Organ donation based on ‘presumed’ consent to donation is now making its way into the law thanks to campaigning papers such as the Mirror, though no attention appears yet to have been paid to its medical aspects, to the relevance of the different definitions of death or to the transplant procedure itself. Debate has centred rather on whether ‘presumed’ consent is indeed consent and whether a change in the law will actually increase organs for transplant, both contentious points.

This is to ignore the following concerns:

§ The fear that organs might be removed before death, which is one of the key reasons why people are reluctant to carry a donor card.

§ The fear that dying patients may be seen as ‘organ resources’ by some clinicians desperate to acquire scarce organs for transplantation.

§ The fear that staff may be over-ready to apply a DNAR (do not attempt resuscitation) order to get much-needed organs.

These were among the reasons given for the abolition of the presumed consent law in Brazil.

Organs from a dead body are of no value; they have to be removed while still functional and as close to their living state as possible. But most people do not appreciate that usually the person from whom they are being removed is on ventilatory life support. The British Medical Association is clear: ‘Once the patient’s heart has stopped beating the organs are no longer suitable for donation . . . In order to obtain organs in good condition, the organs need to be “harvested” as soon as possible after death.’

Were it simply a matter of taking organs from dead bodies there would be no organ shortage.

The problem is finding a potential donor who is clinically defined as brain dead and is on life support. Brain death agreed, surgeons can then remove organs while the heart is still beating and the organs still perfused with oxygenated blood.

Although there is no statutory definition of death in the UK, the Academy of Medical Royal Colleges’s (AoMRC) definition is widely accepted and held to be a gold standard. However some have argued that there is still a degree of public disquiet, alleged medical duplicity and continuing academic dissent surrounding the concept of death. It has been redefined variously since 1968, corresponding with the advent of organ transplantation and the need for ‘fresh’ organs.

In the UK up to the 1970s, all organs for transplantation were donated after ‘circulatory death’ (a non-beating heart). It was then that the definition of ‘brain death’ was introduced. In 1995 the terminology was changed again, to ‘brainstem death’, because residual activity in parts of the brain other than the brainstem had been demonstrated in patients considered to be ‘brain dead’.

The British Transplantation Society uses a definition based on the AoMRC: ‘Death is irreversible and should be regarded as a state in which a patient has permanently lost the capacity for consciousness and brain stem function .’ Death occurs when the heart stops: ‘where cardio-respiratory criteria apply, death can be confirmed following five minutes of continuous cardio-respiratory arrest providing there is no subsequent restoration of artificial cerebral circulation.’.

Waiting five minutes after circulatory death, along with using other test criteria, to confirm death is somewhat reassuring, compared to other countries which wait even less time. But as our knowledge of conscious awareness around the time of death develops, can we be sure that five minutes is sufficient after pulse and respirations cease for the donor truly to die? Many patients have been successfully resuscitated after much longer periods of cardiac arrest.

A BMA report on organ donation from 2000 acknowledges this possibility: ‘Death confirmed by brain stem tests should therefore be seen as the clearest indication of what is commonly understood as “death”, more so than the stopping of the heart, or of breathing, both of which can, in some circumstances, be reversed.’

Despite this possibility, the same BMA report then says that: ‘It is possible for some organs and tissue to be removed for transplantation from non-heartbeating donors for a short period after death’, that is, after cardiac arrest.

One hospital protocol for donation for heart transplantation after cardiac death outlines its practice thus:

First withdraw organ support, then wait for the patient to ‘die’ (ideally within less than 30 minutes of withdrawal) then five minutes after confirmation of death clamp the arterial vessels that supply the brain and restart perfusion of the other vital organs with a form of bypass as well as re-ventilating the lungs in order to optimise the condition of the organs for later donation.

The worry with this protocol is twofold: as the BMA says, people can in some circumstances be resuscitated after the heart stops (unless of course their arteries are then clamped).

Secondly, during those critical 30 minutes of waiting for the patient to die, there will inevitably be extra pressures if organ removal is part of the picture compared with withdrawal of life support when organ donation is not part of it.

These definitions of death raise further concerns. A brainstem dead, but beating-heart, ‘cadaver’ can react to incisions for organ removal with an increase in heart rate and blood pressure. This a common spinal reflex. So the ‘cadaver’ often has to be anaesthetised, or paralysed, to prevent it reacting to the operation, otherwise blood pressure can rise dramatically when an incision is made.

The use of muscle relaxants and even general anaesthesia of donor ‘cadavers’ does not appear to square with the assertion that all integrative function of the body is lost in brain stem death. There may also sometimes be residual hormonal function in the body, there are cases where pregnant women confirmed as brain dead have gestated babies, and there are cases of patients declared brain dead who are maintained on ITU support for months or even years as recorded here and here.

The question is whether this continued functioning or responsiveness of the body as a whole suggests it is truly dead. Could it mean that sometimes a dying person might be misdiagnosed as already dead?. Such uncertainty is by no means the case for most deaths, but it seems to me that there are still some unanswered questions. This is why it is one thing to approve organ donation as a gift, as I have encouraged here, but quite another to presume consent to it.

In the headlong quest to increase the number of organs for transplantation in the UK we do indeed need to question what ‘consent’ is, who owns the body and what is the evidence base for legal change.

On current data it is possible that there are occasional circumstances whereby someone may be misdiagnosed as being brainstem dead when they are not. Only with more openness about and research on the reliability of diagnoses of death can we be unequivocally certain in every case that those declared ‘brain dead’ are indeed dead before their organs are removed.