Cerebral tissue oxygenation and regional oxygen saturation can be used to study cerebral autoregulation in prematurely born infants

The coupling of cerebral intravascular oxygenation (dHbD) with mean arterial blood pressure (MABP) was taken as a reflection of autoregulation assuming constant arterial oxygen content. However, this method is sensitive to movement artifacts. We examined whether the cerebral tissue oxygenation index (cTOI) and regional oxygen saturation (rScO2) may replace dHbD and changes in total Hb (dHbT), respectively. Correlation (COR) and coherence (COH) were used to measure the agreement of MABP with rScO2/dHbT and cTOI/dHbD. dHbD/cTOI and dHbT/rScO2 recordings of, respectively, 34 and 20 preterm infants in need for intensive care were studied during the first days of life. dHbD and cTOI were obtained with the NIRO300 and rScO2 and dHbT with the INVOS4100. Invasive MABP was measured continuously. COR and COH scores of MABP versus dHbD/dHbT were compared with the corresponding ones by replacing dHbD/dHbT by cTOI/rScO2, respectively. Generally, no significant score differences were found for dHbD/cTOI. Differences for dHbT/rScO2 were slightly larger but still within the normal variation of the parameters. Differences become insignificant when restricting calculations to epochs of larger variation in MABP (>10 mm Hg). Hence, we suggest that cTOI and rScO2 can be used to study cerebral autoregulation in newborns.