Extracorporeal membrane oxygenation support of donor abdominal organs in non-heart-beating donors

Current Techniques and Indications for Machine Perfusion and Regional Perfusion in Deceased Donor Liver Transplantation

Since the advent of University of Wisconsin preservation solution in the 1980s, clinicians have learned to work within its confines. While affording improved outcomes, considerable limitations still exist and contribute to the large number of livers that go unused each year, often for fear they may never work. The last 10 years have seen the widespread availability of new perfusion modalities which provide an opportunity for assessing organ viability and prolonged organ storage. This review will discuss the role of in situ normothermic regional perfusion for livers donated after circulatory death. It will also describe the different modalities of ex situ perfusion, both normothermic and hypothermic, and discuss how they are thought to work and the opportunities afforded by them.

Mitochondrial injury during normothermic regional perfusion (NRP) and hypothermic oxygenated perfusion (HOPE) in a rodent model of DCD liver transplantation

BACKGROUND

Normothermic regional perfusion (NRP) and hypothermic-oxygenated-perfusion (HOPE), were both shown to improve outcomes after liver transplantation from donors after circulatory death (DCD). Comparative clinical and mechanistical studies are however lacking.

METHODS

A rodent model of NRP and HOPE, both in the donor, was developed. Following asystolic donor warm ischemia time (DWIT), the abdominal compartment was perfused either with a donor-blood-based-perfusate at 37 °C (NRP) or with oxygenated Belzer-MPS at 10 °C (donor-HOPE) for 2 h. Livers were then procured and underwent 5 h static cold storage (CS), followed by transplantation. Un-perfused and HOPE-treated DCD-livers (after CS) and healthy livers (DBD) with direct implantation after NRP served as controls. Endpoints included the entire spectrum of ischemia-reperfusion-injury.

FINDINGS

Healthy control livers (DBD) showed minimal signs of inflammation during 2 h NRP and achieved 100% posttransplant recipient survival. In contrast, DCD livers with 30 and 60 min DWIT suffered from greater mitochondrial injury and inflammation as measured by increased perfusate Lactate, FMN- and HMGB-1-levels with subsequent Toll-like-receptor activation during NRP. In contrast, donor-HOPE (instead of NRP) led to significantly less mitochondrial-complex-I-injury and inflammation. Results after donor-HOPE were comparable to ex-situ HOPE after CS. Most DCD-liver recipients survived when treated with one HOPE-technique (86%), compared to only 40% after NRP (p = 0.0053). Following a reduction of DWIT (15 min), DCD liver recipients achieved comparable survivals with NRP (80%).

INTERPRETATION

High-risk DCD livers benefit more from HOPE-treatment, either immediately in the donor or after cold storage. Comparative prospective clinical studies are required to translate the results.

FUNDING

Funding was provided by the Swiss National Science Foundation (grant no: 32003B-140776/1, 3200B-153012/1, 320030-189055/1, and 31IC30-166909) and supported by University Careggi (grant no 32003B-140776/1) and the OTT (grant No.: DRGT641/2019, cod.prog. 19CT03) and the Max Planck Society. Work in the A.G. laboratory was partially supported by the NIH R01NS112381 and R21NS125466 grants.

A systematic review and meta-analyses of regional perfusion in donation after circulatory death solid organ transplantation

In donation after circulatory death (DCD), (thoraco)abdominal regional perfusion (RP) restores circulation to a region of the body following death declaration. We systematically reviewed outcomes of solid organ transplantation after RP by searching PubMed, Embase, and Cochrane libraries. Eighty-eight articles reporting on outcomes of liver, kidney, pancreas, heart, and lung transplants or donor/organ utilization were identified. Meta-analyses were conducted when possible. Methodological quality was assessed using National Institutes of Health (NIH)-scoring tools. Case reports (13/88), case series (44/88), retrospective cohort studies (35/88), retrospective matched cohort studies (5/88), and case-control studies (2/88) were identified, with overall fair quality. As blood viscosity and rheology change below 20 °C, studies were grouped as hypothermic (HRP, ≤20 °C) or normothermic (NRP, >20 °C) regional perfusion. Data demonstrate that RP is a safe alternative to in situ cold preservation (ISP) in uncontrolled and controlled DCDs. The scarce HRP data are from before 2005. NRP appears to reduce post-transplant complications, especially biliary complications in controlled DCD livers, compared with ISP. Comparisons for kidney and pancreas with ISP are needed but there is no evidence that NRP is detrimental. Additional data on NRP in thoracic organs are needed. Whether RP increases donor or organ utilization needs further research.

Why DCD Donors Are Dead

Critics of organ donation after circulatory death (DCD) argue that, even if donors are past the point of autoresuscitation, they have not satisfied the "irreversibility" requirement in the circulatory and respiratory criteria for determining death, since their circulation and respiration could be artificially restored. Thus, removing their vital organs violates the "dead-donor" rule. I defend DCD donation against this criticism. I argue that practical medical-ethical considerations, including respect for do-not-resuscitate orders, support interpreting "irreversibility" to mean permanent cessation of circulation and respiration. Assuming a consciousness-related formulation of human death, I then argue that the loss of circulation and respiration is significant, because it leads to the permanent loss of consciousness and thus to the death of the human person. The DNR request by an organ donor should thus be interpreted to mean "do not restore to consciousness." Finally, I respond to an objection that if "irreversibility" has a medical-ethical meaning, it would entail the absurd possibility that one of two individuals in the same physical state could be alive and the other dead-an implication that some think is inconsistent with understanding death as an objective biological state of the organism. I argue that advances in medical technology have created phenomena that challenge the assumption that human death can be understood in strictly biological terms. I argue that ethical and ontological considerations about our nature bear on the definition and determination of death and thus on the permissibility of DCD.

