Normothermic Regional Perfusion Requires Careful Ethical Analysis Before Adoption Into Donation After Circulatory Determination of Death

Advancing the Scientific Basis for Determining Death in Controlled Organ Donation After Circulatory Determination of Death

In controlled organ donation after circulatory determination of death (cDCDD), accurate and timely death determination is critical, yet knowledge gaps persist. Further research to improve the science of defining and determining death by circulatory criteria is therefore warranted. In a workshop sponsored by the National Heart, Lung, and Blood Institute, experts identified research opportunities pertaining to scientific, conceptual, and ethical understandings of DCDD and associated technologies. This article identifies a research strategy to inform the biomedical definition of death, the criteria for its determination, and circulatory death determination in cDCDD. Highlighting knowledge gaps, we propose that further research is needed to inform the observation period following cessation of circulation in pediatric and neonatal populations, the temporal relationship between the cessation of brain and circulatory function after the withdrawal of life-sustaining measures in all patient populations, and the minimal pulse pressures that sustain brain blood flow, perfusion, activity, and function. Additionally, accurate predictive tools to estimate time to asystole following the withdrawal of treatment and alternative monitoring modalities to establish the cessation of circulatory, brainstem, and brain function are needed. The physiologic and conceptual implications of postmortem interventions that resume circulation in cDCDD donors likewise demand attention to inform organ recovery practices. Finally, because jurisdictionally variable definitions of death and the criteria for its determination may impede collaborative research efforts, further work is required to achieve consensus on the physiologic and conceptual rationale for defining and determining death after circulatory arrest.

Sowing "seeds of trust": How trust in normothermic regional perfusion is built in a continuum of care

Normothermic regional perfusion (NRP) is a promising technology to improve organ transplantation outcomes by reversing ischemic injury caused by controlled donation after circulatory determination of death. However, it has not yet been implemented in Canada due to ethical questions. These issues must be resolved to preserve public trust in organ donation and transplantation. This qualitative, constructivist grounded theory study sought to understand how those most impacted by NRP perceived the ethical implications. We interviewed 29 participants across stakeholder groups of donor families, organ recipients, donation and transplantation system leaders, and care providers. The interview protocol included a short presentation about the purpose of NRP and procedures in abdomen versus chest and abdomen NRP, followed by questions probing potential violations of the dead donor rule and concerns regarding brain reperfusion. The results present a grounded theory placing NRP within a trust-building continuum of care for the donor, their family, and organ recipients. Stakeholders consistently described both forms of NRP as an ethical intervention, but their rationales were predicated on assumptions that neurologic criteria for death had been met following circulatory death determination. Empirical validation of these assumptions will help ground the implementation of NRP in a trust-preserving way.

Developing and Expanding Deceased Organ Donation to its Maximum Therapeutic Potential: An Actionable Global Challenge From the 2023 Santander Summit

On November 9 and 10, 2023, the Organización Nacional de Trasplantes (ONT), under the Spanish Presidency of the Council of the European Union, convened in Santander a Global Summit entitled "Towards Global Convergence in Transplantation: Sufficiency, Transparency and Oversight." This article summarizes two distinct but related challenges elaborated at the Santander Summit by Working Group 2 that must be overcome if we are to develop and expand deceased donation worldwide and achieve the goal of self-sufficiency in organ donation and transplantation. Challenge 1: the need for a unified concept of death based on the permanent cessation of brain function. Working group 2 proposed that challenge 1 requires the global community to work toward a uniform, worldwide definition of human death, conceptually unifying circulatory and neurological criteria of death around the cessation of brain function and accepting that permanent cessation of brain function is a valid criterion to determine death. Challenge 2: reducing disparities in deceased donation and increasing organ utilization through donation after the circulatory determination of death (DCDD). Working group 2 proposed that challenge 2 requires the global community to work toward increasing organ utilization through DCDD, expanding DCDD through in situ normothermic regional perfusion, and expanding DCDD through ex situ machine organ perfusion technology. Recommendations for implementation are described.

