Carbon dioxide production index (VCO 2 i) predicts hyperlactatemia during cardiopulmonary bypass in pediatric carDiac surGery (pGDP- VCO 2 i): Study protocol for a nested case-control trial

Abstract

Background

Hyperlactatemia (HL) during cardiopulmonary bypass (CPB) is relatively frequent in infants and associates with increased morbidity and mortality. Studies on adults have shown that carbon dioxide production index (VCO₂i) during CPB is linked to the occurrence of HL, with ‘critical thresholds’ for VCO₂i reported to be 60 mL/min/m². However, considering infants have a higher metabolic rate and lower tolerance to hypoxia, the critical threshold of VCO₂i in infants cannot be replied to the existing adults’ standards. The objective of this study is to investigate the association of VCO₂i during CPB and HL, and explore the critical VCO₂i threshold during CPB in infants.

Methods

VCO₂i predicts hyperlactatemia during cardiopulmonary bypass in pediatric cardiac surgery (pGDP-VCO₂i) is a nested case-control study. A cohort of consecutive pediatric patients of less than 3 years of age, undergoing congenital cardiac surgeries between May 2021 and December 2023 in West China Hospital will be enrolled. The VCO₂i levels of each patient will be recorded every 5 min during CPB. The primary outcome is the rate of HL. The infants will be divided into two groups based on the presence or not of HL. Pre- and intraoperative factors will be tested for independent association with HL. Then, we will make an analysis, and the critical value of VCO₂i will be obtained. The postoperative outcome of patients with or without HL will be compared.

Discussion

This will be the first trial to investigate the association of VCO₂i during CPB and HL, and explore the critical VCO₂i threshold during CPB in pediatrics. The results of this study are expected to lay a foundation for clinical application of goal-directed perfusion (GDP) management strategy, and optimize the perfusion strategy and improve the prognosis of pediatric patients undergoing cardiac surgery.

Trial registration

Chictr.org.cn, ChiCTR2100044296 on 16 March 2021.

Keywords

carbon dioxide production index hyperlactatemia pediatrics cardiopulmonary bypass cardiac surgery

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