An Automated External Defibrillator (AED) is a device used to deliver an electrical shock to the heart in cases of sudden cardiac arrest, analyzing the heart’s rhythm and advising a shock if necessary. Transdermal patches are medicated adhesive patches that deliver a specific dose of medication, like nitroglycerin, nicotine, or pain relief compounds, through the skin and into the bloodstream. When a person collapses and requires defibrillation, the presence of a medication patch on the chest or near the site of AED pad placement creates an immediate and serious complication. Understanding this interaction is a necessary part of emergency preparedness for rescuers, whether they are trained professionals or bystanders.
Why Transdermal Patches Must Be Removed
The answer to whether a transdermal patch must be removed before applying an AED is an unequivocal yes. This immediate removal is mandated for two primary reasons: the effective delivery of the electrical current and the patient’s safety. Failure to remove the patch can compromise the entire resuscitation effort, wasting precious seconds needed to restart the heart.
A patch located directly under an AED pad acts as a physical barrier, impeding the transmission of the necessary electrical energy into the chest cavity. This interference significantly reduces the current that reaches the heart muscle, making the defibrillation attempt ineffective. Beyond the issue of energy transmission, leaving the patch in place creates a severe safety hazard. The materials within the patch, especially those with metallic components, can interact dangerously with the high-energy electrical discharge from the AED.
Electrical Risks and Mechanism of Injury
The danger posed by transdermal patches during defibrillation stems from the way the materials within the patch react to the sudden surge of electrical energy. Many patches, particularly those with foil or metal-containing backings, can heat up rapidly due to the high-voltage electrical discharge. This causes a localized thermal injury and can result in severe burns to the skin where the patch was applied.
A second, distinct electrical risk is the potential for electrical arcing, which is the electrical current jumping over the skin’s surface. The metal or other conductive materials in the patch can facilitate this arcing between the AED pad and the skin, or between the two pads themselves. This uncontrolled current path delivers an ineffective shock to the heart while also creating the possibility of a small explosion or fire. Furthermore, the medication within the patch, particularly if it contains alcohol or other volatile substances, can contribute to this arcing and ignition risk.
The patch itself also acts as an electrical insulator, preventing the defibrillation current from passing effectively through the heart. This resistance forces the electrical energy to seek alternate, less efficient pathways. This further compromises the quality of the shock and the chance of a successful resuscitation.
Immediate Rescuer Actions and Pad Placement
Once a transdermal patch is identified, the rescuer must prioritize its removal with the utmost speed and safety. If available, the rescuer should immediately put on gloves before touching the patch to prevent accidental absorption of the medication through their own skin. The patch should be peeled off quickly and discarded, keeping the interruption to chest compressions as brief as possible.
Following the removal of the patch, the skin beneath it must be wiped clean to remove any residual medication and adhesive material. Medication residue, even after the patch is gone, can still interfere with the adherence of the AED pad or conduct electricity. A dry cloth or gauze should be used to thoroughly dry the area, ensuring maximum contact between the AED pad and the skin, which is essential for effective energy delivery.
The standard placement for AED pads involves placing one pad on the upper right side of the chest, just below the collarbone, and the other on the lower left side of the ribcage. If the original patch location is unavoidable for the standard pad placement, the new AED pad should be placed a short distance away from the site where the patch was removed. The most effective course of action is to adhere to the standard placement locations, ensuring both pads are applied to clean, dry, bare skin that is free from any other patches, scars, or implanted devices.