AJP - Heart and Circulatory Physiology, Vol 246, Issue 5 733-H738, Copyright © 1984 by American Physiological Society
Measurement of cardiac output in adult and newborn animals by ascorbic acid dilution
J. K. Smallwood, K. A. Haselby and R. R. Paradise
We have developed an ascorbic acid-dilution method for measuring cardiac
output which requires minimal blood withdrawal. Ascorbate is injected into
a central venous catheter. The indicator-dilution curve is obtained by
drawing blood from an arterial catheter through an amperometric cell at
0.96 ml/min for 35 s. The current is measured by a picoammeter . A
calibration curve is obtained in 15 s prior to each indicator-dilution
curve. An on-line digital computer measures the curve areas and calculates
the cardiac output. Cardiac outputs of heparinized dogs anesthetized with
pentobarbital and halothane measured by this method (AA) compared closely
to cardiac outputs measured by the dye-dilution method (CG) (AA = 0.96 CG +
20 ml/min, r = 0.98). Both the cardiac output and the arterial blood
pressure remained stable during replicate measurements of the cardiac
output of 1-day-old piglets. This system allows cardiac output
determinations of neonatal subjects without excessive blood removal and,
with further development, should be practical in human neonates.