Organ donation in patients on extracorporeal membrane oxygenation: considerations for determination of death and withdrawal of life support

The use of extracorporeal membrane oxygenation (ECMO) is increasing globally, although mortality in this setting remains high. Patients on ECMO may be potential organ donors in the context of withdrawal of life-sustaining measures (WLSM) or neurologic determination of death (NDD). Nevertheless, there are currently no Canadian standards to guide clinicians on NDD or WLSM for the purposes of organ donation in this patient population. Apnea testing remains fundamental to determining NDD and is an area where ECMO may alter routine procedures. In this review, we outline protocols for the performance of apnea testing and WLSM for patients supported with ECMO, highlighting important technical and physiologic considerations that may affect the determination of death. In addition, we review important considerations for NDD in ECMO, including management of potential confounders, strategies for controlling oxygen and carbon dioxide levels during apnea testing, and the appropriate use of ancillary tests to support NDD. In the context of ECMO support, there is limited evidence to guide NDD and WLSM for the purposes of organ donation. Drawing upon extensive clinical experience, we provide protocols for these processes and review other important considerations in an effort to maximize donor potential in this growing patient population.

In situ normothermic perfusion of livers in controlled circulatory death donation may prevent ischemic cholangiopathy and improve graft survival

Livers from controlled donation after circulatory death (DCD) donors suffer a higher incidence of nonfunction, poor function, and ischemic cholangiopathy. In situ normothermic regional perfusion (NRP) restores a blood supply to the abdominal organs after death using an extracorporeal circulation for a limited period before organ recovery. We undertook a retrospective analysis to evaluate whether NRP was associated with improved outcomes of livers from DCD donors. NRP was performed on 70 DCD donors from whom 43 livers were transplanted. These were compared with 187 non-NRP DCD donor livers transplanted at the same two UK centers in the same period. The use of NRP was associated with a reduction in early allograft dysfunction (12% for NRP vs. 32% for non-NRP livers, P = .0076), 30-day graft loss (2% NRP livers vs. 12% non-NRP livers, P = .0559), freedom from ischemic cholangiopathy (0% vs. 27% for non-NRP livers, P < .0001), and fewer anastomotic strictures (7% vs. 27% non-NRP, P = .0041). After adjusting for other factors in a multivariable analysis, NRP remained significantly associated with freedom from ischemic cholangiopathy (P < .0001). These data suggest that NRP during organ recovery from DCD donors leads to superior liver outcomes compared to conventional organ recovery.

Organ donation protocols

Organ transplantation improves survival and quality of life in patients with end-organ failure. Waiting lists continue to grow across the world despite remarkable advances in the transplantation process, from the creation of public engagement campaigns to the development of critical pathways for the timely identification, referral, approach, and treatment of the potential organ donor. The pathophysiology of dying triggers systemic changes that are intimately related to organ viability. The intensive care management of the potential organ donor optimizes organ function and improves the donation yield, representing a significant step in reducing the mismatch between organ supply and demand. Different beliefs and cultures reflect diverse legislations and donation practices amongst different countries, creating a challenge to standardized practices. Maintaining public trust is necessary for continued progress in organ donation and transplantation, hence the urge for a joint effort in creating uniform protocols that ensure transparent practices within the medical community.

Controlled Donation After Circulatory Determination of Death

Controlled donation after circulatory determination of death (cDCDD) concerns donation after withdrawal of life-sustaining therapy (W-LST). We examine the ethical issues raised by W-LST in the cDCDD context in the light of a review of cDCDD protocols and the ethical literature. Our analysis confirms that W-LST procedures vary considerably among cDCDD centers and that despite existing recommendations, the conflict of interest in the W-LST decision and process might be difficult to avoid, the process of W-LST might interfere with usual end-of-life care, and there is a risk of hastening death. In order to ensure that the practice of W-LST meets already well-established ethical recommendations, we suggest that W-LST should be managed in the ICU by an ICU physician who has been part of the W-LST decision. Recommending extubation for W-LST, when this is not necessarily the preferred procedure, is inconsistent with the recommendation to follow usual W-LST protocol. As the risk of conflicts of interest in the decision of W-LST and in the process of W-LST exists, this should be acknowledged and disclosed. Finally, when cDCDD programs interfere with W-LST and end-of-life care, this should be transparently disclosed to the family, and specific informed consent is necessary.

Recommendations for donation after circulatory death kidney transplantation in Europe

Donation after circulatory death (DCD) donors provides an invaluable source for kidneys for transplantation. Over the last decade, we have observed a substantial increase in the number of DCD kidneys, particularly within Europe. We provide an overview of risk factors associated with DCD kidney function and survival and formulate recommendations from the sixth international conference on organ donation in Paris, for best-practice guidelines. A systematic review of the literature was performed using Ovid Medline, Embase and Cochrane databases. Topics are discussed, including donor selection, organ procurement, organ preservation, recipient selection and transplant management.

