Current practices in deceased organ donor management:

Prediction of Donor Heart Acceptance for Transplant and Its Clinical Implications: Results From The Donor Heart Study

BACKGROUND

Despite a shortage of potential donors for heart transplant in the United States, most potential donor hearts are discarded. We evaluated predictors of donor heart acceptance in the United States and applied machine learning methods to improve prediction.

METHODS

We included a nationwide (2005-2020) cohort of potential heart donors in the United States (n=73 948) from the Scientific Registry of Transplant Recipients and a more recent (2015-2020) rigorously phenotyped cohort of potential donors from DHS (Donor Heart Study; n=4130). We identified predictors of acceptance for heart transplant in both cohorts using multivariate logistic regression, incorporating time-interaction terms to characterize their varying effects over time. We fit models predicting acceptance for transplant in a 50% training subset of DHS using logistic regression, least absolute shrinkage and selection operator, and random forest algorithms and compared their performance in the remaining 50% (test) of the subset.

RESULTS

Predictors of donor heart acceptance were similar in the nationwide and DHS cohorts. Among these, older age (P value for time interaction, 0.0001) has become increasingly predictive of discard over time while other factors, including those related to drug use, infection, and mild cardiac diagnostic abnormalities, have become less influential (P value for time interaction, <0.05 for all). A random forest model (area under the curve, 0.908; accuracy, 0.831) outperformed other prediction algorithms in the test subset and was used as the basis of a novel web-based prediction tool.

CONCLUSIONS

Predictors of donor heart acceptance for transplantation have changed significantly over the last 2 decades, likely reflecting evolving evidence regarding their impact on posttransplant outcomes. Real-time prediction of donor heart acceptance, using our web-based tool, may improve efficiency during donor management and heart allocation.

Critical care specialists, the missing link in organ procurement for transplantation

The procurement process for organ donation begins with the identification of potential organ donors in emergency or critical care units (CCU), followed by their clinical evaluation, diagnostic procedures, and therapeutic interventions, mostly conducted in CCUs. It concludes with the request for organ donation and, if accepted, the retrieval of organs. Despite most interventions occurring in detection units, there has been a neglect of the strategic role played by critical care specialists (CCS) in managing and caring for brain-dead or near-brain-death patients. Questions arise: Are they willing to undertake this responsibility? Do they fully comprehend the nature of organ procurement? Are they aware of the specific interventions required to maintain possible organ donors in optimal physiological condition? Our objective is to examine the role of CCS in organ procurement and propose ways to enhance it, ultimately aiming to increase and enhance organ donation rates.

Clinical outcomes of a prospective randomized comparison of bioreactance monitoring versus pulse-contour analysis in a stroke-volume based goal-directed fluid resuscitation protocol in brain-dead organ donors

Eighty percent of brain-dead (BD) organ donors develop hypotension and are frequently hypovolemic. Fluid resuscitation in a BD donor is controversial. We have previously published our 4-h goal-directed stroke volume (SV)-based fluid resuscitation protocol which significantly decreased time on vasopressors and increased transplanting four or more organs. The SV was measured by pulse-contour analysis (PCA) or an esophageal doppler monitor, both of which are invasive. Thoracic bioreactance (BR) is a non-invasive portable technology that measures SV but has not been studied in BD donors. We performed a randomized prospective comparative study of BR versus PCA technology in our fluid resuscitation protocol in BD donors. Eighty-four donors (53.1%) were randomized to BR and 74 donors to PCA (46.8%). The two groups were well matched based on 24 demographic, social, and initial laboratory factors, without any significant differences between them. There was no difference in the intravenous fluid infused over the 4-h study period [BR 2271 ± 823 vs. PCA 2230 ± 962 mL; p = .77]. There was no difference in the time to wean off vasopressors [BR 108.8 ± 61.8 vs. PCA 150.0 ± 68 min p = .07], nor in the number of donors off vasopressors at the end of the protocol [BR 16 (28.6%) vs. PCA 15 (29.4%); p = .92]. There was no difference in the total number of organs transplanted per donor [BR 3.25 ± 1.77 vs. PCA 3.22 ± 1.75; p = .90], nor in any individual organ transplanted. BR was equivalent to PCA in clinical outcomes and provides a simple, non-invasive, portable technology to monitor fluid resuscitation in organ donors.

[Anaesthesiological management of postmortem organ donors - What Evidence is Out There?]

The transplantation of organs from postmortem organ donors has been a lifesaving and quality-of-life-improving therapy for patients with irreversible organ failure for many years. In Germany, however, there has been an imbalance between the number of organs donated postmortem and the number of patients on the waiting list for years. The anesthesiological management of multiple organ harvesting (MOE) in postmortem organ donors is not an everyday challenge for various reasons: A lack of practical expertise due to the small number of MOE, even at university hospitals (usually < 20 per year), complex pathophysiological changes in the cardiovascular system and other organ functions of the postmortem organ donor and the lack of guidelines complicate anesthesiological management. This paper compiles the existing literature and reviews whether evidence-based recommendations can be derived for anesthesiologic management for MOE.

