Efficacy of intravascular volume resuscitation in dogs with acute cardiac tamponade.
Whether cardiac tamponade causes myocardial ischemia and whether volume resuscitation can improve coronary perfusion pressure and myocardial blood flow were studied by hemodynamic responses to three blood infusions of 15 ml/kg in dogs with left ventricular hypovolemia produced by cardiac tamponade (N = 10) or hemorrhage (N = 10). Coronary perfusion pressure decreased to 37 +/- 2 mm Hg with tamponade and 39 +/- 1 mm Hg with hemorrhage, causing significant blood flow decreases in both ventricles. Myocardial oxygen extraction increased significantly in both groups without affecting lactate extraction. Volume resuscitation after hemorrhage progressively restored hemodynamic variables to baseline values. Volume resuscitation after tamponade did not increase stroke volume, whereas it increased coronary sinus pressure to 19.2 +/- 1.0 mm Hg (p less than 0.05). Coronary perfusion pressure increased to 53 +/- 5 mm Hg following the first infusion (p less than 0.05), but exhibited no further improvement. Tamponade did not produce myocardial ischemia. Coronary perfusion pressure and blood flow were not restored to baseline values with volume resuscitation since coronary sinus pressure rose incrementally with each volume infusion.
Johnston
W E
WE
Department of Anesthesia, Wake Forest University Medical Center, Winston-Salem, NC 27103.
Vinten-Johansen
J
J
McGivor
A C
AC
Santamore
W P
WP
Block
S M
SM
Moulton
K P
KP
D000818:Animals; D001803:Blood Transfusion; D002305:Cardiac Tamponade / Q000150:complications / Q000628:therapy*; D003326:Coronary Circulation; D003327:Coronary Disease / Q000209:etiology; D004285:Dogs; D006470:Hemorrhage / Q000628:therapy; D012151:Resuscitation; D013318:Stroke Volume