Good clinical research practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents III: The 2023 Geneva revision

Comparative potentiating effects of remimazolam, propofol and sevoflurane on rocuronium-induced neuromuscular block: a randomized controlled trial

BACKGROUND

Remimazolam is a new type of ultra-short-acting benzodiazepine. The aim of this study was to investigate the effects of remimazolam, propofol and sevoflurane anesthesia on rocuronium-induced neuromuscular block.

METHODS

Ninety-nine consenting patients were randomly assigned to a remimazolam group (R-group), sevoflurane group (S-group), or propofol group (P-group). Train-of-four (TOF) responses evoked on the abductor digiti minimi muscle to ulnar nerve stimulation following bolus administration of 0.9-mg/kg rocuronium were monitored with electromyography-based neuromuscular monitor. The primary outcomes were times from administration of rocuronium to first reappearance of post-tetanic count (PTC). Free plasma concentrations of rocuronium were concurrently measured at these events.

RESULTS

Ninety patients were analyzed. No significant differences were seen in time to first PTC among the three groups. Mean (± standard deviation) and median (inter-quartile range) times for the reappearance of TOF counts 1 and 2 were significantly prolonged in S-group [50.7 ± 13.9 min, P = 0.043 and 61.6 (54.3-78.0) min, P = 0.020, respectively], when compared with P-group [42.6 ± 10.3 min and 52.9 (45.4-58.8) min, respectively]. However, no significant differences were seen between S-group and R-group. Median (inter-quartile range) free plasma concentration of rocuronium measured at first PTC was significantly lower in R-group [1255 (1126-1717) ng/mL] than in P-group [1717 (1592-1961) ng/mL, P = 0.031].

CONCLUSIONS

These results suggest that the potentiating effects of remimazolam on rocuronium-induced neuromuscular block are weaker than those of sevoflurane and similar to those of propofol.

The effect of neuromuscular blocking reversal agents on perioperative neurocognitive function after general anaesthesia: a systematic review and meta-analysis

BACKGROUND

Perioperative neurocognitive dysfunction (PND) is influenced by various perioperative factors. Recent studies suggest that neuromuscular blocking reversal agents (NMBRs) may impact on PND. However, the results have been inconsistent. Therefore, we aimed to compare the effects of perioperative NMBRs on PND through this systematic review and meta-analysis.

METHODS

We searched PubMed, CENTRAL, Embase, Web of Science, Scopus, and China Biology Medicine from their inception until May 2024. Two reviewers independently identified randomized controlled trials (RCTs) that compared the perioperative use of NMBRs with either a placebo or other NMBRs in patients undergoing general anaesthesia. We assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. The primary outcome was the incidence of PND within 7 days following surgery, while the secondary outcomes included the time required to achieve a Train-of-Four ratio (TOF) ≥ 0.9 after administration of NMBRs, length of stay (LOS) in both the post-anaesthesia care unit (PACU) and the hospital, as well as the risk of adverse events (i.e. postoperative nausea and vomiting (PONV) and mortality).

RESULTS

A total of 10 randomized controlled trials involving 1705 patients compared the effects of NMBRs on PND. Neostigmine and sugammadex are the most commonly used NMBRs in clinical anaesthesia practice. In the primary analyses of all regimens, sugammadex significantly reduced the incidence of PND compared to neostigmine (risk ratio [RR] 0.67; 95% confidence interval [CI]:0.48-0.94; I2 = 0%; P = 0.02; moderate quality). However, the results indicated that there is no significant association between neostigmine and PND when compared to placebo (RR 0.76; 95% CI: 0.55-1.05; I2 = 35%; P = 0.09; moderate quality). The secondary outcomes revealed that sugammadex could significantly shorten the time of TOF ≥ 0.9 compared to neostigmine (mean difference [MD] -4.52; 95%CI: -5.04 to -3.99; I2 = 80%; P < 0.01; Moderate quality). Furthermore, no significant differences were observed in the incidence of adverse events or hospital LOS.

CONCLUSIONS

This meta-analysis demonstrated that the use of sugammadex was associated with improved early perioperative neurocognitive function compared to neostigmine when used to reverse neuromuscular blockade, without an increase in the incidence of adverse events.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42024520287.

Deep neuromuscular block with pipecuronium in patients undergoing laparoscopic surgery - A prospective case series

INTRODUCTION

We tested the feasibility of maintaining low intraabdominal pressures during pipecuronium-induced deep block (post-tetanic count ≥1, train-of-four count = 0) in patients undergoing laparoscopic surgery.

METHODS

Ten adult patients awaiting cardiac surgery or heart transplantation and requiring non-elective abdominal surgery were included. Pipecuronium bromide 0.09 mg/kg was used for muscle relaxation and maintenance of deep block. Top-up doses of pipecuronium (0.01-0.02 mg/kg) were administered when post-tetanic count was 4-8. Intraabdominal pressures were kept below 10 mmHg. Mean arterial pressure was measured intra-arterially. Surgical field view was rated on a 5-point scale (1 = extremely poor, 5 = optimal).

