An Automated External Defibrillator (AED) is a portable device designed to deliver an electrical shock to a person experiencing sudden cardiac arrest, helping to restore a normal heart rhythm. These devices are designed for use by the general public in emergency situations. The overall lifespan of an AED unit is determined by the expiration timelines of its individual, replaceable components. Ensuring the device is always ready depends on monitoring and maintaining these core internal parts.
Inherent Lifespan of Core Components
The main electronic unit, which houses the processor and circuitry, typically has a long service life, often ranging from eight to ten years from the date of manufacture. This timeframe is considered the technical lifespan, during which the manufacturer supports the hardware with potential updates and service. The main unit does not technically expire like consumables, but its effective life is limited by technological relevance and manufacturer support.
The battery is the most frequently replaced component, rated for the device’s standby mode. Most AED batteries are disposable lithium units designed to last between two and five years when installed, depending on the model. Even without use, the battery gradually loses its charge and must be replaced before its printed expiration date to guarantee the device can deliver the necessary shock.
Electrode pads, applied to the patient’s chest to deliver the electrical current, also have strict expiration dates. The shelf life for pads is usually between 18 to 30 months. The primary reason for this expiration is the drying out of the conductive gel that coats the pads. If the gel dries, the pads will not adhere properly to the skin or conduct electricity effectively, rendering them useless during an emergency.
Environmental and Usage Factors Affecting Longevity
External conditions play a significant role in shortening the operational life of a defibrillator’s components, independent of stated expiration dates. Storing an AED in an environment with extreme temperature fluctuations, such as a vehicle trunk, can degrade the device. Excessive heat or cold accelerates the deterioration of the battery’s chemical capacity and causes the conductive gel on the electrode pads to dry out prematurely.
High humidity is another factor that negatively affects the electrode pads, potentially compromising the adhesive and conductivity of the gel. The device’s readiness indicator relies on internal self-tests, which the AED performs regularly to check its battery and circuitry. Frequent self-checks, or a failed check that triggers continuous diagnostic chirping, will draw down the battery’s energy faster than normal standby mode.
Physical damage, such as dropping the unit or exposing it to excessive dust or moisture, can compromise the integrity of the electronics and casing. A damaged AED may fail to operate correctly, requiring immediate service or replacement. When the defibrillator is used to deliver a therapeutic shock, it expends a substantial amount of energy from the battery. The battery and used electrode pads must be replaced immediately after any deployment to ensure the device is ready for the next event.
Procedures for Component Replacement and Device Retirement
Maintaining the readiness of an AED requires a proactive system for tracking the expiration dates of its replaceable parts. Establishing a log and setting reminders for upcoming battery and pad expiration dates is the most effective way to ensure continuous operational status. After any use, a new set of electrode pads and a replacement battery must be acquired and installed right away.
Proper disposal of expired or used components is a regulated step in maintenance. AED batteries, especially lithium types, contain hazardous materials and should not be thrown into regular trash bins due to fire risk and environmental concerns. They must be taken to an electronic recycling center or a designated hazardous waste facility.
When the main AED unit reaches the end of its typical eight-to-ten-year lifespan, or if the manufacturer stops making replacement batteries and pads, the device should be retired. The entire unit is considered electronic waste (e-waste) and must be disposed of through a dedicated recycling program or returned to the manufacturer, rather than being discarded with household trash.