Anaesthesia essentials: Overview

Abstract
Background: Cardiac arrhythmias, particularly atrial fibrillation, are highly prevalent and represent a growing global health burden. Cardiac ablation is a commonly used procedure for the treatment of cardiac arrhythmias, often requiring anaesthesia to ensure patient safety and procedural success. Despite its widespread use, there is no consensus on the optimal anaesthetic strategy, and existing literature mainly addresses isolated techniques or specific populations. The aim of this scoping review is to systematically map the current evidence on anaesthetic methods used during cardiac ablation procedures.

Methods: A scoping review will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) guidelines. A comprehensive search strategy will be applied across multiple databases, including Medline, EMBASE, Cochrane, Scopus and Google Scholar. Eligible studies will include all research on adult patients undergoing cardiac ablation, focusing on any anaesthetic or sedative techniques used. Study selection and data extraction will be performed by independent reviewers, and results will be summarized descriptively.

Results: In the final review, findings will be presented through a descriptive and narrative summary, supplemented by tables, figures and graphs where applicable.

Conclusion: This scoping review will provide a structured overview of the landscape of anaesthesia methods in cardiac ablations. The findings will help uncover knowledge gaps and inform future research and clinical decision-making regarding anaesthesia strategies in the management of cardiac arrhythmias.

Abstract
Background: C. elegans possesses a precisely defined pattern of neuronal activation associated with its quiescent sleep-like state. As for higher-order creatures, this state includes the induction of atonia and immobility. In C. elegans, activation of the GABAergic neuron ALA directly inhibits AVE, a crucial command motor interneuron. By comparing this stereotypical pattern of activation to the activity seen within this neuronal circuit during anesthesia, we may determine if the atonia and immobility observed in anesthetized C. elegans is recruited via the same neuronal mechanism as in quiescence.

Methods: Neuronal activity in C. elegans, as measured by fluorescence intensity of the calcium-indicator GCaMP6s, was captured using light-sheet microscopy under exposure to increasing depths of isoflurane anesthesia (n = 20). Neuronal identities were determined using the NeuroPAL nuclear labeling system. The activity of neurons in the sleep atonia pathway were identified for analysis. Neuronal traces were differentiated, and signal coherence between traces were calculated as Pearson correlation coefficients. Differences among conditions were assessed using ANOVA.

Results: During quiescence, we observe the characteristically strong activation of ALA and RIS, with suppression of other neurons. In the awake animal, neuronal activity in ALA and AVE remains moderately negatively correlated (r = -0.286). However, isoflurane anesthesia in C. elegans does not result in an increase in the negative correlation between these two neurons: we observe a progressive loss and inversion of this baseline negative correlation, resulting in a significantly different positive correlation when deeply anesthetized (r = 0.229: p = 0.003, Type III ANOVA). In comparison, isoflurane anesthesia suppresses the positive correlation between AVE and a strongly-connected key member of the command motor interneuron circuit, AVA (p = 0.007, Type III ANOVA).

Conclusions: Immobility is a fundamental characteristic of both anesthesia and naturally occurring sleep-states. However, we show that, in C. elegans, immobility in the anesthetized state is not produced by activating the innate neurological mechanism of quiescence.

Abstract
Glucagon-like peptide-1 receptor agonists slow gastric emptying and may increase aspiration risk. Recent guidelines suggest using prokinetic agents pre-operatively, but no studies have assessed the efficacy of erythromycin for this purpose. We present a 53-year-old man (weight 110 kg) taking liraglutide and undergoing elective knee arthroscopy. Despite 19 h of fasting and withholding liraglutide, gastric ultrasound revealed a grade 3 antrum with solid content. Intravenous erythromycin 300 mg was administered, causing transient gastrointestinal symptoms. A repeat ultrasound 15 min later showed reduced solid content, although the antrum was not convincingly empty. As the patient declined neuraxial anaesthesia without sedation, a modified rapid sequence induction was performed. An ultrasound scan at the completion of surgery confirmed an empty stomach, and recovery was uneventful. This is the first documented case using gastric ultrasound to assess the effect of erythromycin on a patient taking a glucagon-like peptide-1 receptor agonist. While erythromycin achieved its desired effect within 100 min, the optimal timing for prokinetic administration and subsequent ultrasound assessment remains uncertain. Gastric ultrasound may refine risk stratification and guide prokinetic use for these patients. Further research is needed to determine optimal erythromycin dosing, time to desired effect and side effects to optimise peri-operative management.