Splanchnic hemodynamics and gut mucosal-arterial pco2 gradient
during systemic hypocapnia.
Guzman, Jorge A., M. D. and James A. Kruse, M. D.
From the Division of Pulmonary & Critical Care Medicine, Wayne
State University School of Medicine, Detroit, Michigan.
APStracts 6:0247A, 1999.
The effects of hypocapnia (Paco2 15 torr) on splanchnic hemodynamics
and gut mucosal-arterial Pco2 were studied in seven anesthetized
ventilated dogs. Ileal mucosal and serosal blood flow were estimated
using laser Doppler flowmetry, mucosal Pco2 was measured continuously
using capnometric recirculating gas tonometry, and serosal surface
Po2 was assessed using a polarographic electrode. Hypocapnia was
induced by removal of dead space and maintained for 45 min followed
by 45 min of eucapnia. Mean (+/- SE) baseline Paco2 was 38.1 +/- 1.1
and decreased to 13.8 +/- 1.3 torr after removing dead space. Cardiac
output and portal blood flow decreased significantly with hypocapnia.
Similarly, mucosal and serosal blood flow decreased by 15 +/- 4% and
by 34 +/- 7%, respectively. Also, an increase in the mucosal-arterial
Pco2 gradient of 10.7 torr and a reduction in serosal Po2 of 30 torr
were observed with hypocapnia (P < 0.01 for both). Hypocapnia
caused ileal mucosal and serosal hypoperfusion, with redistribution
of flow favoring the mucosa, accompanied by increased Pco2 gradient
and diminished serosal Po2.
Received 15 March 1999; accepted in final form 26 May 1999.
APS Manuscript Number A201-9.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 14 June 1999