Please, check the current vote about a final tag for external and automated defibrillators. It’s here: http://wiki.openstreetmap.org/wiki/Proposed_features/automated_external_defibrillator#Voting_.282nd.29

Currently, we have 2 tags “medical=aed” and “emergency=aed” but the use of abbreviations and the move from “medical” to “emergency” has never been really approved by the community. Now you have the choice !