Performance goals for dispatcher-assisted cardiopulmonary resuscitation.

A n estimated 600 000 Americans are victims of sudden , unexpected out-of-hospital cardiac arrests each year. 1 Emergency medical services (EMS) providers attempt resuscitation in 360 000 of these " EMS-treated " individuals. EMS crews declare another 240 000 victims dead on arrival because the cardiac arrest was unwitnessed and the victim's body shows physical signs that death has not just occurred. Approximately 9.5% of EMS-treated cardiac arrest victims survive to hospital discharge. However, if one includes the 240 000 victims in whom EMS does not even attempt resuscitation , the likelihood of surviving an out-of-hospital cardiac arrest in the United States is only 5.7%. Stated differently, only 1 in every 18 out-of-hospital cardiac arrest victims in the United States will survive to hospital discharge. Despite these grim statistics, there are things that can be done to better the odds of survival for at least some of the victims. The likelihood of a favorable outcome increases substantially if the event is witnessed, if it occurs in a public place, if bystanders call 9-1-1 and initiate chest compressions promptly, if the initial rhythm is ventricular fibrillation, if an automated external defibrillator is applied and used, and if there is a prompt EMS response. Most of these variables are not under any one individual's direct control but are subject to chance. A notable exception is bystander chest compressions , which, on average, are being performed in only approximately one third of EMS-worked cardiac arrests, but their frequency can be increased 2-fold when 9-1-1 dis-patchers issue instructions that are carried out promptly and effectively. 2–4 Omission of instructions for mouth-to-mouth ventilation, which many laypersons are unwilling to perform on strangers, does not affect survival adversely because of the presence of agonal respirations and because the lung alveoli contain sufficient oxygen to maintain the arterial oxygen saturation >90% for at least 5 to 6 minutes with chest compressions alone. 5–7 In short, early provision of effective chest compressions can continue to deliver lifesaving oxygen to vital organs such as the brain and can " buy time " for EMS crews to arrive on scene. The 9-1-1 dispatchers can issue chest compression instructions only to a caller who is next to a victim if the dispatcher recognizes that a cardiac arrest has likely occurred. It is well recognized that emergency medical dispatchers can be misled by layperson callers thinking that an unconscious person has …