The annual incidence of out-of-hospital sudden cardiac arrest in the United States is estimated to be 350,000 to 400,000, with approximately 200,000 individuals being treated for in-hospital cardiac arrest. The incidence of ventricular fibrillation (VF) as initial rhythm has declined to less than 30% of the sudden cardiac arrests, both in and out of the hospital, possibly because, as the care of cardiac disease has improved, people who arrest have more severe disease.

Survival to hospital discharge varies greatly among communities in the United States: from 1% to 2% to greater than 20% for patients who receive cardiopulmonary resuscitation (CPR) for any abnormal rhythm out of hospital, and 24% for in-hospital adult cardiac arrests from Get With the Guidelines-Resuscitation 2012 data. The key to successful resuscitation is a well-organized community program, consisting of early recognition and activation, early institution of effective CPR, early defibrillation, and postresuscitation care. Survival has been discouragingly unchanged over decades despite factors such as the number of education programs, the increased availability of defibrillators in public places, and the number of first responders. However, over the last several years, there have been reports of improvements due to changes in CPR, most of which have been compiled in the American Heart Association’s 2010 CPR guidelines, which focus on the most important components of resuscitation—the delivery and effectiveness of those components—and postresuscitation care.

The 2010 guidelines place more emphasis on chest compressions of sufficient depth and rate with minimal interruptions because studies have demonstrated that, in the past, approximately one third of compressions were performed at less than the recommended depth, and pauses in compressions frequently accounted for half of the CPR time. Inadequate compression depth and compression pauses decrease the chance of successful defibrillation occurring, whereas periods of continuous chest compressions before shocks are delivered have been reported to increase the defibrillation success rate for ambulance response times of more than 4 to 5 min. Compressions should be at least 2 inches deep at a rate of 100/min, allowing full chest recoil after each compression.

Other changes during the past decade have been in the type of defibrillator used and in the recommendations for defibrillation. Termination of VF is higher with biphasic defibrillators. Delivering only one shock is recommended, not stacks of three, and the shock should be immediately followed by 2 min of CPR before rhythm or pulse checks are performed (Figure 222-1). In patients with continuous electrocardiographic and hemodynamic monitoring (as might occur in the hospital setting), performance of defibrillation may be modified by the physician in charge, especially for arrests of very short duration, such as in the operating room or intensive care unit. If the patient does not have a secured airway, chest compressions and ventilations are given in a 30:2 ratio, but the importance of ventilation is being questioned, particularly for patients with cardiac arrest of cardiac origin. If the patient has an advanced airway device in place (supraglottic airways are increasingly being recommended, particularly for paramedics and emergency medical technicians), compressions are given without pausing for ventilations, which can be interposed at a rate of 8 to 10/min while 100% O₂