Management of the Potential Organ Donor in the ICU: Society of Critical Care Medicine/American College of Chest Physicians/Association of Organ Procurement Organizations Consensus Statement

This document was developed through the collaborative efforts of the Society of Critical Care Medicine, the American College of Chest Physicians, and the Association of Organ Procurement Organizations. Under the auspices of these societies, a multidisciplinary, multi-institutional task force was convened, incorporating expertise in critical care medicine, organ donor management, and transplantation. Members of the task force were divided into 13 subcommittees, each focused on one of the following general or organ-specific areas: death determination using neurologic criteria, donation after circulatory death determination, authorization process, general contraindications to donation, hemodynamic management, endocrine dysfunction and hormone replacement therapy, pediatric donor management, cardiac donation, lung donation, liver donation, kidney donation, small bowel donation, and pancreas donation. Subcommittees were charged with generating a series of management-related questions related to their topic. For each question, subcommittees provided a summary of relevant literature and specific recommendations. The specific recommendations were approved by all members of the task force and then assembled into a complete document. Because the available literature was overwhelmingly comprised of observational studies and case series, representing low-quality evidence, a decision was made that the document would assume the form of a consensus statement rather than a formally graded guideline. The goal of this document is to provide critical care practitioners with essential information and practical recommendations related to management of the potential organ donor, based on the available literature and expert consensus.

Kidney transplantation from pediatric donors in a single Chinese center

To report clinical outcomes of kidney transplantation from pediatric brain and cardiac death donors (DBCD) in a single Chinese center and to investigate its feasibility to expand organ donor pool. 18 recipients, transplanted between August 2011 and October 2013 in the First Affiliated Hospital of Zhengzhou University, receive a single graft from DBCD donors age ranged from 1.5 to 13 years old. Renal function expressed as serum creatinine, blood urea nitrogen as well as eGFR values at 1, 2 weeks as well as 1-, 3-, 6-, and 12-months post-transplantation was evaluated. Graft size was also monitored at the same time by ultrasonography. In addition, delayed graft function, acute rejection, surgical complication as well as patient and graft survival were also assessed. The primary causes of DBCD donors included six cases of severe brain trauma and three cases of cerebral hemorrhage. The mean age of DBCD donors was (7.2 ± 3.4) years (range 1.5-13). The mean weight of DBCD donors was (29.8 ± 15.3) kilogram (range 13-67). The mean height of DBCD donors was (118.3 ± 27.8) centimeter (range 70-173). ECMO was applied to DBCD donors to avoid warm ischemia time and the applicating time was (79.8 ± 44.5) (range 32-180) minutes.There were seven males and 11 females recipients. Among which, 16 recipients were pediatrics and two recipients were adults. The mean age of the recipients was (14.6 ± 9.7) years (range 4-47). The mean weight of recipients was (31.9 ± 12.4) kilogram (range 11-54). The mean height of recipients was (138.0 ± 23.7) centimeter (range 84-172). Renal function recovered to normal within the first-week post-operation except one recipient which occurred acute rejection. Two cases of renal artery stenosis were found 2-week and 3-month post-transplantation, respectively. They subsequently underwent ballon angioplasty and followed up for 8 and 12 months, respectively, and no recurrence was found. One recipient developed ureteral leak. Five weeks later, the ureter leak healed after adequate drainage and prolongation of indwelling catheter. Graft size significantly and continuously increased during the first year, especially in the first 3-month post-transplantation. All the 18 recipients are alive at the last follow-up. Among which, 16 recipients are followed up for 12 months and 1-year recipient/graft survival rate is 100 %. The use of single kidney graft from pediatric DBCD could yield good short-term results.

Retrieval of the pancreas allograft for whole-organ transplantation

Proper pancreas retrieval during multi-organ recovery is one of the cornerstones of technically successful whole-organ pancreas transplantation. With evolving surgical approaches for organ retrieval and implantation, it has become standard to procure the pancreas in conjunction with other abdominal organs without compromising either vasculature, graft quality, or transplant outcomes. This review summarizes the major steps required for proper whole-organ retrieval of the pancreas allograft with suggestions and tips whenever alternative approaches are available.

Preoperative assessment of the deceased-donor kidney: from macroscopic appearance to molecular biomarkers

Variation in deceased-donor kidney quality can significantly affect outcomes after kidney transplantation. Suboptimal organ selection for a given recipient can result in primary nonfunction, premature graft failure, or inappropriate discard of a suitable organ. Appraisal and appropriate selection of deceased-donor kidneys for use in transplantation is therefore critical. A number of predictive tools have been developed to assist the transplant team in evaluating the suitability of a deceased-donor kidney for transplantation to a given recipient. These include stratification of donors into "standard-" or "expanded-criteria" categories based on clinical parameters, pre-implantation biopsy scores, donor risk scores, machine perfusion characteristics, functional kidney weight, donor biomarkers and molecular diagnostic tools, ex vivo viability assessment using postmortem normothermic perfusion, and overall macroscopic appraisal by the surgical team. Consensus as to the role and predictive value of each of these tools is lacking and clinical practice regarding evaluation and selection of kidneys varies considerably.In this review, we seek to critically appraise the literature and evaluate the levels of evidence for tools used to assess deceased-donor kidneys. Although a plethora of appraisal tools exist, very few demonstrate desirable predictive power to be useful in clinical decision-making. Further research using large, well-designed prospective studies is urgently needed to advance this important field of transplantation science.

