Validation of portal blood flow measurement by transit-time
ultrasound flow probes on the portal vein of conscious rats.
D'almeida, Mark S., St[acute]ephane Cailmail, and Didier Lebrec.
Laboratoire d'H[acute]emodynamique Splanchnique, Unit[acute]e de
Recherches de Physiopathologie H[acute]epatique, Institut National de
la Sant[acute]e et de la Recherche M[acute]edicale, U-24,
H[circumflex]opital Beaujon, 92118 Clichy, France
APStracts 3:0237H, 1996.
Direct measurement of portal venous blood flow is technically
difficult, yet crucial for accurate assessment of liver hemodynamic
and metabolic functions. The aim of this investigation was to assess
the feasibility of implanting transit-time ultrasound (TTUS)
perivascular flow probes on the portal vein of the rat and to
validate this technique as a means of directly measuring portal blood
flow in conscious rats. A TTUS flow probe was implanted on the portal
vein of 10 rats. One week later, portal flow was measured in these
rats by the TTUS probes under basal conditions and after
pharmacological manipulation of portal flow by i.v. injections of
Glypressin or infusions of adenosine while the rats were conscious.
Portal flow was simultaneously measured in the same rats using
radioactive microspheres. Basal systemic hemodynamics, regional blood
flows to splanchnic organs and portal blood pressure were not
significantly modified by the presence of the probe on the portal
vein compared to a control group of rats not instrumented with flow
probes. Basal portal flows measured by the TTUS and microsphere
techniques were not different (20.6+2.6 and 17.6+1.3 ml.min-1). After
Glypressin, portal flows measured by the TTUS and microsphere
techniques were 12.3+2.9 and 9.3+1.9 ml.min-1, and in response to
adenosine, increased to 27.2+3.4 and 31.3+4.1 ml.min-1. There was no
significant difference between the TTUS and microsphere flows. The
relationship between absolute flow, as well as the change in flow
measured by the two techniques were linear with slopes approaching
1.0. Thus, TTUS flow probes can be used to directly measure portal
flow from the portal vein in conscious rats. This methodology is as
effective as the standard technique of radioactive microspheres. More
importantly, the TTUS technique allows for continuous direct
measurement of portal flow and eliminates the hazards and sources of
error associated with the radioactive microsphere technique.
Received 17 February 1995; accepted in final form 3 May 1996.
APS Manuscript Number H156-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96