Providing all patients, rich or poor, the same standards of care is one way that Mount Sinai in Chicago tries to live up to its obligations as a nonprofit hospital exempt from taxes. But while a number of nonprofit hospitals have grown into profit machines in recent years, some, like Mount Sinai, have stuck to their charitable mission but struggled financially. Mount Sinai has teetered between a small net income and annual losses as high as $15 million over the past five years.