Which device is critical in conjunction with early defibrillation?

The critical device in conjunction with early defibrillation is the Automated External Defibrillator (AED). AEDs are designed to quickly assess the heart's rhythm and provide an electric shock if necessary to restore a normal rhythm in cases of sudden cardiac arrest. The effectiveness of early defibrillation is significantly enhanced when an AED is used within the first few minutes of a cardiac event, as this can greatly increase the chances of survival.

While other options may play roles in patient care, they are not designed for defibrillation purposes. Personal Digital Assistants (PDAs) are primarily used for managing information and communication, a cardiac monitor provides ongoing observation of heart rhythms but does not administer shocks, and an inhaler is used for respiratory conditions rather than cardiac emergencies. Therefore, the AED is essential for delivering timely defibrillation during cardiac emergencies, making it the correct choice in this scenario.