February 12, 1986

A PORTABLE respirator is in Dorothea Ridenour's bedroom, a $2,500 device that strapped the family budget and was unnecessary until the birth of her son four years ago. In those four years, there have been dozens of trips to the hospital for Mrs. Ridenour, a 28-year-old victim of cystic fibrosis; dozens of times when her son, Charles Jr., stayed with his grandmother in a nearby Bronx apartment, and dozens of sleepless and terror-filled nights for her husband, Charles Sr., a Transit Authority flagman. Mrs. Ridenour's disease, which affects the respiratory and digestive systems and often kills before adolescence, had been under control until her pregnancy. She had been hospitalized only a handful of times, attended school, traveled, played sports, married and worked as a secretary. Then she decided to do the next so-called normal thing - have a child -and managed, as she put it, to ''not quite'' hear the warnings of her doctor, Phyllis Leppert. Dr. Leppert said she did not discourage Mrs. Ridenour's pregnancy but carefully laid out its risks.

Mayor Koch, in a policy reversal, said yesterday that from now on, appointments of most higher-paid municipal employees would need his approval. His hiring policy is ''evolving,'' he said, and he could not say whether hundreds or thousands of employees would be covered by it. Neither could any of his top advisers. ''I want commissioners to find their own people,'' the Mayor said. ''But before they say 'You're hired,' I want to know how they came to that conclusion.'' He does not expect to overrule a commissioner's decision, the Mayor went on, ''but I reserve the right to overrule.''

A State Supreme Court justice ruled yesterday that children with AIDS cannot automatically be excluded from regular classes in New York City public schools. He upheld the city's policy of deciding case by case whether such children should attend normal classes. But the justice, Harold Hyman of Queens, also declared in his 82-page ruling that city officials had developed their policy ''behind the cloak of secrecy,'' and ''perhaps unwittingly, let loose the forces of anxiety and fear.'' He also criticized unidentified ''members of the medical community'' he said had ''exacerbated the fears and fueled the passions'' by their ''professionally irresponsible and baseless characterizations of this disease as a 'plague.' ''

Anatoly B. Shcharansky arrived in Israel today to a joyful welcome from Government leaders, friends and tumultuous crowds of supporters. Mr. Shcharansky, who was freed from a Soviet labor camp on Monday, pledged to continue the struggle for human rights. His wife, Avital, who had campaigned for nine years for his freedom, stood by his side, blinking back tears as well-wishers on the tarmac sang Hebrew wedding songs. Mr. Shcharansky looked stunned at first, but soon displayed the wit and poise for which he was known in the Soviet Union. When he spotted familiar faces of Moscow friends in the crowd, he rushed over and hugged them.

CBS Inc. said yesterday that earnings from continuing operations fell 49.9 percent in the fourth quarter, hurt by much lower profits from the broadcast and publishing divisions. The quarter closed out a tumultuous year for CBS. Faced with a takeover bid by the Atlanta-based entrepreneur Ted Turner, CBS spent $1 billion buying back 21 percent of its stock. Its debt load also increased when it bought 12 magazines from the Ziff-Davis Publishing Company. Meanwhile, the environment for CBS's core businesses was weak.