Cautionary Note regarding calling a helicopter:
Note......they are expensive and generally speaking, someone or some organization will get hit with the bill if the bird is not government owned, operated or funded.
Unless there is extenuating circumstances, rely on the local authorities (medical) to make the call and manage the site. Since we're talking about medical response and not a SAR's response, there is a very good chance the helicopter is owned/operated by a hospital/air ambulance service/contractor/etc. so they will bill it out as such ($8k - $10k plus depending on level of medical care, airtime, etc...) and your insurance may or may not cover it....Check the small print in your policy since it will specifically say. The only time I've seen medevac aircraft not bill out it's airtime is during an agency assists (SAR's, emergencies, etc....)
Finally, there is a whole safety/operating protocol for dealing with helicopters in the wild, such as: communication, inbound prep, landing site survey/selection, landing, prop wash issues, movement around the aircraft, loading and take-off. FWIW.