Doctors call for global consensus on diagnosis of death
There needs to be international agreement on when and how death is diagnosed, two leading doctors suggest.
At a European meeting of anaesthetists they said improvements in technology mean the line between life and death is less clear.
They called for precise guidelines and more research to prevent the rare occasions when people are pronounced dead but are later found to be alive.
The World Health Organisation has begun work to develop a global consensus.
In the majority of cases in hospitals, people are pronounced dead only after doctors have examined their heart, lungs and responsiveness, determining there are no longer any heart and breath sounds and no obvious reaction to the outside world.
'Permanent damage to brain'
But Dr Alex Manara, a consultant anaesthetist at Frenchay Hospital in Bristol, said more than 30 reports in medical literature, describing people who had been determined dead but later found to be alive, had driven scientists to question whether the diagnosis of death can be improved.
At a meeting of the European Society for Anaesthesiology he said that on some occasions doctors do not observe the body for long enough before someone is declared dead.
Dr Manara called for internationally agreed guidelines to ensure doctors observe the body for five minutes, in order not to miss anyone whose heart and lungs spontaneously recover.
Many institutions in the US and Australia have adopted two minutes as the minimum observation period, while the UK and Canada recommend five minutes. Germany currently has no guidelines and Italy proposes that physicians wait 20 minutes before declaring death, particularly when organ donation is being considered.
Dr Jerry Nolan, consultant in intensive care at the Royal United Hospital in Bath, who is not involved in the conference, said: "In hospitals, where patients are monitored closely, and after the appropriate resuscitation has taken place, waiting five minutes to observe the body is a good idea.
"There is evidence to show that once you start going beyond five minutes without a circulation or oxygen to the brain you start seeing permanent damage to brain cells."
At the conference, Ricard Valero, professor of anaesthesia at the University of Barcelona, considered the rarer scenario of patients in intensive care units whose hearts and lungs are kept functioning by machines.
In such scenarios, doctors use the concept of brain death - often conducting neurological tests to monitor any brain activity in the patient.
'Variations don't seem logical'
But the criteria used to establish brain death have slight variations across the globe.
In Canada, for example, one doctor is needed to diagnose brain death; in the UK, two doctors are recommended; and in Spain three doctors are required. The number of neurological tests that have to be performed vary too, as does the time the body is observed before death is declared.
"These variations in practice just do not seem logical," Prof Valero said.
He proposed further research to support a global consensus on the most appropriate criteria to diagnose brain death.
Dr Nolan said: "In principle an international guideline on death is a very good idea. It is likely to help in terms of the movement of doctors between countries and, importantly, with public confidence.
"Italians and Brits are probably built in the same way. It makes sense to have the same criteria for death for both."