Barriers and aids to routine neuromuscular monitoring and consistent reversal practice-A qualitative study

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.

Intraoperative electromyographic monitoring in children using a novel pediatric sensor

Background

Train-of-four (TOF) monitoring is essential in optimizing perioperative outcomes as a means to assess the depth of neuromuscular blockade and confirm recovery following the administration of neuromuscular blocking agents (NMBAs). Quantitative TOF monitoring has been limited in infants and children primarily due to lack of effective equipment. The current study evaluates a novel electromyography (EMG)-based TOF monitor with a recently developed pediatric-sized self-adhesive sensor in infants and children.

Methods

Consented pediatric patients undergoing inpatient surgery requiring the administration of NMBAs were enrolled. The EMG electrode was placed along the ulnar nerve on the volar aspect of the distal forearm. The muscle action potentials from the adductor pollicis muscle were recorded throughout surgery at 20-second intervals. Data from the monitor's built-in memory card were later retrieved and analyzed.

Results

The final study cohort included 51 patients who ranged in age from 0.2 to 7.9 years and in weight from 4.2 to 36.0 kilograms. Thirty patients weighed less than 15 kgs. Supramaximal stimulus current intensity (mA) at a pulse width of 200 μsec was 30 mA in 8%; 40 mA in 29%; 50 mA in 16%; and 60 mA in 20% of the patients. Supramaximal stimulus current intensity (mA) at a pulse width of 300 μsec was 50 mA in 4%; 60 mA in 24%. The muscle action potential baseline amplitude was 8.7 ± 3.3 mV and recovered to 7.2 ± 3.7 mV after antagonism of neuromuscular blockade. The average baseline TOF ratio was 100 ± 3% and recovered to 98 ± 7% after antagonism of neuromuscular blockade. No technical issues were noted with application of the sensor or subsequent use of the monitor.

Conclusion

Neuromuscular monitoring can be performed intraoperatively in pediatric patients who are less than 8 years of age using a novel commercially available EMG-based monitor with a recently developed pediatric sensor. The novel sensor allows use of an EMG-based monitor in infants and children in whom acceleromyography or subjective (visual) observation of the TOF response may not be feasible. Automatic detection of neuromuscular stimulating parameters (supramaximal current intensity level, baseline amplitude of the muscle action potential) was feasible in pediatric patients of all sizes including those weighing less than 15 kilograms or when there was limited access to the extremity being monitored.

Comparison of visual and electromyographic assessments with train-of-four stimulation of the ulnar nerve: a prospective cohort study

PURPOSE

The use of a peripheral nerve stimulator to assess the level of neuromuscular blockade tasks the anesthesia clinician with subjectively assessing the response to neurostimulation. In contrast, objective neuromuscular monitors provide quantitative information. The purpose of this study was to compare subjective evaluations from a peripheral nerve stimulator with objective measurements of neurostimulation responses from a quantitative monitor.

METHODS

Patients were enrolled preoperatively, and intraoperative neuromuscular blockade management was at the discretion of the anesthesiologist. Electromyography electrodes were placed over the dominant or nondominant arm in a randomized fashion. Following onset of nondepolarizing neuromuscular blockade, the ulnar nerve was stimulated, the response was measured with electromyography, and anesthesia clinicians, who were blinded to the objective measurements, subjectively (visually) evaluated the response to neurostimulation.

RESULTS

Fifty patients were enrolled and 666 neurostimulations were performed at 333 different time points. Anesthesia clinicians subjectively overestimated the response of the adductor pollicis muscle following neurostimulation of the ulnar nerve 155/333 (47%) of the time when compared with objective electromyographic measurements. When subjective evaluations and objective measurements differed to any degree, subjective evaluations were higher than objective measurements 155/166 (92%) of the time (95% CI, 87 to 95; P < 0.001), representing significant evidence that subjective evaluation overestimates the response to train-of-four stimulation.

CONCLUSIONS

Subjective observations of a "twitch" do not consistently correspond to objective measurements of neuromuscular blockade with electromyography. Subjective evaluation overestimates the response to neurostimulation and may be unreliable for determining the depth of block or confirming adequate recovery.

Study of 60 Adult Patients to Compare Standard Postoperative Clinical Assessment with Train-of-Four Ratio ≥0.9 on Patient Outcomes Using Postoperative Spirometry and Neuromuscular Function Measurements Following Extubation

