Non‐heart‐beating organ donation – solution or a step too far?

The pool of brain stem dead patients who go on to become heart-beating organ donors seems to be shrinking, probably as a result of improved road safety and prehospital care and more aggressive neurosurgery procedures such as decompressive craniectomy. Non-heart-beating organ donation (NHBD) is one way to increase the organ donor pool. The article by Gratix, Pittard and Bodenham in this edition of Anaesthesia shows that one of the patient groups that was considered to be a potential source of non-heart-beating (NHB) donors may not be as great as was previously assumed, with only 4% of out-of-hospital cardiac arrest patients being potentially suitable for NHBD [1]. This article provides an opportunity to widen the debate regarding NHBD. There appear to be two schools of thought in the medical and transplant community concerning NHBD. The first is that NHBD is a panacea for the nearly 7000 patients on the active transplant waiting list [2], whereas the second would see NHBD as the final creation of Dr Frankenstein with the death of the patient timed and managed for the convenience of organ retrieval. Both views are equally extreme. Before the recognition of brain stem death which allows heart-beating organ donation (HBD), cadaveric organ donation occurred from patients who had been declared dead by traditional cardiorespiratory criteria [3]. It is the failure of the HBD system to meet the shortfall in donor organs that has prompted the renewed interest in NHBD. The major downside to NHBD and the reason that it was originally abandoned in favour of HBD, is the increased warm ischaemic time compared to HBD, as cardiorespiratory failure must, by definition, precede organ donation and will invariably lead to a period of inadequate organ perfusion and diminished quality of the organ and graft survival. An international meeting in Maastricht formulated categories to group potential NHB donors [4]. Originally there were four categories, but recently this has been increased to five [5]: • Category I Dead on arrival; • Category II Unsuccessful resuscitation; • Category III Awaiting cardiac arrest; • Category IV Cardiac arrest in a brain stem dead donor. • Category V Unexpected cardiac arrest in a critically ill patient. Generally categories I, II and V are considered uncontrolled categories, as the timing of death or the arrival into the hospital of a potential donor can not be predicted. Category III, and perhaps IV, is considered controlled as there is some ability to predict and plan for imminent cardiorespiratory death, usually following treatment withdrawal in intensive care. Controlled organ donation is the most common form of NHBD in the UK, USA, the Netherlands, Switzerland and Japan [6-10]. The actual pathological diagnoses leading to death in controlled NHBD are similar neurological ones to those found in HBD, such as subarachnoid haemorrhage, head trauma or hypoxaemic/ hypotensive injury. There is no requirement for this to be so, as the grounds for clinical futility, used in intensive care to justify the withdrawal of life-sustaining treatment, need not have any neurological component. However, systemic illnesses such as sepsis and trauma are likely to have resulted in multi-organ failure so that the organs may not be suitable for donation. Many patients in the intensive care unit will die of these very same neurological diagnoses but never satisfy criteria for brain stem death. It is by utilising this new population of potential donors that NHBD may substantially increase the organ donor pool. A recent editorial in the British Medical Journal suggested there was the potential to increase the liver organ supply by 10–20%, which represented ‘a challenge which the medical profession has to take up.’[11], There were 125 NHB donors in the UK between 2005 and 2006, a yearly increase of 44% and representing 16% of all deceased solid organ donations [2]. Despite this increase, logistical and ethical difficulties remain. Perhaps some of these difficulties become a little more obvious when one considers the process itself. It must first be decided that it is appropriate for a patient on the intensive care unit to have their active life-sustaining treatment withdrawn. A second independent decision must then be made in consultation with the organ donor co-ordinator about the suitability of the patient for NHBD. The current requirements regarding suitability vary with different transplant teams but are generally age less than 70 years for kidneys and 40 years for liver, no CJD or HIV, and an expectation that cardiorespiratory death will occur within 2–3 h after treatment withdrawal. If the patient is considered a potential donor then, after checking on the organ donor register (ODR) for patient ‘consent’ (there is no separation on the register for HBD or NHBD), the family is approached. If the family is in agreement, the donor retrieval team is summoned and made ready and then treatment is withdrawn as per usual local practice. This may include the use of analgesia and sedation, cessation of inotropic support, ventilation on air or terminal tracheal extubation. If longer than 2–3 h elapses and cardiorespiratory death has not occurred, then the donor retrieval team is stood down and the donation of solid organs does not proceed. If cardiorespiratory arrest does occur within this time period then, after 5 min, death is declared. A further additional 5 min is allowed for family goodbyes and then the patient is moved to the theatre operating room where organ retrieval (predominantly kidney and liver but in small numbers pancreas and lung) occurs. There is little need for an anaesthetist working outside intensive care to be involved in this process apart from the co-ordination of theatre availability for the donor retrieval team. A great difficulty in NHBD is the need for a robust diagnosis of medical futility to justify treatment withdrawal. A diagnosis of futility is not and probably can never be as robust as a diagnosis of brain stem death. Added to that is the potential criticism or question of whether all treatment options have been explored. For example, the article in this edition of Anaesthesia makes no mention of the use of hypothermic therapies for these out-of-hospital cardiac arrests, hypothetically raising the question of whether these patients received full appropriate care. Those of us with long memories recall the disastrous effect that a single ‘Panorama’ television programme had on the HBD programme when