Early mortality of surgical treatments of necrotizing enterocolitis: experience of a tertiary neonatal intensive care unit (NICU) in Southwest China: a retrospective cohort study.

Background: The exact mortality and risk factors of necrotizing enterocolitis (NEC) remain uncertain, with inconsistent findings reported in previous studies. This study aims to comprehensively evaluate the early mortality among newborns undergoing surgical treatment for NEC within the context of a single-center investigation, aiming to early detection, timely treatment and reduction of mortality. Methods: We conducted a retrospective cohort analysis in infants, diagnosed with surgical NEC from January 1, 2017 to July 31, 2023 in the Neonatal Intensive Care Unit (NICU) at the Children's Hospital of Chongqing Medical University. According to the physical condition of the infants upon discharge from the hospital, infants were divided into survival group and deceased group (died or underwent treatment termination). A comprehensive dataset was collected from the electronic medical record system, encompassing maternal demographic and clinical characteristics, neonatal demographic features, specific NEC characteristics in the neonates, and detailed information regarding the characteristics of deceased children. Subsequently, basic data were statistically compared between the deceased group and the survival group, and univariate and multivariate logistic regression were used for analysis of the potential causes contributing to mortality. Results: Among the 681 infants diagnosed with NEC, 181 (26.6%) underwent surgical intervention. Of these surgically treated infants, 143 (79.0%) were successfully discharged home, while 38 (21%) either died or underwent treatment termination. Survivors exhibited significantly more favorable neonatal parameters compared to the deceased group. Specifically, survivors were born at a higher gestational age (34.2±3.6 weeks) and had a greater birth weight (2,091.3±811.6 g), in contrast to the deceased group with lower gestational age (32.1±3.7 weeks; P=0.001) and birth weight (1,695.3±727.0 g; P=0.007). Infants who died were more likely to present with fever (P=0.003), bloody stools (P=0.01), absent or diminished bowel sounds (P=0.004), and dyspnea (P=0.004), and significant differences were observed between the two groups in the prevalence of congenital heart disease (CHD) (P=0.01), shock (P<0.001), and the need for ventilator-assisted ventilation (P<0.001) before NEC surgery. Regarding maternal characteristics, no significant differences were found between the two groups. According to multivariable logistic regression analysis, bloody stools [odds ratio (OR) =3.25, 95% confidence interval (CI): 1.25-8.41, P=0.01], fever (OR =0.26, 95% CI: 0.08-0.89, P=0.03), shock before NEC (OR =0.27, 95% CI: 0.08-0.91, P=0.03), procalcitonin (PCT) before surgery (OR =1.02, 95% CI: 1.00-1.04, P=0.003) were all associated with mortality after NEC surgery. Among the 38 deceased infants, 30 (79%) passed away within 1 week post-surgery. Of these, 19 babies discontinued treatment due to severe intestinal lesions, 3 babies required a second operation for various reasons, and 8 babies demonstrated poor treatment outcomes after surgery. Additionally, 7 (18.4%) babies died beyond 1 week post-surgery, and only 1 (2.6%) baby ultimately survived. Conclusions: There is a high mortality of NEC cases after operation. Fever, bloody stool, shock before NEC and PCT before surgery might be four factors significantly associated with increased mortality risk. Understanding the pathogenic characteristics of patients undergoing NEC surgery enables proactive management and creates opportunities for timely interventions that may improve outcomes.