Association of postoperative fluid overload with adverse outcomes after congenital heart surgery: a systematic review and dose-response meta-analysis

Background Pediatric cardiac surgery is commonly associated with acute kidney injury (AKI) and significant fluid retention, which complicate postoperative management and lead to increased rates of morbidity. This meta-analysis aimed to accumulate current literature evidence and evaluate the correlation of fluid overload degree with adverse outcome in patients undergoing congenital heart surgery. Methods Medline, Scopus, CENTRAL, Clinicaltrials.gov , and Google Scholar were systematically searched from inception. All studies reporting the effects of fluid overload on postoperative clinical outcomes were selected. A dose-response meta-analytic method using restricted cubic splines was implemented in R-3.6.1. Results Twelve studies were included, with a total of 3111 pediatric patients. Qualitative synthesis indicated that fluid overload was linked to significantly higher risk of mortality, AKI, prolonged hospital, and intensive care unit (ICU) stay, as well as with increased duration of mechanical ventilation, inotrope need, and infection rate. Meta-analysis demonstrated a linear correlation between fluid overload and the risk of mortality ( χ 2 = 6.22, p value = 0.01) and AKI ( χ 2 = 35.84, p value