“Thus conscience does make cowards of us all”

                                                                        Hamlet, Act III Scene I.

Introduction

The Dead Donor Rule (DDR) states that organs necessary for life cannot be taken from patients until they are dead. Some see the DDR as an important safeguard against the abusive exploitation of patients by doctors who wish to increase the supply of organs. Others believe that it sanctions active euthanasia. In defending the abandonment of the DDR, it is argued that the entire process of organ donation is built upon the delusion that patients who donate are dead. Furthermore it is thought that the current practice of establishing strict criteria for diagnosing death is flawed and that abandonment of the DDR should be complemented by a focus on patient consent and autonomy as the key considerations for organ donation. This paper will focus on the practice of organ donation in the UK but comparisons are made with organ donation programmes in other parts of the world which provide useful insights into the inconsistencies of the DDR.

Current status of organ donation in the UK.

Donation after cardiac death (DCD) has had a renaissance over the last two decades as the major source of donated organs.[1] Prior to this heart-beating donation from brain-dead donors represented the vast majority of cadaveric organ donations in the UK. The decrease in heart-beating donors is due to improvements in the diagnosis and management of severe brain injuries and a decrease in the number of people dying from severe injuries or catastrophic cerebrovascular accidents[2]. The return to DCD whereby the patient is diagnosed as dead based on cardiopulmonary criteria rather than brainstem criteria is beleaguered by ethical problems including deciding when the patient is actually dead.

How do we diagnose death?

            Doctors involved in the process of organ donation face two opposing pressures. The first is to make sure their actions are consistent with the DDR- ensuring the patient is dead before donation can proceed. The second is to initiate the retrieval process as quickly as possible. Given the potential conflict of interest between these two pressures, organ donation policies in the UK rightly insist that doctors diagnosing death must have no involvement in the donation process.[3] Diagnosing the exact moment of death has therefore become a crucial step in these procedures.

Cadaveric organ donation is sourced from two groups of patients: the brain-dead and non-heart-beating organ donors. The separation of these two groups is important because despite both being considered dead, the diagnosis of their death is completely different. Those who support the abandonment of the DDR argue that neither of these patients are actually dead. Instead the medical community has embraced specific definitions of death which may be considered a convenient way of evading the ethical and legal barriers which would prohibit such patients from donating their organs.

Are brain-dead patients really dead?

In the UK (and many other counties) patients diagnosed as brain-dead are legally dead. This diagnosis is based on the irreversible absence of brainstem function and a state of permanent unconsciousness. Such patients require continuous mechanical ventilation without which they would die. Despite these clinical features, their hearts beat independently and they are capable of a number of processes including somatic growth and development, reproduction and physiological control of salt and water balance. To the uninformed observer these patients would appear alive. It has already been asked (and remains unanswered) why the first set of clinical features qualifies the patient as dead and disregards the second set.[4]

In 1968, a Harvard committee established the brain-stem criteria for declaring death and this has become firmly rooted as an ethically sound means of determining death in the UK and many other countries.[5] It must not be overlooked, nor was it hidden, that this committee was convened in an attempt to establish an ethical and legal justification for the retrieval of organs from patients who were in this state.[6] Against this background, it seems fair to suggest that this particular criterion was devised to permit an arbitrary set of clinical findings which would directly lead to an increase in the pool of donor organs. That these findings are arbitrary is most obvious when one examines the disagreement over how many minutes of asystole qualifies as death which is discussed later. Such is the lack of consensus that brain-death qualifies as death that anaesthetists continue to debate whether these patients should be sedated prior to organ donation.[7],[8],[9],[10]

Other attempts to justify the diagnosis in these patients have been sought in another definition of death: ‘the loss of functioning of the organism as a whole’.[11] Originally this definition was true for brain-dead patients who shortly after losing irreversible brain stem function and consciousness would suffer cardiac arrest and die. But advances in intensive care interventions have meant that brain-dead patients can survive for significant periods of time, preserving the functioning of the organism. There has been a relative silence from the medical community in acknowledging the suggestions that brain-death does not qualify as death and the reasons for this are considered later. With this in mind several authors have called for frank admissions that the current criteria for diagnosing death in brain-dead patients cannot withstand scrutiny and should be re-evaluated.[12],[13],[14]

Are patients diagnosed dead by cardio-respiratory criteria really dead?

