Background: The occurrence of necrotizing enterocolitis (NEC) is a common and severe disease of the digestive system in neonates. This study aims to assess the value of the intestinal tissue oxygen saturation (r_intSO₂) combined with the levels of procalcitonin (PCT) and mean platelet volume (MPV) in predicting the severity of NEC in preterm infants.
Methods: This experiment was a retrospective cohort study conducted in the Department of Pediatrics, Hongqi Hospital Affiliated to Mudanjiang Medical University between January 2017 and July 2022. Premature neonates with NEC were enrolled and divided into mild-moderate NEC group and severe NEC group according to Bell’s stage. The general information data, r_intSO₂ and blood parameters such as the white blood cell (WBC) count, platelet count (PLT), PCT, MPV, red blood cell distribution width (RDW), hemoglobin (Hb), C-reactive protein (CRP) were compared between the two groups.
Results: A total of 122 patients were enrolled, including 79 mild-moderate NEC and 43 severe NEC. The r_intSO₂ was lower in severe group than in mild-moderate group (P = 0.042), the PCT and MPV were both higher in severe group than in mild-moderate group (P = 0.048, P = 0.049). The results of logistic regression suggested that the r_intSO₂ (OR = 1.491, P = 0.003), PCT (OR = 3.071, P = 0.001) and MPV (OR = 4.027, P = 0.015) were independent predictive factors for severity of NEC. The area under the curve (AUC) of the r_intSO₂ combined with PCT and MPV showed good diagnostic ability in the severity of NEC.
Conclusion: The r_intSO₂ combined with PCT and MPV may be considered as the early biomarkers in the severity of NEC and could help us to diagnose the case early with early treatment with better prognosis.

Keywords: premature infants, necrotizing enterocolitis, intestinal tissue oxygen saturation, procalcitonin, mean platelet volume