Well, my husband had major surgery a week ago (hernia repair, the first hernia surgery a year ago failed, hernia came back. They couldn't do keyhole surgery the 2nd time, had to be major).
He was sent home on the same day with a catheter. He gets visits from community nurses, but he's very uncomfortable.
I could imagine that Kate wouldn't get kicked out the same day and that she would be given plenty of time to recover in the the hospital, under medial surveillance.