Hydroxyzine Dihydrochloride Premedication Is a Necessity for Pediatric Patients Undergoing Strabismus Surgery: An Observational Prospective Clinical Trial.

Objective: In this single-blind, observational prospective clinical trial, we aimed to determine and compare the effects of premedication with hydroxyzine plus midazolam and midazolam alone on the incidence of oculocardiac reflex (OCR).

Methods: Forty-five patients were divided into three groups. Group M received 0.5 mg/kg midazolam alone, Group H received 0.5 mg/kg hydroxyzine plus 0.5 mg/kg midazolam, and Group HM received 1 mg/kg hydroxyzine plus 0.5 mg/kg midazolam. The Ramsay Sedation Scale (RSS), the heart rates (HR1: after induction of anesthesia; HR2: before retraction of orbital muscle; and HR3: right after retraction of orbital muscle), the muscles with OCR, and the incidence of OCR (20% decrease of the HR right after the traction) were recorded and compared between the three groups.

Results: The mean HR1, HR2, and HR3 values were significantly increased (=0.002, < 0.001, < 0.001) and the incidence of OCR (=0.004) was significantly decreased in Group H and in Group HM (for all, < 0.01) compared to Group M. The most common orbital muscle in which OCR occurred was the rectus medialis.

Conclusion: Premedication with a combination of 0.5 or 1 mg hydroxyzine with 0.5 mg midazolam significantly reduced the incidence of OCR compared to premedication with midazolam alone. This study was registered on https://clinicaltrials.gov/ with number NCT03806270.