OVERVIEW OF CARDIAC ARREST
EPIDEMIOLOGY OF CARDIAC ARREST
Cardiac disease is the most common cause of death in the United States, with estimates ranging between 300,000 and 500,000 deaths annually. The American Heart Association (AHA) estimates that there are approximately 359,000 out-of-hospital cardiac arrests each year. As few as one-fourth of these patients will have an attempted resuscitation. Only 3–11% of prehospital arrests will survive to discharge and have a reasonable functional recovery. Sudden cardiac death is often associated with an underlying history of coronary artery disease, which is seen in 80% of patients. Other causes include massive pulmonary embolism, renal failure, hypoglycemia, thyrotoxicosis, trauma, illicit drugs, and medications. The most common rhythms associated with cardiac arrest are ventricular arrhythmias (ventricular fibrillation [VF] and ventricular tachycardia [VT]). Asystole and pulseless electrical activity (PEA) are the next most common rhythms, at the time of first intervention.
DETERMINANTS OF CARDIAC ARREST SURVIVAL
The two most important factors for survival in the undifferentiated adult cardiac arrest victim are minimizing the elapsed time from patient collapse and the onset of effective cardiopulmonary resuscitation (CPR) and rapid defibrillation. Unfortunately, as many as 85% of arrests occur at home and not in a public place where there may be access to a defibrillator. Studies with patients in VF have demonstrated that for every minute that passes without intervention, the odds of survival decreases by 7–10% (decreased to 3–4% with effective CPR). Other factors related to a positive outcome include witnessed cardiac arrest and early use of advanced life support (ALS). Factors associated with poor prognosis include dyspnea as the presenting complaint, malignancy or sepsis as the underlying cause of cardiac arrest, coexistence of pneumonia, prolonged anoxia, presence of hypotension prior to cardiac arrest, and increasing age.
A patient who is not successfully resuscitated in the field is unlikely to be resuscitated in the emergency department. The risks of transporting a patient who remains in cardiac arrest after ALS procedures have been performed in the field may outweigh the likelihood of a successful resuscitation with good neurologic outcome. Medical directors should consider protocols to determine death and termination of resuscitative efforts in the field.
THE TEAM APPROACH TO CARDIAC ARREST
A resuscitation team has many pivotal participants in a cardiac arrest: the first responder, emergency medical service (EMS) personnel, the emergency department resuscitation team leader, emergency department resuscitation team members, and ancillary personnel. A successful resuscitation depends on a functional team. The responsibilities and expectations for each member must be identified prior to a resuscitation. Attempting to assign these roles after a resuscitation has already begun and will simply add confusion to an already chaotic situation.
The composition of the resuscitation team is based largely on resource availability and institutional preferences. There must be a team leader who is responsible for the ...