Liver Blood Flow in Pregnancy—hepatic Vein Catheterization 1

Abstract

Numerous liver function tests have been devised and most investigators agree that some disturbance in liver function occurs during the toxemias of pregnancy. These changes are of relatively small magnitude and the clinical use of these tests in pregnancy is not widespread. The technique of venous catheterization with resultant sampling of blood directly leaving the liver offers further opportunities for study of liver function. METHODSA method of estimating hepatic blood flow in man based on the "Fick" principle has been described by Bradley and coworkers (1). In their article they point out that "The 'Fick' principle may be applied to any organ provided three facts are known: (1) the concentration of some substance, X, in the blood entering the organ, (2) the concentration of X in the mixed venous blood leaving the organ, and (3) the total amount of X removed from the blood by the organ each minute. Given these data, the blood flow through the organ per minute may be calculated by dividing the total removal rate of X by the amount of X removed from each milliliter of blood as it traverses the organ."The removal rate of X by the liver cannot be measured directly, but an indirect method is available if X can be given at such a rate that its blood level remains constant. Under these conditions, the infusion rate equals the hepatic removal rate, provided that the extraction of X depends entirely upon hepatic activity. Bromsulfalein (BSP) was used as the test substance since it apparently satisfied these conditions. The calculation of hepatic blood flow then can be determined by the following formula: R1 EHEF = 0.01 (P - Tables I, II, and III these peripheral vein hematocrits are starred (*). If the concentration of BSP in the peripheral blood is changing, hepatic blood flow may also be estimated if the plasma volume is determined. In this case, R (the removal rate of BSP by the liver) = I (the infusion rate mgm. per minute) plus or minus AP X V where AP = the rate of change in concentration of BSP in the peripheral blood in mgm. per ml. per minute and V = plasma volume in ml. Plus or minus depends on whether the concentration of BSP in the peripheral blood is rising or falling. If the peripheral concentration is rising, R = I -(AP x V) since less dye is being removed than is administered.If the peripheral concentration is falling, R = I + (AP X V) for the converse reason.Samples of hepatic vein blood are obtained with more or less ease by catheterization of the right hepatic vein with a 100-cm. No. 8 ureteral catheter with a slightly curved through-and-through tip with one eye. The catheter, through which an isotonic saline infusion is running, is inserted in the median basilic vein under local anesthesia. With the patient in the supine position on a fluoroscope table, the catheter is then passed into the subclavian vein, the superior vena cava, the right atrium, the inferior vena cava, and the right hepatic vein. The patient experiences no discomfort during this procedure. The most difficult part of the procedure...

The metabolism of orally and intravenously administered labeled aldosterone in pregnant subjects

“…The 14C/3H ratio of the aldosterone released by mild acid hydrolysis was 100.6 ± 4.5 (SE) % which was significantly higher (P < 0.01) than the 11 The calculated splanchnic extraction of aldosterone in pregnancy is 77%o which is significantly below the observed 90% in nonpregnant patients (measured both by direct hepatic vein catheterization [7] and indirect calculation as in the present study). Theoretically this lowered splanchnic extraction could be the result of increased aldosterone binding to plasma proteins other than to albumin (splanchnic extraction of steroids is not usually lowered by albumin binding [8]).…”

“…This unaltered binding would therefore suggest a reduction of the hepatic metabolism of aldosterone. This could be similar to cortisol disappearance in pregnancy and after estrogen treatment, in which the calculated metabolic clearance rate of free and albumin-bound cortisol is reduced (8, 10) without alteration in hepatic blood flow (11). This is apparently a hepatic cellular effect.…”

“…The combined results for 13 nonpregnant subjects by both single injection and continuous infusion was 1631 + 106 (SE) liters of plasma per day and 1543 + 113 (SE) liters of plasma per day (15 pregnant subjects). The expected decrease in metabolic clearance rate due to the reduced splanchnic extraction (from 95 to 77%) with unchanged hepatic blood flow (11) would have been about 300 liters/day and it seems probably would have been detected. This finding suggests that there is a decrease in splanchnic clearance (unchanged total metabolic clearance) and an increase in extrasplanchnic clearance.…”

Doppler parameters of the maternal hepatic artery blood flow in normal pregnancy: maternal hepatic artery blood flow in normal pregnancy

“…The liver blood flow was first evaluated by Mannell and Taylor more than sixty years ago by catheterization of hepatic vein who had showed that liver blood flow remains constant during the pregnancy [4]. As we didn't measure total liver blood flow, our results are not comparable with cited article.…”

“…Until now, only the absolute values of the liver circulation have been evaluated in the normal pregnancies. Mannell and Taylor, by catheterization of hepatic vein, stated that there are no changes in hepatic blood flow during pregnancy [4], while Nakai et al …”