Association of Intraoperative PaCO2-EtCO2 Gradient With Need for Pulmonary Blood Flow Reconditioning After Bilateral Pulmonary Artery Banding in Hypoplastic Left Heart Syndrome.

OBJECTIVES: To investigate the association between the intraoperative arterial to end-tidal carbon dioxide (PaCO2-EtCO2) gradient and the need for urgent pulmonary blood flow reconditioning after bilateral pulmonary artery banding (bPAB) in neonates with hypoplastic left heart syndrome (HLHS). DESIGN: Retrospective observational study. SETTING: Single-center, tertiary referral center for congenital heart disease. PARTICIPANTS: Thirty-nine neonates with HLHS underwent bPAB between 2018 and 2023. INTERVENTIONS: No intervention was performed. Patients were categorized into 3 groups based on postoperative management: a control group without reconditioning (n = 30), an excessive banding group requiring band loosening (n = 5), and a loose banding group requiring band tightening (n = 4). MEASUREMENTS AND MAIN RESULTS: The PaCO2-EtCO2 gradient and EtCO2/PaCO2 ratio were measured intraoperatively and compared among groups. The gradient increased significantly after bPAB in the excessive banding group (6.6 ± 2.5 to 13.9 ± 3.3 mmHg, p < 0.05), with a similar but nonsignificant increase in the loose banding group. After sternal closure, both reconditioning groups showed higher gradients compared with controls. Exploratory receiver operating characteristic analysis demonstrated an area under the curve of 0.906 (cutoff, 8.8 mmHg) for the PaCO2-EtCO2 gradient and 0.915 (cutoff, 0.792) for the EtCO2/PaCO2 ratio in relation to subsequent urgent pulmonary blood flow reconditioning. CONCLUSIONS: The intraoperative PaCO2-EtCO2 gradient was associated with the subsequent need for urgent pulmonary blood flow reconditioning after bPAB in neonates with HLHS.