RESULTS

Induction dose of 0.09 mg/kg pipecuronium had an onset time of 5.3 (2.3-6.3, 25-75% IQR) min. Deep block was maintained for 51.2 ± 19.7 min. Top-up pipecuronium doses were necessary in 5 patients, 56.0 ± 28.1 min after the first dose. At the end of surgery, neuromuscular block was deep (post-tetanic count 0-6). Administration of 2 mg/kg of sugammadex induced recovery to train-of-four ratio ≥0.9 in 3.5 ± 1.6 min, and to train-of-four ratio = 1.0 in 4.3 ± 1.2 min. Mean intraabdominal pressure was 8.1 ± 1.1 mmHg during pneumoperitoneum. There was no significant change in heart rate (0.0, -2.6 to 0) beats/min.

DISCUSSION

Pipecuronium is a rational alternative when deep neuromuscular block is necessary, because of its long-acting neuromuscular blocking effect that may be antagonized quickly and safely with sugammadex.

REGISTRATION

European Clinical Trials Database registration number: 2022-004114-11, Clinical Trials Database registration number: NCT06517524.

F. M, S. D, M. A. M. C. G, F. A, C. B, F. B. S, J. E. V. Optimal Dose of Magnesium Sulfate Infusion in Obese Patients: A Double-Blind Randomized Trial

Background: Magnesium sulfate reduces opioid use and its associated side effects. However, no consensus exists on whether the optimal dosing should be based on actual body weight or adjusted ideal body weight. The primary objective of this study was to compare postoperative analgesia after magnesium sulfate infusion, using doses calculated based on actual body weight versus adjusted ideal body weight. Methods: This prospective, randomized, double-blind, controlled clinical trial included 75 participants who underwent target-controlled intravenous general anesthesia. The participants were divided into three groups: a control group (CG), a group receiving magnesium sulfate calculated by actual body weight (AWG), and a group receiving magnesium sulfate calculated based on the adjusted ideal body weight (IWG). Results: The AWG had significantly lower pain scores than the CG (p < 0.001) and IWG (p=0.017). Opioid use was similar between the AWG and IWG, but significantly higher in the CG (AWG = IWG, p=0.08; CG > AWG, p < 0.001; CG = IWG, p 0.03). The increase in magnesium concentration did not reach clinically relevant levels. Neuromuscular blockade latency decreased in the groups receiving magnesium sulfate (p < 0.001 in both comparisons) compared to the CG. Conclusion: Calculating the dose of magnesium sulfate based on actual body weight enhances postoperative analgesia. The increase in magnesium concentration was not clinically significant and did not interfere with the action of cisatracurium in the groups receiving magnesium sulfate. Trial Registration: ClinicalTrials.gov identifier: NCT04645719.

Pharmacokinetic-Pharmacodynamic Simulation of Muscle Relaxation Antagonistic Conditions for Post-Operative Recurarization Prevention

Background/Objectives: No study has simulated rocuronium (Rb) effect-site concentrations (Ce_Rb) using real-time data-such as Rb concentrations, train-of-four (TOF) count (TOFC), and TOF ratio (TOFR)-under mechanical Rb administration. Therefore, we aimed to investigate post-operative recurarization and changes in the Ce_Rb after sugammadex (SGX) administration under conditions where Rb dosing was strictly administered using an automated delivery system for total intravenous anesthesia. Methods: This non-interventional, retrospective, observational study included 74 patients from an existing clinical trial who met the study criteria. Rb was automatically administered during surgery to maintain a TOFC of 1. SGX (2 mg/kg) was manually administered post-surgery, and the time until the TOFR reached ≥0.9 (if the time exceeded 3 min, 0.5 mg/kg SGX was added every minute). The results were analyzed using a pharmacokinetic (PK)-pharmacodynamic (PD) simulation model of the Rb-SGX complex. Results: The average total dose of administered SGX was 2.2 ± 0.4 mg/kg (mean ± standard deviation). The time from SGX administration till the TOFR reached ≥0.9 was 2.9 ± 1.1 min. Furthermore, Ce_Rb at recovery (Ce_r) was 0.3 ± 0.2 μg/mL. Notably, no cases showed post-operative recurarization within 24 h of surgery. PK-PD model simulations revealed that Ce_Rb increased again after reaching the lowest Ce_Rb in 72 cases, although no increase was recorded beyond Ce_r, suggesting no numerical risk of recurarization. Conclusions: Our results show that if TOFC of 1 is strictly maintained intraoperatively and SGX is administered till the TOFR reaches ≥0.9, post-operative recurarization does not occur.

