The board of the nonprofit corporation that runs three major Prince George's County health facilities last night fired its chairman, Francis J. Aluisi, who had come under attack from county officials, and replaced him with former county executive Winfield M. Kelly Jr.

The corporation, Community Hospital and Health Care Systems Inc., which runs Prince George's General and Greater Laurel-Beltsville hospitals and the Bowie Health Center, has been a focus of controversy recently because of management problems, internal battles and allegations of conflicts of interest.

Aluisi's ouster was called for last week by several county officials, including County Executive Parris Glendening, after an internal memo to the board's ethics committee surfaced questioning the propriety of a trip Aluisi made with a female companion to a Mexican medical school last December.

Their air fare was paid for by a doctor-sponsored fund. Aluisi repeated last night that he had intended to repay the expenses but "there had been a breakdown in the credit and debit posting."

Robert Brady Jr., the corporation's president and its ranking board member, said in a letter to Aluisi made public last night that "unfortunately the mere public revelation of the known facts and the significant public outcry from county officials leaves me no alternative as the president . . . other than to request your immediate resignation from your position as chairman of the board and as a member of the board of directors."

Aluisi stalked out of an executive (closed) session of the board at Prince George's General Hospital last night and declared that his ouster was "orchestrated and the puppets responded to the commands of the leader." He said the ballots for the vote removing him from office "were preprinted."

Aluisi said that during the meeting he "recommended that the entire board should resign and, if not, at least the executive committee, which was the leadership." He said he believed the board had too little power because "all the decisions were made by the president [Brady]."

The hospital corporation was created by the County Council in the summer of 1983. In the last seven months an internal audit as well as a consultant's study said that the three health facilities were poorly run.

Matters came to a head early in July when the management firm Hospital Corporation of America (HCA) was hired to run the three facilities. As a result the top executive officers of the three facilities were fired. The County Council, frustrated by the board's controversies, began discussions about dissolving the corporation.

Last night Aluisi told reporters that "some members of this board have been in negotitions with HCA for a management contract long before the names [of other management firms] were presented to a selection committee." He said he believed that those board members, whom he would not name, were dealing with HCA in exchange for "promises"and "enticements."

Brady, questioned later, called those allegations "balderdash."

HCA management company vice president Corbett Price said, "I have no knowledge of such enticements."

Kelly said last night that the County Council has agreed to "give me some breathing time" and will postpone hearings on a measure that would dissolve the corporation.

The tally of the vote to oust Aluisi was unavailable. The board has 28 members.

Meyer Emanuel, a former state senator who is a member of the board, left the meeting about a half hour after Aluisi's departure and said that board members "were told that the powers that be wanted his Aluisi's head." Emanuel said he defended Aluisi as chairman. He said that although on the ethics issue Aluisi "didn't do the right thing, that's not the issue here."