The Annals of Thoracic Surgery, Vol 45, 667-673, Copyright © 1988 by The Society of Thoracic Surgeons
Efficacy of intravascular volume resuscitation in dogs with acute cardiac tamponade
WE Johnston, J Vinten-Johansen, AC McGivor, WP Santamore, SM Block and KP Moulton
Department of Anesthesia, Wake Forest University Medical Center, Winston-Salem, NC 27103.
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.