Comparison of supramaximal currents obtained by acceleromyography and electromyography for monitoring the adductor pollicis muscle in pediatric patients

The aim of this study was to compare the supramaximal currents obtained simultaneously by acceleromyography (AMG) TOF-Watch® SX and electromyography (EMG) AF-201P in pediatric patients. Patients aged 2-11 years who underwent elective surgery under general anesthesia were enrolled. AMG and EMG monitors were placed on opposite arms of the patient to stimulate the ulnar nerve and monitor the adductor pollicis muscles following the induction of general anesthesia. After the monitors were calibrated, rocuronium 0.6 mg/kg was administered. Endotracheal intubation was performed when the EMG showed a train-of-four (TOF) count of 0. The primary outcome was the supramaximal current set by each device's calibration. The secondary outcomes were the time from the administration of rocuronium to a TOF count of 0, the baseline and final TOF ratios, and the conditions surrounding intubation. The paired t test and the Wilcoxon signed-rank test were used to analyze parametric and nonparametric data. A P value < 0.05 indicated statistical significance. Clinical data from 25 pediatric patients were analyzed. The supramaximal current was significantly lower with EMG than with AMG (27.4 ± 6.1 vs. 54.2 ± 8.4 mA, p <.001). The time to a TOF count of 0 was significantly shorter with EMG than with AMG (58 [24-170] vs. 75 [26-236] seconds, p <.001). Both the baseline and final TOF ratios were significantly lower with EMG than with AMG. The ease of laryngoscopy was rated as excellent for all patients. The vocal cords were abducted in 76% of patients, and no movement to insertion of the endotracheal tube was confirmed in 96% of patients. We found that the supramaximal current was significantly lower with EMG than with AMG.

Intubating conditions during rapid sequence induction with either rocuronium or suxamethonium in elderly patients. A randomised study

BACKGROUND

During rapid sequence induction, either rocuronium 1.0 mg kg-1 or suxamethonium 1.0 mg kg-1 can be administered to facilitate endotracheal intubation. We hypothezised that rocuronium provided a larger proportion of excellent intubating conditions compared to suxamethonium in elderly patients.

METHODS

A total of 90 patients 80 years or above with American Society of Anesthesiologists physical health Classes I-IV, and a body mass index < 35 kg m-1-2 were randomised to either rocuronium 1.0 mg kg-1 or suxamethonium 1.0 mg kg-1 during rapid sequence induction with intubation using a video laryngoscope. After 60 s, tracheal intubating conditions were evaluated using the Fuchs-Buder scale by a blinded investigator, and the primary outcome was the proportion of patients with excellent intubating conditions. Further outcomes included first pass success rate, intubating conditions according to the intubating difficulty scale (IDS), onset time and postoperative occurrence of muscle soreness, hoarseness and sore throat.

RESULTS

All patients were evaluated for the primary outcome. Excellent intubating conditions occurred in 36 patients (73%) versus 31 (75%) in the rocuronium group and suxamethonium group, respectively (95% confidence interval [CI]: -16 to 20) (p = .82). The first pass success rate was 48 (98%) versus 40 (98%) comparing the rocuronium group with the suxamethonium group, respectively (p = .90). No difference in IDS score was found; median 0 (interquartile ranges [IQR]: 0-1) versus median 0 (IQR: 0-1) (p = .48). Onset time was significantly shorter in the suxamethonium group 99 versus 131 s (p = .01) (95% CI: 7 to 57). Finally, no difference was found in the occurrence of muscle soreness, hoarseness or sore throat postoperatively.

CONCLUSION

No important difference in intubating conditions was found during rapid sequence induction after the administration of either rocuronium 1.0 mg kg-1 or suxamethonium 1.0 mg kg-1 in patients 80 years or above.

EDITORIAL COMMENT

This reports a superiority trial comparing standardised doses of rocuronium and suxamethonium at 60 s for quality of intubating conditions in the rapid sequence context, and this in an elderly cohort. The findings showed no difference between the drugs concerning intubation outcomes, though the onset or time to peak effect was shorter for suxamethonium, again demonstrated in a cohort 80 years old or older.

Train-of-four ratio, counts and post tetanic counts with the Tetragraph electromyograph in comparison to mechanomyography

Automated EMG devices to detect compound muscle action potentials from the adductor pollicis muscle in response to ulnar nerve stimulation, regardless of hand and thumb position, may serve as a better reference ("gold standard") for clinical assessment of neuromuscular function than traditional mechanomyography (MMG) systems that need custom design and validation in lab settings. This evaluation compared the TetraGraph EMG system against a validated MMG device to investigate the accuracy and repeatability of this quantitative EMG monitor for detecting onset, offset and deep neuromuscular block. Simultaneous muscle action potential recordings from the EMG neuromuscular monitor and muscle contractions from an in-house developed MMG monitor in response to ulnar nerve stimulation were obtained from patients having elective surgery requiring neuromuscular block. Train-of-four (TOF) ratios, TOF counts, and post-tetanic counts (PTCs) were recorded simultaneously from the same hand muscle and compared. In total, 685 pairs of simultaneous TOF ratios were evaluated. The mean difference (bias) of TOF ratios between devices was small (- 2.1%). TOF counts from 285 data pairs were within a count of 2 or less 96% of the time. During deep block, PTC comparisons from 215 data pairs were within a count of 2 or less 95% of the time. These findings, along with prior EMG device evaluations, indicate that real-time EMG neuromuscular monitoring technology to detect muscle action potentials from the adductor pollicis in the clinical setting is closely aligned with the force of thumb contraction determined from MMG. The accuracy of quantitative EMG technology of the TetraGraph EMG system lends strong support for this monitor, along with other similarly validated EMG monitors, to become a clinical standard for all phases (onset, depth and reversal) of neuromuscular block in clinical practice.