Effects of polyethylene glycol-20k IV solution on donor management in a canine model of donor brain death

BACKGROUND

Traditionally, vasopressors and crystalloids have been used to stabilize brain dead donors; however, the use of crystalloid is fraught with complications. This study aimed to investigate the effectiveness of a newly developed impermeant solution, polyethylene glycol-20k IV solution (PEG-20k) for resuscitation and support of brain dead organ donors.

METHODS

Brain death was induced in adult beagle dogs and a set volume of PEG-20k or crystalloid solution was given thereafter. The animals were then resuscitated over 16 h with vasopressors and crystalloid as necessary to maintain mean arterial pressure of 80-100 mmHg. The kidneys were procured and cold-stored for 24 h, after which they were analyzed using the isolated perfused kidney model.

RESULTS

The study group required significantly less crystalloid volume and vasopressors while having less urine output and requiring less potassium supplementation than the control group. Though the two groups' mean arterial pressure and lactate levels were comparable, the study group's kidneys showed less preservation injury after short-term reperfusion indexed by decreased lactate dehydrogenase release and higher creatinine clearance than the control group.

CONCLUSIONS

The use of polyethylene glycol-20k IV solution for resuscitating brain dead donors decreases cell swelling and improves intravascular volume, thereby improving end organ oxygen delivery before procurement and so preventing ischemia-reperfusion injury after transplantation.

Organ donor management goals and delayed graft function in adult kidney transplant recipients

BACKGROUND

Delayed graft function (DGF) after kidney transplantation is a common occurrence and correlates with poor graft and patient outcomes. Donor characteristics and care are known to impact DGF. We attempted to show the relationship between achievement of specific donor management goals (DMG) and DGF.

METHODS

This is a retrospective case-control study using data from 14 046 adult kidney donations after brain death from hospitals in 18 organ procurement organizations (OPOs) which were transplanted to adult recipients between 2012 and 2018. Data on DMG compliance and donor, recipient, and ischemia-related factors were used to create multivariable logistic regression models.

RESULTS

The overall rate of DGF was 29.4%. Meeting DMGs for urine output and vasopressor use were associated with decreased risk of DGF. Sensitivity analyses performed with different imputation methods, omitting recipient factors, and analyzing multiple time points yielded largely consistent results.

CONCLUSIONS

The development of DMGs continues to show promise in improving outcomes in the kidney transplant recipient population. Studies have already shown increased kidney utilization in smaller cohorts, as well as other organs, and shown decreased rates of DGF. Additional research and analysis are required to assess interactions between meeting DMGs and correlation versus causality in DMGs and DGF.

Management of the brain-dead organ donor

Organ transplantation is a life-saving intervention for patients suffering from end-stage organ failure, but it relies on the availability of donor organs. However, even when donors are available, the brain-dead organ donor is a clinically complex patient who presents many management challenges. Donor management with a goal of optimization of organ function is essential to maximizing the number of patients who can be helped by each individual donor. Thoughtful critical care management of the potential organ donor, with a focus on meeting donor management goals, can lead to improved donation outcomes.

Whole Blood Thiamine in Organ Donors After the Neurologic Determination of Death

INTRODUCTION

Metabolic resuscitation of organ donors and the attenuation of oxidative stress incurred by organs following brain death and transplantation have the potential to improve organ yield and allograft function. Thiamine (vitamin B1) is a vital coenzyme in both energy metabolism and the production of antioxidants that has not been studied in the donor population.

RESEARCH AIM

To determine the frequency of subclinical thiamine deficiency in brain-dead organ donors and its correlation with demographics, length of hospitalization, donor management, lactic acidosis, and the requirement for vasoactive support.

DESIGN

Prospective cohort study of brain-dead donors managed at a single organ procurement organization's organ recovery facility.

RESULTS

A total 64 donors were enrolled; 24 donors had thiamine levels drawn upon arrival and 40 donors had levels drawn at the time of organ procurement. Whole blood thiamine levels were inversely correlated with the time from death (P = .007) and 20% (8/40) of donors had levels below the normal range at the time of organ procurement. Demographic features of the donor were not associated with thiamine levels although longer hospital stays prior to death were associated with lower levels (P < .05). The presence and resolution of lactic acidosis was not associated with whole blood thiamine level. Higher thiamine levels were associated with earlier discontinuation of vasoactive support (P = .04).

DISCUSSION

Whole blood thiamine deficiency was not uncommon at the time of organ procurement. Thiamine may be associated with the requirement for hemodynamic support.

