Post-operative delirium had multiple risk factors, such as pre-operative anxiety status, post-operative pain, and anesthetic method. We currently decrease pre-operative anxiety by parental accompanying until the children put to sleep. However, references indicate that parental anxiety can increase the post-operative delirium. Heart rate variability was used to measure the anxiety status of parents. We think sympathetic tone elevation measured by heart rate variability may not induce by anxiety alone, thus we want to explore this question by using Stat-Trait Anxiety Inventory questionnaire.

Outcome measures

1. Post-operative emergence delirium, observed with an average duration up to 24 hours
2. Sedatives used in recovery unit

Inclusion criteria:

• American Society Anesthesia (ASA) risks classification I or II

Exclusion criteria:

• Parents who have cognitive problems
• Parents who have difficulty finishing questionnaire

Age younger than 16-year-old who required surgery