Intrapartum fetal surveillance of congenital heart block with pulse oximetry.
BACKGROUND
In cases of fetal congenital heart block, the fetal heart rate (FHR) pattern is uninterpretable, often leading to an operative delivery. Reflectance pulse oximetry, a new technique that continuously measures the fetal arterial oxygen saturation (SaO2) during labor, is potentially useful in intrapartum monitoring of fetuses with this condition.


METHODS
Two fetuses with congenital heart block were monitored with reflectance pulse oximetry and fetal scalp blood sampling. The first patient delivered spontaneously. Adequate signal quality was achieved during 73% of the study time. Mean +/- standard deviation (SD) SaO2 was 53 +/- 14%. Fetal outcome was good. The second patient was delivered by cesarean because of arrest of labor. Oxygen saturation values were obtained during 89% of the study time. The mean SaO2 was 42 +/- 13%. There was a period of 8 minutes with SaO2 values below 20%. Capillary blood pH dropped from 7.33 to 7.25; SaO2 values then returned to levels above 30% and the capillary blood pH normalized. The neonate was born in good condition.


CONCLUSIONS
In fetal congenital heart block, adequate surveillance with FHR monitoring during labor is not possible; therefore, continuous information on fetal oxygenation may be valuable in assessing the fetal condition and may prevent unnecessary obstetric interventions.
van den Berg
P P
PP
Department of Obstetrics and Gynecology, University Hospital Nijmegen, The Netherlands.
Nijland
R
R
van den Brand
S F
SF
Jongsma
H W
HW
Nijhuis
J G
JG
D000328:Adult; D005260:Female; D005315:Fetal Diseases / Q000503:physiopathology*; D005323:Fetal Monitoring / Q000379:methods*; D006327:Heart Block / Q000151:congenital*; D006801:Humans; D010092:Oximetry