Potential negative effects of epinephrine on carotid blood flow and ETCO₂ during active compression-decompression CPR utilizing an impedance threshold device

Objectives: This study examines the effects of IV epinephrine administration on carotid blood flow (CBF) and end tidal CO₂ (ETCO₂) production in a swine model of active compression-decompression CPR with an impedance threshold device (ACD-CPR+ITD). Methods: Six female swine (32±1kg) were anesthetized, intubated and ventilated. Intracranial, thoracic aorta and right atrial pressures were measured via indwelling catheters. CBF was recorded. ETCO₂, SpO₂ and EKG were monitored. V-fib was induced and went untreated for 6min. Three minutes each of standard CPR (STD), STD-CPR+impedance threshold device (ITD) and active compression-decompression (ACD)-CPR+ITD were performed. At minute 9 of the resuscitation, 40μg/kg of IV Epinephrine was administered and ACD-CPR+ITD was continued for 1min. Statistical analysis was performed with a paired t-test. p values of <0.05 were considered statistically significant and all values are reported in mmHg unless otherwise noted. Results: Aortic pressure, cerebral and coronary perfusion pressures increased from STD<STD+ITD<ACD-CPR+ITD (p<0.001). Epinepherine administered during ACD-CPR+ITD signficantly increased mean aortic pressure (29±5 vs 42±12, p=0.01), cerebral perfusion pressure (12±5 vs 22±10, p=0.01), and coronary perfusion pressure (8±7 vs 17±4, p=0.02); however, mean CBF and ETCO₂ decreased (respectively 29±15 vs 14±7.0ml/min, p=0.03; 20±7 vs 18±6, p=0.04). Conclusions: In this model, administration of epinepherine during ACD-CPR+ITD signficantly increased markers of macrocirculation, while significantly decreasing carotid blood flow and ETCO₂. This calls into question the ability of calculated perfusion pressures to accurately reflect oxygen delivery to end organs. The administration of epinepherine during ACD-CPR+ITD does not improve cerebral tissue perfusion.