Treatment of prolonged ventricular fibrillation. Immediate countershock versus high-dose epinephrine and CPR preceding countershock.

Abstract

Background. Early countershock of ventricular fibrillation has been shown to improve immediate and long-term outcome of cardiac arrest. However, a number of investigations in the laboratory and in the clinical population indicate that immediate countershock of prolonged ventricular fibrillation most commonly is followed by asystole or a nonperfusing spontaneous cardiac rhythm, neither of which rarely respond to current therapy. The use of epinephrine in doses greater than those currently recommended has recently been shown to improve both cerebral and myocardial perfusion during cardiopulmonary resuscitation (CPR). The purpose of this study was to compare cardiac resuscitation outcome between immediate countershock of prolonged ventricular fibrillation with high-dose epinephrine therapy and conventional CPR before countershock of prolonged ventricular fibrillation in a canine model.Methods and Results. After sedation, intubation, induction of anesthesia, and instrumentation, ventricular fibrillation was electrically induced in 28 dogs. After 7.5 minutes of ventricular fibrillation, animals were randomly allocated to two treatment groups: group 1, immediate countershock followed by recommended advanced cardiac life support (ACLS) interventions, or group 2, 0.08 mg/kg epinephrine and manual closed-chest CPR before countershock and ACLS. In both groups, ACLS was continued until a spontaneous perfusing rhythm was restored or for 20 minutes (total arrest time, 27.5 minutes). A spontaneous perfusing rhythm was restored in three of 14 group 1 animals and in nine of 14 group 2 animals (p=0.014 by sequential analysis method of Whitehead). Coronary perfusion pressure (aortic minus right atrial pressure during CPR diastole) before countershock was significantly greater in group 2 (21+7 mm Hg) when compared with mean circulatory pressure in group 1 (9+8, p<0.01).Conclusions. The findings of this study suggest that a brief period of myocardial perfusion before countershock improves cardiac resuscitation outcome from prolonged ventricular fibrillation. (Circulation 1992;85:281-287)

Adverse Outcomes of Interrupted Precordial Compression During Automated Defibrillation

“…2,20 -23 In addition, there is increasing evidence that after 4 minutes of untreated cardiac arrest, precordial compression may best precede defibrillation. 24 This prompted us to conduct controlled preclinical studies with a focus on the benefits of chest compression and specifically the possibility that interruptions in chest compression may prove detrimental.…”

“…[17][18][19] Yet, the priority of ventilation over precordial compression was challenged and defined as of questionable benefit in settings of "sudden death" based on both experimental and clinical investigations. 2,20 -23 In addition, there is increasing evidence that after 4 minutes of untreated cardiac arrest, precordial compression may best 24 This prompted us to conduct controlled preclinical studies with a focus on the benefits of chest compression and specifically the possibility that interruptions in chest compression may prove detrimental. Chest compression was introduced to modern medicine in the 19th century but was widely adopted only after 1960.…”

Shortening of cardiopulmonary resuscitation time before the defibrillation worsens the outcome in out-of-hospital VF patients

“…In swine with 8 minutes of untreated VF, CPR for 90 seconds followed by defibrillation shock resulted in physiological benefits and a superior response to initial defibrillation in comparison with immediate defibrillation [14]. In a dog model, a brief CPR before defibrillation improved the resuscitation outcome from prolonged VF [15]. Kolarova et al [16] showed that the rate of restored spontaneous circulation increased in proportion to the duration of CPR before defibrillation.…”

“…Several experimental studies reported that CPR before defibrillation had various benefits [14][15][16]. In swine with 8 minutes of untreated VF, CPR for 90 seconds followed by defibrillation shock resulted in physiological benefits and a superior response to initial defibrillation in comparison with immediate defibrillation [14].…”

Inter Association Task Force Recommendations on Emergency Preparedness andManagement of Sudden Cardiac Arrest in High School andCollege Athletic Programs: A Consensus Statement

“…In animals, outcomes improved for prolonged untreated VF when CPR was initiated before defibrillation compared with immediate defibrillation. 30,31 In some clinical studies, 32,33 survival was improved when CPR was initiated before defibrillation in cases of untreated VF lasting longer than 3 to 5 minutes. Thus, as the duration of cardiac arrest increases, initial chest compressions and oxygen delivery to vital tissues may take priority over defibrillation in some patients, with delay of shock delivery until 1 to 2 minutes of CPR has been completed.…”