A paediatric nurse killed a toddler by injecting him with the wrong drug, Liverpool Crown Court has heard.
Rose Aru is accused of manslaughter
Rose Aru, 59, of Wavertree, denies the manslaughter of 18-month-old Jake McGeouth at Alder Hey Children's Hospital in Liverpool in July 2001.
Mrs Aru was meant to inject Jake, from Blackburn, Lancashire, with the sedative Midazolam but picked up the wrong syringe, the court was told.
Instead he was given a muscle relaxing drug which caused his heart to stop.
The drug, Vecuronium, is a paralyzing agent. Mrs Aru was not authorised to administer either drug.
Jake had been diagnosed as having an enlarged heart, thought to have been caused by blood clots on his lungs.
Prosecuting, Peter Wright QC, said giving the muscle relaxant to Jake was "catastrophic."
"To administer Vecuronium to a child such as Jake, who was not ventilated, was highly dangerous and catastrophic in its consequences because almost immediately the administration had the effect of paralysing Jake's breathing and as a consequence his heart stopped."
Jake was meant to be given a sedative to calm him down after he was taken for a scan to determine the problem and became restless.
The prosecution said Mrs Aru had may not have intended to harm the toddler, but that her actions were so "grossly negligent" that she was guilty of manslaughter.
The case continues.