Doppler jugular flow velocity to differentiate cardiac tamponade from failure

Jugular venous flow velocity (JVFV) was analyzed by the directional Doppler velocity detector in an experimental model to distinguish postoperative acute cardiac tamponade from myocardial failure in eight dogs. Cardiac tamponade was produced by infusion of saline solution into the pericardial cavity; acute myocardial failure was created by temporary occlusion of the left anterior descending artery and circumflex coronary artery. A decrease in mean arterial pressure of only 10% was associated with a decrease in JVFV of 30% +/- 6% (mean +/- SE) in the tamponade group compared to 10% +/- 2% in the myocardial failure group. The difference was statistically significant (P less than .005) and persisted to severe levels of hypotension. An increase in venous pressure to 8 mm Hg resulted in a decrease in JVFV of 41% +/- 11% in the tamponade group. Thus, there is an early notable decrease in JVFV in tamponade, which allows differentiation from myocardial failure.