Democrat Michael Dukakis promised to institute a program of basic health care for poor women and children as the two White House contenders devoted the final days before their presidential debate to cramming for the face-to-face encounter.

While Vice President Bush spent Wednesday engaging in a mock debate and in briefings with advisers, Dukakis conferred with Sen. Bill Bradley of New Jersey on the Sunday night faceoff that was still dogged by logistics problems over lectern heights and the composition of the panel.The Democratic nominee, according to campaign sources, scheduled his own mock debate on Friday and planned to meet with two governors well-versed in the successes and pitfalls of public speaking - Mario Cuomo of New York and Bill Clinton of Arkansas.

Bush, who has limited campaign appearances this week to concentrate on the debate, was making a special exception Thursday for two events, an appearance with President Reagan in Houston and an endorsement from an unusual source.

The Boston Police Patrolman's Association, the largest law enforcement in New England, voted unanimously Wednesday to back Bush's candidacy, saying the Republican - not Massachusetts Gov. Dukakis - would be more attentive to the needs of law enforcement.

Dukakis downplayed the endorsement, citing the association's "history of supporting Republicans" and the backing he has received from other law enforcement organizations, including the Massachusetts Police Association, the International Brotherhood of Police Officers and the Combined Law Enforcement Associations of Texas - Bush's home state.

Nevertheless, Bush campaign spokeswoman Alixe Glen said the vice president will venture into his rival's back yard Thursday to accept the endorsement from the union, which represents 1,500 members.