In December, Marie, who lives in coastal Swampscott, Massachusetts, began having trouble breathing. Three days after Christmas, she woke up gasping for air and dialed 911. “I was so scared,” Marie said later, her hand clutched to her chest. Marie, 63, was admitted to Salem Hospital, north of Boston. The staff treated her chronic obstructive pulmonary disease, a lung condition. A doctor checked on Marie the next day, said her oxygen levels looked good, and told her she was ready for discharge. We are not using Marie’s last name because she, like 1 in 9 hospitalized patients, has a history of ad…