Gilbert Gude, a former House member from Maryland who has headed the Congressional Research Service for the past eight years, announced yesterday that he is resigning as director of the agency.

The Social Security Administration has promoted three people to senior jobs in implementation of its systems modernization plan designed to upgrade SSA's aging computer system. F. Cary Green will become director of the Office of Strategic Planning and Integration. D. Dean Mesterham who will become director of the Office of Computer Processing Operations in SSA's national computer processing center, one of the largest automatic data processing centers in the nation, which prints Social Security cards, maintains wage records and processes beneficiary data for the nation. David D. Truax will have responsibility for planning, management and procurement of ADP equipment, software and services for SSA's data centers. All three have considerable experience outside SSA, Green at the Defense Mapping Agency, Mesterham at Blue Cross-Blue Shield of Illinois and Truax at Hughes Aircraft.

Dr. William H. Foege, former director of the Department of Health and Human Resources' Centers for Disease Control, is new president of the American Public Health Association.

Harvey Vieth of the Office of Community Services has been named to head the HHS Office of Organ Transplantation.

Carol M. McCarthy has been chosen as new president of the American Hospital Association. She has been president of the Massachusetts Hospital Association.