Effect of Standard Cardiopulmonary Resuscitation on Cerebral Blood Flow and Coronary Perfusion Pressure in the Canine Model of Simulated Ventricular Tachycardia

ABSTRACT

PURPOSE: The purpose of this study was 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 was simulated by using a rapid ventricular pacing and ventricular rate was adjusted and maintained at the rate necessary to achieve a 50-mmHg fall in the baseline systolic aortic pressure. External chest compression was initiated after 4 minutes of simulated ventricular tachycardia 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 CO2 tension, were done at baseline, during the simulated ventricular tachycardia (VT), and during the simulated ventricular tachycardia with external chest compression (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 vs 92+/-8 mmHg, p=0.157, 59+/-8 vs 55+/-12 mmHg, p=0.140, and 23+/-8 vs 8+/-2 mmHg, p<0.001, respectively). The carotid blood flow was higher during VT+ECC than during VT (273+/-203 vs 136+/-76 mL/min., p=0.011). The calculated coronary perfusion pressure was lower during VT+ECC than during VT ( 26+/-8 vs 40+/-9 mmHg, p<0.001). The end tidal CO2 tension was not different between VT+ECC and VT. CONCLUSION: In the canine model of simulated ventricular tachycardia, external chest compression had a contradictory hemodynamic effect, including an increase in the cerebral blood flow and a decrease in the coronary perfusion pressure.