BACKGROUND Postoperative tracheal extubation requires optimal timing to ensure patient safety and normal muscle function. The train-of-four ratio (TOFR) of the fourth muscle response compared with the first indicates a non-depolarizing neuromuscular block, and a ratio ≥0.9 can be used as an objective measurement of neuromuscular reversal. This study of 60 adult patients who underwent elective surgery with general anesthesia that included the neuromuscular blocking agent cisatracurium aimed to compare standard postoperative clinical assessment with the TOFR ≥0.9 on patient outcomes using postoperative neuromuscular function assessed by grip strength and ability to sit up unaided and spirometry measurements following extubation. MATERIAL AND METHODS The 30 patients extubated postoperatively in the TOF group were required to have a TOFR ≥0.9, while the 30 patients in the clinical assessment group were awake and following simple commands and had a 5-second head lift and spontaneous breathing with acceptable oxygenation. The main outcomes were the incentive spirometry and grip strength and ability to sit up unaided measured at 10, 30, 50 min and 24 h after extubation. RESULTS The groups had no difference in recovery path of incentive spirometry volume (P=0.072) and no difference in postoperative incentive spirometry decrease from baseline except at 10 min after extubation (P=0.005). There was no difference in handgrip strength and independent sitting between groups. CONCLUSIONS The findings showed that using the TOF ratio ≥0.9 before extubation did not improve early postoperative strength quantified by spirometry volume, handgrip strength, and proportion of unaided sitting.

A survey on the availability, usage and perception of neuromuscular monitors in Europe

PURPOSE

Neuromuscular blocking agents (NMBAs) are routinely administered to patients in a multiplicity of anesthetic settings. Absence of postoperative residual neuromuscular block is widely considered an anesthetic patient safety mandate. Despite the increasing availability of a wider range of commercial quantitative neuromuscular monitors, the availability and use of neuromuscular monitoring devices is deemed to be suboptimal even in countries with above-average health system ratings. The present study aims to more precisely characterize the perceived availability, cost sensitivity and usability of neuromuscular monitoring devices within European anesthesia departments.

METHODS

A pre-registered internet-based survey assessing the availability, cost sensitivity and usability of neuromuscular monitoring devices was distributed as e-mail newsletter by the European Society of Anaesthesiology and Intensive Care (ESAIC) to all of its active full members. The survey was available online for a total of 120 days.

RESULTS

Having targeted a total of 7472 ESAIC members, the survey was completed by a total of 692 anesthesiologists (9.3%) distributed across 37 different European countries. Quantitative monitors were reported to be proportionally more available than qualitative ones (87.6% vs. 62.6%, respectively), as well as in greater monitor-per-operating room ratios. Most anesthesiologists (60.5%) expressed moderate confidence in quantitative monitors, with artifactual recordings and inaccurate measurements being the most frequently encountered issues (25.9%). The commercial pricing of quantitative devices was considered more representative of a device's true value, when compared to qualitative instruments (average cost of €4.500 and €1.000 per device, respectively).

CONCLUSION

The availability of quantitative NMM in European operating theaters has increased in comparison with that reported in previous decades, potentially indicating increasing monitoring rates. European anesthesiologists express moderate confidence in quantitative neuromuscular monitors, along with a sentiment of adequate pricing when compared to their qualitative counterparts. Trust in quantitative monitors is marked by caution and awareness for artifactual recordings, with a consequent expectation that developments focusing on accuracy, reliability and ergonomics of neuromuscular monitors be prioritized.

Neuromuscular monitoring during general anaesthesia: a review of current national and international guidelines

Background

The extent to which neuromuscular monitoring is included in professional anaesthesia society guidelines is unclear. Our aim was to comprehensively review neuromuscular monitoring guidelines published by these societies.

Methods

National societies were identified using the World Federation of Societies of Anaesthesiologists' member list and further manual searches were undertaken to identify multinational societies and specialist medical colleges. A web search and secondary literature search were conducted to locate guidelines for monitoring during anaesthesia. The income of each nation or group of nations was determined using the World Bank classification.

Results

Forty guidelines were identified. Of 38 nations or classifiable groups of nations, 25 (66%) were high-income nations and 13 (34%) were middle-income nations. Neuromuscular monitoring was mentioned in 36 (90%) of the 40 guidelines. Availability of neuromuscular monitoring was mentioned in 17 (47%) guidelines (mandated in eight [47%] and recommended in nine [53%]). Use of neuromuscular monitoring was mentioned in 26 (72%) guidelines (mandated in three [12%] and recommended in 23 [88%]). Quantitative neuromuscular monitoring was specified in nine (25%) of the guidelines, with the type of monitoring unspecified in the remaining 27 (75%) of the 36 guidelines. Quantitative monitoring was only mandated in one guideline, and this was only when monitoring equipment was available.

Conclusions

We identified a gap in the availability of professional anaesthesia society neuromuscular monitoring guidelines, particularly in middle- and low-income nations. Recommendations about availability, use and type of monitoring varied among guidelines. An effort to improve the availability and consistency of guidelines is required.

Improving neuromuscular monitoring and reducing residual neuromuscular blockade via e-learning: A multicentre interrupted time-series study (INVERT study)

Background

Neuromuscular monitoring should be applied routinely to avoid residual neuromuscular block. However, anaesthetists often refrain from applying it, even when the equipment is available. We aimed to increase neuromuscular monitoring in six Danish anaesthesia departments via e‐learning.

Methods

Interrupted time series study, with baseline data from a previous study and prospective data collection after implementation of the module, which was available for 2 weeks from 21 November 2016. We included all patients receiving general anaesthesia with muscle relaxants until 30 April 2017. Main outcome was application of acceleromyography, grouped as succinylcholine only and non‐depolarising relaxants. Secondary outcomes were last recorded train‐of‐four ratio (non‐depolarising) relaxants and score on a ten‐question pre‐ and post‐course multiple‐choice test.

