摘要Background Thered cell distribution width(RDW)is a parameter that reflects the heterogeneity of red blood cell volume and size,and it is commonly used in the diagnosis of anemia in patients.RDW may serve as a predictor of the postoperative prognosis of surgical patients in the intensive care unit.This study evaluated the predictive capability of RDW for outcomes in infants after cardiopulmonary bypass surgery.Methods A retrospective cohort study was conducted at Guangdong Provincial People's Hospital enrolling infants(≤1 year)who underwent cardiac surgery between January 2019 and April 2019.The infants were divided into two groups based on their preoperative RDW levels(＜14.5％and ≥14.5％).The primary outcome measured was the prolonged hospital stay post-operation.The association between RDW levels and prolonged hospital length of stay was evaluated using multivariate Logis-tic regression,presenting the adjusted odds ratio with a 95％confidence interval(CI).Additionally,interaction and subgroup analyses were performed to assess the consistency of these correlations.Results A total of 186 infants were included in the study.After adjusting for potential confounders,multivariate logistic regression models demonstrated a significant association between RDW and prolonged length of stay(LOS)in hospital when treated as a continuous variable(change per 1SD,OR:1.50,95％CI:1.06-2.11,P=0.021).Categorizing RDW as a variable revealed that higher RDW levels(≥14.5％)were significantly associated with an increased risk of prolonged LOS compared to lower levels(＜14.5％)(OR:9.72,95％CI:2.87-32.91,P＜0.001).Receiver operating curves(ROC)analysis showed that RDW levels exhibited relatively higher diagnostic value for predicting prolonged LOS(AUC=0.697,95％CI:0.617-0.776,P＜0.05).Stratified analyses further showed that depending on the variable testing,an association between higher RDW levels and prolonged hospital length of stay in different subgroups was observed.Conclusions Elevated RDW levels in infants undergoing cardiac surgery involving cardiopulmonary bypass may signify prolonged recovery periods.