Hydromorphone reduces emergence agitation in pediatric children undergoing strabismus surgery: a randomized controlled trial

Postoperative agitation (EA) has a high incidence in pediatric strabismus surgery and risk factors including inhaled anesthetics, surgery itself and pain. Hydromorphone, a semi-synthetic opioid, has been widely used in pediatric patients. However, the effect of hydromorphone on postoperative emergence agitation (EA) in pediatric strabismus surgery is not fully clear. Therefore, the investigation of this study is to evaluate the impact of Hydromorphone on the incidence of EA in pediatric strabismus surgery with sevoflurane anesthesia. Eighty-two patients scheduled for strabismus surgery participated in this study were randomly assigned to the hydromorphone group ( n = 41) and the fentanyl group ( n = 41). The sedation score of each patient was evaluated at 15 min, 30 min, and 2 h after extubation. The primary outcome was the incidence of EA according to postoperative sedation score in pediatric patients. And the secondary outcomes were postoperative pain score, family satisfaction, and the incidence of postoperative nausea, dizziness, and vomiting. The present study demonstrated that hydromorphone exhibit superior sedative effects compared to fentanyl at 15 min, 30 min, and 2 h after extubation ( P < 0.01). And hydromorphone significantly reduced the incidence of EA in the post-anesthesia care unit (PACU) ( P < 0.01). In addition, the hydromorphone group showed better analgesic efficacy at 15 and 30 min post-extubation ( P < 0.01), but no statistically significant difference in analgesic effect was observed between the two groups at 2 h after extubation ( P = 0.17). According to questionnaires, parents in hydromorphone group had higher satisfaction with medical care ( P < 0.01), although hydromorphone was associated with dizziness and vomiting. In conclusion, hydromorphone is plausible to reduce the incidence of postoperative agitation and enhances parental satisfaction in pediatric strabismus surgery. The trial was registered prospectively with the Chinese Clinical Trial Registry (ChiCTR). Trial ID: ChiCTR2500113063. Registered on November 24, 2025.