Hypothermic or normothermic abdominal regional perfusion in high-risk donors with extended warm ischemia times: impact on outcomes?

Donation after circulatory determination of death (DCD) has the potential to increase the applicability of transplantation as a treatment for end-stage organ disease; its use is limited, however, by the warm ischemic damage suffered by potential grafts. Abdominal regional perfusion (ARP) has been employed in this setting to not only curtail the deleterious effects of cardiac arrest by re-establishing oxygenated flow but also test and even improve the viability of the kidneys and liver prior to transplantation. In the present review article, we discuss experimental and clinical studies that have been published to date on the use of ARP in DCD, differentiating between its application under hypothermic and normothermic conditions. In addition to describing results that have been achieved thus far, we describe the major obstacles limiting the broader implementation of ARP in this context as well as potential means for improving the effectiveness of this modality in the future.

Development of a preclinical model of donation after circulatory determination of death for translational application

Background

Extracorporeal membranous oxygenation is proposed for abdominal organ procurement from donation after circulatory determination of death (DCD). In France, the national Agency of Biomedicine supervises the procurement of kidneys from DCD, specifying the durations of tolerated warm and cold ischemia. However, no study has determined the optimal conditions of this technique. The aim of this work was to develop a preclinical model of DCD using abdominal normothermic oxygenated recirculation (ANOR). In short, our objectives are to characterize the mechanisms involved during ANOR and its impact on abdominal organs.

Methods

We used Large White pigs weighing between 45 and 55 kg. After 30 minutes of potassium-induced cardiac arrest, the descending thoracic aorta was clamped and ANOR set up between the inferior vena cava and the abdominal aorta for 4 hours. Hemodynamic, respiratory and biochemical parameters were collected. Blood gasometry and biochemistry analysis were performed during the ANOR procedure.

Results

Six ANOR procedures were performed. The surgical procedure is described and intraoperative parameters and biological data are presented. Pump flow rates were between 2.5 and 3 l/min. Hemodynamic, respiratory, and biochemical objectives were achieved under reproducible conditions. Interestingly, animals remained hemodynamically stable following the targeted protocol. Arterial pH was controlled, and natremia and renal function remained stable 4 hours after the procedure was started. Decreased hemoglobin and serum proteins levels, concomitant with increased lactate dehydrogenase activity, were observed as a consequence of the surgery. The serum potassium level was increased, owing to the extracorporeal circulation circuit.

Conclusions

Our ANOR model is the closest to clinical conditions reported in the literature and will allow the study of the systemic and abdominal organ impact of this technique. The translational relevance of the pig will permit the determination of new biomarkers and protocols to improve DCD donor management.

Controversies in defining and determining death in critical care

Circulatory-respiratory or brain tests are widely accepted for definition and determination of death, but have several controversial issues. Both determinations have been stimulated by organ donation, but must be valid independently of this process. Current controversies in brain death include whether the definition is conceptually coherent, whether the whole-brain or brainstem criterion is correct, whether one neurological examination or two should be required, and when to conduct the examination following therapeutic hypothermia. Controversies about the circulatory determination of death include the minimum duration of asystole that is sufficient for death to be declared, and whether the distinction between permanent and irreversible cessation of circulatory functioning is important. In addition, the goal of organ donation raises issues such as the optimal way to time and conduct the request conversation with family members of the patient, and whether the Dead Donor Rule should be abandoned.

Ethical issues in organ transplantation

We discuss ethical issues of organ transplantation including the stewardship tension between physicians' duty to do everything possible for their patients and their duty to serve society by encouraging organ donation. We emphasize consideration of the role of the principles of justice, utility and equity in the just distribution of transplantable organ as scarce resources. We then consider ethical issues of determining death of the organ donor including the remaining controversies in brain death determination and the new controversies raised by circulatory death determination. We need uniformity in standards of death determination, agreement on the duration of asystole before death is declared, and consensus on the allowable circulatory interventions on the newly declared organ donor that are intended to improve organ function. We discuss the importance of maintaining the dead donor rule, despite the argument of some scholars to abandon it.

Critical care of the potential organ donor

Organ transplantation represents one of the great success stories of 20th century medicine. However, its continued success is greatly limited by the shortage of donor organs. This has led to an increased focus within the critical care community on optimal identification and management of the potential organ donor. The multi-organ donor can represent one of the most complex intensive care patients, with numerous competing physiological priorities. However, appropriate management of the donor not only increases the number of organs that can be successfully donated but has long-term implications for the outcomes of multiple recipients. This review outlines current understandings of the physiological derangements seen in the organ donor and evaluates the available evidence for management strategies designed to optimize donation potential and organ recovery. Finally, emerging management strategies for the potential donor are discussed within the current ethical and legal frameworks permitting donation after both brain and circulatory death.

