Using data from electroencephalogram (EEG) obtained through intraoperative depth of anesthesia monitoring devices, combined with clinical symptoms such as postoperative pain and delirium, investigate their correlation and verify whether intraoperative EEG spectral analysis can predict the occurrence of postoperative pain, nausea and vomiting, restlessness, or delirium in patients undergoing surgery.

Due to the complexity of the original EEG waveforms, previous anesthesia depth monitoring systems only calculated a single index, such as Bispectral index (BIS) or patient state index (PSI), to determine the state under anesthesia. However, a single numerical change may not reflect the true state under anesthesia. By analyzing the original EEG waveforms, more information can be obtained, such as density spectral array (DSA) and power spectral density, which can quantify the energy distribution at various brain wave frequencies. This allows anesthesiologists to determine the effects of medication on brain waves and the effects of surgical stimulation on brain waves during surgery.

After obtaining the signed informed consent form, before inducing general anesthesia in the patient entering the operating room, an anesthesia depth monitoring patch is attached to the forehead, and EEG data during anesthesia is collected using the currently used anesthesia depth monitoring device. The monitoring process starts from the beginning of general anesthesia until the end of the surgery, and the EEG recording is stopped only when the patient wakes up from general anesthesia and leaves the operating room.

By using the original EEG during anesthesia depth monitoring to conduct spectral analysis and combining it with common post-anesthesia adverse symptoms such as pain, nausea and vomiting, delirium, and restlessness, a correlation analysis is conducted between the quantified EEG values and postoperative symptoms. This verifies whether intraoperative EEG spectral analysis can predict the occurrence of postoperative complications.

Inclusion Criteria:

1. Aged 20 years or older.
2. Patients who received general anesthesia within the our hospital system.

Exclusion Criteria:

1. Individuals with suspected infections, such as a fever higher than 38.3℃
2. Individuals with renal dysfunction, such as those with creatinine levels higher than 1.5 or those who require long-term dialysis
3. Individuals with cardiac dysfunction, such as those with NYHA class III or higher heart failure or coronary heart disease Individuals with neurological diseases, such as those with brain tumors, dementia, stroke, or epilepsy
4. Vulnerable populations, such as minors (under 20 years of age), pregnant women and fetuses, prisoners, adults who cannot give informed consent, individuals with disabilities, individuals with mental illness, residents of nursing homes or long-term care facilities, or those who may be subject to coercion or unable to make decisions freely.

Patients aged 20 years or older who received general anesthesia within the National Taiwan University Hospital system.