The purpose of this study is to compare the effect of remifentanil on postoperative vomiting in children undergoing strabismus surgery during sevoflurane anesthesia.

Children undergoing strabismus surgery frequently experience postoperative vomiting (POV) that results in dehydration, aspiration pneumonia, bleeding, delayed hospital discharge, as well as decreased parental satisfaction and an unpleasant experience for the pediatric patients. Although administration of perioperative opioids increases POV incidence, remifentanil has less affect the incidence of POV than other opioids such as fentanyl. However, there are few study that evaluate the effects of remifentanil on the incidence of POV. Therefore, the investigators will conducted the study that the effects of remifentanil on the incidence of POV in children undergoing strabismus surgery during sevoflurane anesthesia. One hundred five children from 3 to 6 yr of age, ASA physical status 1 or 2 were assigned randomly selected to one of three groups: high dose remifentanil group (bolus 1.0 mcg/kg; infusion 0.1 mcg/kg/min), low remifentanil group (bolus 0.5 mcg/kg; infusion 0.1 mcg/kg/min), or no remifentanil group (no remifentanil administration). Primary endpoint, the incidence of POV for 24 hours postoperatively, will be compared between three study groups.

Inclusion Criteria:

• children undergoing elective strabismus surgery under sevoflurane anesthesia

Exclusion Criteria:

• children who experienced postoperative retching or vomiting
• children who have taken anti-emetic medications within 24 hours before surgery
• children who experienced motion sickness