Patients who do not meet brain-death criteria but whose continued care is considered futile may be considered for withdrawal of care. Such decisions are made collectively between the clinicians and relatives and take into account any documented or verbal wishes made by the patient. Typically such patients have suffered catastrophic neurological damage such as severe head injuries, subarachnoid haemorrhages and hypoxic brain insults. Protocols for donation after cardiac death (DCD) are developed by individual units across the UK and are summarised in figure 1.

The controversy regarding the diagnosis of death in these patients stems from the declaration of death after five minutes of asystole.[15],[16],[17],[18] At this point the patient is thought to have had ‘irreversible cessation of respiratory and cardiac function and is therefore dead’.[19]  What “irreversible” means in this context is not exactly clear. Efforts to resuscitate patients after five minutes of “downtime” have resulted in successful restoration of independent cardiac and respiratory function.[20] Lynn points out that although the passage of time following cessation of these functions marks the increasing probability that the patient is dead but the exact point of death cannot be established with confidence.[21] As with criticisms levelled at diagnosing death in brain-dead patients, the decision that the passage of five minutes should result in irreversible loss of function seems arbitrary. This becomes even more conspicuous when one considers that Germany and Japan require a stand-down time of two hours and the United States has reported stand-down times of under two minutes.[22] According to these criteria one could be alive in Germany but dead in the UK. These inconsistencies have been recognised and Bell points out that the timing of death is problematic in the UK given the absence of any professional guidelines as to when death can be certified outside of the brainstem death criteria.[23] Given all these contradictions it is not surprising that some have also called for an honest confession that we do not know how long one should wait after cardiopulmonary arrest until death is certified.[24]Bioethicsarticleimage1

Figure 1: Sequence of events recommended by the Intensive Care Society and the Royal Medical Colleges for the withdrawal of care to organ retrieval in the UK.[25]

The danger of relying on definition

Both heart-beating donation and DCD have been shown to suffer from fundamental weaknesses which undermine their claim to ethical integrity. The scientific community appears reluctant to acknowledge these problems but hypocritically defends the DDR as an important ethical safeguard to prevent the exploitation of patients. Brock explains that in making and discussing public policy: ‘we sometimes face choices between truth and consequences […] if truth jeopardises public confidence, it is better to maintain the moral status quo’.[26] This author agrees with the premise but strongly disagrees with the conclusion. A deliberate evasion of responsibility represents a moral squeamishness which is permitted only because it disguises itself as championing the safeguarding of patients. There is perhaps an irrational fear that acknowledging the problems with current practice will lead to a public and media backlash, eroding public trust in the health profession and jeopardising the future of organ donation practices. Such attempts to sensationalise (and demonise) the practice of organ donation[27] have been tried before and often fail to attract any measure of public outrage or distrust.[28] The occasions when organ donation rates have been severely affected, such as when Brazil attempted a strict form of presumed consent which allowed doctors to remove organs regardless of the wishes of the family[29], are so extreme precisely because they evade any involvement from the public. Transparency and public understanding are crucial to the development of organ donation practices. Interestingly some surveys even suggest that issues related to respect for valid consent and the extent of neurological injury may matter more to the public than concerns about whether the patient is already dead at the time of organ removal.[30]

The manipulation of definitions of death has become a Procrustean bed, constantly being added to or rearranged to suit the protocols of different units around the world. Using arbitrary definitions of death is a form of professional sophistry which is more likely to harm public trust in the health service.[31] As Kerridge concludes, ‘the long term viability of transplantation programmes is likely to be better served by telling the truth than trading in fictions’[32]. But one ought to ask why those authors who have “discovered” these misdiagnoses are not more outraged that the practices continue. Indeed several of these authors endorse the continued donation of organs from brain-dead patients and donation after cardiac death but their support is not conditional on the patient being dead.

The paradigm shift

The alternative ethical argument which defends the donation of organs from brain-dead and non-heart-beating donors accommodates the abandonment of the DDR. Instead of using the certification of death as the crucial step in organ donation, it is proposed that the ethics of organ procurement should undergo a paradigm shift from a diagnosis of death to a strong focus on autonomy and nonmaleficence.[33]

Truog proposes an alternative question to selecting individuals for organ donation, asking: ‘When are patients sufficiently close to death or sufficiently neurologically impaired that they can choose to be an organ donor?’[34] This question may seem to be as imprecise as the definition of death but these scenarios commonly occur in intensive care units even when organ donation is not being considered. Deciding to withdraw care from the ‘imminently dying’[35] depends on patient autonomy and informed consent from the family and therefore offers a suitable safeguard to the rights of the patients.

