Predictors of Survival From Out-of-Hospital Cardiac Arrest

From Circulation:

Background— Prior studies have identified key predictors of out-of-hospital cardiac arrest (OHCA), but differences exist in the magnitude of these findings. In this meta-analysis, we evaluated the strength of associations between OHCA and key factors (event witnessed by a bystander or emergency medical services [EMS], provision of bystander cardiopulmonary resuscitation [CPR], initial cardiac rhythm, or the return of spontaneous circulation). We also examined trends in OHCA survival over time.

Methods and Results— An electronic search of PubMed, EMBASE, Web of Science, CINAHL, Cochrane DSR, DARE, ACP Journal Club, and CCTR was conducted (January 1, 1950 to August 21, 2008) for studies reporting OHCA of presumed cardiac etiology in adults. Data were extracted from 79 studies involving 142 740 patients. The pooled survival rate to hospital admission was 23.8% (95% CI, 21.1 to 26.6) and to hospital discharge was 7.6% (95% CI, 6.7 to 8.4). Stratified by baseline rates, survival to hospital discharge was more likely among those: witnessed by a bystander (6.4% to 13.5%), witnessed by EMS (4.9% to 18.2%), who received bystander CPR (3.9% to 16.1%), were found in ventricular fibrillation/ventricular tachycardia (14.8% to 23.0%), or achieved return of spontaneous circulation (15.5% to 33.6%). Although 53% (95% CI, 45.0% to 59.9%) of events were witnessed by a bystander, only 32% (95% CI, 26.7% to 37.8%) received bystander CPR. The number needed to treat to save 1 life ranged from 16 to 23 for EMS-witnessed arrests, 17 to 71 for bystander-witnessed, and 24 to 36 for those receiving bystander CPR, depending on baseline survival rates. The aggregate survival rate of OHCA (7.6%) has not significantly changed in almost 3 decades.

Conclusions— Overall survival from OHCA has been stable for almost 30 years, as have the strong associations between key predictors and survival. Because most OHCA events are witnessed, efforts to improve survival should focus on prompt delivery of interventions of known effectiveness by those who witness the event.

Regional Systems of Care for Out-of-Hospital Cardiac Arrest. A Policy Statement From the American Heart Association

From Circulation:

Abstract—Out-of-hospital cardiac arrest continues to be an important public health problem, with large and important regional variations in outcomes. Survival rates vary widely among patients treated with out-of-hospital cardiac arrest by emergency medical services and among patients transported to the hospital after return of spontaneous circulation. Most regions lack a well-coordinated approach to post–cardiac arrest care. Effective hospital-based interventions for out-of-hospital cardiac arrest exist but are used infrequently. Barriers to implementation of these interventions include lack of knowledge, experience, personnel, resources, and infrastructure. A well-defined relationship between an increased volume of patients or procedures and better outcomes among individual providers and hospitals has been observed for several other clinical disorders. Regional systems of care have improved provider experience and patient outcomes for those with ST-elevation myocardial infarction and life-threatening traumatic injury. This statement describes the rationale for regional systems of care for patients resuscitated from cardiac arrest and the preliminary recommended elements of such systems. Many more people could potentially survive out-of-hospital cardiac arrest if regional systems of cardiac resuscitation were established. A national process is necessary to develop and implement evidence-based guidelines for such systems that must include standards for the categorization, verification, and designation of components of such systems. The time to do so is now.