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.

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

Recent data indicated a high incidence of inappropriate management of neuromuscular block, with a high rate of residual paralysis and relaxant-associated postoperative complications. These data are alarming in that the available neuromuscular monitoring, as well as myorelaxants and their antagonists basically allow well tolerated management of neuromuscular blockade. In this first European Society of Anaesthesiology and Intensive Care (ESAIC) guideline on peri-operative management of neuromuscular block, we aim to present aggregated and evidence-based recommendations to assist clinicians provide best medical care and ensure patient safety. We identified three main clinical questions: Are myorelaxants necessary to facilitate tracheal intubation in adults? Does the intensity of neuromuscular blockade influence a patient's outcome in abdominal surgery? What are the strategies for the diagnosis and treatment of residual paralysis? On the basis of this, PICO (patient, intervention, comparator, outcome) questions were derived that guided a structured literature search. A stepwise approach was used to reduce the number of trials of the initial research ( n  = 24 000) to the finally relevant clinical studies ( n  = 88). GRADE methodology (Grading of Recommendations, Assessment, Development and Evaluation) was used for formulating the recommendations based on the findings of the included studies in conjunction with their methodological quality. A two-step Delphi process was used to determine the agreement of the panel members with the recommendations: R1 We recommend using a muscle relaxant to facilitate tracheal intubation (1A). R2 We recommend the use of muscle relaxants to reduce pharyngeal and/or laryngeal injury following endotracheal intubation (1C). R3 We recommend the use of a fast-acting muscle relaxant for rapid sequence induction intubation (RSII) such as succinylcholine 1 mg kg -1 or rocuronium 0.9 to 1.2 mg kg -1 (1B). R4 We recommend deepening neuromuscular blockade if surgical conditions need to be improved (1B). R5 There is insufficient evidence to recommend deep neuromuscular blockade in general to reduce postoperative pain or decrease the incidence of peri-operative complications. (2C). R6 We recommend the use of ulnar nerve stimulation and quantitative neuromuscular monitoring at the adductor pollicis muscle to exclude residual paralysis (1B). R7 We recommend using sugammadex to antagonise deep, moderate and shallow neuromuscular blockade induced by aminosteroidal agents (rocuronium, vecuronium) (1A). R8 We recommend advanced spontaneous recovery (i.e. TOF ratio >0.2) before starting neostigmine-based reversal and to continue quantitative monitoring of neuromuscular blockade until a TOF ratio of more than 0.9 has been attained. (1C).

Pseudocholinesterase deficiency in ophthalmology: a systematic review

PURPOSE

Unexpected anesthesia-related complications are among the most feared outcomes of ambulatory surgery. One potential culprit is pseudocholinesterase deficiency, which most commonly presents with protracted apnea, necessitating prolonged mechanical ventilation. We report the first case of pseudocholinesterase deficiency in a Bengali person and the first systematic review of pseudocholinesterase deficiency in ophthalmology. This review analyzed the epidemiology, etiologies, presentation, evaluation, and treatment of pseudocholinesterase deficiency.

METHODS

Searches were conducted in PubMed, Embase, and Medline through August of 2022 for publications related to pseudocholinesterase deficiency in ophthalmology. In total, 689 studies were screened by two independent reviewers with 26 full-text articles examined for inclusion eligibility. Nineteen studies were eligible and included in the final analysis.

RESULTS

Of the 16 identified cases of pseudocholinesterase deficiency, nine (56%) were drug-induced, four (25%) were inherited deficiencies, and in one (6%) of the cases, the cause could not be determined. In two (13%) cases, pseudocholinesterase deficiency could not be confirmed or ruled out. The duration of post-operative apnea ranged from 10 minutes to 14 hours. Continued ventilatory support was the main treatment for all cases and all patients made a full recovery.

CONCLUSIONS

Pseudocholinesterase deficiency is a rare, but potentially fatal, anesthetic complication that results in prolonged apnea, respiratory distress, and dependency on ventilators. Ophthalmologists should remain aware of this condition, especially when planning outpatient procedures, as ambulatory centers may have limited resources for managing prolonged post-operative complications.

Feasibility of intraoperative quantitative neuromuscular blockade monitoring in children using electromyography

Background:

Quantitative train-of-four (TOF) monitoring remains essential in optimizing anesthetic outcomes by assessing the depth and recovery from neuromuscular blockade. Despite this, residual neuromuscular blockade, defined as a TOF ratio <0.90, remains a concern in both adult and pediatric patients. Quantitative TOF monitoring has seen limited use in infants and children primarily due to a lack of effective equipment. This study evaluates a new electromyography (EMG)-based TOF monitor in pediatric patients undergoing inpatient surgical procedures including laparoscopic (restricted arm access) surgery.

