Exploration of Autonomic Nervous System by Photoplethysmography

The autonomic nervous system state (ANSS) and the autonomic nervous system state index (ANSSi) - two indices derived from the pulse photo-plethysmography analysis - have been recently advocated as a measure of sympathetic activity in the anesthetized patients, but their validity has not been yet demonstrated. We will conduct a study aiming to assess if ANSS and ANSSi reflect autonomic nervous system modulation on cardiovascular system in healthy humans under general anaesthesia.

Inclusion Criteria:

• aged between 18 and 50 years
• American Society of Anaesthesiologists status I and II

Exclusion Criteria:

• hypertension requiring pharmacological treatment or chronic cardiovascular disease
• arrhythmic cardiac disease (atrial fibrillation, atrial flutter, ectopic beats >5% of normal sinus beats)
• history of alcohol or drug abuse
• obesity (BMI>30)
• diabetes or other endocrine pathology (thyroidal or adrenal)
• peripheral neuropathy or any kind of chronic neurological disease