It's been some time since the North Brookfield Emergency Medical Service has been on sound financial footing, and its future is uncertain at best. And among private, nonprofit ambulance services in Central Massachusetts, that is more and more the norm, rather than the exception. In a league of their own, the nonprofits don't have the revenue stream of private "for-profit" ambulance services that do more patient transports than emergency runs, nor do they have the access of municipal ambulance services to taxpayer dollars.