Truog’s other focus is on the principle of nonmaleficence which instructs doctors to avoid causing the patient any harm. An absolutist interpretation of this principle is completely unrealistic in modern medicine given that so many procedures carry an unavoidable degree of harm (needle injections, chemotherapy etc.). This moral “dilemma” has sensibly been avoided by justifying such actions on the basis of proportionality. Harmful interventions are not contrary to “primum non nocere” provided they are perceived to be in the patient’s best interests. Abandonment of the DDR does not change the fact that the independent decision to withdraw care has been considered as being in the patient’s best interests. Crucially the decision to donate organs always follows on from this decision and can in no way expedite the decision making process. The chronology of this is important since it defends against the histrionic claims made by critics like Renée Fox who argues vehemently (and incoherently- Fox at one point honestly argues that the term “non-heart-beating” donation was coined by doctors purely to convince themselves that these patients were not going to recover) that organ donation has become ‘an ignoble form of cannibalism’.[36] Fox comes close to identifying genuine inconsistencies in the debate about organ donation but instead resorts to demonising the practice altogether- how non-heart-beating organ donation is in any way similar to cannibalism is absent from her critique and she also fails to mention at any point that these patients have all agreed to have their organs donated. A more worthy critique may have focused on the implications of arguing that these patients are not really dead. Indeed, the new ethical paradigm proposed by some has so far not acknowledged that if patients are not dead at the time of donation, the act of donation will be considered by many as active euthanasia.

Would abandonment of Dead Donor Rule sanction active euthanasia?

The removal of organs from living patients would be the direct cause of their death.[37] However it is important to note that although such patients are being actively euthanized, abandonment of the DDR does not sanction the full-scale use of active euthanasia.

            Ethicists today make a distinction between letting die and killing and the prevailing opinion is that withdrawal of care qualifies as the former. The basis of this argument is that the patient’s underlying disease will cause their death when life supportive treatments are withdrawn. This casuistry is currently used to justify the procurement of organs from those who donate after cardiac death. To argue that these patients die by omission rather than an act does not withstand scrutiny. It is helpful to consider the failings of this distinction using the hypothetical example of two patients on mechanical ventilation.[38]

            The first patient chooses to have care withdrawn and the second patient does not. If the first patient dies following treatment withdrawal, the current consensus is that it is the underlying disease which kills the patient. However this conclusion is undermined by the fact that the second patient who has not had the treatment withdrawn still lives. Applying strict criteria of causation, it must be accepted that the cause of the first patient’s death was the removal of life support (i.e. an act not an omission).

Despite this conclusion, the ethical framework for choosing to withdraw care is still defensible. Basing the decision on valid consent and respect for the autonomy of the patient is an ethically coherent basis to withdraw care. In this way, whether the withdrawal of care or removal of organs is the cause of death becomes ethically indistinguishable. It is for society to decide whether the implications of “causing death” are so severe that they discredit the original ethical premise. It should also be noted that this approach focuses directly on patient consent rather than depending on definitions of death which is a surer way of safeguarding public trust than manipulating the definition of death.

Importantly the recognition that withdrawal of care (and the retrieval of organs) is the same as causing death does not sanction active euthanasia. In all these cases organ retrieval depends on the independent decision to withdraw care. The decision to die has already been made and will be actioned one way or another. This is in stark contrast to a terminally ill patient whose quality of life is so poor that they request a lethal dose of medication. The justifications proposed by these patients deserve attention but are beyond the scope of this essay. The salient point is that other treatment options are available to them and they are not dependent on life support. Truog and Miller ask if the decision has been made to cause the patient’s death by withdrawal of care, what difference is there in causing that death through organ retrieval?[39] Bell criticises this position explaining that the distinction fails to acknowledge the inherent conflict of interest generated by the benefit of a third party.[40] These conflicts of interest point to the valid concern that patients could be exploited. But as has been shown, safeguards exist to secure the autonomy of the patient and their relatives and to ensure that the organ retrieval team are kept separate from those who withdraw treatment.

Morally squeamish or morally superior?