Kidney donation after cardiac death

There is continuing disparity between demand for and supply of kidneys for transplantation. This review describes the current state of kidney donation after cardiac death (DCD) and provides recommendations for a way forward. The conversion rate for potential DCD donors varies from 40%-80%. Compared to controlled DCD, uncontrolled DCD is more labour intensive, has a lower conversion rate and a higher discard rate. The super-rapid laparotomy technique involving direct aortic cannulation is preferred over in situ perfusion in controlled DCD donation and is associated with lower kidney discard rates, shorter warm ischaemia times and higher graft survival rates. DCD kidneys showed a 5.73-fold increase in the incidence of delayed graft function (DGF) and a higher primary non function rate compared to donation after brain death kidneys, but the long term graft function is equivalent between the two. The cold ischaemia time is a controllable factor that significantly influences the outcome of allografts, for example, limiting it to < 12 h markedly reduces DGF. DCD kidneys from donors < 50 function like standard criteria kidneys and should be viewed as such. As the majority of DCD kidneys are from controlled donation, incorporation of uncontrolled donation will expand the donor pool. Efforts to maximise the supply of kidneys from DCD include: implementing organ recovery from emergency department setting; improving family consent rate; utilising technological developments to optimise organs either prior to recovery from donors or during storage; improving organ allocation to ensure best utility; and improving viability testing to reduce primary non function.

Current status and recent advances of liver transplantation from donation after cardiac death

The last decade saw increased organ donation activity from donors after cardiac death (DCD). This contributed to a significant proportion of transplant activity. Despite certain drawbacks, liver transplantation from DCD donors continues to supplement the donor pool on the backdrop of a severe organ shortage. Understanding the pathophysiology has provided the basis for modulation of DCD organs that has been proven to be effective outside liver transplantation but remains experimental in liver transplantation models. Research continues on how best to further increase the utility of DCD grafts. Most of the work has been carried out exploring the use of organ preservation using machine assisted perfusion. Both ex-situ and in-situ organ perfusion systems are tested in the liver transplantation setting with promising results. Additional techniques involved pharmacological manipulation of the donor, graft and the recipient. Ethical barriers and end-of-life care pathways are obstacles to widespread clinical application of some of the recent advances to practice. It is likely that some of the DCD offers are in fact probably “prematurely” offered without ideal donor management or even prior to brain death being established. The absolute benefits of DCD exist only if this form of donation supplements the existing deceased donor pool; hence, it is worthwhile revisiting organ donation process enabling us to identify counter remedial measures.

Donation after circulatory death: burying the dead donor rule

Despite continuing controversies regarding the vital status of both brain-dead donors and individuals who undergo donation after circulatory death (DCD), respecting the dead donor rule (DDR) remains the standard moral framework for organ procurement. The DDR increases organ supply without jeopardizing trust in transplantation systems, reassuring society that donors will not experience harm during organ procurement. While the assumption that individuals cannot be harmed once they are dead is reasonable in the case of brain-dead protocols, we argue that the DDR is not an acceptable strategy to protect donors from harm in DCD protocols. We propose a threefold alternative to justify organ procurement practices: (1) ensuring that donors are sufficiently protected from harm; (2) ensuring that they are respected through informed consent; and (3) ensuring that society is fully informed of the inherently debatable nature of any criterion to declare death.

Biliary complications after orthotopic liver transplantation from donors after cardiac death: broad spectrum of disease

BACKGROUND

Donation-after-death liver transplantation (DCD-LT) carries higher complication rates compared with donation-after-brain death liver transplantation (DBD-LT). In this report we describe our experience with biliary complications in DCD-LT with emphasis on anatomical patterns and outcomes.

MATERIALS AND METHODS

We performed retrospective review of patients' medical records from August 2004 to December 2008, during which time total of 26 DCD-LTs were performed. Mean follow-up was 29 months (range 3 to 51 months).

RESULTS

Biliary complications occurred in 12 patients (46%), of whom 9 were related to DCD (35%). Four patients had more than 1 biliary complication, and 4 had concomitant arterial problems (stricture/thrombosis). Treatment of complications included: ERCP (n = 5, 3 resolved), conversion to roux (n = 5, 2 resolved), revision of roux (n = 1), percutaneous transhepatic cholangiography (n = 1), artery revision (n = 3). Three patients with casts had operative extraction of casts depicting a mummified biliary tree; histology showed casts and fibrosis and anastomotic suture material. Six patients underwent retransplantation (23%). Among retransplanted patients, 2 deaths occurred (7.7%).

CONCLUSION

Our experience with DCD-LT reveals a high prevalence of biliary complications with a new and wide spectrum of clinicopathologic findings. Better strategies for prevention of these unique biliary complications are needed to better justify the added risks and costs for performance of DCD-LT.

Rehabilitation of ischemically damaged human kidneys by normothermic extracorporal hemoperfusion in situ with oxygenation and leukocyte depletion

The potential use of donors after cardiac death is an important issue. The crucial point in uncontrolled donors after cardiac death is the warm ischemic time. Definition of the limit of warm ischemic time was 1 of our tasks; an other was to develop a preservation protocol. Five uncontrolled donors kidneys with warm ischemia times up to 80 minutes were exposed to an extracorporal perfusion device for preservation after ischemic damage. We sought to eliminate leukocytes as the main damaging factor in modified donor blood circulating in the device. Recipients of 8 kidneys from this protocol displayed immediate graft function with an average serum creatinine value of 140 +/- 37.9 mmol/L at the end of the second month. Treatment of ischemically damaged kidneys by normothermic extracorporal perfusion with leukocyte depletion before procurement demands further study.

