Vol. 280, Issue 4, H1802-H1806, April 2001
Carbon monoxide wash-in method to determine gas transfer in
vascular beds: application to rat hindlimb
Carolyn S. L.
Cho1,
Allan J.
McLean1,2,3,6,
Laurent P.
Rivory4,
Paul A.
Gatenby1,2,6,
David T. A.
Hardman5, and
David G.
Le
Couteur1,2,3,4,6
1 Canberra Clinical School and Departments of
2 Medicine, 3 Physiology, and 4 Pharmacology,
University of Sydney, New South Wales 2006; 5 Department of
Vascular Surgery, Canberra Hospital, Garran 2605; and
6 John Curtin School of Medical Research, Australian
National University, Australian Capital Territory 0200, Australia
The vascular
barrier to gas transfer is an important physiological parameter;
however, no readily applicable technique exists to quantitate the
process. A simple technique to measure the permeability-surface area
(PS) product for gas transfer in vascular beds is
proposed using wash in of carbon monoxide (CO) and Crone-Renkin
analysis. Wash-in experiments were performed on the perfused
hindlimbs of male Wistar rats (n = 15) by using CO as a
surrogate marker for oxygen and technetium-99m-labeled albumin as the
vascular marker. The use of CO and erythrocyte-free perfusate and the
collection of outflow samples into tubes preloaded with erythrocytes
obviated the need for an anaerobic collection device or consideration
of Hb binding in the analysis. The PS product for CO was
determined from the early extraction as 0.013 ± 0.006 ml · s
1 · g1. Compartmental
analysis revealed that the fractional recovery of CO was 0.45 ± 0.14 and the volume of distribution was 2.31 ± 0.76 ml/g. This
technique detected a small measurable barrier to the transfer of CO
across the hindlimb vasculature and is potentially applicable to other
vascular beds in health and disease.
perfused; permeability; surface area
