The Food and Drug Administration (FDA) approved the first automatic external defibrillator (AED) to be sold without a prescription. Philips Medical System's (Andover, Mass.) HeartStart home defibrillator was specifically designed for lay users, and is approved for use on adults and children who are 8 years of age or older and weigh at least 55 pounds. To use this device on infants and young children, special smaller pads must be obtained by prescription.
The device is intended for use when a person is believed to be in sudden cardiac arrest, does not respond when shaken, is not breathing normally, and has no other signs of circulation. It is not to be used if the person is responsive when shaken or breathing normally.
Once activated, the HeartStart AED guides the user through each step, beginning with attaching the adhesive pads to the victim's bare chest according to the pictures on the pads. Instructions are paced to the user's actions.
When the pads are attached, the defibrillator immediately begins to analyze the person's heart rhythm and detect rhythms that require defibrillation. If the device determines that a shock is needed, there are clear, calm voice instructions and visual prompts guide the user through the defibrillation process. HeartStart then delivers a dose of low-energy biphasic therapy. If a shock is not needed, the device indicates this and coaches users through cardiopulmonary resuscitation (CPR) if necessary. The defibrillator's internal memory can verbally recount events from the last clinical use.
The FDA approved the Heart-Start home defibrillator for nonprescription sale based on its review of data showing that the device could be used without medical supervision. According to the FDA, Philips had to demonstrate that HeartStart could be used safely and effectively by untrained users.
HeartStart is intended for use when a person is believed to be in sudden cardiac arrest.
The HeartStart AED comes with instructions for users to obtain training in CPR in case it is needed instead of a shock. Users are also reminded to call 911 immediately in the event of a possible cardiac arrest.
The HeartStart AED performs daily self-tests to ensure that it will work properly when needed. The typical battery life for the lithium battery is 4 years. The battery capacity delivers a minimum of 90 shocks, or 3 hours of operating time.
Clinician's Critique
Sudden cardiac arrest occurs about every 2 minutes in the United States, and more than 70% occur at home. Studies have shown that if the time from witnessed cardiac arrest to defibrillation can be shortened to less than 4 minutes, survival rates are greatly increased. 1
The spouse (or primary home caregiver) should be required to successfully complete a CPR/AED training course in order to obtain the AED. In addition, the caregiver should routinely practice and fine-tune her skills. We also can not forget about the psychological effects this will undoubtedly have on the care-giver, for example, what if her efforts are not successful, or if her husband survives but experiences severe neurological sequelae?
Further evidence is on the horizon. The Home Automatic External Defibrillator Trial (HAT), sponsored by the National Heart, Lung, and Blood Institute, is currently recruiting patients. The purpose of HAT is to compare home use of an AED to the local emergency medical system in myocardial infarction survivors. The study will not only look at survival rates, but post-arrest neurological impairments and the patient's and spouse's (caregiver's) quality of life. It is expected to be completed in August 2007. 2
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