The purpose of the study is to evaluate the relationship between perioperative electroencephalogram and emergence agitation in the nasal surgery. Previous studies showed that low frequency band wave activity increased during emergence delirium in pediatric patients. It is still not enough to explain the relationship between emergence agitation and electroencephalogram in adults. Researchers will demonstrate the relationship between parameters related electroencephalogram and emergence agitation in adults undergoing nasal surgery.

Researchers use Sedline to perform perioperative EEG measurements of young adult patients undergoing nasal surgery under general anesthesia with sevoflurane. Emergence agitation occurrence and EEG patterns are observed.

The researchers record the patient's sex, type of surgery, pre-education on emergence agitation, preoperative hospital anxiety and depression scale (HADS), postoperative pain, amount of analgesics administered in the surgery/recovery room, and PACU time. Investigators check the correlation between EEG and perioperative variables. Investigators also compare EEG and perioperative variables for those who were given an explanation of emergence agitation and those who were not.

Inclusion Criteria:

• Adult patients aged 19-55 years who are undergoing nasal surgery under general anesthesia using inhalational agent

Exclusion Criteria:

• CNS disease (ex.dementia, stroke, brain tumor, psychological disorder..)
• unable to communicate
• general anesthesia history within 6 months
• disagree to participate in study

This study collects subjects from a tertiary university hospital.