Open Access

ARTICLE

Risk Factors of Decreased Abdominal Tissue Oxygen Saturation in Infants with Congenital Heart Disease after Cardiac Surgery

Dan Li, Rongyuan Zhang, Yuzi Zhou, Yazhou Jiang, Xu Wang, Xia Li^*
Department of Pediatric Cardiac Intensive Care Unit, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences, Beijing, China
* Corresponding Author: Xia Li. Email:

Structural and Congenital Heart Disease https://doi.org/10.32604/schd.2026.081407

Received 01 March 2026; Accepted 23 July 2026; Published online 10 August 2026

Abstract

Background: Infants undergoing surgery for congenital heart disease (CHD) are at high risk of developing gastrointestinal dysfunction (GID). Although abdominal near-infrared spectroscopy (NIRS) for monitoring tissue oxygen saturation (StO₂) has shown clinical promise, its prognostic value remains to be fully elucidated. This study aimed to identify the risk factors associated with postoperative declines in abdominal StO₂ and to evaluate its correlation with clinical outcomes. Methods: A total of 439 infants undergoing cardiac surgery with cardiopulmonary bypass between January 2024 and January 2025 were retrospectively enrolled. Continuous postoperative NIRS monitoring was performed during the first 72 h of PICU admission, with the minimum abdominal StO₂ across four predefined time points recorded. Clinical outcomes were compared between the low StO₂ group (<70%, n = 124) and the adequate StO₂ group (≥70%, n = 315). Binary logistic regression analysis was conducted to identify independent risk factors for postoperative StO₂ decline, adjusting for covariates including prematurity, body weight, lactate, mean arterial pressure, and oxygenation. Results: Compared with the StO₂ ≥ 70% group, patients in the StO₂ < 70% group were younger (with more neonates and preterm infants) and had lower body weights, lower oxygen saturation during induction and immediately post-surgery, lower mean arterial pressure, lower PaO₂ and SpO₂, and higher postoperative arterial lactate (all p < 0.05). Multivariate logistic regression identified lower body weight (OR = 0.46, 95% CI: 0.34–0.62, p < 0.01) and prematurity (OR = 2.96, 95% CI: 1.10–7.98, p = 0.03) as independent risk factors for postoperative abdominal StO₂ decline. Although the overall incidence of early GID was 18.7% with no intergroup difference, patients with reduced abdominal StO₂ experienced significantly prolonged mechanical ventilation, longer PICU and hospital stays, and higher hospital costs (all p < 0.05). Conclusions: Low birth weight and prematurity predispose infants to postoperative abdominal StO₂ decline after CHD surgery; this decline is associated with prolonged recovery times and higher costs, though not significantly correlated with early GID.

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Keywords

Congenital heart disease; gastrointestinal dysfunction; splanchnic near infrared spectroscopy (NIRS); abdominal tissue oxygen saturation

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