Effect of total intravenous anesthesia versus sevoflurane anesthesia on intraoperative facial nerve monitoring: a randomized controlled trial

PURPOSE

Intraoperative facial nerve monitoring (IFNM) facilitates effective nerve preservation during ear and head and neck surgeries. Quantitative differences in the timely feasibility of IFNM during total intravenous anesthesia (TIVA) vs sevoflurane anesthesia have not been investigated.

METHODS

We conducted a randomized controlled trial in which 98 patients undergoing ear surgery were allocated to either the TIVA or sevoflurane group. We used quantitative neuromuscular monitoring of train-of-four (TOF) responses to assess achievements of IFNM-feasible conditions, and recorded the TOF count (TOFC) or TOF ratio of T4/T1 (TOFR). The primary outcome was the time interval between a TOFR of 0.25 and 0.75 (recovery index). The most important secondary outcome was the time to reach a TOFR of 0.25. We also recorded the quality of IFNM, intubation condition, patient-ventilator dyssynchrony, surgeon's satisfaction, and postoperative analgesic and antiemetic requirements.

RESULTS

Ninety-two patients completed the study. The median [interquartile range] recovery index was significantly shorter in the TIVA group (9 [7-11] min) than in the sevoflurane group (34 [24-53] min), with a difference in medians of 25 min (95% confidence interval, 20 to 31; P < 0.001). Before IFNM requests, the time to TOFR of 0.25 was achieved earlier in the TIVA group (34 [29-41] min) than in the sevoflurane group (51 [43-77] min) (P < 0.001). Both groups achieved neuromuscular recovery in time for IFNM without a need for reversal agents.

CONCLUSIONS

Intraoperative facial nerve monitoring was feasible earlier and faster under TIVA than under sevoflurane anesthesia. We suggest that TIVA may be a preferable choice over sevoflurane to meet a surgeon's request for an earlier IFNM.

STUDY REGISTRATION

CRIS.nih.go.kr ( KCT0006676 ); first submitted 7 October 2021.

Improving quantitative neuromuscular monitoring: an education initiative on stimulating electrode placement

Quantitative neuromuscular monitoring reduces the incidence of residual neuromuscular block, but broad acceptance of monitoring has been elusive despite recommendations for quantitative monitoring for decades. Acceptance of quantitative monitoring may, in part, be related to the quality of the data from monitoring systems. This evaluation explored proper stimulating electrode positioning for electromyographic (EMG) monitoring, the impact of an educational intervention on electrode positioning and anesthesia provider (anesthesiologist, resident, anesthetist) confidence in the monitoring data from the device. In a single-center, observations of EMG electrode placement by anesthesia technicians, in 55 adult elective surgery patients were made by an independent observer. Separately, the anesthesia provider satisfaction with EMG derived data was recorded after reversal of neuromuscular block. An educational intervention then occurred on proper electrode positioning, including prior observations of electrode positioning, and prior anesthesia provider satisfaction with the EMG derived data. After the intervention, stimulating electrode position was observed with an additional 60 patients and anesthesia provider satisfaction with the data was again ascertained. The educational intervention significantly increased the proportion of ideal ulnar nerve groove electrode positioning from 74.5% to 95% (P < 0.003) and ideal wrist crease positioning (distal electrode within 2 cm of crease) from 61.8% to 96.7% (P < 0.001). Anesthesia provider confidence with EMG derived information during anesthesia delivery, increased from 67 to 90% after the education (P = 0.005). There was a significant relationship between correct stimulating electrode placement and anesthesia provider confidence in the EMG derived data on neuromuscular block status. An educational intervention to improve EMG electrode positioning proved meaningful. It increased anesthesia provider confidence in the EMG derived data during anesthesia case management.

Comparison of the Effects of Sugammadex Recommended Dose (2 mg/kg) and Fixed Dose of 200 mg on the Reversal of Moderate Neuromuscular Block and Recovery Profile in Adult Patients

Background and Objectives: Neuromuscular blocking agents are essential to ensure optimal surgical conditions during general anesthesia. Sugammadex, a selective binding agent, is widely used to reverse neuromuscular blockade. While weight-based dosing (2 mg/kg for moderate blockade) is recommended, many clinicians administer a fixed dose of 200 mg in clinical practice, potentially leading to overdosing. This study aimed to compare the efficacy and recovery profiles of weight-based and fixed-dose sugammadex in patients undergoing general anesthesia. Materials and Methods: In this randomized controlled trial, 20 patients were divided into two groups: the recommended dose group (R group, 2 mg/kg) and the fixed dose group (F group, 200 mg). Primary outcomes included time to achieve a normalized train-of-four (TOF) ratio of 0.9. Secondary outcomes included recovery time, time to spontaneous respiration, response to verbal commands and extubation, and adverse events. Results: The median time to achieve a normalized TOF ratio of 0.9 was 2.3 min in the R group and 2.0 min in the F group (p = 0.529). Secondary outcomes, including recovery time and time to extubation showed no significant differences. Adverse events were minimal and comparable between groups. Conclusions: The fixed-dose sugammadex (200 mg) demonstrated similar efficacy and safety to weight-based dosing (2 mg/kg) in reversing moderate neuromuscular blockade. These findings do not allow abandoning the recommendation of adjustment for body weight, particularly in patients with low body weight or comorbidities.

