Nearly a quarter of Canadian adults say they or a family member have experienced a preventable medical error, according to a report released Wednesday. Drug errors and infections top the list.

The Canadian Institute for Health Information's fifth annual report (Health Care in Canada 2004) used the institute's studies and Statistics Canada data to examine patient safety. For the first time, it compares how common some errors are.

In May, a comprehensive study in the Canadian Medical Association Journal found preventable medical errors contribute to between 9,000 and 24,000 deaths in Canada a year.

Anesthesia errors have been reduced over the last 10 years

Extrapolating the figures, CIHI said patients spend more than one million extra days in hospital being treated for injuries or complications of their care.

The high number of errors surprised Michael Decter, head of the Health Council of Canada. "We knew we had a problem, we didn't know how big it was. Now that we know ... we've got a lot of work to do."

One in nine adults with health problems reported receiving the wrong medication or dose. The same number contracted an infection such as pneumonia while in hospital, the report said.

Technology such as computerized patient records addresses some types of errors, said Dr. John Wade, head of the new Canadian Patient Safety Institute.

Other "adverse events" such as leaving a sponge in a patient after a procedure are rare. Between 2000-2001 and 2002-2003, it happened to an estimated one in every 6,667 patients.

Figures on birth trauma were presented for the first time. One in 81 babies born vaginally suffers an injury, which can range from mild bruising to severe brain damage the report said.

At Mount Sinai Hospital in Toronto, delivery rooms are making changes to reduce errors, such as drills for emergencies, said obstetrician Dr. Gareth Seaward.

Some areas of health care have shown improvements. Anesthesia errors have been greatly reduced over the last decade and surgeons are less likely to operate on the wrong limb now that the correct limb is marked with permanent marker.

Patient safety advocates say attention and resources need to be focused on other types of patient injuries.