Chapter 93 Organ donation
Intensivists often have responsibility for the care of organ transplant recipients and have seen the benefits they obtain from transplantation. Clinical results continue to improve, despite increasing recipient case complexity and increasing use of organs from extended-criteria deceased donors, and this success continues to drive demand for transplantation.1 At the same time, deaths from road trauma (once the most common cause of death in deceased-donor organ donation) continue to fall in many countries as a result of both primary prevention and better treatment of traumatic brain injury. Decompressive craniectomy in particular is effective in controlling refractory intracranial hypertension2 (and thereby reducing brain death), although whether outcomes are improved overall await the results of two ongoing clinical trials. Similarly, population-based studies have shown falls in the incidence and mortality of subarachnoid haemorrhage3 and perhaps also intracerebral haemorrhage. Treatments for some other conditions which uncommonly contribute to deceased-donor donation (e.g. hypoxic–ischaemic encephalopathy, meningitis) have also improved.
With the exception of the USA, many countries are now experiencing a fall in brain dead organ donation. Transplant numbers have been maintained, or only modestly increased, by other strategies, including donation after cardiac death (DCD, formerly called non-heart beating donation), live donors (including altruistic donors) and the use of split livers for two recipients. There is considerable pressure on intensivists and others to provide a solution to the ‘organ donor shortage’, but less consideration given to restricting access to waiting lists. Despite widespread condemnation of the practice, desperate recipients from wealthy countries take part in ‘transplant tourism’4,5 in Asia (particularly in China, including organs from executed prisoners), Africa and South America. The internet has facilitated a form of altruistic but directed live donation which also is potentially vulnerable to commercial exploitation (e.g. http://www.matchingdonors.com). Slow progress continues in alternative approaches to end-stage organ failure, including artificial organs, xenotransplantation and the engineering of organs and tissues from stem cells, but none is yet available for routine clinical use.
RESPONSIBILITIES OF THE INTENSIVIST
Most intensivists are supportive of deceased-donor organ donation.6 Those who are not should make arrangements with other intensivist colleagues for the care of potential organ donors and discussions with their families.7 Intensivists’ responsibilities include the care of dying patients and of their families in the intensive care unit – the location of organ donation itself. Intensivists therefore must either define and take responsibility for good practice in organ donation, or accept that these processes will be taken over by others with the objective of ‘transforming the greatest possible number of cadavers into real donors’.8 This personal epiphany9,10 is not yet widely shared in intensive care medicine.
CARE OF THE DYING PATIENT AND THEIR FAMILY
Intensivists are familiar with the care of the dying patient, including the need to avoid suffering and maintain patient dignity. The respect of the intensive care unit (ICU) staff for the humanity of the dying person is expressed in the ‘patient comfort care’ provided by the nursing staff, the continued involvement and attentiveness of the medical staff, and in evident compassion of all staff for the family.11
On behalf of all the treating team, an intensivist should establish rapport during an early meeting (e.g. the morning after admission) with the family of every intensive care patient. This is particularly important for families of patients at high risk of death or disability with whom there will often need to be several ‘bad news’ meetings over several days. Family meetings should be attended by whomsoever the family defines itself to include, by the intensivist, and by a member of the nursing staff supporting the family (preferably the ‘bedside nurse’ looking after the patient). If the family wishes, the meeting might include a chaplain, social worker or cultural health worker. The ‘support’ role should be kept separate from the ‘bearer of bad news’ role. Family meetings should be held in a separate private room large enough to accommodate all the participants, away from the bedside and protected from interruption. With evident compassion11 the intensivist should convey an accurate account of the sequence of events, a realistic prognosis (in as much as this is possible) and the immediate treatment plan. Some families find CT or other visual information helpful. There must be enough time to answer any questions that the family may have. At the end of the meeting the intensivist should ascertain that the family understands what has been said11 and agrees with the immediate plan. Ensuring that all team members give the family congruent messages is an essential part of maintaining the trust of the family in the ICU team. Ideally, one intensivist should speak with the family but where this is impractical it is vital that there be detailed and explicit discussions between one intensivist and another before the next family meeting. A relationship of mutual understanding and trust will enable the ICU team and the family to work together through difficult and painful issues, including withdrawal of intensive therapies,12 death of the patient and consideration of organ donation.
Many patients who develop apparent loss of brainstem function do so despite continuance of all available surgical and medical therapy. In these circumstances, brain-oriented intensive therapies (including sedatives, opioids, neuromuscular blockers, hypothermia and osmotherapy) should be withheld pending formal assessment of brain death. In order to meet the preconditions for brain death assessment,7 extracranial homeostasis must be maintained, and these conditions also preserve the possibility of organ donation in the future.
