The Automated External Defibrillator (AED) delivers an electrical shock to the heart during sudden cardiac arrest, restoring a normal rhythm. When a person is wet from rain, sweat, or proximity to water, the question is whether an AED can be used safely and effectively. The answer is yes, but specific safety and efficacy precautions must be followed before the shock is delivered. Hesitation can be fatal, as the chance of survival decreases by approximately 7 to 10 percent every minute defibrillation is delayed. Therefore, the immediate priority is to act quickly while managing the wet environment to ensure the best outcome for the patient and safety for the rescuer.
Mitigating Risk Essential Safety Steps
The presence of water introduces a risk of electrical current flowing through unintended pathways, potentially endangering the rescuer or bystanders. The first safety action is to immediately move the patient from standing water, such as a pool, large puddle, or completely saturated ground, to the driest possible location. This action minimizes the chance of the defibrillation current traveling through the wet ground and inadvertently affecting others nearby.
If the patient is only slightly damp or lying on a moist surface, moving them is still advisable, but the priority shifts to protecting the rescuer. The person operating the AED should ensure their own feet are on a dry surface, stepping onto a towel or a non-conductive object if necessary. While modern AEDs are designed with sealed cases, never attempt to use the device if the patient is fully submerged in water, as this renders the process unsafe and ineffective.
If the patient has been pulled from a pool or is in a heavy downpour, the focus must be on quickly creating a localized dry zone. Removing wet clothing immediately also helps to prevent the moisture from wicking onto the chest area where the pads will be placed. These steps ensure that the electrical energy is contained and directed only where it is needed.
Maximizing Efficacy Preparing the Patient’s Skin
Water on the patient’s skin can significantly reduce the effectiveness of the defibrillation shock. Water acts as a conductor, creating an easier path for the electrical current to travel across the surface of the skin, rather than penetrating through the chest wall to the heart. This phenomenon is known as “current shunting,” where the energy bypasses the intended target, resulting in a failed shock.
To maximize the chance of a successful shock, the patient’s chest must be dried quickly and thoroughly where the pads will adhere. The goal is to ensure a strong adhesive bond between the pads and the skin, which is impossible if the skin is soaking wet. A towel, clothing, or even a rescuer’s hand can be used to rapidly wipe away moisture, focusing specifically on the areas where the electrodes will be placed.
It is not necessary to dry the entire body, as time is a factor that cannot be wasted. A few seconds spent drying the chest is a worthwhile trade-off to ensure the electrical current successfully crosses the heart. The AED pads are designed with a powerful adhesive, so a chest that is merely damp or slightly moist will usually allow for successful application and current delivery. However, any standing water between the pads must be removed to prevent the current from taking the path of least resistance across the skin’s surface.
Addressing Common Misconceptions and Scenarios
A common fear is that using an AED in the rain will cause the entire surrounding area to become electrified. This misconception is dispelled by modern AED technology and adherence to safety protocols. While water conducts electricity, the current delivered is highly localized between the two defibrillation pads on the patient’s chest.
If sudden cardiac arrest occurs outdoors during a rainstorm, the procedure remains the same: proceed with the AED while making simple accommodations. If possible, use an umbrella or clothing to shield the AED unit from direct exposure, although many modern devices have a high ingress protection (IP) rating, meaning they are resistant to water splashes. The primary concern is ensuring the patient’s chest is dry before applying the pads.
Patient Pulled from Water
A scenario involving a patient pulled from a swimming pool requires immediate removal from the water and relocation to a dry area. The electrical energy of the shock could spread through the water, potentially harming anyone else in the pool, and the shock delivered to the patient would be greatly diminished. Once the patient is on dry land, the focus must shift to drying the chest and applying the pads without delay.
The most dangerous action in any wet scenario is the failure to use the AED due to over-cautiousness. By quickly moving the patient to a dry surface, ensuring the rescuer is not standing in water, and drying the skin beneath the pad sites, the procedure becomes both safe and maximally effective.