TORONTO – Pretty well everyone has heard a horror story about a serious hospital mishap: a medication mix-up; a sponge or retractor left in a patient after surgery; the wrong kidney removed.

So it would be no surprise if some patients facing an operation or admission to a medical ward may be somewhat anxious about their care.

And that begs the question: just how safe are Canada’s hospitals?

As it turns out, 138,000 – or one in every 18 – patients admitted to a Canadian hospital in 2014-15 suffered some kind of harmful event that could potentially have been prevented, from getting the wrong drug to developing an infection, a report released Wednesday has found.

Of those 138,000 patients, about 30,000 had more than one adverse event that compromised their care.

Story continues below advertisement

READ MORE: ICU teams across Canada get patients moving to recover faster

“We know that most patients experience safe care, but when harm happens there’s a big impact on patients, families and the health team,” said Kathleen Morris, vice-president of research and analysis at the Canadian Institute for Health Information (CIHI), which compiled the report.

“Preventable harm can occur in all areas of the hospital and it’s everyone’s responsibility to learn as best they can from these events and work to reduce the potential for harm.”

The report, released in conjunction with the Canadian Patient Safety Institute, says the one-in-18 ratio represents almost six per cent of the 2.5 million patients admitted each year to both large and small hospitals across the country, excluding Quebec.

Those most at risk for hospital-related harms are patients with multiple medical conditions, such as cancer and diabetes, who have several specialists involved in their care, said Morris, adding that the more complex a patient’s health status, the higher the rate of harmful incidents.

“We also know that harmful events have the potential to cause serious illness and even death,” she said, but added that data collected by CIHI couldn’t show whether harmful incidents directly caused fatalities.

READ MORE: NSHA study finds links between alcohol and repeat trauma patients

“The death might be due to the harmful event or it could equally be due to a patient who is at higher risk of dying because he or she had more complex conditions.”

Story continues below advertisement

Of the 138,000 patients identified in the report, 17,300 – or one in eight – died while in hospital.

VIDEO: (Sept 12, 2013) Health officials in Ontario are reviewing the results of 3,500 CT scans and mammograms at two hospitals, looking for possible errors. Christina Stevens reports.

Carole Jukosky has first-hand experience with how errors by hospital staff can have fatal consequences.

Her father Herbert Strasser was rushed to an eastern Ontario hospital in August 2011 after his legs suddenly gave out and he collapsed in his home. The 72-year-old retired RCMP officer had spinal decompression surgery the next day, and 10 days later he was transferred to a rehabilitation centre.

But five days after that he was transferred back to the hospital with a urinary tract infection and dangerously elevated blood sugar. He then developed sepsis from an infection at the site of his operation and was also diagnosed with Clostridium difficile, a hard-to-eradicate bacterial infection that can sometimes be picked up in hospitals, especially by patients on antibiotics.

Story continues below advertisement

READ MORE: Advocacy group wants hospital visiting hours extended in Canada

Six weeks after his surgery and being bounced back and forth between hospitals, Strasser died. A coroner’s investigation determined the causes of death were the spinal abscess and complications from the C. difficile, which had severely damaged his colon. After he died, Jukosky was told that an important antibiotic for his spinal abscess had accidentally been discontinued.

The coroner called her father’s case a “perfect storm” of miscues and false assumptions.

Jukosky, a registered nurse who manages two long-term care facilities in her hometown of Fort Erie, Ont., is now emphasizing patient safety even more among her staff – and with the residents and their families.

“I think communication is key,” she said in an interview. “I always encourage families and patients to report immediately if you have a problem. Or if something doesn’t feel right, tell us right away, because it’s hard to go backwards.

“Don’t ever let a health-care professional look at you, tell you something and walk away … you should never be (thinking) ‘What did he say? I don’t know,”‘ she said. “If you don’t understand something, ask the question.”

Chris Power, CEO of the Canadian Patient Safety Institute (CPSI), agreed, saying hospital patients and their loved ones need to be vigilant about all aspects of treatment.

Story continues below advertisement

READ MORE: Microsoft Canada helps SickKids patients heal through interactive tech

“Be as informed as you can be and go into that relationship with your doctor, your nurse or your pharmacist or whomever is providing care, knowing that you’re a partner and you have a right and a responsibility to ask questions and to understand what’s happening with your health care,” she said.

“Don’t just settle for not getting the answers that you need. Don’t walk away with questions on your mind.”

Morris said hospital-related harms, which were measured using a new tracking tool developed by CIHI and the CPSI, found that patients who experienced an adverse event spent an extra four days on average in a hospital bed.

“That may not seem like much, but when it’s put altogether, it results in more than half a million additional hospital days – and that’s equivalent to over 1,600 beds each day or roughly four large hospitals,” representing an estimated cost of $685 million that could be used to help meet the needs of other patients, she said.