Management of the Autonomic Nervous System During Anesthesia

Core Monitoring Requirements

The American Society of Anesthesiologists recommends that all patients undergoing general anesthesia must have continuous ECG, pulse oximetry, non-invasive blood pressure, and capnography monitoring from before induction through recovery to detect autonomic responses and hemodynamic instability 1, 2
These monitors should be checked for correct function and alarm limits set to patient-specific values before induction 1
Monitoring must continue during transfer to the post-anesthesia care unit and throughout recovery 1
Audible alarms should be enabled during anesthesia to detect autonomic-mediated hemodynamic changes 2

Processed EEG monitoring should be used when total intravenous anesthesia is administered with neuromuscular blocking drugs, starting before induction and continuing until full recovery from neuromuscular blockade 1, 2
Processed EEG monitoring reduces anesthetic drug requirements and may decrease postoperative delirium and cognitive dysfunction 3
Anaesthetists should not rely solely on index values but should understand EEG waveforms and power spectral analysis 3

Diabetic patients with cardiac autonomic neuropathy are at increased risk of perioperative hemodynamic instability due to interactions between anesthesia and dysautonomia 4
Preoperative respiratory heart rate variability testing identifies patients at risk for perioperative hemodynamic instability 4
Drugs that may induce orthostatic hypotension should be avoided in patients with confirmed cardiac autonomic neuropathy 4
Vasopressor requirements correlate with the degree of dysautonomia 4
The American Diabetes Association recommends that all obese patients should be assumed to have some degree of sleep-disordered breathing, requiring modification of anesthetic technique to minimize autonomic and respiratory compromise 5, 6
Use short-acting anesthetic agents to reduce prolonged autonomic suppression 5, 6
Employ depth of anesthesia monitoring to limit anesthetic load, particularly with neuromuscular blocking drugs and total intravenous anesthesia 5, 6

Quantitative neuromuscular monitoring should be used whenever neuromuscular blocking drugs are administered, throughout all phases from before initiation until train-of-four ratio >0.9 is confirmed 1, 2
Complete reversal must be verified before extubation to ensure restoration of autonomic-mediated respiratory drive 5, 6

Additional cardiovascular monitoring should be considered based on cardiovascular comorbidity, frailty, emergency nature, or specific surgical requirements 3
Cardiac output monitoring may be used to titrate vasoactive infusions and optimize stroke volume 3
Right heart catheterization with thermodilution remains the most accurate technique 3

Do not assume autonomic function is preserved in patients with metabolic syndrome or diabetes 4
Preoperative autonomic testing should be performed in type 1 diabetes patients with disease duration ≥5 years and all type 2 diabetes patients with microangiopathic complications 4
Avoid excessive anesthetic depth that suppresses autonomic responses beyond surgical requirements 3
Use processed EEG monitoring to titrate anesthetic dose to individual patient needs 3