An Automated External Defibrillator (AED) delivers an electric shock to restore a normal heart rhythm during sudden cardiac arrest. While AEDs are designed for public use, certain environmental factors require immediate attention to maintain treatment effectiveness. Moisture on the patient’s body, especially on the chest, introduces both a safety concern and a procedural challenge for successful defibrillation. Addressing a wet chest quickly is necessary to ensure the life-saving shock reaches the heart muscle effectively.
The Electrical Hazard of Moisture
Moisture, whether from sweat, rain, or being pulled from water, is a conductor of electricity and presents two primary risks during defibrillation. The most immediate concern is that water on the skin allows the electrical current to bypass the heart, reducing the energy delivered to the organ. Instead of the shock penetrating the heart to reset the electrical rhythm, the current may travel across the surface of the chest between the AED pads. This electrical shunting results in an ineffective shock, which significantly decreases the patient’s chance of survival.
The presence of water also introduces a potential safety risk to the rescuer and any bystanders. If the patient is lying in a puddle of water, the electrical discharge can travel through the water and potentially cause a minor sensation or shock to anyone touching the patient. While AED manufacturers have worked to minimize this stray conduction, the fundamental principle remains: a dry environment is always safer and more effective for the procedure.
Step-by-Step Action for a Wet Chest
When encountering a patient with a wet chest, the priority is to dry the area where the AED pads will be placed as quickly as possible. First, the chest must be exposed by cutting or tearing away any clothing, including wet garments, to gain direct access to the skin. Many AED kits include a small pair of scissors for this purpose.
Next, thoroughly wipe the chest area dry using a towel, cloth, or any absorbent material immediately available. This step is crucial because even a thin film of moisture will interfere with the pads’ ability to adhere firmly to the skin. The adhesive on the pads must create a secure, air-free seal to ensure that the electrical energy is directed into the body. If the pads do not stick properly due to wetness, the electrical current can arc or flash over, which reduces the shock’s effectiveness.
The drying process must focus on the entire area where the pads will make contact, and it must be done quickly. Once the skin is completely dry, the pads can be applied firmly, with one pad placed on the upper right side of the chest below the collarbone and the other on the lower left side below the armpit. Immediately after the pads are secured, the cable is connected to the AED, and the device is turned on to begin analysis.
Handling Extreme Wet Conditions
In scenarios involving extreme wetness, such as a patient found in a downpour, lying in a large puddle, or partially submerged, simply drying the chest is not enough. If the patient is in standing water or is significantly saturated, the first action is to safely and quickly move the individual to a dry location. A dry, non-conductive surface, such as a dry patch of ground or a wooden deck, is necessary to isolate the patient and prevent the electrical current from spreading.
If moving the patient is not immediately possible, rescuers should try to minimize the amount of water between the patient and the ground, and ensure they are not standing in water themselves during the shock delivery. While the risk of significant electrical shock to the rescuer in wet conditions is low with modern AEDs, safety protocols still advise caution.
The focus must remain on creating a dry island for the patient, which may involve using a towel or a piece of dry clothing to absorb water from the surrounding area. If the wet condition is due to heavy rain, the rescuer should attempt to shield the patient and the AED unit from further water exposure, perhaps by using an umbrella or moving under a temporary cover. Addressing the environmental hazard first, followed by thoroughly drying the patient’s skin, is necessary to ensure both rescuer safety and the highest chance of a successful defibrillation.