Methods:

Pediatric patients undergoing inpatient surgery requiring the administration of neuromuscular blocking agents (NMBAs) were enrolled. The EMG electrodes were placed along the ulnar nerve on the volar aspect of the arm to provide neurostimulation. The muscle action potentials from the abductor digiti minimi muscle were recorded. Neuromuscular responses were recorded by the device throughout surgery at 20-s intervals until after tracheal extubation. Data recorded on the monitor's built-in memory card were later retrieved and analyzed.

Results:

The study cohort included 100 pediatric patients (62% male). The average age was 11 years (IQR: 8, 13) and the average weight was 39.6 kg (30, 48.7). Automatic detection of supramaximal stimulus was obtained in 95% of patients. The muscle action potential mean baseline amplitude (in mV) was 7.5 mV (6, 9.2). The baseline TOF ratio was 100% (100, 104). After administration of a neuromuscular blocking agent, monitoring of the TOF ratio was successful in 93% of the patients. After antagonism of neuromuscular blockade, monitoring was possible in 94% of patients when using an upgraded algorithm. The baseline amplitude recovered to 6.5 mV (5, 7.8), and the TOF ratio recovered to a mean of 90.1% (90,97) before tracheal extubation.

Conclusion:

Our results indicate that neuromuscular monitoring can be performed intraoperatively in pediatric patients weighing between 20 and 60 kg using the new commercially available EMG-based monitor. Automatic detection of neuromuscular stimulating parameters (supramaximal current intensity level and baseline amplitude of the muscle action potential) by an adult neuromuscular monitor is feasible in pediatric patients receiving nondepolarizing neuromuscular blocking agents.

Unanticipated Profound Paralysis and Sugammadex Dosing Implications After Videoscopic Thoracic Surgery

A bedridden patient with empyema presented for thoracoscopic decortication. During the procedure, despite a post-tetanic count (PTC) of 0 via calibrated quantitative neuromuscular monitoring, persistent diaphragmatic movement impaired operating conditions, so rocuronium was re-dosed. After surgery, the patient had 0 PTC. Sugammadex was titrated to achieve baseline neuromuscular strength, monitoring the effect of each 200-mg dose. Ultimately, 1200 mg was required to achieve baseline strength. We describe monitor troubleshooting, considerations with unexpectedly deep neuromuscular blockade, the importance of routine quantitative neuromuscular monitoring, and one strategy for sugammadex reversal in patients with profound paralysis outside of the standard dosing guidelines.

Recommendations for standards of monitoring during anaesthesia and recovery 2021: Guideline from the Association of Anaesthetists

This guideline updates and replaces the 5th edition of the Standards of Monitoring published in 2015. The aim of this document is to provide guidance on the minimum standards for monitoring of any patient undergoing anaesthesia or sedation under the care of an anaesthetist. The recommendations are primarily aimed at anaesthetists practising in the UK and Ireland, but it is recognised that these guidelines may also be of use in other areas of the world. Minimum standards for monitoring patients during anaesthesia and in the recovery phase are included. There is also guidance on monitoring patients undergoing sedation and during transfer. There are new sections specifically discussing capnography, sedation and regional anaesthesia. In addition, the indications for processed electroencephalogram and neuromuscular monitoring have been updated.

Break the Spasm with Succinylcholine, but Risk Intraoperative Awareness with Undiagnosed Pseudocholinesterase Deficiency

Succinylcholine is a commonly used medication in all aspects of anesthetic care, and there are a number of known side effects and complications associated with its use. However, when succinylcholine is used emergently, anesthesia providers must remain vigilant to undiagnosed conditions that pose additional risks to patients. We report the use of succinylcholine to treat acute, refractory laryngospasm after extubation leading to prolonged neuromuscular paralysis. There are unique challenges presented by this case including the risk of anesthesia awareness with recall due to the cognitive biases that prevent the clinical diagnosis of pseudocholinesterase deficiency.

Neuromuscular monitoring: an update

This review makes an advocacy for neuromuscular blockade monitoring during anaesthesia care, by: (i) describing the fundamental principles of the methods currently available, at the same time emphasizing quantitative recording measurements; (ii) describing the different ways in which muscles respond to the effect of neuromuscular blockade and their use in clinical practice; (iii) presenting results of different studies on timing and agents of neuromuscular block reversal, including a recommendation for sugammadex use and experimental results with calabadion and (iv) in the end emphasizing the need for implementing neuromuscular monitoring as a practice that should be used every time a neuromuscular block is required.

Improving Neuromuscular Monitoring and Reducing Residual Neuromuscular Blockade With E-Learning: Protocol for the Multicenter Interrupted Time Series INVERT Study

Background

Muscle relaxants facilitate endotracheal intubation under general anesthesia and improve surgical conditions. Residual neuromuscular blockade occurs when the patient is still partially paralyzed when awakened after surgery. The condition is associated with subjective discomfort and an increased risk of respiratory complications. Use of an objective neuromuscular monitoring device may prevent residual block. Despite this, many anesthetists refrain from using the device. Efforts to increase the use of objective monitoring are time consuming and require the presence of expert personnel. A neuromuscular monitoring e-learning module might support consistent use of neuromuscular monitoring devices.

