The vagus nerve: current concepts in anaesthesia and ICU management

The vagus nerve (XN) is a major component of the autonomic nervous system. It plays an important role both in the regulation of metabolic homeostasis and in inflammatory modulation. XN tone is dampened in stress conditions (either of inflammatory and/ or infectious origin) and the preservation of parasympathetic function may serve as a biomarker of general health, longevity and vitality. COVID-19 remains a major healthcare issue worldwide. Excessive inflammation and its end organ consequences are key elements in the pathogenesis of COVID-19-induced multiple organ dysfunction, as well as post-COVID-19 syndrome (long COVID). XN stimulation has been hypothesised to control both the SARS-CoV-2 replication and the ensuing inflammation, and could improve the clinical outcomes as an adjunct treatment. Electrical stimulation of the auricular XN (AXNS) is an emerging technology, with few side effects and anaesthetic implications, and is showing promise with respect to the management of gastroparesis, epilepsy, migraine, autoimmune diseases, anxiety and major depressive disorders, obesity, SARS-CoV-2 infection in the intensive care unit (ICU), and long COVID. Continuous vagal tone monitoring in patients with COVID-19 may potentially also be used as a predictive marker of the COVID-19 illness course, and an evaluation of future therapies. Copyright © 2022 The Author(s).