Study of an Intraoperative Frontal Electroencephalographic Marker of Preoperative Frailty in Patients Over 65 Years of Age for Elective Non-cardiac Surgery.

Frailty is a state of vulnerability, characterized by a loss of mechanisms that maintain homeostasis, determining a lower capacity for recovery in the event of a stressful incident. It is one of the risk factors that increase postoperative adverse outcomes in the elderly population. It has been associated with worse results in different surgical settings, including increased mortality, readmission, referral to specialized care units, increased costs and hospital stay. Currently, there are several instruments for diagnosis and screening of frailty. All of them require time for their execution, an experienced evaluator and an adequate validation in the population in which they are intended to be used. The use of frontal electroencephalography during the intraoperative period has become increasingly popular. It allows the monitoring of brain activity during the administration of anesthetics. Various intraoperative electroencephalographic markers, such as alpha spectral power or total spectrum power, have been associated with factors such as preoperative physical activity, preoperative cognitive level, comorbidities, and postoperative delirium. The objective of this study will be to determine an intraoperative frontal electroencephalographic marker of preoperative frailty in ≥ 65 years patients undergoing general anesthesia with Sevoflurane for non-cardiac surgery.