After the inquest, Janine's mother, Mrs Margaret Usher, said it was "horrendous" that 10 doctors in the operating theatre at Withington Hospital, Manchester, were unable to work life-saving equipment because it was so old that none of them was trained to use it.
The two-day inquest heard how Janine, of Ashton-under-Lyne, agreed to surgery on 4 January last year under general anaesthetic after originally intending to have a local anaesthetic. An anaesthetist noticed that her face was swelling as she came round and Janine then suffered a cardiac arrest.
Doctors said gas was not escaping from her body after being pumped in by a ventilator and this affected her heart.
When doctors tried to give her electric shocks from two 25-year-old defibrillator machines, they were unable to because they did not know that at least 5lb of pressure had to be applied to the paddles on her chest. Up to 10 minutes were lost before a third defibrillator, which could be used, was found.
Eventually, doctors had to cut open her chest and manually massage her heart. But Janine never regained consciousness and died six days later at the Royal Manchester Children's Hospital, in Pendlebury.
Giving his verdict, Mr Coppel said the 20-year-old ventilator machine used was regarded as "a good solid work horse" and the mystery of what had gone wrong to cause Janine's breathing problem remained unresolved.
On the use of the defibrillators - which were regularly maintained - he added: "None of them knew about the old-fashioned modus operandi though there was a set of written instructions. I suppose under pressure one doesn't look to see something in writing."
Neil Kinsella, solicitor for the family, said they had been granted legal aid to pursue a negligence claim. "At this stage there is no satisfactory explanation of what went wrong to cause Janine to go into cardiac arrest. The chances of her being resuscitated look as though they were reduced."Reuse content