Pulmonary Complications in Children After Cardiac Surgery and Its Relationship to Neutrophil-Lymphocyte Ratio: A Retrospective Study

Background: This study aimed to investigate the incidence and predisposing factors of pulmonary complications in pediatric patients undergoing cardiac surgery and its relationship with the neutrophil-to-lymphocyte ratio (NLR) in the open-heart surgery intensive care unit (ICU-OH) of the Children’s Medical Center Hospital (CMC) in Tehran, Iran. Methods: In this retrospective cohort study, 457 children who underwent open-heart surgery and were transferred to ICU-OH postoperatively were included. Data on age, gender, weight, hospital stay, and risk adjustment for congenital heart surgery (RACHS-1) scores were collected. The incidence of pulmonary complications and its association with NLR were analyzed. Results: The RACHS-1 risk category distribution: Category 1 (15%, n = 65), category 2 (54%, n = 232), category 3 (23%, n = 99), and category 4 (8%, n = 34). Pulmonary complications occurred in 68 children (15.8%), with the highest incidence in infants under one month (34%, n = 18; P < 0.001). Postoperative NLR levels were significantly higher than preoperative levels and were elevated in patients without pulmonary complications, suggesting NLR as a potential predictive factor. Conclusions: The NLR may serve as a useful biomarker for predicting pulmonary complications in pediatric cardiac surgery patients. Further studies are needed to validate these findings and explore underlying mechanisms.