A Philadelphia emergency medical services coordinator with 15 years' experience in emergency medicine will be the new civilian head of the District's troubled ambulance service, Mayor Marion Barry announced yesterday.

John Michael Cavenagh, 37, was introduced by Barry at an afternoon news conference attended by top city and fire department officials. Barry said Cavenagh "is the first choice, he's the last choice" to head an ambulance division that has been heavily criticized this year for slow response times and sloppy dispatching.

"We have raised the emergency service to a higher level by bringing in a full-time civilian director," Barry said inside Engine Company 4's fire house at 2531 Sherman Ave. NW, adding that he is "committed" to keeping the ambulance division within the fire department.

Between September 1986 and April of this year, there were eight reported cases in which city ambulances were slow getting to patients who later died, and numerous reports of misdirected ambulances and abusive ambulance personnel. Several incidents led to disciplinary action against ambulance division workers.

As the result of an outcry and media reports, a deputy fire chief was named to head the division early this year, but he resigned just weeks after his appointment. In April, Barry announced a search for a full-time civilian director, and another assistant chief was made acting director of the division this summer.

At yesterday's news conference, Cavenagh said, "I made an effort to come here without any preconceived ideas," but he noted that "there are concerns about response times, concerns about the level of training."

The director-designate is a medical coordinator with a division of the Philadelphia Health Management Corp., a private, nonprofit firm that provides a variety of services to the City of Philadelphia, the State of Pennsylvania and foundations in the Philadelphia area.

Cavenagh, who will be paid $68,000 a year, said that he will start work in the District within "weeks or months" and that his objective will be to provide "the highest quality prehospital care in the shortest amount of time" for sick and injured residents.

City Administrator Thomas M. Downs said Cavenagh was chosen for the position from among five candidates, three of whom were seriously considered, and negotiations were completed last week.

Mary Woll, the director of special and emergency care services for the Philadelphia Health Management Corp. and Cavenagh's boss, said Cavenagh is one of four persons in her office who provide clinical classroom training and field training for Philadelphia fire department paramedics.

"They do not have line authority within the fire department," Woll said, as Cavenagh will have here, but act as the "eyes and ears" of the Philadelphia department's medical director, who is also a contractor.

Barry said Cavenagh will be responsible for all civlian and fire department personnel for the city's emergency medical services and announced that Danny Mott, the current program director, will become the acting deputy director of the ambulance divsion.

He added that the city will continue to search for a full-time medical director for the service.

Cavenagh, a physician's assistant who holds an associate medicine degree from Yale University, is a registered emergency medical technician and in 1985 and 1986 was a assistant professor of emergency medicine in the George Washington University medical school here.

All told, since 1973 Cavenagh has held upward of 15 positions in emergency medicine in three states and the District -- including a stint as executive director of a now-defunct Wheaton ambulance service and founder of a paramedic service in Beaver County, Pa. -- and the majority of the positions involved either actual emergency work or training paramedics and emergency medical technicians.

Sharon Spurling, president of the Communications Workers of America local representing dispatchers, said the selection of Cavenagh "gives the civilian personnel a shot in the arm."

Staff writer Karlyn Barker contributed to this report.