Anaesthetic considerations for fertility-sparing surgery and uterine transplantation

A number of benign and malignant gynaecological conditions can cause infertility. Advancements in assisted reproductive technologies have facilitated the rapidly evolving subspecialty of fertility preservation. Regardless of clinical indication, women now have the reproductive autonomy to make fully informed decisions regarding their future fertility. In particular, there has been an increasing interest and demand among patients and healthcare professionals for fertility-sparing surgery. Gynaecologists find themselves continually adapting surgical techniques and introducing novel procedures to facilitate this rapidly emerging field and anaesthetists need to manage the consequent physiological demands intra-operatively. Not only is it important to understand the surgical procedures now undertaken, but also the intra-operative management in an ever evolving field. This article reviews the methods of fertility-sparing surgery and also describes important anaesthetic challenges including peri-operative care for women undergoing complex fertility-sparing surgeries such as uterus transplantation.

Organ utilization - the next hurdle in transplantation?

Nonutilization of organs from consented deceased donors remains a significant factor in limiting patient access to transplantation. Critical to reducing waste is a clear understanding of why organs are not used: accurate metrics are essential to identify the extent and causes of waste but use of these measures as targets or comparators between units/jurisdictions must be done with caution as focus on any one measure may result in unintended adverse consequences. Comparison between centres or countries may be misleading because of variation in definitions, patient or graft characteristics. Two of the most challenging areas to improve appropriate deceased donor organ utilization are appetite for risk and lack of validated tools to help identify an organ that will function appropriately. Currently, the implanting surgeon is widely considered to be accountable for the use of a donated organ so guidelines must be clear to allow and support sensible decisions and recognition that graft failure or inadvertent disease transmission are not necessarily attributable to poor decision-making. Accepting an organ involves balancing risk and benefit for the potential recipient. Novel technologies such as machine perfusion may allow for more robust guidance as to the functioning of the organ.

Organ procurement in a deceased donor

With the increasing demand for organ transplantation, organ procurement from a deceased donor is an essential step for deceased donor organ transplantation. A proper surgical technique for the procurement of an organ graft from a deceased donor must be carried out to avoid any damage to it. Moreover, how to manage deceased donors until they enter the operating room in a stable condition is a critical point to be considered. The establishment of a surgical technique and preoperative management for organ procurement is encouraged to achieve a nationwide standard and consistency for organ graft sharing among the transplant units.

A stroke volume-based fluid resuscitation protocol decreases vasopressor support and may increase organ yield in brain-dead donors

Brain-dead donors are frequently hypovolemic and hypotensive requiring vasopressor support. We studied a stroke volume-based fluid resuscitation and vasopressor weaning protocol prospectively on 64 hypotensive donors, with a recent control cohort of 30 hypotensive donors treated without a protocol. Stroke volume was measured every 30 minutes for 4 hours by pulse contour analysis or esophageal Doppler. A 500 mL saline fluid bolus was infused over 30 minutes and repeated if the stroke volume increased by 10%. No fluid was infused if the stroke volume did not increase by 10%. Vasopressors were weaned every 10 minutes if the mean arterial pressure was greater than 65 mm Hg. The protocol group received 1937 ± 906 mL fluid compared to 1323 ± 919 mL in the control group (P = .003). Mean time on vasopressors was decreased from 957.6 ± 586.2 to 176.3 ± 82.2 minutes (P<.001). Donors in the protocol group were more likely to donate four or more organs than donors in the control group (OR = 4.114, 95% Confidence Interval (CI) = 1.003-16.876). While more organs were transplanted per donor in the protocol group (3.39 ± 1.52) than in the control group (2.93 ± 1.44) (P = .268), the difference did not reach statistical significance. A goal-directed fluid resuscitation protocol decreased organ ischemia and may increase organs transplanted.

Indicadores clínicos para o diagnóstico de enfermagem Síndrome do equilíbrio fisiológico prejudicado para doadores de órgãos

RESUMO Objetivo Selecionar indicadores clínicos para o diagnóstico de enfermagem em desenvolvimento Síndrome do equilíbrio fisiológico prejudicado para potenciais doadores de órgãos em morte encefálica. Método Estudo de consenso de especialistas, realizado através da técnica Delphi, dos indicadores clínicos de um diagnóstico de enfermagem em desenvolvimento. A amostra do estudo foi intencional mediante convite e constituída por 37 enfermeiros que atenderam a critérios de inclusão. Os indicadores que obtiveram um consenso igual ou maior que 70% foram considerados validados. Resultados Especialistas recomendaram 25 dos 44 indicadores avaliados, dos quais oito pertenciam ao grupo Alterações endócrino-metabólicas, sete ao grupo Alterações hemodinâmicas e/ou cardiovasculares, cinco ao grupo Alterações ventilatórias, dois ao grupo Alterações nutricionais e três ao grupo Alterações de coagulação, inflamatórias e/ou imunológicas. Conclusão e implicações para a prática Esse novo diagnóstico de enfermagem pode colaborar com o desenvolvimento de conhecimento da enfermagem na área de doação de órgãos, contribuindo para o ensino e pesquisa, além de acarretar implicações para a prática, proporcionando acurácia diagnóstica e embasando a implementação e a avaliação de intervenções que impactam na melhora da manutenção do potencial doador.