HEMODYNAMIC COMPARISON OF HIGH IMPULSE MANUAL CHEST COMPRESSION AND THORACIC PUMP CPR IN THE INTACT DOG.
Eight adult dogs were chronically instrumented with ascending and descending aortic flow probes while matched micromanometers measured aortic and left ventricular pressures. Coronary perfusion pressure was calculated as the difference between mean diastolic aortic and left ventricular pressures, and brachiocephalic flow was computed as total cardiac output minus descending aortic flow. CPR methods included high impulse manual chest compression at 150/min (HIC), mechanical compression with simultaneous ventilation at 60/min (MC), and pneumatic vest compression at 60 min (V). By multivariate analysis, cardiac output, brachiocephalic flow, and coronary perfusion pressure were significantly better with HIC than with the other techniques studied. Total cardiac output was 44% of control for HIC, but only 21% for MC and 11% for V. Brachiocephalic blood flow (also expressed as % of control) was 44% for HIC, 21% for MC, and 17% for V. Coronary perfusion pressure was 32 mmHg for HIC, 24 mmHg for MC, and 12 mmHg for V. Although results may vary with the physiologic state or the experimental preparation, these data indicate that HIC provides superior hemodynamic support in this animal model.
