Survey of neuromuscular monitoring and assessment of postoperative residual neuromuscular block in a postoperative anaesthetic care unit

Effects of a single dose of rocuronium in patients with different body fat percentages: A randomised controlled trial

The pharmacodynamics in patients with high body fat percentage might be similar to those in obese patients. This randomised controlled clinical trial observed the effects of rocuronium in patients with different percent body fats (PBFs). Fifty-four patients who underwent elective urological or pelvic surgery under general anaesthesia at Shanghai General Hospital were included in the present study; 51 patients were included for data analysis. Patients with normal PBF (<25%) were given a single dose of rocuronium calculated based on total body weight (N-TBW, control group). Patients with a higher PBF (≥25%) were given a single dose of rocuronium calculated based on total body weight (H-TBW). Patients with higher PBF and rocuronium were dosed based on fat-free mass (H-FFM). A train of four (TOF)-Watch acceleromyography monitor was used to measure the effects of the rocuronium. H-TBW (91.9 ± 28.8 s) had significantly shorter onset time than N-TBW and H-FFM (p = 0.003). H-TBW had significantly longer clinical duration time and pharmacological duration time than the other groups (p = 0.000 and 0.000, respectively); the TOF ratio0.25-0.9 time was significantly different among the three groups (p = 0.005). There were no significant differences in the recovery time (p = 0.103) or recovery index (p = 0.159) among the three groups. The effects of rocuronium dosed based on FFM in patients with high PBFs are similar to those in normal patients. A single dose of rocuronium calculated based on TBW might shorten the onset time, prolong the clinical and pharmacological duration times, and prolong the recovery time.

Does the objective measurement of muscle strength improve the detection of postoperative residual muscle weakness?

Background and Aims

The postoperative residual neuromuscular block (PRNB) has a significant impact on patient safety and well-being, but continues to remain underestimated. Objective evaluation of handgrip strength using a force dynamometer can be useful to identify postoperative muscle weakness.

Material and Methods

Thirty-two American Society of Anesthesiologists (ASA) class I and II patients who received general anesthesia were included. Patients were extubated after the train-of-four (TOR) ratio (TOFR) was >0.90 and the clinical criteria for motor power recovery were judged as adequate. The measurements of handgrip strength and peak expiratory flow rate (PEFR) were obtained at baseline, 15 min after extubation, and 1, 2, and 4 h postoperatively. The incidence of significant decline from baseline (>25%) was determined. The correlation between handgrip strength and PEFR was assessed using Spearman correlation. The time to return to baseline for muscle grip strength and PEFR was performed using Kaplan-Meier survival analysis. A P value of 0.05 was considered significant for all tests.

Results

The incidence of the significant decline in handgrip strength from baseline was 100% at 15 and 60 min, 76% at 2 h, and 9.4% at 4 h. There was a strong correlation between muscle grip strength and PEFR (0.89, P < 0.001). None of the patients exhibited the potential complications of PRNB. (PRMB in abstract. It should be uniform) The mean time to return to the baseline value of muscle grip strength was 3.8 h (95% confidence interval [CI] 3.6-3.9), and the mean time to return to baseline for PEFR was 3.2 h (95% CI 2.9-3.4 h).

Conclusion

Objective assessment of muscle grip strength using a force dynamometer has the potential to be a new objective metric to monitor postoperative muscle weakness.

Residual Neuromuscular Blockade and Postoperative Pulmonary Complications in the Post-anesthesia Care Unit: A Prospective Observational Study