Objective

The aim of the study is to assess the effect of a neuromuscular monitoring e-learning module on anesthesia staff’s use of objective neuromuscular monitoring and the incidence of residual neuromuscular blockade in surgical patients at 6 Danish teaching hospitals.

Methods

In this interrupted time series study, we are collecting data repeatedly, in consecutive 3-week periods, before and after the intervention, and we will analyze the effect using segmented regression analysis. Anesthesia departments in the Zealand Region of Denmark are included, and data from all patients receiving a muscle relaxant are collected from the anesthesia information management system MetaVision. We will assess the effect of the module on all levels of potential effect: staff’s knowledge and skills, patient care practice, and patient outcomes. The primary outcome is use of neuromuscular monitoring in patients according to the type of muscle relaxant received. Secondary outcomes include last recorded train-of-four value, administration of reversal agents, and time to discharge from the postanesthesia care unit as well as a multiple-choice test to assess knowledge. The e-learning module was developed based on a needs assessment process, including focus group interviews, surveys, and expert opinions.

Results

The e-learning module was implemented in 6 anesthesia departments on 21 November 2016. Currently, we are collecting postintervention data. The final dataset will include data from more than 10,000 anesthesia procedures. We expect to publish the results in late 2017 or early 2018.

Conclusions

With a dataset consisting of thousands of general anesthesia procedures, the INVERT study will assess whether an e-learning module can increase anesthetists’ use of neuromuscular monitoring.

Trial Registration

Clinicaltrials.gov NCT02925143; https://clinicaltrials.gov/ct2/show/NCT02925143 (Archived by WebCite® at http://www.webcitation.org/6s50iTV2x)

Current Status of Neuromuscular Reversal and Monitoring

Postoperative residual neuromuscular block has been recognized as a potential problem for decades, and it remains so today. Traditional pharmacologic antagonists (anticholinesterases) are ineffective in reversing profound and deep levels of neuromuscular block; at the opposite end of the recovery curve close to full recovery, anticholinesterases may induce paradoxical muscle weakness. The new selective relaxant-binding agent sugammadex can reverse any depth of block from aminosteroid (but not benzylisoquinolinium) relaxants; however, the effective dose to be administered should be chosen based on objective monitoring of the depth of neuromuscular block.

To guide appropriate perioperative management, neuromuscular function assessment with a peripheral nerve stimulator is mandatory. Although in many settings, subjective (visual and tactile) evaluation of muscle responses is used, such evaluation has had limited success in preventing the occurrence of residual paralysis. Clinical evaluations of return of muscle strength (head lift and grip strength) or respiratory parameters (tidal volume and vital capacity) are equally insensitive at detecting neuromuscular weakness. Objective measurement (a train-of-four ratio greater than 0.90) is the only method to determine appropriate timing of tracheal extubation and ensure normal muscle function and patient safety.

Awareness during emergence from anaesthesia: significance of neuromuscular monitoring in patients with butyrylcholinesterase deficiency

BACKGROUND

Butyrylcholinesterase deficiency can result in prolonged paralysis after administration of succinylcholine or mivacurium. We conducted an interview study to assess whether patients with butyrylcholinesterase deficiency were more likely to have experienced awareness during emergence from anaesthesia if neuromuscular monitoring had not been applied.

METHODS

Patients referred during 2004-2012 were included. Data on the use of neuromuscular monitoring were available from a previous study. Interviews, conducted by telephone, included questions about awareness and screening for post-traumatic stress disorder. Reports of panic, hopelessness, suffocation, or a feeling of being dead or dying resulted in the experience being classified further as distressful. Patients were categorized as aware or unaware by investigators blinded to use of neuromuscular monitoring.

RESULTS

Ninety-five patients were eligible to be interviewed. Of the 70 patients interviewed, 35 (50%) were aware while paralysed during emergence. Of these, 28 (80%) were not monitored with a nerve stimulator when awakened, compared with 17 (49%) of the 35 unaware patients (P=0.012, Fisher's exact test). Thirty (86%) aware patients reported distress compared with seven (20%) unaware patients (P<0.001). The aware patients scored higher in screening for post-traumatic stress disorder (P=0.006, Mann-Whitney U-test).

CONCLUSIONS

Butyrylcholinesterase deficiency is a major risk factor for distressing awareness during emergence. Lack of neuromuscular monitoring increases the risk significantly. Neuromuscular monitoring should be applied even when using short-acting neuromuscular blocking agents.