What started as a simple fractured rib led to a Christchurch father bleeding to death in hospital because he was taking part in a clinical drug trial, a Coroner has found.

John MacDonald, 59, suffered from irregular heart rhythms and had been taking part in a clinical trial for a blood-thinning drug for more than a year before he was knocked off his motor scooter in 2009.

Taken to Christchurch Hospital with multiple rib fractures, MacDonald told paramedics he was participating in a clinical trial but he had no idea what drug he was taking because he had been "double-blinded" for scientific accuracy, the report said.

MacDonald was also wearing a medical alert bracelet with a 24-hour hotline but when hospital staff tried the line to find out what drug he was on, there was no answer despite waiting for over 14 minutes.

Two hours after he was admitted, MacDonald became "increasingly unstable" and his vital signs suggested he was losing blood, although he was given eight units.

Medical staff inserted a chest tube to drain the blood from MacDonald's chest. However, MacDonald began "bleeding enormously" and five litres of blood "rapidly drained" from the tube.

Five hours and 45 minutes after his motor scooter accident, the father of two was pronounced dead.

MacDonald's medical notes had been ordered by his physician but he was not told they had arrived until after his death. But the notes did not contain sufficient information relating to the drug anyway, the Coroner said.

One of the trial's principal investigators in Christchurch, Professor Mark Richards, told The Press MacDonald's death was "extremely unfortunate".

"There's a pretty clear answer for his demise," the Otago University professor said.

"If he wasn't on an effective blood thinner it's likely he wouldn't have died bleeding the way he did, but at the same time he had to be on some sort of blood thinner because of his heart condition."

Days after the death, Richards said the Department of Medicine's cardiology research group had asked Canterbury District Health Board to "automatically flag" trial participants.

Richards participated in clinical trials for more than 28 years and said he had never been involved in a case that so "clearly connected" the participant's death and the trial process.

The blood-thinning drug MacDonald was trialling before his death has now been approved and "tens of thousands of people around the world" are using it, Richards said.

Richards and the team working on the trial met MacDonald's family after his death to answer any questions they had, he said.

The results of the Coroner's inquest into MacDonald's death were released yesterday and several recommendations were made, including the need for emergency department staff to be made aware a patient was on a clinical trial and the drugs involved.

After MacDonald's death, Canterbury District Health Board made recommendations to ensure this never happened again.

- © Fairfax NZ News