Results

The post‐intervention data consisted of 6525 cases (3099 (48%) succinylcholine only, 3426 (52%) non‐depolarising relaxants). Analysing all departments, we found a positive pre‐intervention trend in application of acceleromyography for both groups, of estimated 7.5% and 4.8% per year, respectively (p < .001). The monitoring rate increased significantly for succinylcholine in two departments post‐intervention (p = .045 and .010), and for non‐depolarising relaxants in one department (p = .041), but followed by a negative trend of −37.0% per year (p = .041). The rate was already close to 90% at the time of the intervention and the mean last recorded train‐of‐four ratio was 0.97 (SD 0.21), also without a significant change. The median score on the post‐course test increased from 7 (IQR 5–8) to 9 (IQR 8–10) (p < .001, Wilcoxon Signed‐Ranks Test).

Conclusion

We found no overall effect of the e‐learning module on application of neuromuscular monitoring, although the post‐course test indicated an effect on anaesthetists’ knowledge in this field.

Trial registration

Trial registration: Clinicaltrials.gov identifier: NCT02925143. https://clinicaltrials.gov/ct2/show/NCT02925143

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.

Comparison of the TetraGraph and TOFscan for monitoring recovery from neuromuscular blockade in the Post Anesthesia Care Unit

STUDY OBJECTIVE

Comparison of the TetraGraph (TG) and TOFscan (TS) for monitoring recovery from neuromuscular blockade in the Post Anesthesia Care Unit (PACU).

DESIGN

Randomized, multicenter trial.

SETTING

PACU in three tertiary care hospitals.

PATIENTS

120 patients (40 per site) receiving neuromuscular blockade during elective surgery.

INTERVENTIONS

Patients were enrolled preoperatively and intraoperative neuromuscular blockade management was at the discretion of the anesthesiologist. Upon arrival to the PACU, patients were randomized to have either TG or TS placed on their dominant hand. The alternate device (TS or TG) was placed on the non-dominant hand. Following simultaneous ulnar nerve stimulation on each arm, the response of the adductor pollicis was measured.

MEASUREMENTS

Train-of-four ratios (TOFRs) were obtained upon arrival to the PACU (t = 0), after 5 min (t = + 5) and after +10 min (t = + 10).

MAIN RESULTS

There was there was no significant difference in the mean TOFRs obtained with the TG and TS at t = 0 (0.97 ± 0.18 vs 0.94 ± 0.13, P = 0.06, respectively) and t = + 5 (0.96 ± 0.20 vs 0.95 ± 0.12, P = 0.29, respectively). At (t = + 10), there was a statistically significant difference in mean TOFRs obtained with the TG and TS, (0.99 ± 0.14 vs 0.94 ± 0.12, P < 0.001, respectively). The bias between devices at t = 0 was estimated to be 0.03 (95% CI, -0.29 to 0.35, P = 0.26); at t = + 5 min, it was estimated to be 0.02 (95% CI, -0.36 to 0.40, P = 0.54); and at t = +10 min, it was estimated to be 0.05 (95% CI, -0.25 to 0.36, P = 0.77).

CONCLUSIONS

TS and TG provide interchangeable quantitative measurements once the TOF ratio has returned to a value of 0.90 or greater in the PACU.

Barriers and aids to routine neuromuscular monitoring and consistent reversal practice-A qualitative study

Background

Neuromuscular monitoring is recommended whenever a neuromuscular blocking agent is administered, but surveys have demonstrated inconsistent monitoring practices. Using qualitative methods, we aimed to explore barriers and aids to routine neuromuscular monitoring and consistent reversal practice.

Methods

Focus group interviews were conducted to obtain insights into the thoughts and attitudes of individual anaesthetists, as well as the influence of colleagues and department culture. Interviews were conducted at five Danish and one US hospital. Data were analysed using template analysis.

Results

Danish anaesthetists used objective neuromuscular monitoring when administering a non‐depolarizing relaxant, but had challenges with calibrating the monitor and sometimes interpreting measurements. Residents from the US institution used subjective neuromuscular monitoring, objective neuromuscular monitoring was generally not available and most had not used it. Danish anaesthetists used neuromuscular monitoring to assess readiness for extubation, whereas US residents used subjective neuromuscular monitoring, clinical tests like 5‐second head lift and ventilatory parameters. The residents described a lack of consensus between senior anaesthesiologists in reversal practice and monitoring use. Barriers to consistent and correct neuromuscular monitoring identified included unreliable equipment, time pressure, need for training, misconceptions about pharmacokinetics of neuromuscular blocking agents and residual block, lack of standards and guidelines and departmental culture.

Conclusion

Using qualitative methods, we found that though Danish anaesthetists generally apply objective neuromuscular monitoring routinely and residents at the US institution often apply subjective neuromuscular monitoring, barriers to consistent and correct use still exist.