95% CI: 83, 330), with the main contributing components being new bronchospasm or exacerbation of obstructive pulmonary disease.

CONCLUSIONS

Postoperative minimum SpO₂/FiO₂ ratio during PACU admission was similar after reversal of neuromuscular block by sugammadex and neostigmine. Reversal with sugammadex was associated with more pulmonary complications, but most were minor and of little consequence.

Model for predicting early and late-onset postoperative pulmonary complications in perioperative patients receiving neuromuscular blockade: a secondary analysis

Pulmonary complications continue to be the most common adverse event after surgery. The main objective was to carry out two independent predictive models, both for early pulmonary complications in the Post-Anesthesia Care Unit and late-onset pulmonary complications after 30 postoperative days. The secondary objective was to determine whether presenting early complications subsequently causes patients to have other late-onset events. This is a secondary analysis of a cohort study. 714 patients were divided into four groups depending on the neuromuscular blocking agent, and spontaneous or pharmacological reversal. Incidence of late-onset complications if we have not previously had any early complications was 4.96%. If the patient has previously had early complications the incidence of late-onset complications was 22.02%. If airway obstruction occurs, the risk of atelectasis increased from 6.88 to 22.58% (p = 0.002). If hypoxemia occurs, the incidence increased from 5.82 to 21.79% (p < 0.001). Based on our predictive models, we conclude that diabetes mellitus and preoperative anemia are two risk factors for early and late-onset postoperative pulmonary complications, respectively. Hypoxemia and airway obstruction in Post-Anesthesia Care Unit increased four times the risk of the development of pneumonia and atelectasis at 30 postoperative days.

Primary Lateral Sclerosis: Can Rocuronium Be an Option?

Primary lateral sclerosis (PLS) is a neurodegenerative motor neuron disorder that is characterized by corticospinal and corticobulbar dysfunction. In this disease, muscle relaxants in general anesthesia should be used with extreme caution. A 67-year-old woman with a history of PLS was scheduled for laparoscopic gastrostomy due to long-term dysphagia. In the preoperative assessment, she presented a tetrapyramidal syndrome with generalized muscle weakness. A priming dose of 5 mg of rocuronium was administered and the train-of-four (TOF) ratio (T4/T1) after 60 seconds was 70% so induction was followed with fentanyl, propofol, and additional 40 mg of rocuronium. After 90 seconds when T1 was lost, the patient was intubated. During surgery, the TOF ratio increased progressively until 65%, 22 minutes after a final bolus of 10 mg of rocuronium. Prior to emergence, 150 mg of sugammadex was given and neuromuscular block reversal was evidenced with a TOF ratio > 90%. As it was decided to perform the surgery laparoscopically, general anesthesia with a neuromuscular blockade was necessary. Since it is reported that patients with motor neuron diseases show an increased sensibility to non-depolarizing muscle relaxants (NDMR), these agents should be used cautiously. Adversely to what studies document, no augmented responsiveness was shown in TOF monitoring, so the standard dose of 0.6 mg/kg of rocuronium was safely given. A final bolus of NDMR was administered after 54 minutes, demonstrating a similar pharmacokinetics profile in terms of duration of action as reported in several studies (45-70 minutes). In addition, a full and rapid neuromuscular blockade recovery with 2 mg/kg of sugammadex was seen, as previously demonstrated in a case series.

Cardiac arrest following sugammadex administration

A 68-year-old man underwent elective surgical repair of an abdominal wall hernia under general anaesthesia. The operation required muscle relaxation, for which we used rocuronium. Following completion of surgery, 180 mg sugammadex was administered intravenously. Shortly afterwards, the patient became severely bradycardic with hypotension, refractory to treatment with ephedrine. This progressed to a pulseless electrical activity cardiac arrest. After 4 min of cardiopulmonary resuscitation, there was return of spontaneous circulation and, following a period of haemodynamic stability in which general anaesthesia was maintained, the patient emerged from anaesthesia without incident. He remained haemodynamically stable until discharge. Post-resuscitation investigations including the serum tryptase level were unremarkable except for a mild respiratory acidosis and slightly elevated D-dimers. Sugammadex-induced bradycardia has previously been described, but its mechanism remains unknown. We believe that sugammadex was the cause of cardiac arrest in this case because of the timing and sequence of events, the evolution to pulseless electric activity and the relatively uneventful post-arrest clinical course. We hope that our report will help to promote awareness about this potential complication of a now commonly-used drug.