Abstract
Although fetal arterial levels of oxygen and glucose are less than half adult levels there is no information about tissue extraction of these substrates in the intact fetus. We studied fetal myocardial extraction of oxygen, glucose, lactate and pyruvate in 12 fetal lambs in utero, 1-4 days post-op. We placed catheters in inferior vena cava, carotid artery (CA), and coronary sinus (CS) via the hemiazygous vein. From simultaneously withdrawn blood, CA and CS O2 content, blood glucose, lactate and pyruvate were measured. Myocardial blood flow (cc/min/100g) of left ventricle (MBF/min/100gmLV) was calculated by the nuclide-labelled microsphere method. Myocardial extraction of substrate/min/100g of left ventricle (MV/min/100gmLV) was calculated as CA minus CS level of each substrate (Δ-AV) times MBF/min/100gmLV. MBF/min/100gmLV was 166±19 (mean±SEM), twice the value for normal adult humans and dogs. CA levels of O2, glucose, lactate and pyruvate (uM/L) were 3244±199, 1069±122, 2120±327 and 117±14, respectively. Δ-AV for O2, glucose, lactate and pyruvate (uM/L) were 2117±100, 99±18, 524±88, and 49±9, half the value of normal adults. MV/min/100gmLV (uM/L) for O2, glucose, lactate and pyruvate were 333±30, 18±4, 76±16, and 7±2, respectively, equal to values for normal adults. We conclude that fetal myocardial extraction/min/100gmLV of O2 and glucose are equal to values obtained from healthy adults, despite the lower arterial levels of O2 and glucose present in utero. This is accomplished by higher fetal myocardial blood flow.
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Fisher, D., Rudolph, A. & Heymann, M. 101 MYOCARDIAL EXTRACTION OF OXYGEN AND CARBOHYDRATES IN THE LAMB FETUS IN UTERO. Pediatr Res 12 (Suppl 4), 380 (1978). https://doi.org/10.1203/00006450-197804001-00106
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DOI: https://doi.org/10.1203/00006450-197804001-00106