Without Medicare Part B's shield, patient's family owes $81,000 for a single air-ambulance flight

Debra Prichard was a retired factory worker who was careful with her money, including what she spent on medical care, said her daughter, Alicia Wieberg. "She was the kind of person who didn't go to the doctor for anything."

That ended last year, when the rural Tennessee resident suffered a devastating stroke and several aneurysms. She twice was rushed from her local hospital to Vanderbilt University Medical Center in Nashville, 79 miles away, where she was treated by brain specialists. She died October 31 at age 70.

One of Prichard's trips to the Nashville hospital was via helicopter ambulance. Wieberg said she had heard such flights could be pricey, but she didn't realize how extraordinary the charge would be — or how her mother's skimping on Medicare coverage could leave the family on the hook.