            Regardless of the convincing justifications for abandoning the DDR, it is clear that retrieving vital organs from living patients would be intolerable to many doctors. Whether one agrees with the flawed distinction between withdrawal of care and killing, many doctors would be unwilling to participate in such procedures. A consensus has been built over many years which perceives current practices as ethically sound and it is unreasonable to expect all doctors (and the public) to instantly accept a new criteria. But it is equally unfair to say that these doctors possess a moral superiority over those who challenge the inherent problems of this process. These tensions unveil the mutability of society’s ethical conscience. Ethics and morality change with time and such changes have throughout history been responsible for progress and development. Truog and his colleagues explained that their views are ‘offered not as fiats but as proposals’ (personal communication with author) and only wish for public debate to try and shift the ethical paradigm upon which decisions are made. A charge of moral recklessness is unfair and fails to acknowledge the coherency of their arguments.

Conclusion

Organ donation has the potential to transform the lives of thousands of people across the UK and the rest of the world. It is right that society is cautious not to sacrifice its moral and ethical integrity in order to meet this need. But the abandonment of the DDR and its accompanying ethical justification offers a hopeful and ethically coherent alternative to current practice. In return it asks only for dialogue and debate from the wider community to try and establish whether as a society we are ready to embrace the ethical arguments which favour it. Only the dogmatic claim to possess an absolute morality and science should have no part in this. All we can do as scientists is recognise the struggle between the hope of advancement and fear of the unknown. It is a recognition best articulated by Professor Jacob Bronowski who reconciled this struggle with a humble admission of our dependence on establishing our moral and ethical conscience through a framework of debate and deliberation[41].

 

Works Cited

Ad hoc committee of the Harvard Medical School to examine the definition of death. A definition of irreversible coma. JAMA 1968; 15: 22-28.

BBC. The Ascent of Man, 1973, television programme, British Broadcasting Corporation, UK.

Bell MDD. Non-heart-beating organ donation: old procurement strategy- new ethical problems. Journal of Medical Ethics 2003; 29: 176-181.

Bell MDD. Non-heart beating organ donation: clinical process and fundamental issues. Brit Jour Anaesth 2005; 94: 474-478.

Bell MDD. Redefining the ethical and legal foundations of organ procurement. Crit Care Med 2004; 32: 1241.

Boucek MM, Mashburn C, Dunn SM, Frizell R, Edwards L, Pietra B et al. Paediatric heart transplantation after declaration of cardiocirculatory death. New England Journal of Medicine 2008; 359: 709-714.

Brock DW. The role of the public in public policy on the definition of death. In: The definition of death: contemporary controversies. Youngner SJ, Arnold RM, Schapiro R (Eds). Baltimore, John Hopkins University Press, 1999.

Csillag C. Brazil abolishes “presumed consent” in organ donation. Lancet 1998; 352: 1367.

Dalgleish D: Brain stem death: Healthcare workers have difficulty accepting current management. Letter. Br Med J 2000; 321:635.

Evans DW. Seeking an ethical and legal way of procuring transplantable organs from the dying without further attempts to redefine human death. Philosophy, Ethics and Humanities in Medicine 2007; 2: 11.

Fox RC. “An ignoble form of cannibalism”: Reflections of the Pittsburgh Protocol for procuring organs from non-heart-beating cadavers. Kennedy Institute of Ethics Journal 1993; 2: 231-239.

Gardiner D, Riley B. Non-heart-beating organ donation – solution or a step too far! Anaesthesia 2007; 62: 431-433.

Intensive Care Society. Guidelines for Adult Organ and Tissue Donation, 2005. Accessed on 09/12/10 from <http://www.ics.ac.uk/intensive_care_professional/standards_and_guidelines/organ_and_tissue_donation_2005>.

Keep PJ: Anaesthesia for organ donation in the brainstem dead. Letter, comment. Anaesthesia 2000; 55:590

Kerridge IH, Saul P, Lowe M, McPhee J & Williams D. Death, dying and donation: organ transplantation and the diagnosis of death. J Med Ethics 2002; 28: 89-9.

Koppelman ER. The Dead Donor Rule and the Concept of Death: Severing the Ties That Bind Them. The American Journal of Bioethics 2003; 3: 1-8

Lizza JP. Persons, Humanity, and the Definition of Death. Baltimore, John Hopkins University Press, 2005.

