Estimating the Potential Pool of Uncontrolled DCD Donors in the United States

Discussion

In this national study of the largest registry of ED visits in the United States between 2013 and 2016, we estimated that there were 9828 (range: 9454–10 202) potential uDCD donors per year. If maximally utilized, these donors could nearly double the number of deceased donors in the United States. These potential donors were young and otherwise healthy, 2 factors that would portend excellent long-term graft and patient survival for recipients of these organs.

To our knowledge, this is the first estimate of the number of medically suitable uDCD donors from a population of patients located in hospitals in the United States. Our estimate is significantly smaller than national scaling of out-of-hospital cardiac arrests in New York City;^[23] however, our study included only ED deaths (versus those in the field) and excluded deaths based on medical suitability. Patients who had ED deaths would more readily have access to high-quality and consistent ACLS, teams with expertise to pronounce death, advanced organ preservation technology, ability to obtain family assent, and surgical capability for expeditious organ procurement.

Development of a successful uDCD program depends not only on technical knowledge and skills, but also a well-developed logistical plan for activation of the uDCD pathway including transplant and trauma surgeons, emergency medicine physicians, Organ Procurement Organization professionals, and perfusionists. The finding that 76.5% of potential uDCD donors were in academic institutions supports feasibility of uDCD in the United States because these institutions would likely have the expertise, personnel, and capacity to implement uDCD protocols.

This study has several key strengths. NEDS is a nationally representative cohort that enabled us to capture cause of death information from otherwise healthy potential uDCD donors. Ordinarily to qualify as a potential donor, an individual must have died in a hospital, making NEDS the correct "denominator." Patients were excluded based on the presence of comorbid conditions incompatible with solid organ donation.

Estimates derived from datasets not originally designed to answer our research question are, of course, somewhat limited and based on a number of assumptions. As with any large database, the accuracy of coding in NEDS is variable. This may have overestimated our results by not having accurately captured all relevant diagnostic and comorbidity information. Thus, our criteria were extremely conservative for whom we deemed eligible donors and we may have, in fact, underestimated the pool. Though we identified potential donors whose causes of death were ordinarily compatible with solid organ donation, not all of these patients would have been medically suitable organ donors, possibly overestimating our results. Thus, we excluded patients with diagnosis codes for any metabolic derangement, which may have resulted in an overly conservative estimate.

In spite of several major logistical and ethical challenges, implementing uDCD in the United States would not be an insurmountable task.^[24] An analogous situation is the legalization of transplants between HIV + patients.^[21,25] Though the ultimate goal of that effort was to reverse a national law and change national transplant practice, the initial steps involved estimating the potential pool of donors to demonstrate feasibility, engaging relevant stakeholders to demonstrate priority, risk/benefit and need, and lastly engaging policy-makers to help initiate changes in national practice.^[26]

While the medical reasons for excluding potential donors have changed over time, there may be several other concerns that merit discussion. First, there is the ever-present possibility of a population-based association of deceased donation prior to family authorization, which may result in a decrease in overall rates of donation. However, previous experience in Washington, DC in the 1990s demonstrated that organ preservation can legally begin prior to family assent,^[27] and families, in general, have supported uDCD protocols.^[28] Second, despite a large pool of potential donors, the implementation of uDCD may result in a less-than-acceptable discard rate.^[29–31] For example, in a single-center study from Spain, organs from more than half of potential donors were not recovered due to poor compliance with protocols, medical reasons, unsuccessful bypass connection, or family refusal.^[9] Furthermore, rates of transplant vary (51.3%-64.8%) among kidneys that are recovered.^[32] Thus, based on the European experience, if we apply the most conservative estimates to our national estimation of 9828 potential donors, if only 50% of donors were utilized, this would result in 4914 donors. Among those potential donors, we can assume that 60% were registered donors (driver's license, donor card, and state registry), resulting in ≈3000 donors.^[33] If only 50% of those kidneys were transplanted, that would still increase KT by ≈3000 per year.

These are important considerations that will have to be addressed by the transplant community with appropriate administrative safeguards and input from community members, transplant surgeons, trauma surgeons, bioethicists, and legal experts.^[5] Only upon implementing uDCD protocols would the transplant community be able to monitor rates of donation and decide the ultimate balance between increased organ availability and potential changes in image or attitude.

The findings of this study support the exploration of logistical and ethical barriers to uDCD in the United States. While donor selection and recipient management will require careful clinical judgment, uDCD donors represent a significant potential source of organs for many patients on the waiting list and if fully implemented, uDCD donation could nearly double the number of deceased donors in the United States. uDCD donation has the potential to have a great public health impact on the transplantation system.

American Journal of Transplantation. 2020;20(10):2842-2846. © 2020 Blackwell Publishing