Background Neuromuscular blocking agents (NMBAs) are employed during general anesthesia induction for endotracheal intubation and to facilitate specific surgeries requiring muscle relaxation. However, residual neuromuscular blockade (RNMB) can lead to respiratory complications in post-anesthesia care units (PACUs). This study investigates RNMB incidence in PACUs and its association with postoperative airway and respiratory issues. Methods A prospective observational study on patients undergoing general anesthesia with NMBAs was conducted at the Department of Anesthesia, Salmaniya Medical Complex, Bahrain, over six months (April to September 2023). Train-of-four (TOF) ratios were calculated using an acceleromyograph upon PACU arrival. Data on demographics, perioperative variables, and postoperative complications were recorded. Results Among 82 patients, 30 (36.6%) had RNMB upon PACU arrival. RNMB incidence declined: 17.1% at 10 minutes, 6.1% at 20 minutes, and 2.4% at 30 minutes, resolving by 40 minutes. Demographics and procedure duration showed no correlation with RNMB. Postoperative respiratory complications affected 23.2% of patients, notably higher in those with RNMB (p = 0.001). Among patients with TOF <90% at PACU arrival, 46.7% experienced complications compared to 9.6% with TOF ≥90% (p<0.001). Participants without RNMB had a significantly higher weight (p = 0.046). Airway support was required for 30% of patients, all with TOF <90% (p<0.001). Conclusion This study emphasizes the importance of assessing and monitoring neuromuscular function to detect and prevent RNMB in PACUs. RNMB presence correlated with an increased susceptibility to postoperative respiratory complications. Regular quantitative neuromuscular monitoring is advisable in clinical practice to proactively mitigate RNMB incidence and its complications.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Abstract No.: ABS3480 : Dynamometer based hand grip strength as a clinical tool for objective assessment of post-operative residual muscle weakness

Background and Aims:

Residual neuromuscular block is a known postoperative complication. Even after train of four (TOF) ratio of >0.9, there is a possibility of neuromuscular blockade causing respiratory dysfunction. Primary objective was assessment of postoperative residual muscle weakness with dynamometer. Secondary objective was time of recovery to baseline strength.

Methods:

This was a single centre, prospective, observational study. We enroled 50 patients undergoing surgery under general anesthesia. The patients of Americal Society of Anesthesiologists physical status I-II, aged 18-60 years and undergoing surgery under general anaesthesia were included. The patients with surgery including fracture, deformity involving dominant upper limb and pre-existing neuromuscular diseases were excluded from the study. Baseline handgrip strength with dynamometer and peak expiratory flow rate (PEFR) were observed before induction of anaesthesia. Trachea was extubated with TOF ratio >0.9. Values monitored at 15 minutes after extubation,at regular intervals of 15 minutes until 1 hour, 30 minutes until 4 hours and hourly until 6 hours.

Results:

Muscle strength remained 50 to 60% of baseline at 15 minutes, 75% at 45 minutes and reached 100% of baseline at 210 minutes after endotracheal extubation. PEFR remained 50 - 60 % of baseline at 15minutes, 75% of baseline at 60 minutes and reached 100% of baseline at 180 minutes after endotracheal extubation (Table 1).

Conclusion:

A significant reduction in the postoperative muscle strength was detected using objective force dynamometer to measure handgrip strength even when TOF ratio had returned to 1 with no clinical signs of muscle weakness.

Dynamometer based hand grip strength as a clinical tool for objective assessment of post-operative residual muscle weakness

Background and Aims:

Residual neuromuscular block continues to be a significant postoperative complication despite neuromuscular monitoring. This study aims to determine the applicability of a hand-held forced dynamometer for hand grip strength assessment as an objective measure of residual muscle weakness.

Methods:

The study included patients undergoing surgery under general anaesthesia. A demonstration was given to the patient on the usage of a dynamometer for handgrip strength and a peak expiratory flow meter for peak expiratory flow rate (PEFR) and baseline values were recorded. The parameters were monitored at 15 minutes post-extubation and again at intervals of 15 minutes until one hour, half-hourly until four hours, and hourly until six hours post-operatively. Paired t-test was used for comparison of baseline muscle strength and PEFR with the parameters at different time points. Association between muscle strength and PEFR was tested with the Pearson-correlation test.

Results:

Muscle strength was 50 to 60%, 75% and 100% of baseline at 15, 45 and 210 minutes after extubation, respectively. PEFR was 50 to 60%, 75% and 100% of baseline at 15, 60 and 180 minutes after extubation. The Pearson-correlation test established a positive correlation between handgrip strength and PEFR (correlation-coefficient 0.86).

Conclusion:

A significant reduction in the postoperative muscle strength can be detected using an objective forced dynamometer to measure handgrip strength even when train of four count has returned to unity and even when there are no clinical signs of muscle weakness. The residual muscle weakness is significant enough to affect the PEFR in the postoperative period.