Lynn J. Are The Patients Who Become Organ Donors Under The Pittsburgh Protocol For “Non-Heart-Beating Donors” Really Dead? Kennedy Institute of Ethics Journal 1993; 3: 167-178

Maleck WH, Piper SN, Triem J, Boldt J, Zittel FU. Unexpected return of spontaneous circulation after cessation of resuscitation (Lazarus phenomenon). Resuscitation 1998; 39: 125-128

Miller FG, Truog RD. “Rethinking the ethics of vital organ donations.” Hastings Centre Report 2008; 38: 38-46

Moers C, Leuvenink HGD, Ploeg RJ. Non-heart beating organ donation: overview and future perspectives. European Society for Organ Transplantation 2007; 20: 567-575.

Potts M, Evans DW. Does it matter that organ donors are not dead? Ethical and policy implications. J Med Ethics 2004; 31: 406-409

Poulton B, Garfield M: The implications of anaesthetising the brainstem dead: 1. Anaesthesia 2000; 55:695

Ridley S, Bonner S, Bray K, Falvey S, Mackay J, Manara A et al. UK guidance for non-heart-beating donation. Brit Jour Anaesth 2005; 95: 592-595

Robertson J. The Dead Donor Rule. Hastings Center Report 1999; 29: 6-14

Shemie SD. Clarifying the paradigm for the ethics of donation and transplantation: Was ‘dead’ really so clear before organ donation? Philosophy, Ethics and Humanities in Medicine 2007; 2: 18.

Truog RD. Brain Death – Too flawed to endure, too ingrained to abandon. Journal of Law, Medicine, and Ethics 2007; 35: 273-281

Truog RD & Robinson WM. Role of brain death and the dead donor rule in the ethics of organ transplantation. Crit Care Med 2003; 31: 2391-2396

Truog RD, Miller FG. The Dead Donor Rule and Organ Transplantation. New England Journal of Medicine 2008; 359; 7.

UK guidance for non-heart-beating donation. Brit Journal of Anaesthesia 2005; 95: 592-595

Verheijde JL, Rady MY, McGregor J. Recovery of transplantable organs after cardiac or circulatory death: Transforming the paradigm for the ethics of organ donation. Philosophy, Ethics and Humanities in Medicine 2007; 2: 8

Woodcock TE. New act regulating human organ transplantation could facilitate organ donation. BMJ 2002; 324: 1099

Young PJ, Matta BF: Anaesthesia for organ donation in the brainstem dead: Why bother? Anaesthesia 2000; 55:105–106

Younger SJ. Some must die. In: Organ Transplantation: Meanings and Realities. Youngner SJ, Fox R, O’Connell L (Eds). Madison, WI, University of Wisconsin Press, 1996

 

[1] Moers C, Leuvenink HGD, Ploeg RJ. Non-heart beating organ donation: overview and future perspectives. European Society for Organ Transplantation 2007; 20: 567-575.

[2] Ridley S, Bonner S, Bray K, Falvey S, Mackay J, Manara A et al. UK guidance for non-heart-beating donation. Brit Jour Anaesth 2005; 95: 592-595.

[3] UK guidance for non-heart-beating donation. Brit Journal of Anaesthesia 2005; 95: 592-595.

[4] Truog RD. Brain Death – Too flawed to endure, too ingrained to abandon. Journal of Law, Medicine, and Ethics 2007; 35: 273-281.

[5] Ad hoc committee of the Harvard Medical School to examine the definition of death. A definition of irreversible coma. JAMA 1968; 15: 22-28.

[6] Evans DW. Seeking an ethical and legal way of procuring transplantable organs from the dying without further attempts to redefine human death. Philosophy, Ethics and Humanities in Medicine 2007; 2: 11.

[7] Young PJ, Matta BF: Anaesthesia for organ donation in the brainstem dead: Why bother? Anaesthesia 2000; 55: 105–106.

[8] Dalgleish D: Brain stem death: Healthcare workers have difficulty accepting current management. Letter. Br Med J 2000; 321: 635.

[9] Keep PJ: Anaesthesia for organ donation in the brainstem dead. Letter, comment. Anaesthesia 2000; 55: 590.

[10] Poulton B, Garfield M: The implications of anaesthetising the brainstem dead: 1. Anaesthesia 2000; 55: 695.

[11] Lizza JP. Persons, Humanity, and the Definition of Death. Baltimore, John Hopkins University Press, 2005.

[12] Woodcock TE. New act regulating human organ transplantation could facilitate organ donation. BMJ 2002; 324: 1099.

