Cerebral Doppler Resistance Index (RI) is associated with regional cerebral oxygenation.

Abstract

To investigate, if there is an association between the Resistance Index (RI) in anterior cerebral artery (ACA), a parameter of cerebral perfusion, and regional cerebral oxygenation (cTOI) in preterm infants within the first 24 hours after birth. Post-hoc analysis of data of a prospective randomised controlled trial "Avoiding Hypotension in Preterm Infants" (ClinicalTrials.gov identifier: NCT01910467). cTOI was measured using near-infrared spectroscopy (NIRS) (NIRO-200NX, Hamamatsu, Japan). The NIRS sensor was placed on the left forehead within six hours after birth and cTOI was measured continuously for 24 hours. Peripheral arterial oxygen saturation (SpO2) and heart rate (HR) were continuously measured by pulse oximetry. During the first 24 hours after birth a cranial ultrasound was routinely performed by a neonatologist in each preterm infant including measurement of RI in the ACA. For analyses RI was correlated to cTOI, SpO2, and HR. Between October 2013 and December 2016, 108 preterm infants with mean (SD) gestational age and birth weight of 32.7 (1.9) weeks and 1845 (485) g were included into the trial and cranial ultrasound data of 80 preterm infants were available and analysed in the present study. There was a statistically significant negative correlation between RI and cTOI (p=0.0001 / ρ=-0.438). RI did neither correlate with SpO2 nor with HR. In preterm infants during the first 24 hours after birth: increasing RI values were associated with lower cTOI values in preterm infants.