Anaesthesia essentials: Overview

Abstract
Volatile anaesthetic agents such as sevoflurane contribute to greenhouse gas emissions, and selecting low fresh gas flows on anaesthetic machines minimises their waste. Facilitating improvements in sevoflurane use requires the education, motivation, and standardised evaluation of anaesthetists. There is currently no standard of practice related to the efficiency of anaesthetic gas delivery per case. We conducted a multi-component study termed 'Low With The Flow' (LWTF) to directly address these requirements by educating and motivating anaesthetists to reduce fresh gas flow and thereby sevoflurane use. We introduced a novel metric, the 'volatile efficiency ratio' (VER), able to be calculated on Draeger Primus™, the Draeger Atlan™ family and Draeger Perseus A500™ machines, to audit sevoflurane use in a case-by-case fashion, and assess whether the intervention could achieve a set VER target. The LWTF intervention significantly improved the efficiency of sevoflurane delivery (VER 0.46 pre-intervention (n = 518) versus VER 0.57 post-intervention (n = 531), 95% confidence interval 0.092 to 0.129, P < 0.0001) resulting in a calculated average of 1.3 kg carbon dioxide equivalent emissions reduction and approximately AUD 3.50 saving per case. Consequently, the financial and environmental outcomes from sevoflurane delivery were considerably reduced. Our LWTF intervention provides a valuable model for other anaesthetic departments to investigate and address the global environmental and financial burdens related to their volatile anaesthetic use. For anaesthetists using anaesthesia machines that do not facilitate calculation of VER, an approach using components of our LWTF intervention may still reduce the environmental and financial impacts associated with administration of volatile anaesthesia.

Abstract
Catheter ablation has become a central part of the non-pharmacological treatment of cardiac arrhythmias. It can be performed under conscious sedation, deep sedation, or general anesthesia, but it is getting clear that the incidence of complications during the procedure and the success rate of treatment (with no recurrence of arrhythmia) may be strongly influenced by sedation or anesthesia method. In particular, in sedated patients, ablation procedure may frequently cause severe pain, and the most common adverse events are related to sedation methods. Therefore, anesthesiologists will increasingly be asked to take care of the patients undergoing catheter ablation. In this article, we describe what anesthesiologists should know about ablation procedure and its associated problems, to provide appropriate anesthesia care to patients undergoing catheter ablation.

Abstract
Psychedelic drugs, known for their perception-altering properties, are gaining popularity in the treatment of mental health and pain disorders. As exploratory studies demonstrate clinical efficacy with few adverse events, it is expected that more patients will ingest psychedelic drugs. For therapeutic reasons, as with any drug, anaesthesiologists must be aware of its physiological effects and contraindications to ensure the safe provision of anaesthesia. Psilocybin is a 5HT1A and 5HT2A serotonin receptor agonist thought to act on excitatory and inhibitory neurons in the brain. Acute ingestion causes sympathetic nervous system activation, which can precipitate haemodynamic instability. Activation of the 5HT serotonin receptors can also place the patient at risk of serotonin syndrome. Chronic use increases plasma concentrations of cortisol, which has implications on prophylactic stress-dosing of glucocorticoids preoperatively. Lysergic acid diethylamide (LSD), a synthetic psychoactive substance, is also a 5HT2A agonist. LSD has been shown to potentiate opioid analgesics, and monoamine oxidase (MAO) inhibition. Historical reports suggest that LSD has anticholinesterase activity and can prolong neuromuscular block with depolarising muscle relaxants. Mescaline is a poorly understood psychedelic with similar autonomic effects. Historical studies have shown decreased neuromuscular transmission and an association with malignant hyperthermia. When managing patients who have consumed psychedelics drugs, it is important to consider delaying surgery whenever possible, to allow acute intoxication to wane. A high degree of suspicion and an understanding of management principles is vital to the safe conduct of anaesthesia. Future research should explore therapeutic doses of psychedelic drugs to understand physiologic effects at various concentrations