Original Article

Indexed oxygen delivery during pediatric cardiopulmonary bypass is a modifiable risk factor for postoperative acute kidney injury

¹ Department of Cardiovascular Perfusion, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
² Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
³ Children’s Hospital of Philadelphia, Cardiac Center, Division of Cardiothoracic Surgery, Philadelphia, PA 19104, USA
⁴ Information Services Department, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
⁵ Stanford University School of Medicine, Lucile Packard Children’s Hospital, Department of Pediatrics, Division of Pediatric Cardiology, Palo Alto, CA 94304, USA

^* Corresponding author: dreherm@chop.edu

Received: 20 April 2023
Accepted: 7 July 2023

Abstract

Background: Acute kidney injury after pediatric cardiac surgery is a common complication with few established modifiable risk factors. We sought to characterize whether indexed oxygen delivery during cardiopulmonary bypass was associated with postoperative acute kidney injury in a large pediatric cohort. Methods: This was a retrospective analysis of patients under 1 year old undergoing cardiac surgery with cardiopulmonary bypass between January 1, 2013, and January 1, 2020. Receiver operating characteristic curves across values ranging from 260 to 400 mL/min/m² were used to identify the indexed oxygen delivery most significantly associated with acute kidney injury risk. Results: We included 980 patients with acute kidney injury occurring in 212 (21.2%). After adjusting for covariates associated with acute kidney injury, an indexed oxygen delivery threshold of 340 mL/min/m² predicted acute kidney injury in STAT 4 and 5 neonates (area under the curve = 0.66, 95% CI = 0.60 – 0.72, sensitivity = 56.1%, specificity = 69.4%). An indexed oxygen delivery threshold of 400 mL/min/m² predicted acute kidney injury in STAT 1-3 infants (area under the curve = 0.65, 95% CI = 0.58 – 0.72, sensitivity = 52.6%, specificity = 74.6%). Conclusion: Indexed oxygen delivery during cardiopulmonary bypass is a modifiable variable independently associated with postoperative acute kidney injury in specific pediatric populations. Strategies aimed at maintaining oxygen delivery greater than 340 mL/min/m² in complex neonates and greater than 400 mL/min/m² in infants may reduce the occurrence of postoperative acute kidney injury in the pediatric population.