Oxygen Delivery in Pediatric Cardiac Surgery and its Association with Acute Kidney Injury using Machine Learning
Abstract
Objective
Acute kidney injury (AKI) following pediatric cardiac surgery with cardiopulmonary bypass is a frequently reported complication. This study aims to determine the critical oxygen delivery (DO2i) threshold associated with postoperative AKI in pediatric patients during cardiopulmonary bypass, and whether it remains clinically important in the context of other known independent risk factors.
Methods
A single institution, retrospective study, encompassing 396 pediatric patients, who underwent heart surgery between April 2019 and April 2021 was undertaken. Time spent below DO2i thresholds was compared to determine the critical value for all stages of AKI occurring within 48 hours of surgery. DO2i threshold was then included in a classification analysis with known risk factors including nephrotoxic drug usage, surgical complexity, intraoperative data, comorbidities and ventricular function data, and vasoactive inotrope requirement to determine DO2i predictive importance.
Results
Logistic regression models demonstrated cumulative time spent below a DO2i value of 350ml/min/m2 was associated with AKI. Random forest models, incorporating established risk factors, demonstrated DO2i threshold still displayed predictive importance. Patients who developed post-CPB AKI were significantly younger, had significantly longer CPB and ischemic times, and required significantly higher inotrope support post-surgery.
Conclusions
The present data supports previous findings that DO2i during CPB is an independent risk factor for AKI development in pediatric patients. Furthermore, the data support previous suggestions of a higher threshold value in children compared to adults and indicate that adjustments in DO2i management may reduce incidence of postoperative AKI in the pediatric cardiac surgery population.