The time it takes for an AED to analyze a cardiac arrest victims electrocardiogram, charge and deliver a shock is called the hands-off interval because cardiopulmonary resuscitation (CPR) chest compressions must stop then. Researchers found indications that the shorter the time between stopping chest compressions and when a shock is delivered, the better a persons chance of surviving ventricular fibrillation. Ventricular fibrillation is the chaotic heart rhythm that causes cardiac arrest and sudden cardiac death.
According to the American Heart Association, about 250,000 people a year die of coronary heart disease without being hospitalized. Thats about half of all deaths from coronary heart disease more than 680 Americans each day. Most of these are sudden deaths caused by cardiac arrest. Our study suggests that not only do you need to act quickly to get an AED on the scene of a cardiac arrest, but you also should move as quickly as possible from CPR to defibrillation, says study author Trygve Eftestol, Dr. Ing., an associate professor at Stavanger University College, Stavanger, Norway.
To determine the link between the hands-off interval and survival, researchers studied 634 hands-off intervals in 156 patients with ventricular fibrillation in which AEDs were used for resuscitation attempts. The duration of hands-off intervals varied by a median of 20 seconds.
Researchers grouped cardiac arrest victims according to their initial probability (high, medium or low) of return of spontaneous circulation (ROSC), which was estimated from the starting point of the ECG readings of their hands-off intervals.