Reversal of neuromuscular block

The Influence of Acid-Base Balance on Anesthetic Muscle Relaxants: A Comprehensive Review on Clinical Applications and Mechanisms

Muscle relaxants have broad application in anesthesiology. They can be used for safe intubation, preparing the patient for surgery, or improving mechanical ventilation. Muscle relaxants can be classified based on their mechanism of action into depolarizing and non-depolarizing muscle relaxants and centrally acting muscle relaxants. Non-depolarizing neuromuscular blocking drugs (NMBDs) (eg, tubocurarine, atracurium, pipecuronium, mivacurium, pancuronium, rocuronium, vecuronium) act as competitive antagonists of nicotine receptors. By doing so, these drugs hinder the depolarizing effect of acetylcholine, thereby eliminating the potential stimulation of muscle fibers. Depolarizing drugs like succinylcholine and decamethonium induce an initial activation (depolarization) of the receptor followed by a sustained and steady blockade. These drugs do not act as competitive antagonists; instead, they function as more enduring agonists compared to acetylcholine itself. Many factors can influence the duration of action of these drugs. Among them, electrolyte disturbances and disruptions in acid-base balance can have an impact. Acidosis increases the potency of non-depolarizing muscle relaxants, while alkalosis induces resistance to their effects. In depolarizing drugs, acidosis and alkalosis produce opposite effects. The results of studies on the impact of acid-base balance disturbances on non-depolarizing relaxants have been conflicting. This work is based on the available literature and the authors' experience. This article aimed to review the use of anesthetic muscle relaxants in patients with acid-base disturbances.

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.

General Anesthetic Care of Obese Patients Undergoing Surgery: A Review of Current Anesthetic Considerations and Recent Advances

Obesity has long been linked to adverse health effects over time. As the prevalence of obesity continues to rise, it is important to anticipate and minimize the complications that obesity brings in the anesthesia setting during surgery. Anesthetic departments must recognize the innumerable risks when managing patients with obesity undergoing surgery, including anatomical and physiological changes as well as comorbidities such as diabetes, cardiovascular diseases, and malignancies. Therefore, the purpose of this review is to analyze the current literature and evaluate the current and recent advances in anesthetic care of obese patients undergoing surgery, to better understand the specific challenges this patient population faces. A greater understanding of the differences between anesthetic care for obese patients can help to improve patient care and the specificity of treatment. The examination of the literature will focus on differing patient outcomes and safety precautions in obese patients as compared to the general population. Specifically highlighting the differences in pre-operative, intra-operative, and post-operative care, with the aim to identify issues and present possible solutions.

Association between one-session bilateral whole-lung lavage and periprocedural complications in patients with pulmonary alveolar proteinosis: a retrospective cohort study

BACKGROUND

Whole lung lavage (WLL) has been recognized as the most effective therapy of severe pulmonary alveolar proteinosis (PAP). Most centers perform the lavage of each lung in two sessions under general anesthesia at an interval of several days to weeks. Compared with two-session WLL, one-session bilateral sequential WLL only requires general anesthesia once. However, the safety of one-session WLL in PAP patients has not been assessed by large cohort studies. In this study, we aimed to investigate the association between the mode of WLL procedure (one-session or two-session) and the risk of periprocedural complications in PAP patients.

METHODS

In this single-center retrospective cohort study, we included adult patients who were diagnosed as PAP and had undergone WLL procedures under general anesthesia from 2000 to 2022. Patients requiring extra-corporeal oxygenation during WLL were excluded. Since some patients received multiple WLL procedures, we considered each procedure in one-session or two-session group as a unique unit in our analysis. The primary outcome was the occurrence of any complications during hospitalization, including termination of WLL procedure due to fluid leakage or refractory hypoxemia, bronchospasm, delayed endotracheal extubation, cardiovascular event, pneumothorax, and fever.

RESULTS

We included a total of 175 WLL procedures (118 patients), with 48 in the two-session group and 127 in the one-session group. Periprocedural complications occurred in 17 (35.4%) and 39 (30.7%) procedures in the two-session and the one-session groups, respectively. The risk of periprocedural complications did not differ significantly between groups, after adjusting the unbalanced confounders in a multivariable model (odds ratio 0.95, 95% confidence interval 0.34 to 2.69, P 0.929) or by inverse probability of treatment weighting (odds ratio 0.70, 95% confidence interval 0.30 to 1.54, P 0.379). Compared with the two-session WLL group, the one-session WLL group had a shorter postprocedural length of hospitalization and comparable decrease in alveolar-arterial oxygen tension gradient from baseline.

CONCLUSIONS

One-session bilateral WLL was not associated with an increased risk of periprocedural complications compared with two-session WLL in PAP patients. Experienced physicians may consider performing one-session WLL in view of the comparable safety and efficacy and potential advantages of saving time.

Highly Water-Soluble Cucurbit[8]uril Derivative as a Broad-Spectrum Neuromuscular Block Reversal Agent

Broad-spectrum agents for the reversal of residual curarization induced by neuromuscular blocking agents are of great significance. Here, we report a highly water-soluble cucurbit[8]uril (CB[8]) derivative as a broad-spectrum neuromuscular block reversal agent induced by both benzylisquinolinium and aminosteroid neuromuscular block agents by the supramolecular sequestration strategy. The UV/Vis competition titration assays suggest the high binding affinity of the CB[8] derivative toward both benzylisquinolinium-type cisatracurium besylate and aminosteroid-type rocuronium, vecuronium, and pancuronium, at the level of 10⁷ M^-1. In vivo studies demonstrate that the administration of the CB[8] derivative could significantly accelerate the recovery time compared to the placebo or neostigmine groups. The reversal activity of the CB[8] derivative is comparable to or higher than that of clinically approved sugammadex. Acute toxicity evaluations reveal that the CB[8]-derivative displays outstanding biocompatibility, with the maximum tolerance dose as high as 960 mg kg^-1.