Doctors failed to follow instructions when inserting catheter lines into nine children and it resulted in surgical wire being left lodged near the children’s hearts, the Australian Associated Press reports.

A health watchdog group reported last month that doctors found wire near the hearts of the children, all of whom had peripheral inserted central catheter lines used to administer chemotherapy drugs and antibiotics.

A PICC line is a long, soft, plastic tube placed into a large vein near the bend of a child's elbow. After the line is inserted, the nurse or doctor guides the tube up into a large vein near heart. It is then used to administer drugs.

The soft wire in the line was supposed to be removed after guiding the catheter into place, but doctors in these nine cases failed to do this, according to the report.

The Therapeutic Goods Administration said Friday an investigation found no flaws with the PICC lines themselves. Investigators blamed a lack of information for the problem.

The children had been treated at Mater Children's and Townsville hospitals in Queensland, Australia.

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