Journal of Applied Physiology, Vol 56, Issue 5 1361-1368, Copyright © 1984 by American Physiological Society
Albumin-induced plasma volume expansion: diurnal and temperature effects
R. W. Hubbard, W. T. Matthew, D. Horstman, R. Francesconi, M. Mager and M. N. Sawka
To develop a reliable procedure for the acute expansion of plasma volume
(PV), 26 male volunteers were randomly assigned to either a thermoneutral
(25 degrees C and 40% relative humidity) or hot-dry (37 degrees C and 25%
relative humidity) environment; subsequently each subject was seated for at
least 1 h and then infused intravenously with either 100 or 200 ml of a 25%
albumin solution or 0.9% saline. On the day before each infusion, PV was
estimated by dye dilution using indocyanine green. Net percent change in PV
(using hematocrit and hemoglobin values) was calculated at 1, 3, 6, 9, 12,
and 24 h postinfusion. The PV of subjects residing in the heat after a
100-ml saline infusion increased significantly over 1-h values at 6, 9, and
12 h postinfusion but not at 24 h. The same trend, although not
significant, was apparent at room temperature. The data suggest a slow
isooncotic circadian pattern of PV expansion and contraction. The infusion
of hyperoncotic albumin produced rapid expansion of plasma volume. With the
low dose (25 g) at 1 h postinfusion, the expansion was 379 +/- 102 ml in
the heat and 301 +/- 160 ml at room temperature. With the high dose (50 g)
at 1 h postinfusion, the expansion was 479 +/- 84 ml in the heat and 427
+/- 147 ml at room temperature. The high dose produced an expansion that
persisted for at least 9 h in subjects in either environment. The data
suggest a mechanism for the retention of fluid during heat acclimatization
and a useful procedure for plasma volume expansion in humans.
