Abstract 84: Lack of Epinephrine Effect on Hemodynamics, VF Waveform Characteristics and Resuscitability during Prolonged Cardiac Arrest in Pigs
Background: Epinephrine is recommended at fixed intervals during CPR, although the hemodynamic and clinical effects of repetitive doses are questioned. VF waveform analysis predicts coronary perfusion pressure (CPP) and resuscitability. We hypothesized that epinephrine administration after prolonged cardiac arrest does not affect hemodynamics and resuscitability in pigs.
Methods: After four minutes of cardiac arrest, followed by four minutes of BLS and six minutes of ACLS (with epinephrine 0.02 mg kg-1), 14 pigs were randomized (at T0 minutes) to receive a second dose of epinephrine (0.02 mg kg-1) or saline in a peripheral vein followed by ACLS with continuous mechanical chest compressions for three minutes (T1, T2, T3) and a single attempt of defibrillation. CPP, cortical cerebral blood flow (CCBF), femoral blood flow (FBF), and VF waveform (Slope) were analyzed in minute intervals. Autopsy was performed immediately after euthanasia.
Results: There were no differences in CPP, Slope (Table⇓), CCBF or FBF between the epinephrine and placebo group at any time point. Four pigs achieved return of spontaneous circulation (ROSC), three in the epinephrine and one in the placebo group, OR (95% CI) 4.5 (0.3, 60), P=0.6. A “stone heart” was present in four and five pigs in the epinephrine and placebo groups, respectively. Significant differences in CPP, CCBF and Slope values were seen in pigs that achieved ROSC (n=4) vs. no-ROSC (n=10) (table⇓) and in pigs that did not develop “stone heart” (n=5) vs. those that developed “stone heart” (n=9) at all time points. No pigs that developed “stone heart” had ROSC.
Conclusion: The second dose of epinephrine administered fourteen minutes after cardiac arrest did not have significant hemodynamic effects on CPP compared to placebo. The lack of effect may be due to the development of “stone heart”. ROSC was predicted by VF waveform analysis.