Abstract 2661: Prompt Post-shock Chest Compressions Improves Outcome in a Model of Out-of-Hospital VF with Acute Myocardial Infarction
Introduction: Out-of-hospital VF cardiac arrests typically defibrillate into a pulseless rhythm (asystole or pulseless electrical activity). Many of these arrests are associated with acute myocardial infarctions. The first defibrillator available is generally an automated external defibrillator (AED) with instructions to keep hands off the victim after each shock during requisite delays for automated rhythm analyses and shock advisories. Therefore, the first post-shock chest compressions (CC) are often delayed 40 – 60 seconds. Because delays in CC prevent the necessary myocardial perfusion for successful resuscitation from a pulseless rhythm, a brief period of post-shock CC may be a superior resuscitation strategy.
Hypothesis: In a swine model of out-of-hospital VF with acute myocardial infarction, 48-hour survival is improved by prompt post-shock CC compared with standard AED care.
Methods: After placing a steel plug in the mid-left anterior descending coronary artery and then 5 minutes of untreated VF followed by a 200J biphasic shock, 50 swine (27±1 kg) were randomly provided with:
standard AED care (with typical delays before post-shock CC) or
2 minutes of prompt post-shock CC without regard to cardiac rhythm; each followed by simulated out-of-hospital resuscitation.
Successfully resuscitated animals received 2 hours of intensive care support and were evaluated for 48-hour survival and neurologic outcome.
Results: Animals did not differ in terms of pre-VF hemodynamics, blood gases, or weights. Return of spontaneous circulation (ROSC), 48-hour survival (Surv-48), and good neurologic outcome (Good Neuro) in Table⇓. Swine with Good Neuro were grossly normal (Cerebral Performance Category-1).
Conclusion: In this swine model of out-of-hospital VF with an acute myocardial infarction, prompt post-shock chest compressions resulted in better outcomes than AED care with delay of post-shock CC until after simulated rhythm analysis and shock advisory.