Is quantitative neuromuscular monitoring mandatory after administration of the recommended dose of sugammadex? A prospective observational study

BACKGROUND

Some anaesthetists wonder whether confirming a train-of-four ratio (TOFR) ≥0.9 is necessary when using sugammadex to antagonise neuromuscular blockade (NMB). In this study, we aimed to determine whether using sugammadex at the recommended dose under neuromuscular monitoring (NMM) would ensure complete recovery, even without further NMM.

METHODS

This prospective observational study included 51 patients who underwent robot-assisted surgery under general anaesthesia between March and May 2023. At the end of surgery, sugammadex was administered (2 mg/kg for a train-of-four (TOF) count ≥1 and 4 mg/kg for a TOF count = 0 and a post-tetanic count ≥1). NMM was discontinued, and subsequent recovery was completed at the discretion of the attending anaesthetist. TOFR was measured twice immediately upon admission to the post-anaesthesia care unit (PACU). The primary outcome was the incidence of a non-normalised TOFR (nTOFR) <0.9 upon arrival in PACU. The secondary outcomes were the incidences of a nTOFR <0.7 or 1.0, symptoms/signs of residual NMB (diplopia, dyspnoea, and desaturation) and recovery profiles in PACU.

RESULTS

The incidence of a nTOFR <0.9 upon arrival in PACU was 5.9% (3/51 patients). No patient had a nTOFR <0.7, and 47.1% (24 patients) had a nTOFR <1.0, but no patients showed clinical symptoms/signs of residual NMB.

CONCLUSIONS

When the recommended dose of sugammadex was administered under qualitative NMM, residual NMB at the time of PACU arrival occurred frequently, indicating that quantitative NMM is necessary to ensure adequate recovery.

REGISTRATION

ClinicalTrials, NCT05760560.

Success rate of acceleromyographic neuromuscular monitoring based on the depth of anesthesia at the time of sugammadex antagonism: a randomized controlled trial

OBJECTIVE

We aimed to compare the success of non-normalized acceleromyographic neuromuscular monitoring and recovery profiles based on the depth of anesthesia at the time of sugammadex administration.

METHODS

Patients undergoing general anesthesia were prospectively and randomly allocated to two groups. In the BIS60 group, sugammadex was administered when there was a bispectral index (BIS) <60 and anesthesia was maintained until a train-of-four ratio ≥1.0 was obtained, whereas in the BIS70 group, anesthesia was stopped at the completion of surgery, sugammadex was administered when the BIS was >70, and the recovery of neuromuscular function was monitored. The recovery profile and the incidence of emergence agitation of the two groups were compared.

RESULTS

The success rate of neuromuscular monitoring was significantly higher for the BIS60 group than for the BIS70 group (100% vs. 37.5%, respectively). The time taken for recovery for the two groups was comparable. The incidence of emergence agitation was significantly lower in the BIS60 group than in the BIS70 group (23.3% vs. 56.3%, respectively).

CONCLUSION

After the administration of sugammadex, the maintenance of anesthesia until the full recovery of neuromuscular function increases the success rate of neuromuscular monitoring without delaying recovery and reduces the risk of emergence agitation.Clinical trial registration: CRIS registration number KCT0007899 (https://cris.nih.go.kr/).

The Effect of Remimazolam on the Baseline TOF Ratio: A Prospective, Clinical Study

Background: Remimazolam is a newly developed benzodiazepine. Early recovery from anesthesia because of its ultra-short acting effect and less hemodynamic side effects has been reported as the specific advantages of remimazolam. Therefore, the maintenance of anesthesia with propofol may be sometimes switched to remimazolam anesthesia maintenance during surgery because of the risk of delayed awakening and unstable hemodynamics. In the present study, to determine the influence of switching anesthesia from propofol to remimazolam on the baseline TOF ratio, the TOF ratio under remimazolam anesthesia maintenance without any neuromuscular blocking agents was compared to that calibrated after induction of general anesthesia with propofol. Methods: Twelve patients scheduled for elective surgery under general anesthesia in the supine position were investigated. After induction of general anesthesia with remifentanil and propofol, a supraglottic airway was inserted without neuromuscular blockade, and TOF stimulation every 15 s at the adductor pollicis muscle was started with acceleromyography. After stable baseline responses to TOF stimulation being obtained for at least 10 min under propofol anesthesia, the anesthetic agent was switched to remimazolam and TOF stimulation every 15 s was maintained for a further 60 min without any interruption. In each case, the averaged TOF ratio during the last 10 min of TOF monitoring was compared to that during the 10 min immediately before the beginning of remimazolam infusion using a paired t-test. Results: There were no significant differences in the TOF ratios before and after switching anesthesia to remimazolam (1.07 ± 0.03 vs. 1.07 ± 0.03, p=0.325). Conclusion: Switching anesthesia from propofol to remimazolam does not affect the baseline TOF ratio.

