Improving survival in out of hospital cardiac arrest a prospective synthesis of best practice

Cardiac arrest is the leading cause of death in the United States. By reviewing and analyzing the successes and failures of resuscitation efforts, it has been possible to identify critical components which have come to be known as the “Chain of Survival:” Early Recognition, Early CPR, Early Defibrillation, Early ALS, and Early Post Resuscitative Care. A failure in any one of the five links will result in a failed resuscitation. Early Recognition is the beginning of the resuscitation effort and includes a number of related components. Witnessed cardiac arrests, those that are seen or heard to occur, have a significantly higher chance of survival than those which are unwitnessed. Properly identifying agonal gasps: irregular, forceful, reflexive breaths which can occur during cardiac arrest, is key to recognition of arrest and activation of the emergency response system. Emergency dispatchers trained to recognize cardiac arrest, as well as to initiate Early CPR via telephonic instruction, have been identified as key personnel in the resuscitation effort. Once professional rescuers have been dispatched, response delays due to distance and traffic can be costly. The use of new technologies like GPS and traffic signal preemption (as well as the use of Police, Fire and EMS in conjunction) has been shown to make it possible to get qualified persons to the scene of a cardiac arrest more safely and more quickly. Once on scene, early, high quality CPR has been shown to dramatically improve survival. After just 8 minutes without assistance, a victim of cardiac arrest has a near zero percent chance of survival. CPR of high quality has been shown to help maintain survivability until more definitive care can be obtained. Early Defibrillation is another key component to survival in many cardiac arrests. While CPR can sustain organ function briefly, cardiac arrest is rarely reversed without defibrillation. Increasingly widespread prevalence of public automated external defibrillators (AEDs) has made Early Defibrillation easier. Furthermore, increased use of AEDs by lay and professional rescuers has called into question the value of more traditional, higher risk interventions like intubation and medication administration. Early ALS interventions have been a staple of resuscitation for decades, but there is little data to support the use of these interventions during cardiac arrest. Early Post-Resuscitative Care, however, has been shown to be an area where invasive ALS interventions can and do make a difference in improved survival. By looking at the body of research for links in the Chain of Survival, opportunities for improvement of resuscitation were identified. Persons who spend significant time around an individual at high risk for heart disease should be educated on possible precipitating symptoms of a myocardial infarct or other early signs of potential cardiac arrest. Persons likely to encounter a cardiac arrest should likewise be trained not only in how to recognize cardiac arrest (through the combination of unresponsiveness and abnormal breathing) but also to initiate basic care via compressions-only CPR. Emergency dispatchers should be increasingly trained to recognize cardiac arrest, as well how to effectively provide dispatcher assisted CPR. The focus of these efforts should be high quality CPR and the early deployment of defibrillation. The use of AEDs by bystanders should be encouraged whenever possible. The emphasis on CPR and use of an AED should be paramount, with invasive ALS interventions eschewed for the simpler and more effective therapies. Once ROSC has been obtained, the use of ALS interventions in unstable patients has been shown not only to prevent death due to transient hemodynamic instability, but also to improve the likelihood of survival with little to no neurological deficit. By embracing the chain of survival, and identifying the critical areas in need of research and improvement, it is possible to provide recommendations that may lead to improved survival from cardiac arrest