Fetal heart rate patterns during delivery complicated by hypoxia and acidosis - a computer-aided analysis.

Background: Using the naked eye, evaluation of fetal heart-rate (FHR) patterns remains difficult and is not complete. Computer-aided analysis of the FHR offers the opportunity to analyse FHR patterns completely and to detect all changes possibly due to hypoxia and acidosis. It was the goal of this study to make these hypoxic changes of the FHR visible and to compare them directly with normal tracings.

Basic principles of the foetal heart rate during delivery without hypoxia and acidosis.

Background: Using naked-eye evaluation of foetal heart rate (FHR) patterns remains difficult and is not complete. Computer-aided analysis of the FHR offers the opportunity to analyse the FHR completely and to detect all changes due to hypoxia and acidosis. In order to better understand these changes FHR patterns in non-acidotic foetuses should be studied by first separating FHR into (i) basal FHR (baseline) and (ii) all decelerations.

The clinical significance of base excess (BEB) and base excess in the extracellular fluid compartment (BEEcf) with and without correction to real oxygen saturation of haemoglobin.

Background: Besides actual pH, base excess [ctH (+)(B) (mmol/l)] is of major importance since it is meant to reflect lactate acidosis due to foetal hypoxia; In vivo BE (B) is not independent from pCO (2). Independence is achieved by using the extended extracellular fluid (Ecf) for dilution of haemoglobin (cHb (B)) thus reducing cHb (B) to cHb (B)/3 (in the foetus to cHb (B)/4). Correction of ctH (+)(B) from the normally low foetal oxygen saturation by reoxygenation of Hb increases ctH (+)(B), resulting in 4 different variables: ctH (+)(B,act) (=BE (B)), ctH (+)(Ecf,act) (standard BE), ctH (+)(B,ox.