The depth of neuromuscular blockade is not related to chest wall elastance and respiratory mechanics in moderate to severe acute respiratory distress syndrome patients. A prospective cohort study

BACKGROUND

Data concerning the depth of neuromuscular blockade (NMB) required for effective relaxation of the respiratory muscles in ARDS are scarce. We hypothesised that complete versus partial NMB can modify respiratory mechanics.

METHOD

Prospective study to compare the respiratory mechanics of ARDS patients according to the NMB depth. Each patient was analysed at two times: deep NMB (facial train of four count (TOFC) = 0) and intermediate NMB (TOFC >0). The primary endpoint was the comparison of chest wall elastance (ELCW) according to the NMB level.

RESULTS

33 ARDS patients were analysed. There was no statistical difference between the ELCW at TOFC = 0 compared to TOFC >0: 7 cmH2O/l [5.7-9.5] versus 7 cmH2O/l [5.3-10.8] (p = 0.36). The depth of NMB did not modify the expiratory nor inspiratory oesophageal pressure (Pesexp = 8 cmH2O [5-9.5] at TOFC = 0 versus 7 cmH2O [5-10] at TOFC >0; (p = 0.16) and Pesinsp = 10 cmH2O [8.2-13] at TOFC = 0 versus 10 cmH2O [8-13] at TOFC >0; (p = 0.12)).

CONCLUSION

In ARDS, the relaxation of the respiratory muscles seems to be independent of the NMB level.

A compressomyograph train of four monitoring device

The monitoring of the neuromuscular blockade is critical for patient's safety during and after surgery. The monitoring of neuromuscular blockade often requires the use of Train of Four (TOF) technique. During a TOF test two electrodes are attached to the ulnar nerve, and a series of four electric pulses are applied. The electrical stimulation causes the thumb to twitch, and the amount of twitch varies depending on the amount of neuromuscular blockade in patient's system. Current medical devices used to assist anesthesiologists to perform TOF monitoring often require free hand movement and do not provide accurate or reliable results. The goal of this work is to design, prototype and test a new medical device that provides reliable TOF results when thumb movement is restricted. A medical device that uses a pressurized catheter balloon to detect the response thumb twitch of the TOF test is created. An analytical model, numerical study, and mechanical finger testing were employed to create an optimum design. The design is tested through a pilot human subjects study. No significant correlation is reported with subjects' properties, including hand size.

Neuromuscular end-point predictive capability of published rocuronium pharmacokinetic/pharmacodynamic models: An observational trial

BACKGROUND

Objective neuromuscular monitoring remains the single most reliable method to ensure optimal perioperative neuromuscular management. Nevertheless, the prediction of clinical neuromuscular endpoints by means of Pharmacokinetic (PK) and Pharmacodynamic (PD) modelling has the potential to complement monitoring and improve perioperative neuromuscular management.s STUDY OBJECTIVE: The present study aims to assess the performance of published Rocuronium PK/PD models in predicting intraoperative Train-of-four (TOF) ratios when benchmarked against electromyographic TOF measurements.

DESIGN

Observational trial.

SETTING

Tertiary Belgian hospital, from August 2020 up to September 2021.

PATIENTS AND INTERVENTIONS

Seventy-four patients undergoing general anaesthesia for elective surgery requiring the administration of rocuronium and subject to continuous EMG neuromuscular monitoring were included. PK/PD-simulated TOF ratios were plotted and synchronised with their measured electromyographic counterparts and their differences analysed by means of Predictive Error derivatives (Varvel criteria).

MAIN RESULTS

Published rocuronium PK/PD models overestimated clinically registered TOF ratios. The models of Wierda, Szenohradszky, Cooper, Alvarez-Gomez and McCoy showed significant predictive consistency between themselves, displaying Median Absolute Performance Errors between 38% and 41%, and intra-individual differences (Wobble) between 14 and 15%. The Kleijn model outperformed the former with a lower Median Absolute Performance Error (16%, 95%CI [0.01; 57]) and Wobble (11%, 95%CI [0.01; 34]). All models displayed considerably wide 95% confidence intervals for all performance metrics, suggesting a significantly variable performance.

CONCLUSIONS

Simulated TOF ratios based on published PK/PD models do not accurately predict real intraoperative TOF ratio dynamics.

TRIAL REGISTRATION

NCT04518761 (clinicaltrials.gov), registered on 19 August 2020.

