Paddy, if rapid response by a trained team in response to a 911 call is important to you, then don't move to the DR. Service like that does not exist. When you live here, you just have to accept the fact that if trained medical care is required within the first few minutes of a heart attack, for example, then you are a goner unless God chooses to let you live another day.
I live in Sosua. In case of a medical emergency, one way or another (including taxi), the victim needs to be gotten to Centro Medico Bournigal for emergency care. Figure about an hour, including the confusion, etc., of figuring out who to call, etc.
Or you can call Servi Med in Cabarete, and a doctor will get to you within an hour. But if you need any medical service, he will arrange to get you to Centro Medico Bournigal.
You can stay at Centro Medico Bournigal, or go to a hospital in Santiago or Santo Domingo by ambulance once you are stabilized, or even by helicopter if your condition warrants it. Since we established all our medical contacts at Clinica Abreu in Santo Domingo, that is where we would go once able to make the trip.
If this doesn't sound like what you are looking for in your retirement years, then you should reconsider your plan to move to the DR.