BOSTON -- It is the oath every doctor takes: Above all, do no harm. Yet every year in American hospitals as many as 100,000 patients die from unintentional but largely preventable errors, infections and other harm. Many more are injured, some permanently.

Sue Nevins, a nurse who works at a small Massachusetts hospital knows both sides of the hospital error dilemma. Just two days after Christmas 2006, she had a small benign tumor removed from behind her ear.

When she woke up after surgery, she remembers that her "face was really numb. When my family met me in the hallway," she recalled, "My daughter started crying. And that's when I realized that something had happened to my face."

During the operation, a problem had occurred. The nerve that controlled the right side of Nevins' face had been damaged.

"I couldn't smile. I was starting to drool a lot, and as the hours went on, I got worse," she said.

Nevins' surgery did not take place in Boston, but medical errors are a reality everywhere.

"There are a lot of things that cause harm in hospitals. People don't like to talk about it, but it is true," said Paul Levy, CEO of Boston's Beth Israel Deaconess Medical Center. Levy is one of the few hospital leaders nationwide who has publicly pledged to reduce preventable harm.

In fact, hospitals pose either the fourth or fifth biggest health risk in the U.S. The groundbreaking 1999 Institute of Medicine report that estimated 100,000 deaths from hospital-related harm each year has held up for a decade. And it represents more people than those killed in car crashes and by breast cancer combined. Making Nevins' case both more powerful, and more painful, is that the hospital where her surgical damage occurred, is the same hospital where she works.

"This was a good doctor, that something happened to," she said tearfully. "I wanted to make sure they were okay."

Linda Kenney knows the pain Nevins still feels. Kenney nearly died during surgery ten years ago.

"I had tubes from everywhere. That was, I'm sure, horrible for my husband," Kenney said. But for her, the "worst part was the emotional impact later, and nobody really letting me know that was going to happen."

Since her unintended medical outcome, Kenney has dedicated her life to making hospitals safer through the Chestnut Hill-based non-profit that she founded. The group is called Medically Inducted Trauma Support Services (MITSS).

In her role as founder, president and executive director, she hears countless stories from patients suffering from, and living with the unintended consequences of surgical errors and outcomes. Too often, she said, patients are left in the dark, told little by doctors and hospital administrators.

"It's so isolating, they leave the hospital they get no support they feel alone, abandoned often. When they're ignored and lied to, it adds another injury," said Kenney. Nevins is back at her old job, but forever changed. In the two years since her ordeal began, she has had to re-learn how to eat. She chokes easily, and sometimes drools because of the damaged nerve in her face. She said it has dealt a blow to her confidence socially, and credits continued medical care with helping to minimize the visual impact of her nerve damage.

Yet a decade after the IOM report, Nevins and Kenney remain among the man frustrated - systemic changes are not coming fast enough.

"This is a national thing," said Nevins. "It's not related to one hospital, one patient, one doctor

But one Boston hospital is setting an ambitious goal. Levy is on the record as saying that his medical center has set out to eliminate preventable harm by 2012. Levy said, "Now, we may not quite get there but if we don't quite succeed we still will have saved a lot of lives."

For Nevins, the issue is more personal. "My biggest thing is, that no patient ever feel as badly as I did, as lonely, wondering, did I matter?"

Both Nevins and Kenney reconciled with their doctors. They want the public to know what they have learned first-hand; that the doctors and nurses involved when things don't go as expected suffer just as much as the patients.

Kenney says when there's an unintended outcome at a hospital patients want to know four things, including details of what happened. “They want an apology. They want to know what the institution's going to do to make sure that it doesn't happen again. And then they want support.”