Effect of quantitative versus qualitative neuromuscular blockade monitoring on rocuronium consumption in patients undergoing abdominal and gynecological surgery: a retrospective cohort study

The level of neuromuscular blockade can be assessed by subjective (qualitative) and objective (quantitative) methods. This study aims to compare the dosage of the neuromuscular blocking agents (NMBA) rocuronium and the need for reversion by sugammadex between those methods. A retrospective, observational analysis was conducted. In the tactile qualitative-neuromuscular monitoring-group (tactile NMM) (n = 244), muscle contractions were assessed tactilely. In the quantitative neuromuscular monitoring-group (n = 295), contractions were accessed using an acceleromyograph. Primary endpoints were dosage of rocuronium per minute operation-time (milligram per kilogram bodyweight per minute (mg/kgBW/min)), count of repeated rocuronium administrations and use of sugammadex. Secondary endpoints were: NMM use before repeated NMBA application or extubation, time to extubation, post-operative oxygen demand. A total of n = 539 patients were included. n = 244 patients were examined with tactile NMM and 295 patients by quantitative NMM. Quantitative NMM use resulted in significantly lower rocuronium dosing (tactile NMM: 0.01 (± 0.007) mg/kgBW/min vs. quantitative NMM: 0.008 (± 0.006) mg/kgBW/min (p < 0.001)). In quantitative NMM use fewer repetitions of rocuronium application were necessary (tactile NMM: 83% (n = 202) vs. quantitative NMM: 71% (n = 208) p = 0.007). Overall, 24% (n = 58) in the tactile NMM-group, and 20% (n = 60) in the quantitative NMM-group received sugammadex ((p = 0.3), OR: 1.21 (0.81-1.82)). Significantly fewer patients in the quantitative NMM-group required oxygen-supply postoperative (quantitative NMM: 43% (n = 120)) vs. tactile NMM: 57% (n = 128)) (p = 0.002). The use of quantitative assessment of NMBA results in a lower overall dosage and requires fewer repetitions of rocuronium application. Therefore, quantitative monitoring systems should be used to monitor NMBA intraoperatively to reduce NMBA dosing, while achieving continuous neuromuscular blockade.

Influence of rocuronium on achieving optimal vagal stimulation during intraoperative nerve monitoring in thyroid surgery

BACKGROUND

In the present study we determine the feasibility of intraoperative neuromonitoring following the administration of a nondepolarizing neuromuscular blocking agent during thyroid operations, as well as the influence of rocuronium on the achievement of optimal vagal stimulation during intraoperative neuromonitoring in thyroid surgery. We further investigate whether accelerometry is a reliable approach to obtaining an ipsilateral vagus signal prior to recurrent laryngeal nerve dissection.

METHODS

Included in the study were 61 thyroidectomized patients whose demographic data, indications, type of surgery, vagus, and recurrent nerve values before and after resection were obtained. We created five groups of patients based on the twitch values recorded during ipsilateral vagus stimulation prior to the recurrent laryngeal nerve dissection: (1) <10%, (2) 11-25%, (3) 26-50%, (4) 51-75% and (5) >75%.

RESULTS

The average electromyography amplitudes of the vagus nerve prior to the determination of the recurrent laryngeal nerve for each group were 552 μV, 463 μV, 543 μV, 513 μV and 551 μV, respectively. No difference between the groups was observed in this regard (p > 0.05).

CONCLUSION

It can be expected that as soon as the effects of neuromuscular blockers on the peripheral muscles begin to abate, it will be possible to obtain the ipsilateral vagus signal prior to recurrent laryngeal nerve dissection at the desired levels. It can be concluded from this study that accelerometry using the pollicis muscle is an unreliable tool for the interpretation of the proper electromyography signals of the vagus nerve prior to the determination of the recurrent laryngeal nerve.

Sugammadex versus neostigmine for reversal of rocuronium-induced neuromuscular blockade: A randomized, double-blinded study of thoracic surgical patients evaluating hypoxic episodes in the early postoperative period

STUDY OBJECTIVE

This objective of this study was to determine if reversal of rocuronium-induced neuromuscular blockade with sugammadex versus neostigmine results in a decreased number of hypoxic episodes in the early postoperative period in patients undergoing thoracic surgery with single lung ventilation.

DESIGN

Single-center, randomized, double-blind, two-arm clinical trial.

SETTING

Operating room and postanesthesia care unit.

PATIENTS

92 subjects aged ≥18, American Society of Anesthesiologists physical status II-IV, and undergoing a thoracic operation necessitating single lung ventilation.

INTERVENTIONS

Subjects received either 2 mg/kg sugammadex or 50 μg/kg neostigmine with 8 μg/kg glycopyrrolate for reversal of moderate neuromuscular blockade.

MEASUREMENTS

For the first 90 min postoperatively, all episodes of hypoxia were recorded. Neuromuscular monitoring was performed with acceleromyography (TOF-Watch® SX) and the train of four (TOF) was recorded at 2, 5, 10, and 15 min after administration of the neuromuscular reversal agent.

MAIN RESULTS

Subjects who received neostigmine had a median of 1 episode (interquartile range IQR: 0-2.2) of hypoxia versus subjects who received sugammadex who had a median of 0 episodes (IQR: 0-1) (p = 0.009). The mean time to recovery of TOF ≥ 0.9 was significantly faster with sugammadex at 10 min (95% confidence interval CI: 5-15) compared with neostigmine at 40 min (95% CI: 15-53) (p < 0.001).

CONCLUSIONS

In thoracic surgical patients necessitating single lung ventilation, sugammadex provides faster reversal of moderate neuromuscular blockade and results in a decreased number of postoperative hypoxic episodes compared with neostigmine.