Authors: Michael Souter, M.B., Ch.B., FRCA, FNCS
ASA Monitor 11 2018, Vol.82, 20-22.
Prior to a consensus on the definition of brain death, successful organ donation from deceased subjects occurred with rapid procurement after their circulatory arrest and swift progression to reimplantation.
The dead donor rule – stating that living patients must not be killed by organ retrieval – was thus easily satisfied.1 Cadaveric donors could not be harmed by the procedure, and existing limited abilities for resuscitation did not challenge the concept that a loss of circulation inevitably caused loss of life.
Following the development of valid criteria for neuro-logical death by the Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death,2 patients declared brain dead quickly became the preferable candidates for organ donation as their organs were sustained by an active circulation, reducing the burden of ischemic injury.
However, the demand for organs has always exceeded available supply. Attention consequently returned to procurement from patients dying from cardiac arrest – namely donation after circulatory death (DCD). After the precedent of Karen Anne Quinlan,3 increasing societal recognition of patient autonomy allowed discontinuation of care that would not improve or sustain an acceptable quality of life. As such, the removal of that care could and did happen electively, opening the door for subsequent scheduled procurement of organs after death.
In 1995, the Maastricht protocol identified two main possible pathways, namely:
- a) “uncontrolled” – where similar to previous practice, donors were rapidly evaluated and organs procured swiftly after death from unexpected cardiac arrest and
- b) “controlled” – where donors (or their families) authorized removal of organs in patients after their death from circulatory arrest, following a planned withdrawal of life-supporting treatment, i.e., DCD.4
DCD has now established itself as a viable means of organ procurement in the U.S., contributing 18 percent of donors in 2018 (based on Organ Procurement and Transplantation Network data as of August 22, 2018). Candidate organs include kidneys, liver, pancreas and recently lungs, with anesthesiologists being asked to reintubate and ventilate. Experimental protocols for DCD heart procurement are currently in development. DCD also presents a significant number of ethical concerns and questions that have evolved their answers in the two subsequent decades, and anesthesiologists should develop some awareness of the issues in a relatively new area of practice.
- 1. Does withdrawal of treatment with subsequent procurement of organs breach the dead donor rule?
- A critical component of DCD is the independence of a decision by patients or their surrogates to end life-sustaining therapy from any subsequent consideration of organ donation. This does not mean that potential donors cannot signify their intent to donate in the future, but rather that critically ill patients cannot be approached to consider organ donation before making an end-of-life decision. Only when that decision has been made can federally regulated organ procurement organizations (OPOs) make a request for donation from the patient or surrogates.
- 2. How long does it take to be considered dead after cessation of circulatory activity?
- The brain has no metabolic reserve, and with cardiac arrest, loss of neurologic function swiftly follows loss of oxygenated flow, although cardiopulmonary resuscitation can render that loss of function transient rather than irreversible.
- While progression to irreversibility is time-dependent, intervening factors like temperature, vascular disease and metabolic effects of sedation confound accurate prediction of time required to reach the stage of anoxic brain death. Alternatively, a prior determination not to resuscitate would render loss of neurologic function permanent. While this latter approach was pragmatically and philosophically credible, concern persisted for potential autoresuscitation before procurement and the breach of the dead donor rule, i.e., how likely was a spontaneous return of circulation and, hence, the possibility of neurologic function?
- Based on a limited series of observations by De Vita and others,5,6 the Institute of Medicine (now the National Academy of Medicine) recommend-ed five minutes of ab-sent circulatory activity, while the Society of Critical Care Medicine recommended at least two minutes and no more than five minutes to consider cessation of circulation as permanent.7,8 A permanent cessation of neurological function would therefore follow that permanent cessation of circulatory activity.
- 1. How is the viability of procured organs affected by end-of-life care?
- Organs vary in their susceptibility to ischemia-reperfusion injury. From the time of withdrawal of physiological support until death, organs are vulnerable to accumulated cellular injury, accentuated by metabolic demand, hypotension and hypoxia.
- This is summed up as “warm ischemia time” (WIT). Each type of organ has a different threshold of WIT beyond which graft function is compromised – 30 minutes for the liver, 60 minutes for lungs and 90-120 minutes for kidneys. Going beyond these time points may present real risks to recipients that are sometimes fatal.
- 4. Who should manage end-of-life care to avoid conflict of interest?
