Cerebral Oxygenation in Very Preterm Newborn Neonates Measured During the First Three Days of Life: Correlation with the Index of Arterial Blood Gas

Background: Very premature infants with cerebral hemorrhage often have decreased cerebral oxygenation (CrSO2) monitored by near-infrared spectroscopy (NIRS) in the first few days after birth. This study aimed to analyze the correlation between NIRS data of very premature infants monitored in the first 72 hours of life and clinical data, as well as their impact on cerebral oxygenation and cerebral fractional tissue oxygen extraction  ( cFTOE ) Methods:  From July 2017 to June 2019, neonates of gestation age between 28 to 31 weeks were recruited from the Seventh medical center of Chinese PLA general hospital, Beijing, China. While arterial blood gas(ABG) analysis was monitored from neonates' admission to 72 hours after birth, data such as CrSO2, transcutaneous arterial oxygen saturation (SpO2), oxygen saturation (SaO2), heart rate(HR), and mean arterial blood pressure (MABP) were collected simultaneously. cFTOE was calculated as follows: cFTOE = [(SpO2 - CrSO2)/SpO2]. Head ultrasounds were generally obtained at 6–48 hours, 1week, and 1month of age. The linear mixed model was used to analyze the blood gas value, CrSO2, cFTOE, and other system signals.    Findings: 145 newborns were included in this study. CrSO2 was significantly related to partial pressure of oxygen (PaO2), glucose (Glu) within 72 hours after birth (F=6·53 and 5·82, respectively, P<0·05). Compared with intraventricular hemorrhage (IVH) infants, CrSO2  was decreased and cFTOE was increased over time at three days old neonates without IVH. In contrast, infants with IVH had gradually increased CrSO2 and decreased cFTOE within 72 hours after birth, and compared to infants without IVH they had lower mean CrSO2 (P<0·05) and higher mean cFTOE (P<0·05).     Interpretation: Newborns with lower CrSO2 and higher cFTOE, who were prone to occur hypoperfusion or hypoglycemia. Neonates with IVH had lower CrSO2 and higher cFTOE within 72 hours after birth, and the change trends of them were opposed to the infants without IVH. Funding: National Natural  Science Foundation of China supported this study(81471492). Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: This study was a prospective cohort study and the protocol was approved by the ethics committee of Seventh medical center of Chinese PLA general hospital.