Kidney from uncontrolled donors after cardiac death with one hour warm ischemic time: resuscitation by extracorporal normothermic abdominal perfusion "in situ" by leukocytes-free oxygenated blood

The availability of brain death donors is restricted by many factors. Use of uncontrolled donors after cardiac death could be a promising perspective, but the limiting factor in uncontrolled donation after cardiac death is the warm ischemic time. The purpose of our work was to develop an in situ kidney preservation protocol with application of the extracorporal normothermic abdominal perfusion for organ resuscitation in uncontrolled donors after cardiac death. The main attention was paid to the elimination of leukocytes as the key damaging factor from modified donor oxygenated blood circulating in the device. In 2009, we had 10 uncontrolled donors with warm ischemic time from 45 to 92 min; a normothermic extracorporal perfusion device was applied, providing preservation and restoration of kidney after ischemic damage. In 6 out of 20 kidney recipients, graft function was recovered immediately. All kidney grafts are functioning, and to the end of the third month, the average creatinine was 118.5 ± 19.9 mM. Treatment of ischemically damaged kidney by normothermic extracorporal perfusion with leukocyte depletion before procurement seems to be a challenging protocol for expanding donors' pool and demands further study.

The use of in-situ normothermic extracorporeal perfusion and leukocyte depletion for resuscitation of human donor kidneys

The unexploited potential of donors after cardiac death is an actual issue for all countries where organ transplantation is performed. The crucial point in uncontrolled donation after cardiac death is the warm ischemic time. The primary purpose of our work was to define the limits of warm ischemic time. Another purpose was the development of an in situ kidney preservation protocol. In 8 uncontrolled donors with warm ischemic time from 45 to 91 minutes, a normothermic extracorporeal perfusion device was applied, providing preservation and restoration of the kidney after ischemic damage. Main attention was paid to the elimination of leukocytes as the key damaging factor from modified donor blood circulating in the device. In 6 out of 16 kidney recipients, graft function was recovered immediately and, by the end of the third month, the average creatinine was 117.9±21.9 mmol/L. Treatment of ischemically damaged kidneys by normothermic extracorporeal perfusion, with leukocyte depletion before procurement, seems to be a challenging protocol and demands further study. Implementation of perfusion systems in organ procurement practice could lead to a partial solution in the organ deficit problem.

The circulatory-respiratory determination of death in organ donation

OBJECTIVE

Death statutes permit physicians to declare death on the basis of irreversible cessation of circulatory-respiratory or brain functions. The growing practice of organ donation after circulatory determination of death now requires physicians to exercise greater specificity in circulatory-respiratory death determination. We studied circulatory-respiratory death determination to clarify its concept, practice, and application to innovative circulatory determination of death protocols.

RESULTS

It is ethically and legally appropriate to procure organs when permanent cessation (will not return) of circulation and respiration has occurred but before irreversible cessation (cannot return) has occurred because permanent cessation: 1) is an established medical practice standard for determining death; 2) is the meaning of "irreversible" in the Uniform Determination of Death Act; and 3) does not violate the "Dead Donor Rule."

CONCLUSIONS

The use of unmodified extracorporeal membrane oxygenation in the circulatory determination of death donor after death is declared should be abandoned because, by restoring brain circulation, it retroactively negates the previous death determination. Modifications of extracorporeal membrane oxygenation that avoid this problem by excluding brain circulation are contrived, invasive, and, if used, should require consent of surrogates. Heart donation in circulatory determination of death is acceptable if proper standards are followed to declare donor death after establishing the permanent cessation of circulation. Pending additional data on "auto-resuscitation," we recommend that all circulatory determination of death programs should utilize the prevailing standard of 2 to 5 mins of demonstrated mechanical asystole before declaring death.

Lung physiology during ECS resuscitation of DCD donors followed by in situ assessment of lung function

Extracorporeal cardiopulmonary support (ECS) of donors after cardiac death (DCD) has been shown to improve abdominal organs for transplantation. This study assesses whether pulmonary congestion occurs during ECS with the heart arrested and describes an in vivo method to assess if lungs are suitable for transplantation from DCD donors after ECS resuscitation. Cardiac arrest was induced in 30 kg pigs, followed by 10 min of warm ischemia. Cannulae were placed into the right atrium (RA) and iliac artery, and veno-arterial ECS was initiated for 90 min with lungs inflated, group 1 (n = 5) or deflated, group 2 (n = 3). Left atrial pressures were measured as a marker for pulmonary congestion. After 90 min of ECS, lung function was evaluated. Cannulae were placed into the pulmonary artery (PA) and left ventricle (LV). A second pump was included, and ECS was converted to a bi-ventricular (bi-VAD) system. The RVAD drained from the RA and pumped into the PA, and the LVAD drained the LV and pumped into the iliac. This brought the lungs back into circulation for a 1-hr assessment period. The oxygenator was turned off, and ventilation was restarted. Flows, blood gases, PA and left atrial pressures, and compliance were recorded. In both the groups, LA pressure was <15 mm Hg during ECS. During the lung assessment period, PA flows were 1.4-2.2 L/min. PO2 was >300 mm Hg, with normal PCO2. Extracorporeal cardiopulmonary support resuscitation of DCD donors is feasible and allows for assessment of function before procurement. Extracorporeal cardiopulmonary support does not cause pulmonary congestion, and the lungs retain adequate function for transplantation. Compliance correlated with lung function.

