427 Prenatal prediction of the fetal to neonatal cardiovascular transition

Abstract

We sought to evaluate changes in the fetal pulmonary artery Doppler following maternal hyperoxygenation during the third trimester of pregnancy and correlate those findings with neonatal echocardiograph indices. Forty-six women with a singleton pregnancy ≥31weeks’ gestational age(GA) were prospectively recruited. Pulsatility index(PI),Resistance index(RI), acceleration time(AT) and ejection time(ET) were measured in the distal fetal pulmonary artery (PA). Doppler measurements were taken at baseline and following maternal hyperoxygenation(MH) for 10minutes.Reactivity to MH was considered where a decrease in PAPI was ≥10% from the baseline. Within 24hours of life a neonatal functional echocardiogram was performed to assess right ventricular systolic pressures,PAAT,ejection fraction(EF) and left ventricular cardiac output(LVCO). The median GA was 35weeks. There was a decrease in fetal PAPI and PARI and an increase in PAAT leading to an increase in AT:ET following MH (Table 1).Fetuses that responded to MH had an increased LVCO and EF. These findings were not dependent on LV size or mitral valve (MV) annular diameter but were related to an increased MV inflow.The PA reactivity was not associated with maternal age, BMI or GA at the time of MH (Table 2).The effect of MH on neonatal LVCO and EF was not dependent on mode of delivery or GA at delivery but on the prenatal response to MH. Maternal hyperoxygenation in the third trimester is associated with significant changes in fetal PA Doppler waveforms.An increased LVCO and EF in the neonates who responded to MH,suggests that MH may prove to be a more reliable predictor of postnatal cardio-pulmonary dysfunction compared to the prenatal evaluation of anatomic structures alone. The response to MH predicted neonatal LVCO suggesting that there is a cohort of infants who may be identified by MH,that may have an increased vulnerability to deal with neonatal illness, due to a limited ability to optimise LV preload. This warrants further exploration to establish the ability of MH to predict the neonatal cardiovascular transition.View Large Image Figure ViewerDownload Hi-res image Download (PPT)