Ethical Issues in Normothermic Regional Perfusion in Controlled Organ Donation After Determination of Death by Circulatory Criteria: A Scoping Review

Normothermic regional perfusion (NRP) is a surgical technique that can improve the quality and number of organs recovered for donation after the determination of death by circulatory criteria. Despite its promise, adoption of NRP has been hindered because of unresolved ethical issues. To inform stakeholders, this scoping review provides an impartial overview of the major ethical controversies surrounding NRP. We undertook this review according to a modified 5-step methodology proposed by Arksey and O'Malley. Publications were retrieved through MEDLINE and Embase. Gray literature was sourced from Canadian organ donation organizations, English-language organ donation organization websites, and through our research networks. Three reviewers independently screened all documents for inclusion, extracted data, and participated in content analysis. Disagreements were resolved through consensus meetings. Seventy-one documents substantively engaging with ethical issues in NRP were included for full-text analysis. We identified 6 major themes encompassing a range of overlapping ethical debates: (1) the compatibility of NRP with the dead donor rule, the injunction that organ recovery cannot cause death, (2) the risk of donor harm posed by NRP, (3) uncertainties regarding consent requirements for NRP, (4) risks to stakeholder trust posed by NRP, (5) the implications of NRP for justice, and (6) NRP's potential to benefits of NRP for stakeholders. We found no agreement on the ethical permissibility of NRP. However, some debates may be resolved through additional empirical study. As decision-makers contemplate the adoption of NRP, it is critical to address the ethical issues facing the technique to ensure stakeholder trust in deceased donation and transplantation systems is preserved.

Normothermic Regional Perfusion in Controlled Donation After the Circulatory Determination of Death: Understanding Where the Benefit Lies

Controlled donation after the circulatory determination of death (cDCDD) has emerged as a strategy to increase the availability of organs for clinical use. Traditionally, organs from cDCDD donors have been subject to standard rapid recovery (SRR) with poor posttransplant outcomes of abdominal organs, particularly the liver, and limited organ utilization. Normothermic regional perfusion (NRP), based on the use of extracorporeal membrane oxygenation devices, consists of the in situ perfusion of organs that will be subject to transplantation with oxygenated blood under normothermic conditions after the declaration of death and before organ recovery. NRP is a potential solution to address the limitations of traditional recovery methods. It has become normal practice in several European countries and has been recently introduced in the United States. The increased use of NRP in cDCDD has occurred as a result of a growing body of evidence on its association with improved posttransplant outcomes and organ utilization compared with SRR. However, the expansion of NRP is precluded by obstacles of an organizational, legal, and ethical nature. This article details the technique of both abdominal and thoracoabdominal NRP. Based on the available evidence, it describes its benefits in terms of posttransplant outcomes of abdominal and thoracic organs and organ utilization. It addresses cost-effectiveness aspects of NRP, as well as logistical and ethical obstacles that limit the implementation of this innovative preservation strategy.

Restoring the Organism as a Whole: Does NRP Resurrect the Dead?

The introduction of normothermic regional perfusion (NRP) in controlled donation after circulatory determination of death (cDCDD) protocols is by some regarded as controversial and ethically troublesome. One of the main concerns that opponents have about introducing NRP in cDCDD protocols is that reestablishing circulation will negate the determination of death by circulatory criteria, potentially resuscitating the donor. In this article, I argue that this is not the case. If we take a closer look at the concept of death underlying the circulatory criterion for determination of death, we find that the purpose of the criterion is to show whether the organism as a whole has died. I argue that this purpose is fulfilled by the circulatory criterion in cDCDD protocols, and that applying NRP does not negate the determination of death or resuscitate the donor.