Non-heartbeating donation of kidneys for transplantation

There is a persistent shortage of kidneys available for transplantation. In the early 1980s, therefore, we published the concept of non-heartbeating (NHB) donation; that is, procurement of kidneys from donors whose death has been accompanied by irreversible circulatory arrest. NHB donors are generally categorized using four definitions; category III (awaiting cardiac arrest) and category IV (cardiac arrest while braindead)--or 'controlled'--donors are the most suitable for initiating NHB donation programs. Delayed graft function is associated with use of kidneys from such donors, but has no effect on graft survival in the short or long term. Use of kidneys from category I (dead upon arrival at hospital) and category II (unsuccessfully resuscitated), or 'uncontrolled', donors is likewise associated with delayed graft function, but also with an increased risk of primary nonfunction. Viability testing of donated organs from these sources is a prerequisite for transplantation. Machine preservation parameters and enzyme release measurements help to distinguish viable from nonviable kidneys. The proportion of NHB donor kidneys in the total pool of postmortem kidneys differs considerably between countries. In The Netherlands, the proportion is nearly 50%. This figure is markedly higher than that in the US and Canada, where national programs have now been initiated to increase rates of NHB donation. In the future, warm preservation techniques might facilitate better viability testing, thereby increasing NHB donation from category I and II donors and further reducing the shortage of kidneys available for transplantation.

Expanding the donor pool: use of renal transplants from non-heart-beating donors supported with extracorporeal membrane oxygenation

In response to organ shortage, we used the renal grafts from non-heart-beating donors (NHBDs). Extracorporeal membrane oxygenation (ECMO) was used to maintain NHBDs before organ procurement. We compared the results of renal transplantation from different donors, including heart-beating donors (HBDs), living-related donors (LDs), and NHBDs supported with ECMO. From February 1998 to June 2003, we recruited 219 patients receiving renal transplantation at National Taiwan University Hospital. Among them, 31 received kidneys from NHBDs supported with ECMO, 120 from HBDs, and 68 from LDs. Multiple organ transplant recipients were not included in this study. We compared the graft survival, serum creatinine levels, and estimated glomerular filtration rates of the three groups. The rate of delayed graft function was higher in NHBD recipients (41.9%) than in HBD recipients (27.0%) and LD recipients (10.9%) (p = 0.003). In the NHBD group, the recipients of grafts with delayed function had significantly longer ECMO runs (63.1 +/- 3.0 min) than those without delayed function (53.7 +/- 2.5 min) (p = 0.024). Estimated glomerular filtration rate (p = 0.472) and mean serum creatinine level (p = 0.286) were not significantly different between the three groups using a longitudinal approach. The 5-yr graft survival rates for NHBD (88.4%, 95% CI: 0.680-0.962), HBD (83.2%, 95% CI: 0.728-0.899), and LD transplant recipients (89.3%, 95% CI: 0.619-0.974) were not significantly different (p = 0.239). The 5-yr patient survival rates for NHBD, HBD, and LD transplant recipients were 100, 93.0 (95% CI: 0.859-0.966) and 100% respectively. The long-term allograft survival and function of kidneys from NHBDs supported by ECMO, HBD, and LD did not differ significantly. Long ECMO running time tended to delay graft function.

Extracorporeal support for organ donation after cardiac death effectively expands the donor pool

BACKGROUND

We sought to evaluate the effect on short-term outcomes of normothermic, extracorporeal perfusion (ECMO) for donation of abdominal organs for transplantation after cardiac death (DCD). Study parameters included increase in number of donors and organs, types of organs procured, and viability of kidneys transplanted.

METHODS

We retrospectively reviewed medical record data for all patients enrolled in our ECMO-supported DCD donor protocol between 10/1/2000 to 2/01/2004. We also reviewed the records for all patients undergoing organ donation after brain-death (DBD) during the study period at our institution. Recipient data were obtained and analyzed for all kidneys procured from both groups.

RESULTS

Twenty patients were enrolled in our DCD protocol and underwent attempted organ donation. Fifteen patients completed the protocol; 3 maintained cardiac function throughout the prescribed 60 minutes after withdrawal of life support, and two patients' organs were deemed unsuitable for transplantation. Fourteen (70%) of the DCD donor patients originated on the trauma service and six (30%) were from other clinical services. The DCD program increased the potential donor pool by 33% (61 versus 81 patients) and the number of kidneys transplanted by 24% (100 versus 124). A total of 24 kidney, 5 liver, and 1 pancreas transplants were performed with these organs. Two of 24 (8.3%) DCD kidneys had delayed graft function. There were no perioperative rejection episodes or deaths.

CONCLUSION

The implementation of a DCD protocol using extracorporeal perfusion increased the potential organ donor pool at our institution by 33%. This was accomplished without short term adverse effect on organ function compared with kidneys transplanted from DBD donors.