its erroneous content resulted in a loss in public confidence in the diagnosis of brain stem death. Any similar doubt over decisions to withdraw life-sustaining treatment would be a potential disaster for any NHBD programme. The recent Times newspaper article with the headline ‘‘Doctors’ left elderly stroke victim to starve to death”[12] may give a foretaste of the imaginary “Doctors' gave substandard care so they could have my son's organs.” Some relatives may not accept that the decision to withdraw treatment and the request for organ donation are separate issues. A request for organ donation during a withdrawal conversation might result in hardening relatives' attitudes to the continuation of futile treatment. Alternatively, it may well be that the doctor's perception of difficulty is greater than actually occurs [13]. Another difficulty in NHBD is defining when death occurs. In HBD, and despite ongoing controversies, there have been 30 years of medical and legal acceptance of the diagnosis of brain stem death in the UK. The acceptance of cardiovascular death is long-standing in the public and medical communities. The public find it easy to understand that death has occurred if someone's heart has permanently stopped rather than the neurological construct of brain stem death. In the US this distinction in the criteria for diagnosing death has led to the adoption of a different organ donor nomenclature. NHBD is ‘Donation after Cardiac Death’ and HBD is ‘Donation after Brain Death’. The US nomenclature clearly links the type of donation to the criteria used to diagnose death and this has some advantages. Death is a pathological process and not an event, yet in law clinicians are asked to assign a moment of death. Distinguishing between the two criteria allows a more self-explanatory basis for assigning a moment of death. An important difference between the two criteria of death is the timing of when this moment is assigned. In brain stem death, although cardiovascular instability is a common problem, there is no requirement for rapid (within minutes) diagnosis of death. Many brain stem death protocols even demand a minimum set time interval between the first and second sets of brain stem tests. It is therefore usual in HBD that the time frame over which death is diagnosed and the time to starting surgical organ retrieval are prolonged. Such relative luxury of time is not available in NHBD. The need to reduce warm ischaemic damage to the organs requires a much-compacted time frame for diagnosing death and starting surgical organ retrieval, ideally to an period of about 15 min. Despite the much greater acceptance of a diagnosis of death by traditional cardiovascular criteria compared to brain stem death, uncertainty may be introduced by the time frame in which this diagnosis needs to be carried out. What then is an appropriate period of cardiorespiratory arrest before death can legitimately be declared? The Intensive Care Society (ICS) guideline is 5 min, as documented by ECG and absent arterial waveform [14]. The ICS guideline references a paper published in 2000 by the US Institute of Medicine for the chosen period of 5 min. However, the Institute of Medicine paper acknowledges the uncertainty and lack of scientific evidence for this guidance [15]. With only weak evidence to justify the 5-min time frame, perhaps we should be wary of ignoring the case reports of auto-resuscitation (Lazarus phenomenon) in the literature. At least 20 such cases have been described in the literature since the first description in 1982 [16, 17]. One of our colleagues has seen this occur in our intensive care after the declaration of death, although the return of cardiac output was not sustained, suggesting that the actual frequency of Lazarus phenomenon may be much higher than that stated in the literature. It has been suggested that, at 10 min, this exceedingly rare event is rarer still [18]. The compacted time frame required to facilitate NHBD may lead to the perception that undue haste has been employed. Such concerns may only be addressed by the publication and take-up of nationally agreed guidelines such as those recently adopted in Canada [19]. A joint statement from the Academy of Medical Royal Colleges may be forthcoming in the near future. In the US, a more explicit premorbid intervention policy is practised to reduce warm ischaemic time, whereby it is standard for physical procedures such as femoral cannulation, and medications such as heparin, to be administered to the dying intensive care patient for the purpose of facilitating rapid organ preservation and NHBD. Such premorbid intervention would be considered by many in the UK as not being in the patient's best interests and therefore inappropriate. It is also standard in some centres for withdrawal of life-sustaining treatment to be carried out in the operating theatre, again to reduce warm ischaemic time. Anaesthetists would be likely be involved if such a protocol were introduced into the UK. The 5-min time frame of cardiorespiratory arrest is considered by some centres in the US to be too stringent, such that they are happy to start the retrieval process after only 2 min of pulseless electrical activity (PEA) as evidenced by an absent arterial waveform. Indeed, an astonished audience at the 3rd International NHBD Conference in London in 2006 heard that, in experimental work in a US centre, extracorporeal membrane oxygenation (ECMO) is started after 2 min of PEA via precannulated femoral vessels, and the heart is often seen to restart. The authors consider this to be a step too far in managing the dying process and the ethics of premorbid intervention, and cannot conceive that UK doctors would allow someone who had died in this manner to have oxygenated blood perfused not only to their heart but also to their, albeit neurologically damaged, brain. At present our Intensive Care Unit does not have a NHBD programme and, as a consultant intensive care body, we have opposed introducing such a protocol until our concerns have been addressed and there is a consensus opinion. The patient in whom continued treatment is obviously futile, who will have treatment withdrawn, yet would have wished to be an organ donor, will not become a solid organ donor in our institution. Our donor co-ordinator informs us that there were 20 potential NHB donors last year compared to 23 brain stem dead patients. To watch as a wish to donate goes unfulfilled is a strong argument against all our concerns.

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