To try and enlighten people on the cost of operating ANY helicopter for EMS(or police), all one has to do is to look to many jurisdictions in North America. Being from Canada I will use that as an example.
In Alberta, where I was before coming here to Antigua, STARS has been the main EMS provider. It is a non-profit organisation that uses charitable donations and fundraisers for its operating revenue. When I left ten years ago they had 3 helicopters in 2 cities. These cities combined (and the surrounding communities) comprise nearly 2 million people. The provincial and munincipal governments could not justify the need with the cost. The police in Calgary have a helicopter, it was also paid for by charitable donations and fundraisers, for the same reasons. And Alberta is one of the wealthiest provinces in Canada as well.
In Toronto, the munincipal authorities still cannot justify spending the money on a police helicopter in an area that is roughly 6 million people.
So now put that into perspective with our small island populations and it can be deduced that the revenue needed to run a helicopter (police or EMS) is just not there with such a small population base.
Helicopters are very expensive toys, that's why we don't see many (in relation to airplanes)parked at airports around the world. With a 4 to 6 passenger helicopter, you can triple or quadruple the operating costs of a similar sized airplane. That doesn't include the purchase price.