Yes they do, LifeFlight covers a large region, they are not exclusive to one specific area, like any medical air service.
Virginia has the state police "Medivac", up here in New York we have MercyFlight, and numerous others, you'll have to listen to the talkgroup on said system, and then listen for calls in your area, but as I said, their operations in Oregon is listed as "Statewide EMS", so they'll switch to the tower based off what information they need to dispatch for the operations of the area, however I do not see anything listed exclusively to them in Washington.
Does anyone have frequencies for Life Flight, and Emergency in Columbia County, Oregon . . ..and Cowlitz County, Washington . .??