AJP - Endocrinology and Metabolism, Vol 254, Issue 3 E287-E291, Copyright © 1988 by American Physiological Society
Free and total catecholamines in critical illness
P. D. Woolf, R. W. Hamill, L. A. Lee and J. V. McDonald
Department of Medicine, University of Rochester, School of Medicine and Dentistry, New York 14642.
The magnitude of circulating free and total (free plus conjugated)
catecholamine responses to a strong and sustained stimulus was investigated
in four groups of patients: traumatic brain injury (n = 24), vascular brain
injury (n = 10), polysystem trauma (n = 7) and medical/surgical patients in
an intensive care unit (n = 29). Despite significant three- to sevenfold
elevations in both free and total norepinephrine (NE) and epinephrine (E),
the ratio of free to total NE and E remained constant over a very broad
range of values. The proportion of free E was twice normal (30.1-33.5 vs.
16.2%) in all but patients with polytrauma, whereas the percentage of free
NE was unchanged in all patients (43.0%). All dopamine (DA) parameters
remained generally normal. In the patients with traumatic or vascular brain
injury, significant inverse correlations were present between the degree of
neurological dysfunction, as indicated by the concomitant Glasgow coma
score, and free NE, E, and DA and total NE and DA levels. Thus, during
conditions of intense and prolonged catecholamine release, the proportion
of free catecholamine remains constant and the total as well as free
catecholamine concentration is proportional to the Glasgow coma score.
