HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 98/5/1862    most recent 01018.2004v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Tsang, J. Y. C. Articles by Hlastala, M. P. Search for Related Content PubMed PubMed Citation Articles by Tsang, J. Y. C. Articles by Hlastala, M. P.

Spatial pattern of ventilation-perfusion mismatch following acute pulmonary thromboembolism in pigs

¹James Hogg iCAPTURE Research Laboratory, Vancouver, British Columbia, Canada; and Departments of ²Physiology and Biophysics and ³Medicine, University of Washington, Seattle, Washington

Submitted 15 September 2004 ; accepted in final form 29 November 2004

We studied the spatial distribution of the abnormal ventilation-perfusion (A/) units in a porcine model of acute pulmonary thromboembolism (APTE), using the fluorescent microsphere (FMS) technique. Four piglets (22 kg) were anesthetized and ventilated with room air in the prone position. Each received 20 g of preformed blood clots at time t = 0 min via a large-bore central venous catheter, until the mean pulmonary arterial pressure reached 2.5 times baseline. The distributions of regional A and blood flow () at five time points (t = –30, –5, 30, 60, 120 min) were mapped by FMS of 10 distinct colors, i.e., aerosolization of 1-µm FMS for labeling A and intravenous injection of 15-µm FMS for labeling . Our results showed that, at t = 30 min following APTE, mean A/ (A/ = 2.48 ± 1.12) and A/ heterogeneity (log SD A/ = 1.76 ± 0.23) were significantly increased. There were also significant increases in physiological dead space (11.2 ± 12.7% at 60 min), but the shunt fraction (A/ = 0) remained minimal. Cluster analyses showed that the low A/ units were mainly seen in the least embolized regions, whereas the high A/ units and dead space were found in the peripheral subpleural regions distal to the clots. At 60 and 120 min, there were modest recoveries in the hemodynamics and gas exchange toward baseline. Redistribution pattern was mostly seen in regional , whereas A remained relatively unchanged. We concluded that the hypoxemia seen after APTE could be explained by the mechanical diversion of to the less embolized regions because of the vascular obstruction by clots elsewhere. These low A/ units created by high flow, rather than low A, accounted for most of the resultant hypoxemia.

acute pulmonary embolism; cluster analyses; fluorescent microspheres; gas exchange; hypoxemia; regional blood flow; regional ventilation

This article has been cited by other articles:

				H. T. Robertson and M. P. Hlastala Microsphere maps of regional blood flow and regional ventilation J Appl Physiol, March 1, 2007; 102(3): 1265 - 1272. [Abstract] [Full Text] [PDF]