A report released yesterday suggests that the kind of human error that resulted in a cancer patient treated at a hospital in Alberta, Canada, receiving a fatal dose of chemotherapy drugs has occurred at least seven times in other cancer centres in North America.
Denise Melanson of Rainbow Lake, Alberta, a teacher’s assistant and mother of two teenage sons, died in August last year at the age of 43 after receiving an accidental overdose of chemotherapy drugs.
Melanson was being treated at the Cross Cancer Institute in Edmonton, Alberta, for an advanced but treatable cancer of the nasal passage (nasalpharyngeal carcinoma).
She was given an electronic pump containing a four day dose of two chemotherapy drugs, 5-fluorouracil and cisplatin, to administer to herself at home. But unfortunately the pump was programmed to dispense the dose in four hours and not four days.
Melanson herself noticed that the medication had run out before it should have and quickly returned to the hospital where the error was discovered. She died 22 days later. The coroner gave the cause of death as “sequelae of fluorouracil toxicity”.
Following the tragedy, the Alberta Cancer Board, the provincial health authority responsible, launched two investigations into the matter. One investigation was by the Institute for Safe Medication Practices (ISMP Canada), and the other by the Health Quality Council of Alberta (HQCA).
Both investigations have now completed and presented their findings and recommendations, which according to Dr Tony Fields, Alberta Cancer Board Vice President, Medical Affairs and Community Oncology will begin immediately.
“We intend to minimize opportunities for this type of error to reoccur, here or anywhere else,” said Fields.
“These substantive reviews will help us do that. We are briefing staff at our 17 Alberta Cancer Board facilities today and have hired a senior pharmacist to lead the implementation of recommendations immediately,” he added.
Fields said the Alberta Cancer Board were surprised to hear that similar errors had occurred before. In researching this the investigators found cases of similar errors at other cancer centres outside of Alberta, but gave no exact details.
“We were not able to learn from the mistakes of others, but we’ll ensure others can learn from ours,” said Fields.
ISMP said that it was not just the fact the nurse had incorrectly calculated the dose and programmed it into the machine that led to Denise Melanson’s death.
According to David U, President and CEO of ISMP, in this case:
“A combination of actions and conditions, which on their own would not have caused the death, happened simultaneously with tragic result.”
U said there were three main contributors to Denise Melanson’s death. First the overdose itself, secondly the design of the chemotherapy protocol (one wonders why a fatal dose is given to a patient in one bag), and thirdly the inability to do something about it once the lethal dose had been administered (for example, there is a distinct lack of literature on how to mitigate a fatal dose of fluorouracil).
In tracing the steps within each of these contributing areas U said that the ISMP investigators:
“Found several causal chains leading to each of these primary areas.”
The HCQA investigation also focused on systemic rather than the human error element of the events surrounding the tragedy.
They emphasize the importance of learning from this and putting in place system changes to minimize this kind of error.
According to the ISMP report the human error resulted from a nurse trying to convert a dose rate based on milligrams over four days into one based on millilitres per hour. The nurse could not find a calculator and did the conversion mentally and using pen and paper.
Expecting human beings to perform perfectly, every day, without fail is not a reasonable assumption to make when designing a system to minimize risks. Instead, the underlying design assumption should accept that humans sometimes, albeit rarely, make mistakes, so what other checks and balances are needed to ensure the damage of such mistakes are minimized?
There are two tragedies here: the death of Denise Melanson and the fact that the staff who cared for her, who must also feel terrible about all this, were denied the opportunity to learn from the mistakes of others. Let us hope the learning spreads far and wide this time.
The Alberta Cancer Board have posted the full report on their website.
Written by: Catharine Paddock
Writer: Medical News Today