We asked to a staff of digestive endoscopy and of the operating room to interpret the EEG traces obtained from a single dry electrode device to estimate the level of anesthesia during colonoscopy. They are required to produce a rank value (1 to 3) proportional to the anesthesia level. The rank values of anesthesia evaluated through the EEG traces will be correlated to the typically used "bispectral index" values simultaneously acquired. The expected efficacy of a low-cost single dry-electrode EEG would allow the monitoring of the level of anesthesia during non operating room procedures such as colonoscopy.

Monitoring of the level of anesthesia has two primary functions: to reduce the incidence of awareness during operation and to avoid too deep anesthesia that is associated with increased risks of mortality and postoperative cognitive impairment. This monitoring can be performed by processed EEG such as "Bispectral Index" that provides a simple interpretation numerical value proportional to the anesthesia level. Nevertheless, "Bispectral index" requires specific tools and disposable material that increases costs for non operating room procedure. Colonoscopy is a non operating room procedure typically performed without or with light sedation, less frequently requires deep sedation. The latter is performed by using Propofol a drug that has a low therapeutic index and might be associated with adverse effects such as respiratory depression, aspiration related to loss of airway reflexes and hypotension. The aim of the present study is to evaluate the reliable interpretation of the raw EEG traces by a staff of digestive endoscopy and operating room for monitoring the level of sedation during non operative room anesthesia to avoid adverse effects.

Inclusion Criteria:

• anesthesiologists and nursing staff of the operating room

Exclusion Criteria:

• specific knowledge of electroencephalography

All the anesthesiologists and nursing staff of the digestive endoscopy and operating room of the Volterra Hospital

the modalities of this option have not yet been decided