Measurement of right ventricular volume by conductance catheter in
the closed chest pig.
Stamato, Theresa M., Richard S. Szwarc, and Lee N. Benson.
The Hospital for Sick Children, University of Toronto Medical
School, Toronto, Ontario, Canada
APStracts 2:0216H, 1995.
This study details the effects of changes in right ventricle (RV)
volume on the conductance catheter gain factor both over a broad
volume range and within the cardiac cycle. In 7, closed chest,
anaesthetized pigs, a conductance catheter was introduced
transvenously and positioned to span the RV long axis, including the
outflow tract. Parallel conductance was determined using a saline
dilution technique. Conductance volume gain factor ([alpha]) was
computed using stroke volume obtained by thermodilution over a range
of volumes obtained by volume loading or sustained partial occlusion
of the inferior caval vein. The chest was then opened and an
ultrasonic flow probe placed around the pulmonary artery and the
conductance derived RV volume was compared to the pulmonary flow
integral over the course of ejection. When volume was varied over a
broad range, an inverse relation between RV volume and [alpha] was
observed (p < 0.001). This did not cause significant non-linearity
of the conductance volume-relation. The relation was also relatively
linear during the course of ejection within the cardiac cycle. These
results indicate that the conductance catheter may be employed, using
the described technique, to assess RV volume under steady state
conditions.
Received 30 January 1995; accepted in final form 15 April 1995.
APS Manuscript Number H81-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 May 1995.