Comparison of measurements obtained with TOF-Cuff placed on the arm and the TOF-Scan on the adductor pollicis muscle during general anaesthesia using mivacurium: a prospective observational clinical trial

Adequate neuromuscular monitoring of patients is essential to verify complete recovery of neuromuscular function before tracheal extubation. This study aimed to assess the correlation between the values acquired from the brachialis muscle using TOF-Cuff and those obtained from the adductor pollicis muscle with TOF-Scan during anaesthesia with mivacurium. Twenty-five patients were enrolled in the observational clinical trial, with the TOF-Cuff positioned on the upper arm and the TOF-Scan on the thumb. Train-of-four (TOF) values were simultaneously recorded by both devices at 30-second intervals before intubation. Subsequently, measurements were taken every 5 min until the removal of the endotracheal tube. Bland-Altman analyses were conducted to compare assessed endpoints obtained by using the TOF-Cuff and the TOF-Scan. The median onset time measured with TOF-Cuff was numerically longer compared to the TOF-Scan score (120 s vs. 90 s, P = 0.42). Spearman rank correlation revealed a significant positive correlation between onset times measured by TOF-Cuff and TOF-Scan (R = 0.73, P = 0.0001, 95% CI 0.446 to 0.875). For the time to recovery assessed with both methods, Spearman correlation coefficient was R = 0.35 and did not reach statistical significance (P = 0.1). Multiplying the time to recovery from the last dose (according to TOF-Scan) by 0.43 to 2.66, provided concordance with the TOF-Cuff result for the entire range of study group. Conclusion. The concordance between the TOF-Scan on the adductor pollicis and the TOF-Cuff on the upper limb was found to be good. However, both devices showed a false-negative result in patients with clinical symptoms of preterm recovery.

ClC-1 Inhibition as a Mechanism for Accelerating Skeletal Muscle Recovery After Neuromuscular Block in Rats

Neuromuscular blocking agents are used commonly to induce skeletal muscle relaxation during surgery. While muscle relaxation facilitates surgical procedures and tracheal intubation, adequate recovery of muscle function after surgery is required to support pulmonary function, and even mild residual neuromuscular block increases the risk of severe postoperative pulmonary complications. While recovery of muscle function after surgery involving neuromuscular blocking agents can be monitored and, in addition, be accelerated by use of current antagonists (reversal agents), there is a clear clinical need for a safe drug to antagonize all types of neuromuscular blocking agents. Here, we show that inhibition of the skeletal muscle-specific chloride ion (Cl-) channel, the ClC-1 channel, markedly accelerates recovery of both single contraction (twitch) and, important physiologically, sustained (tetanic) contractions in a rat model mimicking neuromuscular blocking agent-induced muscle block used during surgery. This suggests ClC-1 inhibition as a mechanism for fast and efficacious recovery of neuromuscular function induced by any neuromuscular blocking agents.

Neuromuscular blockade monitoring in pediatric patients

The administration of neuromuscular blocking agents (NMBAs), the cornerstone of pediatric anesthesia, facilitates intubation and muscle relaxation during surgery. However, NMBAs can also lead to serious complications including respiratory depression, residual paralysis, and prolonged recovery. Neuromuscular monitoring (NMM) in pediatric patients is therefore essential, as it is in adults, to ensure adequate paralysis during surgery and prompt recovery from NMBA-induced paralysis. This article aimed to provide a comprehensive overview of NMM in pediatric anesthesia including the various available methods, their advantages and disadvantages, and the importance of a standardized NMM approach.

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.

Area under the curve and amplitude of the compound motor action potential are clinically interchangeable quantitative measures of neuromuscular block: a method comparison study

Background

Current guidelines recommend quantitative neuromuscular block monitoring during neuromuscular blocking agent administration. Monitors using surface electromyography (EMG) determine compound motor action potential (cMAP) amplitude or area under the curve (AUC). Rigorous evaluation of the interchangeability of these methods is lacking but necessary for clinical and research assurance that EMG interpretations of the depth of neuromuscular block are not affected by the methodology.

Methods

Digitised EMG waveforms were studied from 48 patients given rocuronium during two published studies. The EMG amplitudes and AUCs were calculated pairwise from all cMAPs classified as valid by visual inspection. Ratios of the first twitch (T1) to the control T1 before administration of rocuronium (T1c) and train-of-four ratios (TOFRs) were compared using repeated measures Bland-Altman analysis.

Results

Among the 2419 paired T1/T1c differences where the average T1/T1c was ≤0.2, eight (0.33%) were outside prespecified clinical limits of agreement (-0.148 to 0.164). Among the 1781 paired TOFR differences where the average TOFR was ≥0.8, 70 (3.93%) were outside the prespecified clinical limits of agreement ((-0.109 to 0.134). Among all 7286 T1/T1c paired differences, the mean bias was 0.32 (95% confidence interval 0.202-0.043), and among all 5559 paired TOFR differences, the mean bias was 0.011 (95% confidence interval 0.0050-0.017). Among paired T1/T1c and TOFR differences, Lin's concordance correlation coefficients were 0.98 and 0.995, respectively. Repeatability coefficients for T1/T1c and TOFR were <0.08, with no differences between methods.

