Po2 measurements in the rat intestinal microcirculation. Sinaasappel, M., C. Donkersloot, J. Van Bommel, and C. Ince. Department of Anesthesiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9,1105 AZ Amsterdam, The Netherlands. Phone 31-20-5665242, Fax 31-20-6979004, email M.Sinaasappel@AMC.UVA.NL
APStracts 6:0059G, 1999.
Microvascular partial oxygen pressure (Po2) data measured with the quenched phosphorescence of Pd-porphine with optical fibers has provided new insight into the behavior of the microvascular oxygenation in models of shock. However, the actual microcirculatory compartment measured by this fiber technique has not yet been demonstrated. The purpose of this study was to investigate whether the Po2 of the intestines, as measured using a fiber phosphorimeter, reflects the microvascular compartment. To this end, a new intravital phosphorimeter with an improved sensitivity for high Po2 levels (up to 180 mmHg) was developed and validated. With this set-up Po2 values were measured at different inspired oxygen fractions (15, 25 and 50% O2) in first order arterioles, capillaries and venules of the ileum of rats. Simultaneously the Po2 was measured with an optical fiber attached to another phosphorimeter. The correlation of the PO2 in the capillaries and 1V vessels with fiber optic measurements show excellent correlation (R2 = 0.94 slope 0.99). We therefore conclude that values measured with the fiber phosphorimeter correlate with the capillary and venular Po2.

Received 25 August 1998; accepted in final form 25 February 1999.
APS Manuscript Number G344-8.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 5 March 1999