Beyond the Final Heartbeat: Neurological Perspectives on Normothermic Regional Perfusion for Organ Donation after Circulatory Death

Normothermic regional perfusion (NRP) has recently been used to augment organ donation after circulatory death (DCD) to improve the quantity and quality of transplantable organs. In DCD-NRP, after withdrawal of life-sustaining therapies and cardiopulmonary arrest, patients are cannulated onto extracorporeal membrane oxygenation to reestablish blood flow to targeted organs including the heart. During this process, aortic arch vessels are ligated to restrict cerebral blood flow. We review ethical challenges including whether the brain is sufficiently reperfused through collateral circulation to allow reemergence of consciousness or pain perception, whether resumption of cardiac activity nullifies the patient's prior death determination, and whether specific authorization for DCD-NRP is required. ANN NEUROL 2024;95:1035-1039.

Knowledge gaps in heart and lung donation after the circulatory determination of death: Report of a workshop of the National Heart, Lung, and Blood Institute

In a workshop sponsored by the U.S. National Heart, Lung, and Blood Institute, experts identified current knowledge gaps and research opportunities in the scientific, conceptual, and ethical understanding of organ donation after the circulatory determination of death and its technologies. To minimize organ injury from warm ischemia and produce better recipient outcomes, innovative techniques to perfuse and oxygenate organs postmortem in situ, such as thoracoabdominal normothermic regional perfusion, are being implemented in several medical centers in the US and elsewhere. These technologies have improved organ outcomes but have raised ethical and legal questions. Re-establishing donor circulation postmortem can be viewed as invalidating the condition of permanent cessation of circulation on which the earlier death determination was made and clamping arch vessels to exclude brain circulation can be viewed as inducing brain death. Alternatively, TA-NRP can be viewed as localized in-situ organ perfusion, not whole-body resuscitation, that does not invalidate death determination. Further scientific, conceptual, and ethical studies, such as those identified in this workshop, can inform and help resolve controversies raised by this practice.

The Unified Brain-Based Determination of Death Conceptually Justifies Death Determination in DCDD and NRP Protocols

Organ donation after the circulatory determination of death requires the permanent cessation of circulation while organ donation after the brain determination of death requires the irreversible cessation of brain functions. The unified brain-based determination of death connects the brain and circulatory death criteria for circulatory death determination in organ donation as follows: permanent cessation of systemic circulation causes permanent cessation of brain circulation which causes permanent cessation of brain perfusion which causes permanent cessation of brain function. The relevant circulation that must cease in circulatory death determination is that to the brain. Eliminating brain circulation from the donor ECMO organ perfusion circuit in thoracoabdominal NRP protocols satisfies the unified brain-based determination of death but only if the complete cessation of brain circulation can be proved. Despite its medical and physiologic rationale, the unified brain-based determination of death remains inconsistent with the Uniform Determination of Death Act.

Maintaining the permanence principle of death during normothermic regional perfusion in controlled donation after the circulatory determination of death: Results of a prospective clinical study

One concern about the use of normothermic regional perfusion (NRP) in controlled donation after the circulatory determination of death (cDCD) is that the brain may be perfused. We aimed to demonstrate that certain technical maneuvers preclude such brain perfusion. A nonrandomized trial was performed on cDCD donors. In abdominal normothermic regional perfusion (A-NRP), the thoracic aorta was blocked with an intra-aortic occlusion balloon. In thoracoabdominal normothermic regional perfusion (TA-NRP), the arch vessels were clamped and the cephalad ends vented to the atmosphere. The mean intracranial arterial blood pressure (ICBP) was invasively measured at the circle of Willis. Ten cDCD donors subject to A-NRP or TA-NRP were included. Mean ICBP and mean blood pressure at the thoracic and the abdominal aorta during the circulatory arrest were 17 (standard deviation [SD], 3), 17 (SD, 3), and 18 (SD, 4) mmHg, respectively. When A-NRP started, pressure at the abdominal aorta increased to 50 (SD, 13) mmHg, while the ICBP remained unchanged. When TA-NRP was initiated, thoracic aorta pressure increased to 71 (SD, 18) mmHg, but the ICBP remained unmodified. Recorded values of ICBP during NRP were 10 mmHg. In conclusion, appropriate technical measures applied during NRP preclude perfusion of the brain in cDCD. This study might help to expand NRP and increase the number of organs available for transplantation.