Conclusions

Quantitative assessment neuromuscular block depth is clinically interchangeable when calculated using cMAP amplitude or the AUC.

Onset time, duration of action, and intubating conditions after mivacurium in elderly and younger patients

BACKGROUND

The neuromuscular blocking agent mivacurium can be used during anesthesia to facilitate tracheal intubation. Data on onset time, duration of action, and effect on intubating conditions in patients 80 years and older are however limited. We hypothesized that onset time and duration of action of mivacurium would be longer in elderly patients than in younger adults.

METHODS

This prospective observational study included 35 elderly (≥80 years) and 35 younger (18-40 years) patients. Induction of anesthesia comprised fentanyl 1-3 μg kg-1 and propofol 1.5-2.5 mg kg-1 and propofol and remifentanil for maintenance. Acceleromyography was used for monitoring neuromuscular blockade. The primary outcome was onset time defined as time from injection of mivacurium 0.2 mg kg-1 to a train-of-four (TOF) count of zero. Other outcomes included duration of action (time to TOF ratio ≥0.9), intubating conditions using the Fuchs-Buder scale and the intubating difficulty scale (IDS), and occurrence of hoarseness and sore throat postoperatively.

RESULTS

No difference was found in onset time comparing elderly with younger patients; 219 s (SD 45) versus 203 s (SD 74) (difference: 16 s (95% CI: -45 to 14), p = .30). Duration of action was significantly longer in elderly patients compared with younger patients; 52 min (SD 17) versus 30 min (SD 8) (difference: 22 min [95% CI: 15 to 28], p < .001). No difference was found in the proportion of excellent intubating conditions (Fuchs-Buder); 31/35 (89%) versus 26/35 (74%) (p = .12) or IDS score (p = .13). A larger proportion of younger patients reported sore throat 24 h postoperatively; 34% versus 0%, p = .0002. No difference was found in hoarseness.

CONCLUSION

No difference in onset time of mivacurium 0.2 mg kg-1 was found comparing elderly and younger patients. However, elderly patients had significantly longer duration of action. No difference was found in intubating conditions.

Spontaneous recovery from neuromuscular block after a single dose of a muscle relaxant in pediatric patients: A systematic review using a network meta-analytic and meta-regression approach

BACKGROUND

Age-related differences in the pharmacokinetics and pharmacodynamics of neuromuscular blocking agents (NMBAs) and the short duration of many surgical procedures put pediatric patients at risk of postoperative residual curarization (PORC). To date, the duration of neuromuscular blocking agent effect in children has not been analyzed in a quantitative review. The current meta-analysis aimed to compare spontaneous recovery following administration of various types and doses of neuromuscular blocking agents and to quantify the effect of prognostic variables associated with the recovery time in pediatric patients.

METHOD

We searched for randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that compared the time to 25% T1 (t25), from 25% to 75% T1 (RI25-75), and to ≥90% train-of-four (tTOF90) neuromuscular recovery between common neuromuscular blocking agent treatments administered as a single bolus to healthy pediatric participants. We compared spontaneous t25, RI25-75, and tTOF90 between (1) neuromuscular blocking agent treatments and (2) age groups receiving a given neuromuscular blocking agent intervention and anesthesia technique. Bayesian random-effects network and pairwise meta-analyses along with meta-regression were used to evaluate the results.

RESULTS

We used data from 71 randomized controlled trials/controlled clinical trials including 4319 participants. Network meta-analysis allowed for the juxtaposition and ranking of spontaneous t25, RI25-75, and tTOF90 following common neuromuscular blocking agent interventions. For all neuromuscular blocking agents a log-linear relationship between dose and duration of action was found. With the neuromuscular blocking agent treatments studied, the average tTOF90 (mean[CrI95]) in children (>2-11 y) was 41.96 [14.35, 69.50] and 17.06 [5.99, 28.30] min shorter than in neonates (<28 d) and infants (28 d-12 M), respectively. We found a negative log-linear correlation between age and duration of neuromuscular blocking agent effect. The difference in the tTOF90 (mean[CrI95]) between children and other age groups increased by 21.66 [8.82, 34.53] min with the use of aminosteroid neuromuscular blocking agents and by 24.73 [7.92, 41.43] min with the addition of sevoflurane/isoflurane for anesthesia maintenance.

CONCLUSIONS

The times to neuromuscular recovery are highly variable. These can decrease significantly with age and are prolonged when volatile anesthetics are administered. This variability, combined with the short duration of many pediatric surgical procedures, makes quantitative neuromuscular monitoring mandatory even after a single dose of neuromuscular blocking agent.

A Practical Dosing Algorithm for Deep Neuromuscular Blockade during Total Intravenous Anesthesia: ROCURITHM

BACKGROUND

The number of trials investigating the effects of deep neuromuscular blockade (NMB) on surgical conditions and patient outcomes is steadily increasing. Consensus on which surgical procedures benefit from deep NMB (a posttetanic count [PTC] of 1 to 2) and how to implement it has not been reached. The European Society of Anaesthesiology and Intensive Care does not advise routine application but recommends use of deep NMB to improve surgical conditions on indication. This study investigates the optimal dosing strategy to reach and maintain adequate deep NMB during total intravenous anesthesia.