- End-of-life care for organ donors should be indistinct from that of other end-of-life patients and is best managed by the existing patient care team using institutionally developed protocols. Concern for conflicts of interest necessitated a further ethical rule – that the procurement/transplant team cannot in any sense participate in the end-of-life care of the donor. They cannot be present in the same room as the donating patient prior to death, nor can they declare death. That principle of separation has been broken on occasion, e.g., where medication dosage or fre-quency was increased with a perceived aim of accelerating the death of the patient, with consequences for the medical personnel involved.9 One may argue that since death is the intent, what is wrong with facilitating a more rapid progres-sion? The answer lies in the ethical basis of DCD, i.e., that the patient or surrogate has chosento cease futile or undesired treatment, with death as an expected result. The delivery of a bolus dose of opiate to induce apnea has to be considered as euthanasia, and the distinction between these two approaches is critical.
- 5. How may donating patients may be appropriately cared for and comforted during the end of life?
- Another key principle guiding end-of-life care is the principle of double effect, where it is ethically permissible to deliver medication that may have the undesirable effect of accelerating death – as long as the intent is to treat pain or discomfort, particularly that arising from withdrawal of life-sustaining therapy. An example would be the use of opiate to treat dyspnea in a recently extubated patient. Titration of the opiate is key – enough for symptomatic control but not enough to directly induce death.
- 6. Where should end-of-life care be managed in DCD?
- Limitation of WIT may affect the site of end-of-life care. On declaration of death, the donor’s organs should be procured as rapidly as possible. That has led many to initiate withdrawal of life-sustaining therapy in the actual O.R. or adjacent PACU. The expected presence of families requires a significant amount of preprocedural education of both staff and the family, allowing relatives to be present for death, with either they or the patient moved to a different area in a dignified, compassionate, yet timely manner. This is best done using institutionally agreed-upon practice protocols.
- 7. Are there any permissible donation procedures prior to death?
- Certain procedures can be considered to offer benefit in facilitating successful donation without actively compromising the patient, e.g., starting antibiotics, taking blood samples for serology. Other procedures such as large vessel cannulation, vasodilator or heparin administration may be considered but will always require carefully informed consent from patients or surrogates. Any procedure likely to cause pain or distress is unlikely to be ethical.
- 8. How does all of this affect anesthesiologists?
- Anesthesiologists practicing critical care or palliative care may obviously be involved in the care of DCD patients. However, many have not been involved with these patients, except within a minority of institutions where anesthesiologists had agreed to declare death in the O.R. With DCD lung procurement came a requirement for reintubation and ventilation postmortem for inflation and limitation of atelectasis as well as facilitation of bronchoscopy. That task naturally fell to anesthesia personnel within the O.R. suite – rendering that individual a member of the procurement/transplant team. This challenges those institutions where the anesthesiologist had either agreed to declare death in the O.R. or been involved in end-of-life care. Ethical practice requires that separate individuals declare/manage death from those re-intubating the donor after death. Anesthesiologists should familiarize themselves with institutional DCD protocols and engage in a preprocedural discussion with OPO’s to resolve any questions on timing and workflow.
The complexity of the issues presented above could perhaps induce the anesthesiologist to avoid involvement in DCD.10 However, that would ignore an ethical duty to support the wishes of the donor and improve the survival of possible recipients. Coupled with these imperatives is very real evidence of benefit to grieving families provided by appropriately conducted and supported organ donation.11,12
Preferably, each department of anesthesiology should be aware of and get involved in the construction, review and maintenance of DCD policies within their host institutions.13
Advice and model elements for incorporation into such policies are located within a newly revised ASA Statement on Controlled Organ Donation After Circulatory Death, derived from collaboration between the ASA committees on Ethics, Critical Care Medicine and Transplant Anesthesia.14
References:
1. Robertson JA . The dead donor rule. Hastings Cent Rep. 1999;29(6):6-14.
2. A definition of irreversible coma. Report of the Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death. JAMA. 1968;205(6):337-340.
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14. American Society of Anesthesiologists Committees on Transplant Anesthesia, Critical Care Medicine, and Ethics. Statement on Controlled Organ Donation After Circulatory Death. https://www.asahq.org/quality-and-practice-management/standards-and-guidelines/statement-on-controlled-organ-donation-after-circulatory-death. Published October 25, 2017. Last accessed September 11, 2018.
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