NEW YORK - Despite a decade of efforts to improve patient safety in hospitals -- initially inspired by a seminal report on the problem from the U.S. Institute of Medicine in 2000 -- harmful errors and accidents are still common, new research suggests.

The study, published in the New England Journal of Medicine, showed that between 2002 and 2007, the number of patients experiencing infections acquired in the hospital, medication errors, complications from diagnostic techniques or treatments, and other such "harms" did not change.

Researchers looked at 2,300 patient admission records from 10 randomly selected hospitals in North Carolina. They found 588 incidents of patient harm resulting from medical procedures, medications, or other causes. Two-thirds of these complications were considered preventable by reviewers at the hospitals themselves.

Recently, the U.S. Office of the Inspector General released a report estimating that medical complications contribute to 180,000 patient deaths per year, and that overall, these complications cost Medicare up to $4.4 billion annually.

"These harms are still very common, and there's no evidence that they're improving," said the current study's lead author Dr. Christopher Landrigan, a physician at Brigham and Women's Hospital in Boston. "The problem is that the methods that have been best proven to improve care have not been implemented across the nation."

Those methods include computerizing patient records and drug prescription orders, limiting the number of consecutive hours that residents and nurses work, and using checklists for surgical procedures, among others.

Landrigan pointed to one example of such protective measures at work -hospitals in Michigan have worked to decrease the number of bloodstream infections using a checklist developed at Johns Hopkins a few years ago. One study shows that these hospitals have kept the number of infections close to zero in the three years after implementing the checklist.

Infections acquired in the hospital proved to be one of the most common complications found in the study, but the types of harm done to patients varied widely and included falls, unintended injury during surgery, low blood pressure and low blood sugar. Close to 85 percent of the complications were temporary and treatable, but 3 percent were permanent, 8.5 percent were deemed life-threatening and 2.4 percent "caused or contributed to a patient's death."

The study was designed to be able to detect a reduction of 25 percent or more in the number of harmful incidents over the six-year study period. The lack of such change seen in the North Carolina hospitals suggests that the Institute of Medicine's stated goal of a 50 percent reduction in national patient rates has yet to be achieved.

Samantha Chao, a specialist in studies on the quality of patient care at the Institute of Medicine, said that while there's still a long way to go in improving patient safety, we shouldn't ignore the successes. To Chao, the biggest success of the past decade is simply getting hospitals to be more aware of patient safety and medical errors, though actually seeing that awareness turn to action takes time.

"Methods to change patient safety are going to be implemented differently at different hospitals because each place is has it's own system," said Chao, who was not involved with the study.

The key to improving patient safety is an overall cultural shift within hospitals and medical care centers, said Dr. Lucian Leape, a health policy analyst at Harvard University and co-author of the 2000 Institute of Medicine report.

"In order to change the way we do things, we have to work effectively as teams, and to become a good team is difficult in healthcare because that's not how it's set up, that's not how we train our doctors," said Leape, who also served as an advisor for the current study.

But it's not just about doctors and healthcare professionals, suggested Leape - the need for cultural change also applies to patients.

"We're moving to the time where more and more people think it's appropriate for the patient to play a more important role in their own care, to make sure they're getting the right medicine," he explained. "Some patients are uncomfortable doing that, but asking a doctor to double check something isn't insulting them, it's just recognizing that mistakes can be made."

He suggested that simply asking your doctor to make sure he's washed his hands, or talking with your doctor about drug interactions, can go a long way toward ensuring your own safety.