[Transcutaneously measured carbon dioxide partial pressure in non-hypoxic fetuses during labor]

Using the newly developed Severinghaus electrode we performed measurements of the transcutaneous carbon dioxide partial pressure (tcPco2) in 81 non-hypoxic fetuses during labor. The calibration and measuring temperature was 39 degrees C. After a correction with a factor of 13% the transcutaneous Pco2 values corresponded well with the blood values of the Pco2 from FBA respectively the umbilical artery. While during the first stage of labor we found only a gradual rise in the tcPco2 level, we observed a rapid rise at the end of the second stage. Analysing the influence of clinical factors on the fetal tcPco2 level we found statistically significant higher levels during the first stage of labor in primipara compared with multipara. However there was no significant difference dependent on gestational age, the age of the mother and the birthweight.