974 Non-invasive transabdominal assessment of In-Utero fetal oxygen saturation in a hypoxic lamb model

Fetal heart rate monitoring is a poor predictor of fetal hypoxia due to its high false-positive rate. Utilizing novel transabdominal pulse oximeter (TFO), this study aimed demonstrate the feasibility non-invasive and direct assessment arterial blood oxygen saturation in-utero (SaO2) in hypoxic lamb model. was induced 3 gravid term ewes (137.3±3.2 days gestation) by placing an inflatable balloon catheter infrarenal aorta via common femoral artery (Fig 1). A carotid line placed for continuous hemodynamic gases (ABG). The uterus closed around right forelimb, laparotomy closed, leaving limb exposed conventional oximetry. fetus’s depth from ewe’s skin determined, TFO device on abdomen. aortic inflated stepwise fashion decrease distal mean pressure (dMAP) 5mmHg increments. At each step, dMAP maintained 10 min, ABGs were recorded at 2.5, 5, 10-min marks. fully deflated after two consecutive measurements SaO2 <15%. fetus recovered 45 gradient repeated second round. level, average measured (SpO2) compared SaO2. SpO2 2A) found be highly correlative (R=0.64 p<0.0001) 2B). ex-utero clinical readings forelimb had weak correlation with (R=0.16 p<0.0003). depth, composed abdominal wall uterine thickness, 15.0±4.3mm (SD). can measure based despite intervening maternal anatomy. potentially improve accuracy detection. Future research will focus intrapartum validation models human pregnancies.View Large Image Figure ViewerDownload Hi-res image Download (PPT)