Goal-Directed Perfusion to Reduce Acute Kidney Injury after Paediatric Cardiac Surgery (GDP-Akip): Study Protocol for A Prospective Randomised Controlled Trial

Introduction

Cardiac surgery-associated acute kidney injury (CS-AKI) occurs in up to 40%~60% of paediatric patients and increases postoperative morbidity and mortality. A goal-directed perfusion (GDP) strategy aimed at maintaining indexed oxygen delivery (DO₂i) above the critical threshold (reported to be 260~300 mL/min/m² in adults) during cardiopulmonary bypass (CPB), is effective in reducing the incidence of CS-AKI. However, no clear standards of paediatric critical DO₂i exist. Our prior prospective cohort study exploring the critical DO₂i threshold during paediatric CPB has found the nadir DO₂i <353 mL/min/m² was an independent risk predictor of CS-AKI. Based on this background, this trial is designed to further determine whether the implementation of the GDP initiative aimed at maintaining DO₂i ≥360 mL/min/m² would reduce the rate of CS-AKI in paediatrics and improve clinical outcome.

Methods and analysis

This is a prospective, single-centre, randomised controlled trial. In total, 166 paediatric patients undergoing cardiac surgery will be randomly allocated to the GDP group or control group. Patients in the GDP arm will be treated with a GDP strategy during CPB aimed to maintain DO₂i at ≥360 mL/min/m² (to ensure safely above the risk DO₂i threshold we found). The perfusion strategy for patients in the control arm will be factored on body surface area and temperature. The primary outcome is the rate of postoperative CS-AKI (it is defined according to paediatric Risk, Injury, Failure, Loss of renal function and End-stage renal disease criteria). The secondary end points include: (1) the other oxygen metabolism parameters during CPB; (2) major complication and all-cause mortality (in-hospital or within 30 days postoperatively); (3) short-term clinical outcomes (ie, time to extubation, mechanical ventilation time, hospital stay).