Effect of standard cardiopulmonary resuscitation on cerebral blood flow and coronary perfusion pressure in the canine model of simulated ventricular tachycardia

Abstract

Study objectives: The purpose of this study is to evaluate the hemodynamic effects of external chest compression in state of the heart's beating. Methods: Ten mongrel dogs were used in this study. Ventricular tachycardia (VT) was simulated by using a rapid ventricular pacing, and ventricular rate was adjusted and maintained at the rate necessary to achieve a 50-mm Hg decrease in the baseline systolic aortic pressure. External chest compression (ECC) was initiated after 4 minutes of simulated VT and was continued for 4 minutes. Hemodynamic measurements, including the systolic and the diastolic aortic pressure, the right atrial pressure, the carotid blood flow, and the end-tidal CO 2 tension, were done at baseline during simulated VT and during simulated VT with ECC (VT+ECC). Results: The systolic aortic pressure, the diastolic aortic pressure, and the mean right atrial pressure were higher during VT+ECC than during VT (99±12 versus 92±8 mm Hg, P =.157, 59±8 versus 55±12 mm Hg, P =.140, and 23±8 versus 8±2 mm Hg, P =.000, respectively). The carotid blood flow was higher during VT+ECC than during VT (273±203 versus 136±76 mL/minute, P =.011). The calculated coronary perfusion pressure was lower during VT+ECC than during VT (26±8 versus 40±9 mm Hg, P =.000). The end-tidal CO 2 tension was not different between VT+ECC and VT. Conclusion: In the canine model of simulated VT, ECC had a contradictory hemodynamic effect, including an increase in the cerebral blood flow and a decrease in the coronary perfusion pressure.