Risk factors for acute gastrointestinal injury after cardiac surgery in underweight children with congenital heart disease: a single-center retrospective study.

Background: Acute gastrointestinal injury (AGI) is an underrecognized complication after cardiac surgery in children with congenital heart disease (CHD), particularly in those with low body weight. This study aimed to identify independent risk factors for postoperative AGI in underweight children (≤10 kg) undergoing CHD surgery. Methods: This single‑center retrospective study enrolled 386 underweight children who underwent CHD surgery between October 2021 and July 2022. Patients were divided into AGI and non‑AGI groups based on postoperative occurrence. Multivariate binary logistic regression was performed to identify independent risk factors. Results: Of the 386 enrolled patients, 91 cases (23.6%) developed clinically significant postoperative AGI. Multivariate analysis demonstrated that the minimum intraoperative rectal temperature (P=0.002) was an independent risk factor. In addition, patients with AGI had significantly longer duration of mechanical ventilation, longer intensive care unit (ICU) stay and longer overall hospital stay (all P<0.001). They also presented with higher transfusion requirements and a higher rate of extubation failure (P<0.001). Conclusions: The minimum intraoperative rectal temperature is an independent risk factor for AGI in underweight children with CHD. Early identification of this factor facilitates risk stratification and guides targeted perioperative gastrointestinal protection strategies, thereby improving therapeutic outcomes in this high‑risk population.