Abstract 19: Does Prearrest Adrenergic Integrity Affect Pressor Response? A Comparison of Epinephrine and Vasopressin in a Spontaneous Ventricular Fibrillation Swine Model
Objectives: Coronary perfusion pressure (CPP) during resuscitation from cardiac arrest has been shown to correlate with return of spontaneous circulation. Beta blockers are commonly prescribed to patients at risk of sudden death. We sought to compare the CPP response to vasopressin vs. epinephrine in a swine model of cardiac arrest following pre-arrest adrenergic blockade.
Methods: Eight anesthetized and instrumented swine were administered 0.1 mg epinephrine and arterial pressure and heart rate response were measured. An infusion of labetalol was then initiated and animals periodically challenged with epinephrine until adrenergic blockade was confirmed. The LAD was occluded to produce VF. After 7 minutes of untreated VF, mechanical chest compressions were initiated. After 1 minute of compressions, 1 mg epinephrine was given while CPP was recorded. When CPP values had returned to pre-epinephrine levels, vasopressin, 40U, was given. Differences in CPP (post-vasopressor - pre-vasopressor) were compared within animals for the epinephrine and vasopressin response and with eight, non-beta blocked, historical controls using Bayesian statistics with a non-informative prior.
Results: The CPP response following epinephrine was 15.1 mmHg lower in beta-blocked animals compared to non-beta blocked animals (95% Highest Posterior Density [HPD] 2.9 – 27.2 mmHg lower). CPP went up 18.4 mmHg more following vasopressin when compared to epinephrine (95% HPD 8.2 – 29.1 mmHg). The posterior probability of a higher CPP response from vasopressin (vs. epinephrine) was 0.999. The posterior probability estimates for the CPP response following vasopressor administration are shown in the table.
Conclusions: Pre-arrest adrenergic blockade blunts the CPP response to epinephrine. Superior augmentation of CPP is attained with vasopressin under these conditions. Prearrest medical therapy may affect response to resuscitation interventions.
- © 2010 by American Heart Association, Inc.