Effects of volume expansion and vasodilators in acute pericardial tamponade

Pharmacologic therapy may be useful as emergency treatment for acute pericardial tamponade while preparing for pericardiocentesis. We studied the effects of volume expansion and vasodilators in acute pericardial tamponade in spontaneously breathing mongrel dogs. Hemodynamic parameters and blood flow (15-μm microspheres) to brain, heart, kidney, colon, stomach, liver, and temporalis muscle were measured. Arterial pressure and cardiac output rose, and blood flow to all major organs, except stomach, increased after volume expansion (n=17) by infusion of 20 ml/kg of dextran after tamponade. With nitroprusside (8-75 μg/min) after volume expansion (n=5), ventricular filling pressures were reduced to control levels, whereas the favorable effects of volume expansion on cardiac output, blood pressure, and kidney and heart blood flow were maintained. Hydralazine alone or hydralazine plus volume expansion was not as effective as the combination of nitroprusside and volume expansion. Thus, volume expansion alone or the combination of volume expansion and nitroprusside infusion should be beneficial as emergency therapy while preparing for pericardiocentesis in patients with acute pericardial tamponade.