This study is a prospective cohort study that records bilateral frontal EEG data from patients undergoing elective non-cardiac or non-neurosurgical surgeries and divides them into different age groups based on age. All patients received maintenance of general anesthesia with desflurane, and the periodic and aperiodic components, permutation cross mutual information (PCMI), and phase lag entropy (PLE) of EEG data were analyzed under different states of wakefulness, general anesthesia, and recovery. Professional correlation analysis methods were used to analyze the EEG spectrum.

This study investigates how the aging brain responds to general anesthesia (GA). As global populations grow older, an increasing number of elderly patients require surgery with GA. However, the aging brain undergoes significant changes, such as a reduction in brain volume (atrophy) and a decreased ability to metabolize drugs. These factors can make anesthesia riskier for older adults, potentially leading to complications like delayed recovery or post-operative cognitive dysfunction. Currently, most anesthesia monitoring systems are designed based on data from younger, healthier adults and may not accurately reflect the brain state of an elderly patient. This study aims to address this critical gap by analyzing the brain's electrical signals (via EEG) across different age groups to understand how aging influences the brain's response to anesthesia.

The research team enrolled 47 patients, aged between 19 and 82 years, who were scheduled for surgery requiring general anesthesia with desflurane. Participants were divided into three age groups for comparison: young adults (18-40 years), middle-aged adults (40-65 years), and older adults (over 65 years). The investigators analyzed the periodic and aperiodic component, permutation cross mutual information (PCMI) and phase lag entropy (PLE) of EEG data in the states of awake, GA, and recovery.

Inclusion Criteria:

1. Age ≥ 18 years old, male or female not limited
2. Patients who undergo elective non cardiac surgery or non neurosurgical surgery;
3. ASA classification levels 1-3

Exclusion Criteria:

1. Individuals with central nervous system disorders such as autism, attention deficit/hyperactivity disorder, epilepsy, or any congenital mental illness;
2. Patients with any contraindications to the use of desflurane, such as those with a history of malignant hyperthermia (MH), allergies to halogenated anesthetics, and patients with significantly elevated intracranial pressure (ICP);
3. Patients with unstable clinical conditions, such as severe hypotension or circulatory failure

Patients from a tertiary hospital