Alveolar liquid clearance is increased by endogenous catecholamines
in hemorrhagic shock in rats.
Pittet, J. F., T. J. Brenner, K. Modelska, and M. A. Matthay.
Departments of Anesthesia and Medicine, and Cardiovascular Research
Institute, Univ. of California, San Francisco, CA, 94143
APStracts 3:0159A, 1996.
The primary objective of this study was to test the hypothesis that
hemorrhagic shock would stimulate alveolar liquid clearance by a
catecholamine-dependent mechanism. Anesthetized rats were hemorrhaged
to a mean arterial pressure of 30 mmHg for 90 minutes, but they were
not resuscitated. Alveolar liquid clearance was measured by the
concentration of labeled and unlabeled protein over 2 hours in an
isoosmolar, physiologic solution of 5% albumin that had been
instilled into one lung. Hemorrhaged rats developed a severe
metabolic acidosis that was associated with a 5- to 10-fold rise in
plasma epinephrine levels. There was a 60% increase in alveolar
liquid clearance in the hemorrhaged rats compared with controls
(hemorrhagic shock: 55 6% vs controls: 34 7%, p < 0.05). Amiloride
(10-4 M) or propranolol (10-4 M) inhibited the increase in alveolar
liquid clearance. Thus, the endogenous release of catecholamines
associated with hemorrhagic shock markedly stimulates alveolar fluid
clearance by a adrenergic mediated stimulation of active sodium
transport. This data suggests a new, previously unrecognized
mechanism that may protect against alveolar flooding in the acute
phase of hemorrhagic shock.
Received 3 November 1995; accepted in final form 12 March 1996.
APS Manuscript Number A1165-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96