METHODS

Data from three trials investigating deep NMB during laparoscopic surgery with total intravenous anesthesia (n = 424) were pooled to analyze the required rocuronium dose, when to start continuous infusion, and how to adjust. The resulting algorithm was validated (n = 32) and compared to the success rate in ongoing studies in which the algorithm was not used (n = 180).

RESULTS

The mean rocuronium dose based on actual bodyweight for PTC 1 to 2 was (mean ± SD) 1.0 ± 0.27 mg · kg-1 ·h-1 in the trials, in which mean duration of surgery was 116 min. An induction dose of 0.6 mg ·kg-1 led to a PTC of 1 to 5 in a quarter of patients after a mean of 11 min. The remaining patients were equally divided over too shallow (additional bolus and direct start of continuous infusion) or too deep; a 15-min wait after PTC of 0 for return of PTC to 1 or higher. Using the proposed algorithm, a mean 76% of all 5-min measurements throughout surgery were on target PTC 1 to 2 in the validation cohort. The algorithm performed significantly better than anesthesiology residents without the algorithm, even after a learning curve from 0 to 20 patients (42% on target, P ≤ 0.001, Cohen's d = 1.4 [95% CI, 0.9 to 1.8]) to 81 to 100 patients (61% on target, P ≤ 0.05, Cohen's d = 0.7 [95% CI, 0.1 to 1.2]).

CONCLUSIONS

This study proposes a dosing algorithm for deep NMB with rocuronium in patients receiving total intravenous anesthesia.

EDITOR’S PERSPECTIVE

Pediatric Intraoperative Electromyographic Responses at the Adductor Pollicis and Flexor Hallucis Brevis Muscles: A Prospective, Comparative Analysis

BACKGROUND

Peripheral nerve stimulation with a train-of-four (TOF) pattern can be used intraoperatively to evaluate the depth of neuromuscular block and confirm recovery from neuromuscular blocking agents (NMBAs). Quantitative monitoring can be challenging in infants and children due to patient size, equipment technology, and limited access to monitoring sites. Although the adductor pollicis muscle is the preferred site of monitoring, the foot is an alternative when the hands are unavailable. However, there is little information on comparative evoked neuromuscular responses at those 2 sites.

METHODS

Pediatric patients undergoing inpatient surgery requiring NMBA administration were studied after informed consent. Electromyographic (EMG) monitoring was performed simultaneously in each participant at the hand (ulnar nerve, adductor pollicis muscle) and the foot (posterior tibial nerve, flexor hallucis brevis muscle).

RESULTS

Fifty patients with a mean age of 3.0 ± standard deviation (SD) 2.9 years were studied. The baseline first twitch amplitude (T1) of TOF at the foot (12.46 mV) was 4.47 mV higher than at the hand (P <.0001). The baseline TOF ratio (TOFR) before NMBA administration and the maximum TOFR after antagonism with sugammadex were not different at the 2 sites. The onset time until the T1 decreased to 10% or 5% of the baseline value (T1) was delayed by approximately 90 seconds (both P =.014) at the foot compared with the hand. The TOFR at the foot recovered (TOFR ≥0.9) 191 seconds later than when this threshold was achieved at the hand (P =.017). After antagonism, T1 did not return to its baseline value, a typical finding with EMG monitoring, but the fractional recovery (maximum T1 at recovery divided by the baseline T1) at the hand and foot was not different, 0.81 and 0.77, respectively (P =.68). The final TOFR achieved at recovery was approximately 100% and was not different between the 2 sites.

CONCLUSIONS

Although this study in young children demonstrated the feasibility of TOF monitoring, interpretation of the depth of neuromuscular block needs to consider the delayed onset and the delayed recovery of TOFR at the foot compared to the hand. The delay in achieving these end points when monitoring the foot may impact the timing of tracheal intubation and assessment of adequate recovery of neuromuscular block to allow tracheal extubation (ie, TOFR ≥0.9).

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.

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.

Macrocycles and Acyclic Cucurbit[n]urils as Pseudo[2]catenane Partners for Long-Acting Neuromuscular Blocks and Rapid Reversal In Vivo

Long-acting neuromuscular blocks followed by rapid reversal may provide prolonged surgeries with improved conditions by omitting repetitive or continuous administration of the neuromuscular blocking agent (NMBA), eliminating residual neuromuscular block and minimizing postoperative recovery, which, however, is not clinically available. Here, we demonstrate that imidazolium-based macrocycles (IMCs) and acyclic cucurbit[n]urils (ACBs) can form such partners by functioning as long-acting NMBAs and rapid reversal agents through a pseudo[2]catenation mechanism based on stable complexation with Ka values of over 109 M-1. In vivo experiments with rats reveal that, at the dose of 2- and 3-fold ED90, one IMC attains a duration of action corresponding to 158 or 442 min for human adults, covering most of prolonged surgeries. The block can be reversed by one ACB with recovery time significantly shorter than that achieved by sugammadex for reversing the block of rocuronium, the clinically most widely used intermediate-acting NMBA.

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.