Measurement of Portal Blood Flow in Calves by Dye-Dilution

Abstract

Portal blood flow was measured by continuous recording and on-line computer analysis of dye-dilution curves. Portal blood flow, calculated from 724 acceptable dye-dilution curves recorded in five calves, averaged 37.08 ± .44 ml/ (min × kg body weight). When sheath and (or) thrombus formation about the tip of the injection catheter prevented accurate dye injection, curves were atypical and unacceptable. Rapid and repeatable dye injection was facilitated by a pneumatic injector. Duplicates in sequence of 128 dyedilution curves were recorded by two dadtometers connected in series to study the effect of arrival time (time from dye injection to inception of the dilution curve) on portal blood flow. There were no differences in areas of first and second curves when arrival times were greater than 6 sec. Therefore, the dye had spectrally stabilized and did not contribute to errors in flow with arrival times of at least 6 sec. No differences in blood flow values were observed after injections of dye at the onset of either inspiration or expiration. Because dye-dilution curves were recorded over several respiratory cycles, any effect of respiration on portal flow was insignificant. There was no significant effect of site of dye injection (mesenteric, ruminal, or duodenal vein) on portal blood of flow. © 1972, American Dairy Science Association. All rights reserved.