Lax supervision of residents at U.S. teaching hospitals puts patients at risk

A college freshman shaking with fever seeks help at a hospital. A disabled man struggling to breathe is rushed to the ER. A teenager suffers internal bleeding after surgery.

All patients in great need. All treated by resident doctors-in-training, with little supervision. All dead after receiving substandard care.

The tragedies of Libby Zion, Devron Matthews and Lewis Blackman echo cases of compromised care that have emerged this year from Parkland Memorial Hospital in Dallas. But they span decades and come from teaching hospitals nationwide.