An Automated External Defibrillator (AED) is a medical device designed to deliver an electrical shock to a person experiencing sudden cardiac arrest. The success of this life-saving intervention hinges on the condition of its components, particularly the electrode pads. These pads are the interface between the device and the patient, monitoring the heart’s rhythm and conducting the defibrillating electrical current. Because the pads are the only way for the AED to analyze the situation and deliver therapy, their readiness is critical, which is why their expiration date demands attention.
The Critical Answer: Should Expired Pads Be Used?
Expired AED pads should not be considered a reliable option for a rescue, and standard protocol requires their immediate replacement when the expiration date is reached. Using expired consumables introduces an unnecessary risk of compromised performance during a time-sensitive event. The manufacturer’s expiration date acts as a guarantee of the pads’ effectiveness and reliability, ensuring they will function as designed when needed most.
However, in the rare situation of a witnessed cardiac arrest where an AED is present but the pads are expired, and no other pads are immediately available, the expired pads should still be used. A diminished chance of success with potentially faulty pads is better than no chance at all. This represents an absolute last resort, underscoring that routine maintenance is the only way to guarantee the device is rescue-ready.
Understanding Pad Degradation and Failure Points
The expiration date printed on AED pads (typically 18 to 30 months) is directly related to the physical and chemical breakdown of their materials. The most significant factor is the degradation of the conductive hydrogel applied to the surface. This gel reduces electrical resistance and ensures a seamless pathway for the therapeutic shock to reach the heart.
Over time, even within a sealed package, this conductive gel can dry out, reducing its ability to adhere properly to the patient’s skin. Poor adhesion creates a gap between the pad and the chest, increasing electrical resistance. This can cause the shock to be ineffective or result in skin burns. If the pads do not stick firmly, they may detach during cardiopulmonary resuscitation (CPR) compressions, interrupting rhythm analysis and therapy delivery.
Reduced conductivity from the degraded gel also impairs the AED’s ability to accurately analyze the patient’s heart rhythm. The pads contain sensors that monitor electrical activity, and a poor connection can lead to an inaccurate assessment or prevent the AED from advising a shock. This degradation compromises the entire life-saving sequence.
Protocol for Replacement and Unit Maintenance
Maintaining an AED requires a proactive approach focused on all consumable components, including pads and batteries. Both have specific shelf lives and must be tracked carefully, as the AED is only as functional as its weakest link. Most manufacturers recommend a visual inspection at least monthly to confirm the readiness indicator light is green.
The electrode pads should be replaced immediately after a single use, regardless of whether a shock was delivered, as they are single-use items. The expiration date must be checked regularly, and replacement pads should be ordered in advance to prevent any gap in readiness. Battery life typically ranges from two to five years and should be monitored with the same diligence.
It is helpful to establish a maintenance log or schedule to track all expiration dates for adult pads, pediatric pads, and the battery. Adherence to the manufacturer’s specific guidelines for replacement is paramount, ensuring the device remains compliant and reliable. Failing to replace expired components can lead to complete device failure during an emergency.