Continuous measurement of rat gastric blood flow using Doppler flowmeter

We describe the use of pulsed Doppler flowmetry to permit continuous measurement of gastric blood flow in the anesthetized rat. The aims of this study were: 1) to assess the stability of blood flow during Doppler flowmetry; 2) to assess the ability of Doppler flowmetry to record rapid, transient blood flow changes; and 3) to validate Doppler flowmetry against an established blood flow measurement technique using labeled microspheres. Measurements over 3-h periods with a Doppler probe placed on the left gastric artery showed that there was an initial 30-min stabilization period; after this the mean percentage coefficient of variation, indicating intraindividual variability for blood flow, was < 10% for the remaining 150 min. The infusion of norepinephrine produced rapid, transient blood flow changes, including the typical "autoregulatory escape" and "postinfusion hyperemia," both of which were detected by Doppler flowmetry. The accuracy of pulsed Doppler flowmetry in measuring gastric blood flow was established by the demonstration of a highly significant agreement between blood flow measured by the Doppler flowmetry and microsphere techniques. These data indicate that pulsed Doppler flowmetry is an accurate method for the continuous measurement of left gastric artery blood flow in the rat.