AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 4 907-R911, Copyright © 1991 by American Physiological Society
Influence of splenectomy on hemodynamics during cardiac tamponade
B. D. Hoit, M. Gabel and N. O. Fowler
Division of Cardiology, University of Cincinnati Medical Center, Ohio 45267.
The effect of prior splenectomy on the hemodynamics of cardiac tamponade
was investigated in 15 closed-chest pentobarbital sodium-anesthetized dogs.
Hemodynamics were compared at baseline and during staged cardiac tamponade
(pericardial pressures of 5, 10, and 15 mmHg) at control (n = 15) and after
splenectomy (n = 8) and sham operation (n = 7). The fall in mean arterial
pressure with cardiac tamponade was significantly greater in splenectomized
dogs than in either sham-operated or control dogs (P less than 0.001).
Cardiac output was more depressed at the third level of cardiac tamponade
in splenectomized than in sham-operated or control dogs (12.8 +/- 14.5 vs.
29.3 +/- 8.7 and 25.4 +/- 9.4 ml.min-1.kg-1, respectively; both P less than
0.05 vs. splenectomy). Hemodynamic failure, defined as an inability to
maintain mean arterial pressure greater than 50 mmHg for 5 min, occurred at
a lower pericardial pressure in splenectomized than in sham-operated dogs
(13.1 +/- 3.8 vs. 18.1 +/- 3.5 mmHg, P less than 0.05). Hematocrit
increased significantly with cardiac tamponade in controls and
sham-operated but not splenectomized dogs. The percent increase in
hematocrit from baseline to the third stage of cardiac tamponade was 19.6
+/- 9.8 and 22.3 +/- 5.6% in control and sham dogs, respectively. Thus the
canine spleen plays an important role in cardiovascular compensation to
cardiac tamponade. Parallel changes in hematocrit suggest that a part of
this response is due to splenic autotransfusion.
