A surgeon lost his temper and killed a teenage leukaemia patient during a routine operation, a court was told.

Kenneth Woodburn, 39, from Idless, near Truro, Cornwall, was trying to insert a catheter into the chest of Kelly Dent, 16, when the procedure went wrong, Exeter Crown Court was told.

John Bevan QC, for the prosecution, said it was "a very sad case all round". He told the jury that Kelly was diagnosed with acute myeloid leukaemia, a life-threatening disease of the bone marrow affecting the production of healthy blood, in early 1998.

Chemotherapy treatment had been progressing well at the time of the operation at Treliske Hospital, Truro, in September 1998. But because of difficulties during an initial attempt to insert a catheter to administer drugs and take samples, Mr Woodburn was brought in the following day for a fresh attempt. Mr Bevan said: "Sadly what should have been a reasonably simple and certainly not sophisticated or complicated operation, albeit she was under general anaesthetic, went disastrously wrong.

"Initial frustration and irritation gave way to anger and aggression and went far beyond normal theatre language and behaviour," he said. "Then Woodburn lost his temper with the patient because the operation did not go smoothly." As a direct result of the operation, part of the patient's heart was punctured and she died from massive internal blood loss.

Mr Bevan said the defendant was normally accepted to be a competent and respected vascular surgeon. But on this "rare if not unique occasion" there were a variety of factors to do with shortness of time because of an appointment elsewhere that allowed him 40 minutes to complete the operation.

A number of things going wrong, as well as the normal tension and stress of the operating theatre, caused him to lose his temper and act in a way that eventually became dangerous to her health, it was claimed. "Negligence, if it is proved by the evidence, amounts we say to an offence of manslaughter or unlawful killing," Mr Bevan said.

During an interview with police, Mr Woodburn accepted that something he had done during the operation must have produced damage that led to Kelly's death. She had died from a rare but recognised complication. The surgeon denies manslaughter.

The trial continues.