Effect of Low-dose Ketamine Infusion on Opioid Consumption in Children Undergoing Open Cardiac Surgery: A Randomized Controlled Double-Blind Study

Abstract

Objective: This study was designed to evaluate the effect of low-dose ketamine infusion on the perioperative consumption of opioids in pediatric open cardiac surgery.

Design: A randomized, controlled, double-blinded single-center study was conducted.

Setting: The study took place in a tertiary care children's hospital.

Participants: Patients of both sexes aged 2-12 years who underwent cardiac surgery were included.

Interventions: Patients in the ketamine group received a bolus of 0.3 mg/kg of ketamine before skin incision followed by continuous intraoperative infusion of 0.25 mg/kg/h and postoperative infusion of 0.1 mg/kg/h for 24 h. Patients in the control groups received volumes of normal saline either bolus or continuous infusion like that of the ketamine group.

Measurements and main results: The primary outcome was the total dose of fentanyl consumed over the first 24 hours postoperatively. Secondary outcomes were intraoperative fentanyl consumption, time to extubation, modified objective pain score, and incidence of vomiting, pruritus, diplopia, or hallucinations. A total of 80 patients were recruited but the final analysis was done on 35 patients in the ketamine group and 34 in the control group. Fentanyl consumption during surgery and in the first 24 hours postoperatively was significantly lower in the ketamine than the control group. Patients in both the ketamine and control groups had similar times to extubation. Modified objective pain scores were significantly lower in the ketamine group than the control group. None of the patients in either group had diplopia or hallucinations.

Conclusions: Low-dose ketamine infusion in children undergoing open cardiac surgery reduced intra- and postoperative opioid consumption and postoperative pain scores. Moreover, ketamine did not cause diplopia or hallucinations.

Keywords: analgesia; cardiac surgery; children; ketamine; opioid.