Effect of perioperative autonomic nervous system imbalance on surgical outcomes: a systematic review

Abstract

The autonomic nervous system (ANS) is essential for maintaining physiological homeostasis. Autonomic nervous system imbalance, characterised by sympathetic hyperactivation and low parasympathetic tone, can occur during the perioperative period. These changes drive systemic stress responses, cardiovascular instability, impaired tissue repair, and immunosuppression, which in turn increase infection risk, neurocognitive decline, and multiorgan dysfunction. Surgical trauma, anaesthesia, pain, hypothermia, and psychological stressors all contribute to this dysregulation, and consequently low parasympathetic tone results in the cholinergic anti-inflammatory pathway being less effective. High sympathetic nervous system activity promotes catecholamine surges and pro-inflammatory cytokine release. Pharmacological interventions, including dexmedetomidine and β-blockers, together with nonpharmacological strategies, such as electroacupuncture and temperature management, are measures that have potential to restore ANS balance. This systematic review covers ANS-mediated organ regulation, pathophysiological consequences of perioperative dysautonomia, and evidence-based therapeutic strategies. By integrating findings from multiple basic and clinical studies, the pivotal roles of ANS modulation in mitigating postoperative complications, including neurocognitive disorders, immunosuppression, and cancer recurrence, are discussed. Maintaining balance of the sympathetic and parasympathetic nervous systems is an important prospect in perioperative medicine that could benefit surgical patients' short- or long-term recovery.

Keywords: autonomic nervous system; parasympathetic tone; perioperative autonomic imbalance; perioperative outcomes; vagus nerve stimulation.

Fig 1

Autonomic nervous system (ANS) regulates specific molecules, pathways, and effects produced in various organs. BAT, brown adipose tissue; GABA, γ-aminobutyric acid; JAK, Janus kinase; PSNS, parasympathetic nervous system; PVN, paraventricular nucleus; SNS, sympathetic nervous system; STAT, signal transducer and activator of transcription. Created with elements from https://BioRender.com.

Fig 2

Perioperative assessment methods, indicators, and clinical significance of autonomic nerves system (ANS) activity. These indicators respond and ANS function to varying degrees. ACh, acetylcholine; AChE, acetylcholinesterase; BChE, butyrylcholinesterase; BDNF, brain-derived neurotrophic factor; CRP, C-reactive protein; EDA, electrodermal activity; GSR, galvanic skin response; HF, high-frequency spectrums; LF, low frequency; NPY, neuropeptide Y; pNN50, the percentage of successive normal sinus RR intervals >50 ms; PPG, photoplethysmography; PSNS, parasympathetic nervous system; RMSSD, the root mean square of the successive normal sinus RR interval difference; SDANN, the standard deviation of the averaged normal sinus RR intervals for all 5-min segments; SDNN, the standard deviation of all normal sinus RR intervals during 24 h; SNS, sympathetic nervous system; SP, skin potential; SS, skin susceptance; TP, total power; ULF, ultra-low frequency; VLF, very low frequency. Created with elements from https://BioRender.com.

Fig 3

An imbalance in autonomic nervous system (ANS) activity after surgery can hinder recovery and increase the risk of neurocognitive disorders, infections, and other complications. AKI, acute kidney injury; GFR, glomerular filtration rate; PSNS, parasympathetic nervous system; SIRS, systemic inflammatory response syndrome; SNS, sympathetic nervous system. Created with elements from https://BioRender.com.

Fig 4

Treatment measures and related mechanisms of perioperative autonomic nervous system (ANS) tone rebalance. PND, postoperative neurocognitive disorders; PSNS, parasympathetic nervous system; SNS, sympathetic nervous system. Created with elements from https://BioRender.com.