Regional blood volume changes during acute pericardial tamponade.
Using radionuclide blood pool imaging, we evaluated sequential changes in heart, lung, liver, and spleen intravascular volumes were evaluated before and during acute pericardial tamponade in 9 anesthetized dogs. Tamponade resulted in an abrupt (less than 1 min) decline in mean right heart (-30 +/- 5%, p less than 0.001 vs control) and left heart volumes (-27 +/- 4%, p less than 0.001 vs control), with a concomitant reduction in pulmonary volume (-17 +/- 3%, p less than 0.01 vs control). Within this short time frame, both hepatic (+19 +/- 3%) and splenic (+16 +/- 4%, both p less than 0.01 vs control) volumes rose. Five min after the production of tamponade, right and left heart volumes were still significantly reduced (-28 +/- 4, p less than 0.005 vs control and -23 +/- 2%, p less than 0.005 vs control), though pulmonary (+2 +/- 5%, p = NS vs control), hepatic (+7 +/- 3%, p less than 0.05 vs control) and splenic (+9 +/- 3%, p less than 0.05 vs control) volumes had returned toward baseline values. These volume changes were similar at 20 min after tamponade. Thus, tamponade resulted in a sudden shunting of blood from the central to the peripheral circulation, initially from both the lungs and heart. After 5 min pulmonary volumes returned to baseline values, while splenic and hepatic volumes remained slightly, though significantly elevated.
D000208:Acute Disease; D000818:Animals; D001810:Blood Volume; D002305:Cardiac Tamponade / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003326:Coronary Circulation; D004285:Dogs; D006439:Hemodynamics; D008102:Liver Circulation; D008176:Lung Volume Measurements; D011877:Radionuclide Imaging; D012039:Regional Blood Flow