Correlation between transcutaneous pCO2 and the corresponding values of fetal blood--a study at a measuring temperature of 39 degrees C.

Continuous transcutaneous monitoring of fetal carbon dioxide partial pressure (tcpCO2) may become an important new method for investigating the physiology and pathophysiology of the fetus during labor, as well as an additional tool for fetal surveillance. In order to contribute to the standardization of this newly developed method, we measured tcpCO2 during labor in 105 fetuses. We then compared the transcutaneous pCO2 with the pCO2 of fetal blood gas analysis; the correlation between these two parameters was significant. The relationship between transcutaneous pCO2 and the pH from fetal scalp blood is described, as is the influence of the stage of labor on the correlation between transcutaneous monitoring and blood samples. tcpCO2 during labor appears to be a helpful additional tool, especially in fetuses with pathologic heart rate patterns in whom multiple fetal blood gas analysis would otherwise be necessary.