Effect of Sub-Anesthetic Dose Esketamine on Oculocardiac Reflex in Children Undergoing Day-Case Strabismus Surgery: A Randomized Controlled Trial
Purpose The oculocardiac reflex (OCR) is a frequent and potentially hazardous complication during pediatric strabismus surgery. Achieving hemodynamic stability while ensuring rapid recovery is critical in day-case anesthesia. This study aimed to evaluate the efficacy of a sub-anesthetic dose of esketamine in reducing the incidence of OCR in children undergoing day-case strabismus surgery under total intravenous anesthesia (TIVA). Patients and Methods This prospective, randomized, double-blind, placebo-controlled trial enrolled 204 children (aged 2–12 years, ASA I–II) scheduled for elective strabismus surgery. Patients were randomized (1:1) to receive either intravenous esketamine (0.2 mg/kg) or an equal volume of normal saline following laryngeal mask airway insertion. All patients received standardized TIVA with propofol and remifentanil. The primary outcome was the overall incidence of OCR (defined as a heart rate decrease >20% from baseline or arrhythmia upon muscle traction). Secondary outcomes included OCR incidence during three distinct surgical stages: Stage I (conjunctival incision), Stage II (active muscle mobilization and dissection), and Stage III (static sustained muscle traction), as well as severe OCR (<50 bpm), and postoperative recovery quality. Results The overall incidence of OCR was significantly lower in the esketamine group compared to the control group (38.2% vs 70.6%; P < 0.05). Heart rates dynamics varied by stage, with the highest OCR incidence occurring during Stage II (37.3% vs 70.6%; P <0.05) compared to Stage III (1.0% vs 6.9%; P =0.071) in both groups. Heart rates in the esketamine group were significantly higher during conjunctival incision (Stage I) and muscle dissection (Stage II) (P < 0.001). For both groups, Stage II was associated with the highest incidence of OCR. Although the incidence of severe OCR was lower in the esketamine group (2.9% vs 8.8%), the difference was not statistically significant. There were no significant differences between groups regarding postoperative nausea and vomiting, emergence agitation, or time to discharge. Conclusion A single sub-anesthetic dose of esketamine (0.2 mg/kg) effectively reduces the incidence of OCR and enhances hemodynamic stability in children undergoing day-case strabismus surgery. This regimen provides a safe prophylactic strategy without compromising recovery quality or increasing postoperative adverse events.