Same Shock, Different Defibrillator — the Interface Is the Hazard

Two defibrillator / monitors stocked in the same hospital differ in energy defaults, mode selection (manual vs AED, sync vs defib), button placement, and even labels for the same function. A clinician who moves between models in a crisis carries the wrong mental model — the difference between devices becomes the hazard in the seconds that matter.

A peer-reviewed human-factors study of four manual defibrillators found the number of operator 'assistances' needed for the same tasks ranged from 16 on the easiest device to 63 on the hardest — a roughly fourfold spread in interface difficulty — with non-standard labels, mixed touchscreen / button workflows, and mode-switch traps. Energy defaults also differ by waveform. This is EON's signature lens: not one broken device, but the inconsistency between devices. (Comparative usability of manual defibrillators, Resuscitation Plus, 2024.)

1. Defib A: biphasic, one energy default, a physical mode dial, shock button front-right.
2. Defib B: a different energy default, a touchscreen mode workflow, shock button elsewhere.
3. Defib C: entering AED mode first requires exiting pacing mode — a hidden step.
4. The clinician acts on the layout learned from the last device used.
5. Same intended shock, different delivered action — decided by which model was grabbed.

Usability spread quantified — 16 vs 63 operator assistances across four defibrillators for identical tasks; real-world switching-error rates are not quantified in public sources. (Resuscitation Plus, 2024)

A rescue slowed or misdelivered by an unfamiliar interface. Shown through the two divergent defibrillator faces side by side — never the patient.