Acid-base and metabolic parameters and cerebral oxygenation during the immediate transition after birth—A two-center observational study

Abstract

Objective The association between blood glucose level and cerebral oxygenation (cerebral regional oxygen saturation [crSO2] and cerebral fractional tissue oxygen extraction [FTOE]) in neonates has already been described. Aim of the present study was to investigate if acid-base and other metabolic parameters have an impact on cerebral oxygenation immediately after birth in preterm and term neonates. Study design Post-hoc analyses of secondary outcome parameters of two prospective observational studies were performed. Preterm and term neonates born by caesarean section were included, in whom i) cerebral near-infrared spectroscopy (NIRS) measurements were performed during the first 15 minutes after birth and ii) a capillary blood gas analysis was performed between 10 and 20 minutes after birth. Vital signs were routinely monitored with pulse oximetry (arterial oxygen saturation [SpO2] and heart rate [HR]). Correlation analyses were performed to investigate potential associations between acid-base and metabolic parameters (lactate [LAC], pH-value [pH], base-excess [BE] and bicarbonate [HCO3]) from capillary blood and NIRS-derived crSO2 and FTOE at 15 minutes after birth. Results One-hundred-fifty-seven neonates, 42 preterm neonates (median gestational age [IQR] 34.0 weeks [3.3], median birth weight 1845g [592]) and 115 term neonates (median gestational age [IQR] 38.9 weeks [1.0], median birth weight 3230g [570]) were included in the study. Median crSO2 [IQR] values at 15 minutes after birth were 82% [16] in preterm neonates and 83% [12] in term neonates. Median FTOE [IQR] values at 15 minutes after birth were 0.13 [0.15] in preterm neonates and 0.14 [0.14] in term neonates. In preterm neonates, higher LAC and lower pH and BE were associated with lower crSO2 and higher FTOE. In term neonates, higher HCO3 was associated with higher FTOE. Conclusion There were significant associations between several acid-base and metabolic parameters and cerebral oxygenation in preterm neonates, while in term neonates only HCO3 correlated positively with FTOE.

Acid base and metabolic parameters of the umbilical cord blood and cerebral oxygenation immediately after birth

“…The correlations in the present study were observed despite the fairly narrow lactate range within the study population with values <2.9 mmol/L. Similar findings with negative correlations between lactate levels obtained from capillary blood and crSO 2 and with positive correlations between lactate levels and cFTOE in preterm neonates 15 min after birth were published by Mattersberger et al ( 20 ) as well as by Janaillac et al ( 21 ) in extremely preterm infants in the first 72 h after birth. The observed correlations could be explained by the fact that lactic acidemia induces pulmonary vasoconstriction and decreases cardiac stroke volume as a result of impaired cardiac contractility ( 22 ).…”

“…BE is used for quantification of changes in metabolic acid-base status and together with umbilical artery pH it is crucial to estimate the risk for newborn cerebral damage (40,41). Mattersberger et al (20) indicated positive correlations between HCO 3 measured 15 min postnatally and cFTOE in term neonates and correlations of lower pH and BE also measured 15 min postnatally with lower crSO 2 and higher cFTOE in preterm neonates. A point of innovation of the present study compared to Mattersberger et al is the fact that by using umbilical cord blood the blood sampling is immediately after birth and might help to predict changes in the transition period and especially predict cerebral oxygenation in this vulnerable period (42).…”