Assessment of liver function during extracorporeal membrane oxygenation in the non-heart beating donor swine

INTRODUCTION

Although the use of non-heart beating donors (NHBD) could bridge the widening gap between organ demand and supply, its application to liver transplantation is limited due to warm ischemia (WI), biliary tree injury, and inadequate organ assessment. Warm blood reperfusion using extracorporeal membrane oxygenation (ECMO) can be a suitable option to reduce WI in organs from NHBD, allowing one to determine hepatic flow characteristics and bile production and facilitating assessment of organ viability.

METHODS

This work evaluates the use of warm blood veno-arterial ECMO reperfusion in NHBD swine. Systemic and hepatic hemodynamics, bile, urine, and mixed venous blood were measured. After baseline data collection, 10 kU heparin was given intravenously followed by 1 g KCl to elicit cardiac arrest (CA). ECMO was started after 30 or 60 minutes of CA and kept running for 120 minutes.

RESULTS

One-way repeated measures analysis of variance (ANOVA) with Tukey test analysis was used within a group. Two-way ANOVA was used between groups. ECMO can restore venous SO2 and pH in both groups; the values were close to baseline in the 30-minute CA group. Also, in this group, bile production was > 65% from baseline early during reperfusion and its value was lower in the longer CA group < 55% (P < .001). Aspartate aminotransferase (AST) was doubled at the end of ECMO support in the 60-minute CA group (P < .05).

CONCLUSION

In this preheparinized NHBD swine model, ECMO support restores liver perfusion, oxygenation, and bile production after 60 minutes of CA. Quantification and analysis of bile production could be a determinant of liver function during ECMO resuscitation, and it may be a predictor of graft viability before transplantation.

Retrieving organs from non-heart-beating organ donors: a review of medical and ethical issues

PURPOSE

The increasing gap between numbers of individuals awaiting organ replacement surgery and the supply of organs available for transplant underpins attempts to increase the number of organs available. One practice, used in other countries, is the recovery of organs from non-heart-beating organ donors (NHBD). The purpose of this review is to discuss ethical issues surrounding the use of organs from these donors.

SOURCE

Narrative review from selected Medline references, and other published reports.

PRINCIPAL FINDINGS

NHBD protocols have been established in many countries including the United States. Despite numerous publications, and extensive debate in the literature, significant ethical issues remain unresolved in the retrieval of organs from donors that have died from cessation of cardiac activity. The ethical concerns primarily arise in the determination of death, the tension between the time constraints on recovering organs viable for transplantation, and procedures to enhance organ viability. Despite a concerted effort in the United States, less than half of the organ procurement organizations have NHBD protocols.

CONCLUSION

Canadian centres can learn from the difficulties encountered in other centres that have developed NHBD protocols. A moratorium on Canadian NHBD protocols should be considered until a National consensus reflecting Canadian values has been undertaken.

Extracorporeal carbon dioxide removal to control arterial pH and PACO2 in a heart-beating donor with acute lung injury

BACKGROUND

Arteriovenous carbon dioxide (AVCO2R) removal is a technique of pumpless extracorporeal carbon dioxide removal. This system has been used successively to control pH and PaCO2 in patients with acute lung injury who could not be adequately ventilated. This report describes the use of this technology in an organ donor awaiting harvesting.

METHODS

AVCO2R was implanted using a hollow-fiber oxygenator attached to 12 F and 14 F vascular cannulas that were inserted into the femoral artery and vein, respectively. Oxygen was attached to the oxygenator to provide the sweep gas.

RESULTS

The PaCO2 and arterial pH promptly corrected after support was initiated (from 83-42 mm Hg and 7.18-7.38, respectively).

CONCLUSION

This case describes the successful use of pumpless arteriovenous extracorporeal removal of CO2 in a heart-beating donor awaiting organ harvest.

Total recovery of heart grafts of non-heart-beating donors after 3 hours of hypothermic coronary oxygen persufflation preservation in an orthotopic pig transplantation model

BACKGROUND

The coronary oxygen persufflation (COP) technique has been previously shown to allow prolonged heart preservation of 14 hr with optimal recovery in a pig model of orthotopic transplantation. This technique may be applicable to hearts grafted from non-heart-beating donors (NHBD).

METHODS

Experiments were performed on pigs to test the effectiveness of oxygenated preservation, using COP for preservation of NHBD hearts. After 16 min of in situ normothermic ischemia, the hearts were flushed with histidine-tryptophan-ketoglutarate (HTK) solution or modified HTK solution (mBHTK) including 30 mmol/L 2,3-butanedione monoxime, 40 mg/L hyaluronidase,15 micromol/L adenosine, and 50 micromol/L calcium. Hearts were stored in the flush solutions for 3.3 hr or additionally persufflated with gaseous oxygen through the coronary arteries (COP) and transplanted orthotopically.

RESULTS

Simple storage in HTK did not allow recovery of these hearts, whereas mBHTK storage resulted in improved function with 1.1 L/min cardiac output. The cardiac output reached 2.8 L/min (68% of normal values) with a left ventricular developed pressure of 101 mm Hg only after mBHTK+COP. Then the hearts were able to guarantee the circulation of the recipient for the test period after weaning from the heart-lung machine.

CONCLUSIONS

Even in an NHBD with more than 15 min of in situ ischemia, the use of COP in combination with mBHTK solution for 3.3-hr storage of the heart allows excellent recovery of transplanted hearts and normal weaning from the heart-lung machine. This indicates that COP combined with mBHTK may be an optimal preservation technique for use with NHBD hearts.