[13] Kerridge IH, Saul P, Lowe M, McPhee J & Williams D. Death, dying and donation: organ transplantation and the diagnosis of death. J Med Ethics 2002; 28: 89-94.

[14] Truog RD & Robinson WM. Role of brain death and the dead donor rule in the ethics of organ transplantation. Crit Care Med 2003; 31: 2391-2396.

[15] Shemie SD. Clarifying the paradigm for the ethics of donation and transplantation: Was ‘dead’ really so clear before organ donation? Philosophy, Ethics and Humanities in Medicine 2007; 2: 18.

[16] Robertson J. The Dead Donor Rule. Hastings Center Report 1999; 29: 6-14.

[17] Koppelman ER. The Dead Donor Rule and the Concept of Death: Severing the Ties That Bind Them. The American Journal of Bioethics 2003; 3: 1-8.

[18] Gardiner D, Riley B. Non-heart-beating organ donation – solution or a step too far! Anaesthesia 2007; 62: 431-433.

[19] Intensive Care Society. Guidelines for Adult Organ and Tissue Donation, 2005. Accessed on 09/12/10 from <http://www.ics.ac.uk/intensive_care_professional/standards_and_guidelines/organ_and_tissue_donation_2005>.

[20] Maleck WH, Piper SN, Triem J, Boldt J, Zittel FU. Unexpected return of spontaneous circulation after cessation of resuscitation (Lazarus phenomenon). Resuscitation 1998; 39: 125-128.

[21] Lynn J. Are The Patients Who Become Organ Donors Under The Pittsburgh Protocol For “Non-Heart-Beating Donors” Really Dead? Kennedy Institute of Ethics Journal 1993; 3: 167-178.

[22] Boucek MM, Mashburn C, Dunn SM, Frizell R, Edwards L, Pietra B et al. Paediatric heart transplantation after declaration of cardiocirculatory death. New England Journal of Medicine 2008; 359: 709-714.

[23] Bell MDD. Non-heart beating organ donation: clinical process and fundamental issues. Brit Jour Anaesth 2005; 94: 474-478.

[24] Evans, 2007.

[25] Intensive Care Society. Guidelines for Adult Organ and Tissue Donation, 2005. Accessed on 09/12/10 from <http://www.ics.ac.uk/intensive_care_professional/standards_and_guidelines/organ_and_tissue_donation_2005>.

[26] Brock DW. The role of the public in public policy on the definition of death. In: The definition of death: contemporary controversies. Youngner SJ, Arnold RM, Schapiro R (Eds). Baltimore, John Hopkins University Press, 1999.

[27] Younger SJ. Some must die. In: Organ Transplantation: Meanings and Realities. Youngner SJ, Fox R, O’Connell L (Eds). Madison, WI, University of Wisconsin Press, 1996.

[28] Truog & Robinson, 2003.

[29] Csillag C. Brazil abolishes “presumed consent” in organ donation. Lancet 1998; 352: 1367.

[30] Truog RD, Miller FG. The Dead Donor Rule and Organ Transplantation. New England Journal of Medicine 2008; 359; 7.

[31] Bell MDD. Non-heart-beating organ donation: old procurement strategy- new ethical problems. Journal of Medical Ethics 2003; 29: 176-181.

[32] Kerridge et. al., 2002.

[33]Verheijde JL, Rady MY, McGregor J. Recovery of transplantable organs after cardiac or circulatory death: Transforming the paradigm for the ethics of organ donation. Philosophy, Ethics and Humanities in Medicine 2007; 2: 8.

[34] Truog & Robinson, 2003.

[35] Ibid.

[36] Fox RC. “An ignoble form of cannibalism”: Reflections of the Pittsburgh Protocol for procuring organs from non-heart-beating cadavers. Kennedy Institute of Ethics Journal 1993; 2: 231-239.

[37] Potts M, Evans DW. Does it matter that organ donors are not dead? Ethical and policy implications. J Med Ethics 2004; 31: 406-409.

[38] Miller FG, Truog RD. “Rethinking the ethics of vital organ donations.” Hastings Centre Report 2008; 38: 38-46.

[39] Miller & Truog, 2008.

[40] Bell MDD. Redefining the ethical and legal foundations of organ procurement. Crit Care Med 2004; 32: 1241.

[41] BBC. The Ascent of Man, 1973, television programme, British Broadcasting Corporation, UK.