AJP - Gastrointestinal and Liver Physiology, Vol 253, Issue 4 573-G581, Copyright © 1987 by American Physiological Society
Hybrid blood flow probe for simultaneous H2 clearance and laser-Doppler velocimetry
G. R. DiResta, J. W. Kiel, G. L. Riedel, P. Kaplan and A. P. Shepherd
Department of Physiology, University of Texas Health Science Center, San Antonio 78284.
To perform two independent regional blood flow measurements in tissue
volumes of similar dimensions, we designed a hybrid blood flow probe
capable of measuring regional perfusion by both laser-Doppler velocimetry
(LDV) and H2 clearance. The probe consisted of two fiber-optic light guides
to conduct light between the surface of tissue of interest and a
laser-Doppler blood flowmeter. Also contained within the probe were a
platinum 25-microns H2-sensing electrode and a 125-microns H2-generating
electrode. The probe can thus be used to measure local perfusion with H2
clearance. The H2 can either be inhaled or can be generated
electrochemically at the locus of interest. Evaluation of the probe in the
canine gastric mucosa indicated 1) that the relationship between mucosal
flow measurements made simultaneously with H2 clearance and LDV was highly
significant and linear and 2) that H2 clearance could potentially be used
to calibrate the laser-Doppler blood flowmeter in absolute units. The
methods of constructing the flow probes are discussed in detail.
