AJP - Regulatory, Integrative and Comparative Physiology, Vol 248, Issue 3 293-R301, Copyright © 1985 by American Physiological Society
Splenic red cell sequestration and blood volume measurements in conscious pigs
J. P. Hannon, C. A. Bossone and W. G. Rodkey
When estimated by the dilution of 51Cr-labeled red blood cells under nearly
basal conditions, immature splenectomized pigs (n = 20) had a circulating
red cell volume of 17.8 +/- 1.64 (SD) ml/kg. At an assumed body-to-large
vessel hematocrit (BH:LH) ratio of 0.9, plasma volume was 49.6 +/- 3.12
ml/kg and blood volume 67.3 +/- 3.67 ml/kg. Sham-operated pigs (n = 20) had
a circulating red cell volume of 16.2 +/- 1.39 ml/kg, a plasma volume of
51.1 +/- 3.42 ml/kg, and blood volume of 67.2 +/- 4.12 ml/kg. Kinetic
analysis of early 51Cr loss from the circulating blood of the sham-operated
pigs indicated a splenic red cell sequestration of 4.5 +/- 0.89 ml/kg and a
t1/2 of 9.76 +/- 1.93 min for splenic red cell turnover. Epinephrine
injection (n = 6) and physical restraint (n = 8) caused rapid mobilization
of splenic red blood cells in sham-operated pigs. Volume estimates in
splenectomized pigs (n = 7) based on simultaneous dilutions of 51Cr-labeled
red blood cells and 125I-labeled bovine albumin gave circulating red cell,
plasma, and blood volumes of 18.4 +/- 2.46, 60.7 +/- 4.01, and 79.0 +/-
3.51 ml/kg, respectively, and a BH:LH ratio of 0.756 +/- 0.029. The latter
value may have reflected an overestimation of plasma volume by the
125I-labeled albumin procedure.
