Intraoperative hypotension is associated with postoperative acute kidney injury in infants undergoing cardiac surgery

Pediatric cardiac surgery is associated with a 3%-40% incidence of acute kidney injury (AKI). We aimed to study the contribution of intraoperative hypotension to the development of AKI in this population.

In this prospective single-center observational study, patients aged 1 month-18 years undergoing cardiac surgery with cardiopulmonary bypass (CPB) were included. The incidence of AKI, defined by the Kidney Disease Improving Global Outcomes criteria, was calculated. Intraoperative hypotension was defined as a value below the age and height-adjusted 5^th centile for the patient. The relationship of AKI to patient demographics, Risk adjustment in congenital heart surgery (RACHS)-1 score, CPB duration, cumulative hypotension, duration of hypotension, time-weighted cumulative hypotension, and intensive care unit (ICU) outcomes were assessed. Subgroup analysis was performed for infants.

In the 150 patients included in the study, the incidence of AKI was 34% (n = 51), of which 63% (n = 32) had stage 1 AKI and 72.5% (n = 37) had transient AKI. The age, height, and weight were lesser in patients who developed AKI. The RACHS-1 score, peak intraoperative lactate, first ICU lactate, intraoperative blood transfusion volume, postoperative mechanical ventilation duration, ICU stay, and mortality were higher in patients who developed AKI. Only in the infant subgroup were the cumulative hypotension and duration of hypotension higher in patients who developed AKI.

AKI is common postpediatric cardiac surgery, with the majority being of low severity and transient nature. Intraoperative hypotension is associated with AKI in infants undergoing cardiac surgery.