By Christos Lazaridis.
Thoraco-abdominal normothermic regional perfusion (TA-NRP) is a relatively novel technique for donation after the circulatory determination of death (DCDD). In short, after declaration of death by circulatory criteria (as in conventional DCDD), the circulation to the brain is surgically excluded followed by extracorporeal membrane oxygenation (ECMO) and perfusion of the thoracoabdominal organs. This modification to DCDD has merits in terms of decreasing warm ischemic time, and lowering costs as compared to ex situ machine perfusion of donor organs. However, major controversy has ensued as critics have opposed the procedure in violating legal and ethical norms that govern organ transplantation practices. For these reasons, countries like Australia have banned the procedure, the UK has paused for further review, and in the US the controversy remains unresolved with few centers performing TA-NRP against opposition from scholars and professional societies such as the American College of Physicians.
In this piece I aim to critically examine the central issue of ethical permissibility in performing TA-NRP. The charge has been made that the procedure violates the dead donor rule (DDR) which holds that vital organs may be procured only from patients who are dead and that clinicians may not cause death while or for the purpose of procuring vital organs. For the charge to be coherent, the following must obtain:
- The original death determination becomes invalid by actions undertaken after conventional DCDD death declaration.
- Vital organs are extracted from an alive patient causing their death.
The objection focuses on the fact that circulation to thoraco-abdominal organs is restored. It is this event that invalidates the death determination and makes the donor alive.
Now consider the following scenario: a patient is taken to the operating room (OR) for DCDD. After declaration of death a terrible mishap occurs, and the dead donor is decapitated. Although this would be a gruesome accident affecting a dead individual, the OR team initiates ECMO to restore perfusion to the rest of the body. What is the proper description of this situation? It seems that TA-NRP critics must say that this decapitated body is an alive patient, and that the removal of vital thoracoabdominal organs would be an act of killing this patient. It may be conceivable, under some views about the metaphysics of biologic organisms, to argue that this body is an alive human organism (for example based on the persistence of integrative homeostatic functions), but to consider this an alive patient is absurd. If anyone is dead, then the decapitated are most certainly dead. For the objection to go through, one would have to convincingly argue that restoring circulation in a decapitated human body, restores life to the patient who owned that body.
This thought experiment may be easily dismissed as gruesome fiction, nevertheless, during TA-NRP something analogous to decapitation takes place in the form of “vascular decerebration” (not a formal medical term but I think descriptive enough). A further problem arises in asking is vascular decerebration a permissible action to perform on a dead donor? I am not sure why it would not be when procedures such as flushing the body with ice-cold preservation fluid (as in conventional DCDD), and extraction of the heart and other organs are not only standard but defining of what organ transplantation entails. What is so special about clamping aortic arch vessels on a dead donor?
The thought experiment means to establish that on metaphysical and ethical grounds, the claim that the patient is revived by ECMO in TA-NRP is misguided and misconstrued. It is also true though, that these conclusions may not ground legal permissibility. As a closing remark, I would say that if that is the case, if the law contradicts the practice, then so much worse for the law. The upshot is that we can change the law to realign it with our best supported convictions. In fact, the discussion of how one understands and grounds death determination in TA-NRP, should make it clearer that death determination should be based on a single set of unifying criteria, and these should be about brain functions and their physiological surrogate, cerebral circulation.
Author: Christos Lazaridis
Affiliations: Department of Neurology, MacLean Center for Clinical Medical Ethics, The University of Chicago
Competing interests: None declared
Social media accounts of post author: @ChristosLazari3