Early in July, Mary Brennan-Taylor stepped to the head of a class of medical students at the University at Buffalo–SUNY and proceeded to describe the cascade of events that killed her mother. Alice Brennan, 88, was independent and anything but frail when she was admitted to the hospital on July 13, 2009, with a mild case of gout. "I figured she had 10 more years as the life of the party," her daughter says. But doctors prescribed a muscle relaxant that isn't used for gout—and in fact is prominently displayed on a list of drugs that should be avoided in the elderly. Unsteady on her feet as a result, Brennan suffered a scary fall in rehab and lost the ability to walk. Back in the hospital, poor infection control measures led to a series of infections, each one nastier and harder to treat than the last. On August 29 that year, Brennan died in a hospice of sepsis, a systemwide reaction to severe bloodstream infections.

"Dear God, you shouldn't go into a hospital a fairly robust 88-year-old woman with gout and die 48 days later of sepsis," says Brennan-Taylor, who directs a number of social services programs for a YWCA in the Buffalo area. "It shouldn't happen."

Brennan-Taylor's subsequent crusade to eliminate medical errors—besides lecturing to medical students, she has also shared her mother's story at a federal government hearing on medical data—places her at the forefront of one of the most urgent movements in medicine: a nationwide effort to rethink the risk-ridden and chaotic medical system and place safety and quality at its heart. It is a gargantuan task. In 1999, the Institute of Medicine report, "To Err is Human: Building a Safer Health System," charged that mistakes and unsafe practices in U.S. hospitals kill at least 44,000 patients a year and possibly twice as many, a number likened to the carnage that would occur if a jumbo jetliner went down daily in the country.

"I don't think that crashing a 727 jet every day and killing everybody aboard is a good standard of care in U.S. hospitals," says author, speaker, and corporate adviser Paul Levy, the former CEO of Beth Israel Deaconess Medical Center in Boston, whose "Not Running a Hospital" blog is about improving healthcare. "If that happened in aviation, they would shut the airlines down."

But more than a decade after that scathing report, patients are still plagued by medication errors and wrong diagnoses that lead to unnecessary surgery and chemotherapy. They still have surgery on the wrong body part, and wake up with foreign objects stitched or stapled inside. A 2010 government analysis found that 134,000 Medicare beneficiaries were suffering adverse events every month, many of which were "clearly or likely preventable." A separate five-year study of North Carolina hospitals, published in the New England Journal of Medicine in November 2010, showed that, in 25 percent of all admissions, the medical care harmed patients. And a study published in Health Affairs in April 2011 revealed that the standard methods hospitals use to detect medical errors fail over 90 percent of the time.

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The trouble is, far too many hospitals take safety for granted, says Donald Berwick, former administrator of the federal Centers for Medicare and Medicaid Services and a pioneer of the patient-safety movement. "There's a sense that safety's important," he says, but the prevailing attitude is " 'we're too busy right now,' or 'we can do a few things, but not transformative work.' "

What will it take to make hospitals safer for patients? Richard Brilli, chief medical officer at Nationwide Children's Hospital in Columbus, Ohio, says there's just one acceptable course of action: Commit to eliminating medical errors and harmful practices altogether. "I couldn't look a family in the eye and say we aspire to be 50 percent better," Brilli says. "There is no higher goal than zero harm events."

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Zero heroes. Three years ago Brilli and his team announced that they would aim to eliminate preventable harm to patients by 2013, by making patient safety central to every medical and surgical protocol. To track their progress, they created what they call a preventable-harm index, a simple list of all hospital-acquired infections, adverse drug events, cardiac arrests, major surgical complications, hospital-acquired pressure ulcers, and serious falls, with the total being patients who were injured but shouldn't have been. When mistakes occur, hospital staffers are encouraged to report them. "We can't fix things that we don't know are happening," Brilli says. Each report triggers a review, often leading to changes in protocols, procedures, or technology. Anyone who needs added training gets it; anyone found to have taken a shortcut could be reprimanded. Those who advance the cause, whether they're clerks or heart surgeons, are acclaimed as "Zero Heroes."