Withdrawal of intensive therapies is common practice in Australasian ICUs.12–14 In the setting of severe brain damage this first involves assembling definitive prognostic information. Although neurophysiology and imaging provide important supportive information, a sedative-free clinical assessment of CNS function is an essential aspect of prognostication. During the period of sedative-free CNS assessment, some patients will suffer apparent loss of brainstem function. If brain death does not occur, but devastating brain damage has clearly occurred, those treating the patient (e.g. intensivists, neurosurgeons and others) should achieve a consensus view of prognosis and a recommended treatment plan, which might include withdrawal of intensive treatments (e.g. artificial airway, ventilatory or inotropic support, further neurosurgery). The intensivist should then discuss the prognosis and recommended plan with the family and facilitate a consensus. Withdrawal of treatment may subsequently occur, either because death is seen to be imminent and inevitable or because the likely survival outcome would not be in accord with the patient’s previously expressed wishes or inferred best interests. Such a decision to limit or withdraw treatment is guided by the principles of non-malfeasance and respect for autonomy.15 It is appropriate to withdraw all intensive therapies from such patients, while continuing to provide ‘comfort care’ to the patient and support to the family.15
IDENTIFICATION OF THE POTENTIAL FOR ORGAN DONATION TO OCCUR
Most ICUs admit patients with very severe brain damage whose probability of recovery is low. The rationale for this practice is to identify any (small) subgroup of patients with reversible conditions and provide them with the necessary treatment to facilitate their recovery. There are, however, more extreme situations when the chance of recovery is thought so remote that admission of the patient to ICU would not ordinarily occur. Some intensivists advocate admitting these patients to ICU solely to allow for the future possibility that organ donation may occur, sometimes with accompanying explicit discussion and agreement of the family to such a plan.16 Although it seems likely16 that such an utilitarian approach might increase the number of organs available for transplant, ethical,17 legal18 and clinical17 objections to the practice have all been raised.
Organ donation is possible in most situations where brain death has been confirmed. The absolute general contraindications to organ donation are few and present in a small minority of brain-dead patients. They include situations where there is an unacceptably high risk of transmission of malignancy or infection to the recipient, or where the function of the possible donor organs is likely to be unacceptably poor. Most extracerebral malignancies and certain infections (e.g. HIV) are likely to remain absolute contraindications but other donor factors (e.g. advanced age, recent bacterial sepsis,19 treated HSV encephalitis, positive HCV20 or HBV20 serology, some ‘apparently cured’ malignancies) are no longer absolute contraindications. Intensivists should discuss the specific issue with the appropriate agency (donor coordinator or organ procurement organisation) rather than decide that organ donation is contraindicated on medical grounds. Similarly, the organ-specific contraindications to organ donation have reduced in recent years as the outcomes of recipients transplanted with donor organs formerly rejected have been found to be acceptable.21 Finally, all contraindications vary somewhat between transplant centres and continue to change in a more permissive direction. Intensivists should discuss these organ-specific issues with the donor coordinator or appropriate agency before deciding that any particular organ is unsuitable for possible donation and subsequent transplantation. In most jurisdictions an appropriate authority (e.g. a coroner or medical examiner) may legally interdict organ donation under certain circumstances (e.g. homicide) and this issue must also be clarified with the donor coordinator. The donor coordinator will clarify with the transplant teams whether any organ donation is possible and whether particular organs may not be suitable, and the intensivist should ensure that the information (Table 93.1) necessary for these decisions is provided.
DETERMINATION OF BRAIN DEATH
This is a clinical responsibility of the intensivist and must be carried out according to appropriate codes of practice or clinical guidelines (see Chapter 46). The determination of brain death7,22,23 involves several stages:
The examination and determination of brain death is facilitated by a proforma and should be documented in the medical record. When clinical examination is confounded (e.g. by barbiturate coma), then absent cerebral blood flow must instead be demonstrated by reliable imaging.7
The intensivist should convey the fact of brain death and its medical and legal implications to the family. It can be difficult to accept brain death as death, given the life-like appearance of the skin, the rise and fall of the chest and the warmth of the hands that are preserved by ventilatory and circulatory support.24 Some family members appreciate an offer to view the (second) clinical examination for brain death (taking care to explain beforehand the possibility of spinal reflexes), or the cerebral blood flow study when clinical examination is confounded. This may help them to understand and accept the final awful implication of this diagnosis. Intensivists should be open to offering these options.
DONATION AFTER CARDIAC DEATH
In all but Category III the situation is ‘uncontrolled’.25
DCD practice varies considerably worldwide. Category II donors are most common in the Dutch experience but donation does occur from all categories. Almost all DCD donors in the UK, USA, Canada and Australasia are Category III (and a very few are Category IV). By contrast, in Spain, although withdrawal of treatment in ICU is far less common than in Holland or the UK,26,27 and Category III donors are rare, immediate postmortem organ preservation measures (including cardiopulmonary bypass) can be implemented with prior consent and most DCD donors are Category I and II.28 Recent advocates for DCD commonly assert that ‘all organ donation occurred this way’ before brain death was accepted as legal death. Although organs were removed after circulatory arrest, there are differences which are not discussed and which negate the assertion that the processes are identical. Although brain death was not accepted as legal death, the syndrome had been recognised many years earlier (e.g. absent cerebral blood flow29 was reported in 1956 and the clinical syndrome30 in 1959). The final awful meaning of the brain death syndrome (‘apnoea, fixed dilated pupils, polyuria, hyperglycaemia and spontaneous hypothermia’31) was understood by intensivists and nephrologists and conveyed to families at that time, prior to a discussion of organ donation (PB Doak, RV Trubuhovich, personal communications). Organ donation was not discussed with the family if some brainstem function (usually only a tracheal reflex) was known to be present. Apnoea at hypercarbia was not specifically tested for but the shared expectation of the family and the treating team was that the patient would not breathe after withdrawal of ventilatory support (although a few did, for a short time and inadequately). Cardiac arrest usually occurred in 15–20 minutes, at which point death was declared and the kidneys were removed.