Critics of the new Medicare cost controls charge that limited payments to hospitals for most Medicare patients encourage hospitals to discharge some patients prematurely.

The families of Medicare patients have sent the House Select Committee on Aging these and many other examples of what seems to be a kind of human ping pong:

* A 76-year-old man in the state of Washington fell off a ladder last June, hit his head and has remained in a coma since. He was hospitalized but soon discharged to a nursing home. He developed more complications and was returned to the hospital.

That has now happened four times in all. One nursing home refused to admit him at all. Its director said he was "too sick" for nursing home care. The hospital replied that he was not sick enough for hospitalization "by present standards." He is now a patient in still another nursing home, but the family is being billed for private duty nursing and rental of special equipment, items Medicare does not cover.

* After a series of disabling falls, a suburban Detroit man, 88, was hospitalized last July for pneumonia, as well as heart disease and dementia. On Aug. 3 he was transferred to a nursing home, where he wheeled himself to a staircase and tumbled down the stairs.

He was sent back to the hospital emergency room to be checked. He lay on a stretcher for 12 hours, unfed, awaiting attention. He was then admitted but discharged again on Aug. 29 to a nursing home, which refused to accept him. He was back in the hospital within a few hours. Within a few days he died. A rural Oklahoma woman of 75 was admitted to a hospital last month with pneumonia and a bladder infection. She was sent to a nursing home after a week, but in early February became sick and feverish and had to be sent back to the hospital.

Her doctor admitted to her family that she had been discharged from the hospital the first time though neither her lungs nor her bladder were completely normal.

"You know," he explained, "we do have these guidelines now."