Cardiac Arrest

Abstract

The modern treatment of cardiac arrest is an increasingly complex medical procedure with a rapidly changing array of therapeutic approaches designed to restore life to victims of sudden death. The two primary goals of providing artificial circulation and defibrillation to halt ventricular fibrillation continue to evolve since they were established 60 years ago. The evolution of artificial circulation includes efforts to optimize manual CPR, external mechanical CPR devices designed to augment circulation, and may soon advance further into the rapid deployment of specially designed internal emergency cardiopulmonary bypass devices. The development of defibrillation technologies has progressed from bulky internal defibrillators paddles applied directly to the heart, to manually controlled external defibrillators, to automatic external defibrillators that can now be obtained over-the- counter for widespread use in the community or home. But the modern treatment of cardiac arrest now involves more than merely providing circulation and defibrillation. As suggested by a three phase model of treatment, newer approaches targeting patients who have suffered a more prolonged cardiac arrest include treatment of the metabolic phase of cardiac arrest with therapeutic hypothermia, agents to treat or prevent reperfusion injury, new strategies specifically focused on pulseless electrical activity, which is the presenting rhythm in at least one-third of cardiac arrests, and aggressive post resuscitation care. There are discoveries at the cellular and molecular level regarding ischemia and reperfusion pathobiology that may be translated into future new therapies. On the near horizon is the combination of advanced cardiopulmonary bypass plus a “cocktail” of multiple agents targeted at restoration of normal metabolism and prevention of reperfusion injury, as this holds the promise of restoring life to many patients for whom our current therapies fail.

Dissociated Oxygen Consumption and Carbon Dioxide Production in the Post–Cardiac Arrest Rat: A Novel Metabolic Phenotype

“…Patients with long untreated arrest times have the worst outcomes,2, 3, 4 in part because there is much to learn about the injury sustained by patients resuscitated from prolonged CA. The loss of blood flow caused by CA is widely acknowledged to cause a metabolic pathology, but we struggle to measure the effect of this pathology at the bedside.…”

“…There are promising clinical treatments, such as therapeutic hypothermia, ischemic postconditioning, and controlled reperfusion, which improve survival in preclinical studies and are hypothesized to address postresuscitation metabolic disorders 10, 11, 12, 13. However, there are a number of randomized controlled clinical trials that show no benefit,14, 15, 16, 17, 18 in part as a result of the lack of an ability to differentiate patients with treatable metabolic injury, patients who might live with proper treatment, from patients who do not have a metabolic injury, patients who will live, or from patients with untreatable metabolic injury, patients who will not live 4, 19, 20, 21…”

Out of Hospital Cardiac Arrest: A Current Review of the Literature that Informed the 2015 American Heart Association Guidelines Update

“…11,12 This distinction between causative cardiac rhythms in SCA is important given the significantly different survival rates and therapeutic role of defibrillation. The importance of early defibrillation in the management of ventricular defibrillation was demonstrated in a study of patients who experienced in-hospital cardiac arrest; patients who received prompt defibrillation had a survival to discharge rate of 39.3% whereas patients in whom defibrillation was delayed by two minutes or more from the onset of VF had a survival to discharge rate of 22.2%.…”

System for open-chest, multidirectional electrical defibrillation

“…The chance of survival drops by ~5% for every minute of untreated VF (Larsen et al, 1993). Electrical defibrillation, which consists of the application of a brief, high-intensity electrical shock to the heart, is the most effective therapy in the early phase of VF (Koster et al, 2006;Patil et al, 2015).…”