Abstract 139: A Short Pause in Chest Compressions Before Defibrillation Increases the Chance for Successful Return of Spontaneous Circulation During CPR
Background: Minimizing chest compression interruptions during CPR has been associated with improved outcomes in patients with cardiac arrest. Delivering defibrillation shocks while performing chest compressions may offer an advantage. We hypothesized that delivering shocks with on going chest compressions would be superior to a pre-shock compressions pause of ten seconds in achieving ROSC following the shock.
Methods: 39 pigs had 15 minutes of untreated ventricular fibrillation. Animals received standard CPR for 4 minutes before the first biphasic 150 J DC defibrillation attempt. If animals did not achieve return of spontaneous circulation (ROSC), shocks were attempted every 30 seconds for a total of 3 times at which time another 2-min cycle of CPR was performed until the next shock. All animals received one dose of 0.5 mg of epinephrine one minute before the first shock. Animals were randomized to receive the first shock either during on going compressions or after a 10 second pause in compressions. The subsequent shocks were delivered in a 2:1 fashion either during continuous compression or after following a 10 second pause respectively. After shock delivery, CPR was immediately restarted. ROSC was assessed by the rise of the diastolic aortic pressure and the presence of QRS complexes between compressions artifacts and verified by stopping compressions. ROSC was defined as first occurrence of QRS resulting in MAP >50mmHg for more than 30 seconds.
Results: A total of 149 biphasic shocks (200J) were delivered. 38 shocks were successful and achieved ROSC in 38 pigs. Resuscitated pigs received on average 3.8±2 shocks. 20 out of 49 shocks (40%) delivered after a 10-sec pause of chest compressions resulted in ROSC. Only 18 out of 101 shocks (18%) delivered during ongoing chest compressions resulted in ROSC. Shocks delivered after a 10-sec pause of chest compressions significantly increased the chance to convert VF into ROSC compared to shocks delivered during chest compression [Odds Ratio: 3.87, 95% CI (1.81-8.2); p=0.0005].
Conclusion: Contrary to our hypothesis, after prolonged untreated VF and 4 minutes of CPR, a 10 second pause in chest compressions before defibrillation shock delivery was significantly associated with a higher chance of ROSC
- © 2012 by American Heart Association, Inc.