Heart Transplant and Donors After Circulatory Death: A Clinical-Preclinical Systematic Review

INTRODUCTION

Heart transplantation is the treatment of choice for end-stage heart failure. There is a mismatch between the number of donor hearts available and the number of patients awaiting transplantation. Expanding the donor pool is critically important. The use of hearts donated following circulatory death is one approach to increasing the number of available donor hearts.

MATERIALS AND METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines utilizing Pubmed/MEDLINE and Embase. Articles including adult human studies and preclinical animal studies of heart transplantation following donation after circulatory death were included. Studies of pediatric populations or including organs other than heart were excluded.

RESULTS

Clinical experience and preclinical studies are reviewed. Clinical experience with direct procurement, normothermic regional perfusion, and machine perfusion are included. Preclinical studies addressing organ function assessment and enhancement of performance of marginal organs through preischemic, procurement, preservation, and reperfusion maneuvers are included. Articles addressing the ethical considerations of thoracic transplantation following circulatory death are also reviewed.

CONCLUSIONS

Heart transplantation utilizing organs procured following circulatory death is a promising method to increase the donor pool and offer life-saving transplantation to patients on the waitlist living with end-stage heart failure. There is robust ongoing preclinical and clinical research to optimize this technique and improve organ yield. There are also ongoing ethical considerations that must be addressed by consensus before wide adoption of this approach.

On the ethical permissibility of in situ reperfusion in cardiac transplantation after the declaration of circulatory death

Transplant surgeons in the USA have begun performing a novel organ procurement protocol in the setting of circulatory death. Unlike traditional donation after circulatory death (DCD) protocols, in situ normothermic perfusion DCD involves reperfusing organs, including the heart, while still contained in the donor body. Some commentators, including the American College of Physicians, have claimed that in situ reperfusion after circulatory death violates the widely accepted Dead Donor Rule (DDR) and conclude that in situ reperfusion is ethically impermissible. In this paper I argue that, in terms of respecting the DDR, in situ reperfusion cardiac transplantation does not differ from traditional DCD cardiac transplantation. I do this by introducing and defending a refined conception of circulatory death, namely vegetative state function permanentism I also argue against the controversial brain occlusion feature of the in situ reperfusion DCD protocol, on the basis that it is ethically unnecessary and generates the problematic appearance of ethical dubiousness.

Evaluation of functional warm ischemia time during controlled donation after circulatory determination of death using normothermic regional perfusion (ECMO-TT): A prospective multicenter cohort study

BACKGROUND

Controlled donation after circulatory determination of death (cDCD) seems an effective way to mitigate the critical shortage of available organs for transplant worldwide. As a recently developed procedure for organ retrieval, some questions remain unsolved such as the uncertainty regarding the effect of functional warm ischemia time (FWIT) on organs´ viability.

METHODS

We developed a multicenter prospective cohort study collecting all data from evaluated organs during cDCD from 2017 to 2020. All the procedures related to cDCD were performed with normothermic regional perfusion. The analysis included organ retrieval as endpoint and FWIT as exposure of interest. The effect of FWIT on the likelihood for organ retrieval was evaluated with Relative distribution analysis.

RESULTS

A total amount of 507 organs´ related information was analyzed from 95 organ donors. Median donor age was 62 years, and 63% of donors were male. Stroke was the most common diagnosis before withdrawal of life-sustaining therapy (61%), followed by anoxic encephalopathy (21%). This analysis showed that length of FWIT was inversely associated with organ retrieval rates for liver, kidneys, and pancreas. No statistically significant association was found for lungs.

CONCLUSIONS

Results showed an inverse association between functional warm ischemia time (FWIT) and retrieval rate. We also have postulated optimal FWIT's thresholds for organ retrieval. FWIT for liver retrieval remained between 6 and less than 11 min and in case of kidneys and pancreas, the optimal FWIT for retrieval was 6 to 12 min. These results could be valuable to improve organ utilization and for future analysis.