Potential negative effects of epinephrine on carotid blood flow and ETCo2 during active compression-decompression CPR utilizing an impedance threshold device [abstract]
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Background: Early and frequent epinephrine administration is advocated by ACLS; however, epinephrine research has been conducted primarily with standard CPR (STD). Active compression-decompression CPR with an impedance threshold device (ACD-CPR + ITD) has become the standard of care for out of hospital cardiac arrest in our area. The hemodynamic effects of IV epinephrine under this technique are not known.
Objectives: To determine the hemodynamic effects of IV epinephrine in a swine model undergoing ACDCPR+ITD. Methods: Six female swine (32 ± 1Kg) were anesthetized, intubated, and mechanically ventilated. Intracranial, thoracic aorta, and right atrial pressures were recorded via indwelling catheters. Carotid blood flow (CBF) was recorded via Doppler. ETC02, Sp02, and EKG were monitored. Ventricular fibrillation was induced and went untreated for 6 minutes. Three minutes each of standard CPR (STD), STD-CPR+ITD, and ACDCPR+ITD was preformed. At minute 9 of the resuscitation, 40 lg/Kg of IV epinephrine was administered and ACD-CPR+ITD was continued for 1 minute. Statistical analysis was performed with a paired t-test. Results: Aortic pressure and calculated cerebral and carotid perfusion pressures increased from STD < STD+ITD < ACD-CPR+ITD (p ’ 0.001). Epinepherine administered during ACD-CPR+ITD signficantly increased mean aortic (29 ± 5vs42 ± 12, p = 0.01), cerebral (12 ± 5 vs 22 ± 10, p = 0.01), and coronary perfusion pressures (8 ± 7 vs 17 ± 4, p = 0.02); however, mean CBF and ETCO2 decreased (respectively 29 ± 15 vs 14 ± 7.0, p = 0.03; 20 ± 7 vs 18 ± 6, p = 0.04). Conclusion: The administration of epinepherine during ACD-CPR+ITD signficantly increased markers of macrocirculation, while significantly decreasing ETCO2, a proxy for organ perfusion. While the calculated cerebral perfusion pressures increased, the directly measured CBF decreased. This calls into question the ability of calculated perfusion pressures to accurately reflect blood flow and oxygen delivery to end organs.