Zeitschrift für Geburtshilfe und Neonatologie
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Foetal hypoxia may lead to multi-organ failure and cerebral injury. Usually this process is accompanied by severe metabolic acidosis. The base excess (BE) determined in umbilical artery (UA) blood is the most appropriate parameter to evaluate metabolic acidosis. The correct determination of BE therefore is of paramount importance both for the jeopardised foetus and the obstetrician in litigation. In blood, BE is dependent on the oxygen saturation [sO2 (%)] of haemoglobin (cHb). Due to the normally low foetal pO2 values in UA blood (median: ca. 18 mmHg) sO2 is low as well; therefore computational correction of BE to - by definition - 100 % oxygen saturation seems to be mandatory. This paper presents an analysis of this complex problem in obstetrics. ⋯ Correction of BE in UA, i. e., correction of BE to 100 % oxygen saturation using the (calculated) actual oxygen saturation (%) of the blood sample is mandatory in perinatal medicine. Correction uniformly leads to lower BE values (median: 2.7 mmol / L) and significantly higher correlation coefficients with important clinical variables (e. g., the APGAR index).