There was a recent (very rare) event in Connecticut (USA) where a spark from a Defibrillator caused a fire on the patient in an ambulance. This event would certainly be a concern in the confined area of a rotorcraft with a potentially oxygen rich environment around the patient. Perhaps procedures developed for use in flight could address (reduce) chance of sparking.
Details of the event are at the following links:
EMS Network
http://www.cnn.com/TRANSCRIPTS/0401/29/lol.02.html