Efficacy of Intravascular Volume Resuscitation in Dogs with Acute Cardiac Tamponade

Abstract 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 p