Acls

Part 3: Overview of CPR
e have always known that CPR is not a single skill but a series of assessments and interventions. More recently we have become aware that cardiac arrest is not a single problem and that the steps of CPR may need to vary depending on the type or etiology of the cardiac arrest. At the 2005 Consensus Conference researchers debated all aspects of detection and treatment ofcardiac arrest. Yet the last summation returned to the beginning question: how do we get more bystanders and healthcare providers to learn CPR and perform it well?

W

Epidemiology
Sudden cardiac arrest (SCA) is a leading cause of death in the United States and Canada.1–3 Although estimates of the annual number of deaths due to out-of-hospital SCA vary widely,1,2,4,5 data from the Centers forDisease Control and Prevention estimates that in the United States approximately 330 000 people die annually in the out-of-hospital and emergency department settings from coronary heart disease. About 250 000 of these deaths occur in the out-of-hospital setting.1,6 The annual incidence of SCA in North America is 0.55 per 1000 population.3,4

some blood to the coronary arteries and brain.18,19 CPRis also important immediately after shock delivery; most victims demonstrate asystole or pulseless electrical activity (PEA) for several minutes after defibrillation. CPR can convert these rhythms to a perfusing rhythm.20 –22 Not all adult deaths are due to SCA and VF. An unknown number have an asphyxial mechanism, as in drowning or drug overdose. Asphyxia is also the mechanism of cardiac arrestin most children, although about 5% to 15% have VF.23–25 Studies in animals have shown that the best results for resuscitation from asphyxial arrest are obtained by a combination of chest compressions and ventilations, although chest compressions alone are better than doing nothing.26,27

Differences in CPR Recommendations by Age of Victim and Rescuer
Simplification
The authors of the 2005 AHAGuidelines for CPR and ECC simplified the BLS sequences, particularly for lay rescuers, to minimize differences in the steps and techniques of CPR used for infant, child, and adult victims. For the first time, a universal compression-ventilation ratio (30:2) is recommended for all single rescuers of infant, child, and adult victims (excluding newborns). Some skills (eg, rescue breathing withoutchest compressions) will no longer be taught to lay rescuers. The goal of these changes is to make CPR easier for all rescuers to learn, remember, and perform.

Cardiac Arrest and the Chain of Survival
Most victims of SCA demonstrate ventricular fibrillation (VF) at some point in their arrest.3–5 Several phases of VF have been described,7 and resuscitation is most successful if defibrillation isperformed in about the first 5 minutes after collapse. Because the interval between call to the emergency medical services (EMS) system and arrival of EMS personnel at the victim’s side is typically longer than 5 minutes,8 achieving high survival rates depends on a public trained in CPR and on well-organized public access defibrillation programs.9,10 The best results of lay rescuer CPR andautomated external defibrillation programs have occurred in controlled environments, with trained, motivated personnel, a planned and practiced response, and short response times. Examples of such environments are airports,9 airlines,11 casinos,12 and hospitals (see Part 4: “Adult Basic Life Support”). Significant improvement in survival from out-ofhospital VF SCA also has been reported inwell-organized police CPR and AED rescuer programs.13 CPR is important both before and after shock delivery. When performed immediately after collapse from VF SCA, CPR can double or triple the victim’s chance of survival.14 –17 CPR should be provided until an automated external defibrillator (AED) or manual defibrillator is available. After about 5 minutes of VF with no treatment, outcome may be better if...