Details

Autor(en) / Beteiligte

• Tsang, John Y. C
• Lamm, Wayne J. E
• Swenson, Erik R

Titel

Regional CO2 tension quantitatively mediates homeostatic redistribution of ventilation following acute pulmonary thromboembolism in pigs

Ist Teil von

• Journal of applied physiology (1985), 2009-09, Vol.107 (3), p.755-762

Ort / Verlag

Bethesda, MD: Am Physiological Soc

Erscheinungsjahr

2009

Quelle

MEDLINE

Beschreibungen/Notizen

• 1 James Hogg iCAPTURE Research Laboratory, Division of Critical Care Medicine, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; and 2 Department of Medicine, University of Washington, and 3 Medical Service, Veterans Affairs Puget Sound Health Care System, Seattle, Washington Submitted 6 March 2009 ; accepted in final form 10 July 2009 Previous studies reported that regional CO 2 tension might affect regional ventilation ( ) following acute pulmonary thromboembolism (APTE). We investigated the pathophysiology and magnitude of these changes. Eight anesthetized and ventilated piglets received autologous clots at time = 0 min until mean pulmonary artery pressure was 2.5 times baseline. The distribution of and perfusion ( ) at four different times (–5, 30, 60, 120 min) was mapped by fluorescent microspheres. Regional and were examined postmortem by sectioning the air-dried lung into 900–1,000 samples of 2 cm 3 each. After the redistribution of regional by APTE, but in the scenario assuming that no shift had yet occurred, CO 2 tension in different lung regions at 30 min post-APTE (P X CO 2 ) was estimated from the / data and divided into four distinct clusters: i.e., P X CO 2 < 10 Torr; 10 < P X CO 2 < 25 Torr; 25 < P X CO 2 < 50 Torr; P X CO 2 > 50 Torr. Our data showed that the clusters in higher / regions (with a P X CO 2 < 25 Torr) received 35% less when measured within 30 min of APTE, whereas, in contrast, the lower / regions showed no statistically significant increases in their . However, after 30 min, there was minimal further redistribution of . We conclude that there are significant compensatory shifts out of regions of low CO 2 tension soon following APTE, and that these variations in regional CO 2 tension, which initiate CO 2 -dependent changes in airway resistance and lung parenchymal compliance, can lead to improved gas exchange. carbon dioxide; cluster analysis; distribution of ventilation; fluorescent microspheres; gas exchange Address for reprint requests and other correspondence: J. Y. C. Tsang, James Hogg iCAPTURE Research Laboratory, 1081 Burrard St., Vancouver, BC, Canada V6Z 1Y6