AJP - Regulatory, Integrative and Comparative Physiology, Vol 248, Issue 6 724-R731, Copyright © 1985 by American Physiological Society
Cardiovascular function and fluid compartments in newborn canine hemorrhagic shock
J. W. Horton and D. Coln
Hemorrhage in the adult disrupts cellular function, resulting in a
redistribution of fluids and electrolytes. There is little data about the
effects of hemorrhage on body fluids in the neonate. The purpose of this
study was to determine the effects of hemorrhage on cardiovascular
function, coronary blood flow, red blood cell mass (RBCM), plasma volume
(PV), and extracellular fluid (ECF) volume in newborn dogs. Group 1
consisted of 88 dogs, 1-20 days old, and group 2 was 81 dogs, 3-6 wk old.
There is a significantly higher ECF volume in younger (256 +/- 10 ml/kg)
compared with older puppies (121 +/- 5 ml/kg). A 40% hemorrhage caused ECF
to fall less in the younger (-27%) than in the older puppies (-51%),
whereas PV and RBCM decreased to a similar extent in both groups. After
returning shed blood, PV and RBCM returned to prehemorrhage values, but
there was a 12% deficit in functional ECF volume in both groups. A similar
degree of bradycardia, myocardial depression, and acidosis occurred in both
groups during shock and after returning shed blood. Cardiac output and
coronary blood flow, measured only in group 2, fell significantly in shock
(-60 and -50%, respectively; P less than 0.05) and remained below control
values after returning shed blood. Our data indicate that inadequate
perfusion of the myocardium and persistent acidosis impairs cardiac
function in newborn shock.
