[Value of measuring fetal oxygen saturation for reducing the need for fetal blood analysis in abnormal cardiotocogram. Experiences with 2 sensor generations of fetal reflexion pulse oximetry].
OBJECTIVE
Does the knowledge of fetal oxygen saturation allow to avoid fetal scalp blood sampling and to predict a pH < or = 7.25 of the fetal blood sample?


METHODS
Out of a group of 135 fetuses we determined the median, the 10th, 5th and 3rd percentile of oxygen saturation values by a blinded fetal pulse oximeter. Due to abnormal FHR-patterns, 110 fetal scalp blood samples (FBA) were assessed by the technique introduced by Saling. The pH of these FBA's ranged from 7,16-7,48 (median 7,28). We chose a 20 minute period before the FBA and calculated the individual median and percentiles. According to the pH of < or = 7,25 in FBA we calculated the chi-square test for significance.


RESULTS
The median of <35% SpO2 has a sensitivity of 23%, specificity of 77%, positive predictive value of 27% and a negative predictive value of 73%.


CONCLUSIONS
Fetal oxygen saturation alone shows a high specificity and a low sensitivity for pH < 7,25. In addition to FHR monitoring, pulse oximetry.
Luttkus
A
A
Abt. für Geburtshilfe, Humboldt-Universität Berlin.
Friedmann
W
W
Dudenhausen
J W
JW
D001784:Blood Gas Analysis / Q000295:instrumentation*; D015148:Cardiotocography / Q000295:instrumentation*; D005260:Female; D005311:Fetal Hypoxia / Q000097:blood / Q000175:diagnosis*; D005323:Fetal Monitoring / Q000295:instrumentation*; D006340:Heart Rate, Fetal / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D010092:Oximetry / Q000295:instrumentation*; D011247:Pregnancy; D012016:Reference Values; D012680:Sensitivity and Specificity
Bedeutung der fetalen Sauerstoffsättingungsmessung zur Reduktion von Fetalblutanalysen bei suspektem Kardiotokogramm. Erfahrungen mit zwei Sensorgenerationen der Reflexionspulsoximetrie am Feten.