A medical safety agency has issued a warning after receiving two reports in which hospitalized newborn babies were mistakenly given breast milk through IV lines into their bloodstream.

Safety experts first warned about this medical error decades ago, but say it's still being repeated, putting fragile babies at risk.

The Institute for Safe Medication Practices Canada says it's received two reports in which babies in Canadian hospitals almost died because of the error.

The premature infants had been hooked up to both IV lines and nasogastric (NG) tubes, which is a feeding tube that goes through the nose, down the throat and into the stomach. The babies were supposed to receive their mothers' breast milk through their NG tubes. Instead, the unsterilized milk was mistakenly administered through the IV line.

Both babies went into distress shortly after and both required emergency medical care, and had to be transferred to the neonatal intensive care units at larger hospitals. While both survived, it was a mistake that could have easily caused organ failure, and death.

Doctors first warned about the possibility for mix-up back in 1972, after a baby was administered breast milk through the IV line and died. The error cropped up again in 2006, after a U.S. baby developed seizures and "respiratory distress" after receiving breast milk intravenously.

The error is another example of what can go wrong in busy neonatal units, but doctors note it's also possible to mix up IV lines and feeding tubes in patients other than babies.

Barbara Farlow, of the group Patients For Patient Safety Canada, says a solution to the problem needs to be found.

"Accidents happen, and so we need to learn from them," she says, noting that of the 20,000 deaths each year from unintended harm, a third are known to be preventable.

That's why her group supports the recommendations for change issued by the Institute for Safe Medication Practices of Canada. They're asking hospitals to urgently review their infant feeding systems.

"It is really important that hospitals looks at what equipment they have and how it is being used and work together with front-line professionals so they understand where the mistakes can occur," says ISMP Canada's Christine Koczmara.

ISMP Canada notes that the tubing on IV lines should not have the same connectors that could allow a syringe full of breast milk or other feeding liquid to be screwed onto an IV line.

Feeding tubes should also be distinct from the tubes used for IV lines so that they could not be mixed up, such as by using different colours of tubing.

The Association for the Advancement of Medical Instrumentation is planning changes to its international standards, in an effort to reduce tubing misconnection errors. But until those changes are fully phased in, doctors and nurses are being warned to watch for further errors.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip