Abstract: Objective To investigate the value of methemoglobin(MetHb) in early identification of neonatal infection in premature infants with gastrointestinal symptoms at onset of the disease.Methods Premature infants who were hospitalized in the NICU from September 2021 to August 2022,with gastrointestinal symptoms at onset were included in this study.All the participants were admitted to our hospital within 24 hours of onset.The related indicators such as C-reactive protein(CRP),serum amyloid A(SAA) and MetHb were measured before antibiotic therapy.MaxMetHb(%) was defined as the ratio of the highest MetHb to hemoglobin monitored during active disease.The CRP,SAA and MaxMetHb between infected and non-infected neonates were compared.The receiver operating characteristic(ROC) curve was used to evaluate the efficacy of those indicators in early identification of neonatal infection.Results Among the 53 premature infants with gastrointestinal symptoms at onset,29 subjects were infected and the remaining 24 were non-infected.However,there was no significant difference in the gastrointestinal symptoms between those two groups,suggesting that gastrointestinal symptoms were not specific in premature infants with infection.Compared to those non-infected subjects,CRP,SAA,neutrophils%(Neu%) and MaxMetHb were significantly increased in those infected neonates,while the eosinophils% was significantly lower(all P<0.05).In addition,the fasting time,course of antibiotic use and special antibiotic use rate of infected neonates were significantly higher than those of the non-infected(all P<0.001).MaxMetHb could be used for the early identification of neonatal infection,with its optimal cut-off point being 1.6%,with sensitivity of 86.2%,specificity of 62.5%,and area under the curve(AUC) of 0.766,and 75.5%(40/53) subjects could be successfully identified.When combining CRP and Neu% with MaxMetHb,the sensitivity,specificity and AUC could be further improved up to 93.1%,87.5%,and 0.961,respectively,and 90.6% patients(48/53) could be successfully identified.Conclusion MaxMetHb,combined with CRP and Neu%,is considered to be a suitable indicator for early identification of neonatal infection for premature infants with gastrointestinal symptoms at onset.

Key words:

Neonatal infection, Gastrointestinal symptoms, Methemoglobin, C-reactive protein, Premature infant