Background: Neonatal antibiotic exposure can have long term unintended consequences. Kaiser Permanente Neonatal Early-Onset Sepsis (EOS) Calculator (KSS), was developed to accurately quantify the risk of EOS in newborns. Near-infrared spectroscopy (NIRS), a skin sensor-based monitoring technique, has been shown to provide useful oxygenation data demonstrating altered metabolism (e.g., increased oxygen extraction), for conditions such as infection, anemia and metabolic acidosis. Our hypothesis is that cerebral tissue oxygen extraction will directly correlate with EOS risk.
Objective: Our objective is to determine the degree of correlation between cerebral oxygen extraction and the KSS.
Design/Methods: We designed an observational cohort study. 30 infants would be needed to demonstrate a correlation with 80% power and two-tailed alpha of 0.05. Data was collected on 30 term neonates admitted to NICU with a diagnosis of chorioamnionitis. Cerebral and peripheral NIRS probes were placed on these neonates for 30 minutes between 6-24 hours of life. Primary outcome was to determine the degree of correlation between cerebral oxygen extraction and the KSS.
Results: Average gestational of neonates was 38.7 weeks with 63% being born to mothers who were GBS positive. We found that elevated KSS correlated with increased cerebral tissue oxygen extraction, p-value 0.03. There is a significant relationship between elevated KSS and increased cumulative (Cerebral + Peripheral) NIRS monitoring suggesting that this may be related to a general inflammatory process in these patients, p-value 0.05. There appears to be a trend between early (12 hr) CRP and cerebral tissue oxygen extraction.
Conclusion: A correlation between increased cerebral tissue oxygen extraction and a general inflammatory process taking place in full term neonates with maternal chorioamnionitis would represent a timely advance with broad implications given the common nature of presumed EOS.
