Impact of intensive care on renal function before graft harvest: results of a monocentric study

Effect of Cardiac Arrest in Brain-dead Donors on Kidney Graft Function

BACKGROUND

Cardiac arrest (CA) causes renal ischemia in one-third of brain-dead kidney donors before procurement. We hypothesized that the graft function depends on the time interval between CA and organ procurement.

METHODS

We conducted a retrospective population-based study on a prospectively curated database. We included 1469 kidney transplantations from donors with a history of resuscitated CA in 2015-2017 in France. CA was the cause of death (primary CA) or an intercurrent event (secondary CA). The main outcome was the percentage of delayed graft function, defined by the use of renal replacement therapy within the first week posttransplantation.

RESULTS

Delayed graft function occurred in 31.7% of kidney transplantations and was associated with donor function, vasopressors, cardiovascular history, donor and recipient age, body mass index, cold ischemia time, and time to procurement after primary cardiac arrest. Short cold ischemia time, perfusion device use, and the absence of cardiovascular comorbidities were protected by multivariate analysis, whereas time <3 d from primary CA to procurement was associated with delayed graft function (odds ratio 1.38).

CONCLUSIONS

This is the first description of time to procurement after a primary CA as a risk factor for delayed graft function. Delaying procurement after CA should be evaluated in interventional studies.

A porcine model to study the effect of brain death on kidney genomic responses

Introduction

A majority of transplanted organs come from donors after brain death (BD). Renal grafts from these donors have higher delayed graft function and lower long-term survival rates compared to living donors. We designed a novel porcine BD model to better delineate the incompletely understood inflammatory response to BD, hypothesizing that adhesion molecule pathways would be upregulated in BD.

Methods

Animals were anesthetized and instrumented with monitors and a balloon catheter, then randomized to control and BD groups. BD was induced by inflating the balloon catheter and animals were maintained for 6 hours. RNA was extracted from kidneys, and gene expression pattern was determined.

Results

In total, 902 gene pairs were differently expressed between groups. Eleven selected pathways were upregulated after BD, including cell adhesion molecules.

Conclusions

These results should be confirmed in human organ donors. Treatment strategies should target involved pathways and lessen the negative effects of BD on transplantable organs.

Guidelines for the management of a brain death donor in the rhesus macaque: A translational transplant model

Introduction

The development of a translatable brain death animal model has significant potential to advance not only transplant research, but also the understanding of the pathophysiologic changes that occur in brain death and severe traumatic brain injury. The aim of this paper is to describe a rhesus macaque model of brain death designed to simulate the average time and medical management described in the human literature.

Methods

Following approval by the Institutional Animal Care and Use Committee, a brain death model was developed. Non-human primates were monitored and maintained for 20 hours after brain death induction. Vasoactive agents and fluid boluses were administered to maintain hemodynamic stability. Endocrine derangements, particularly diabetes insipidus, were aggressively managed.

Results

A total of 9 rhesus macaque animals were included in the study. The expected hemodynamic instability of brain death in a rostral to caudal fashion was documented in terms of blood pressure and heart rate changes. During the maintenance phase of brain death, the animal’s temperature and hemodynamics were maintained with goals of mean arterial pressure greater than 60mmHg and heart rate within 20 beats per minute of baseline. Resuscitation protocols are described so that future investigators may reproduce this model.

Conclusion

We have developed a reproducible large animal primate model of brain death which simulates clinical scenarios and treatment. Our model offers the opportunity for researchers to have translational model to test the efficacy of therapeutic strategies prior to human clinical trials.

Effects of mechanical ventilation on gene expression profiles in renal allografts from brain dead rats

Pathophysiological changes of brain death (BD) are impairing distal organ function and harming potential renal allografts. Whether ventilation strategies influence the quality of renal allografts from BD donors has not been thoroughly studied. 28 adult male Wistar rats were randomly assigned to four groups: 1) no brain death (NBD) with low tidal volume/low positive endexpiratory pressure (PEEP) titrated to minimal static elastance of the respiratory system (LVT/OLPEEP); 2) NBD with high tidal volume/low PEEP (HVT/LPEEP); 3) brain death (BD) with LVT/OLPEEP; and 4) BD with HVT/LPEEP. We hypothesized that HVT/LPEEP in BD leads to increased interleukin 6 (IL-6) gene expression and impairs potential renal allografts after six hours of mechanical ventilation. We assessed inflammatory cytokines in serum, genome wide gene expression profiles and quantitative PCR (qPCR) in kidney tissue. The influence of BD on renal gene-expression profiles was greater than the influence of the ventilation strategy. In BD, LVT ventilation did not influence the inflammatory parameters or kidney function in our experimental model.

The effect of brain death protocol duration on potential donor losses due to cardiac arrest

BACKGROUND

The severe inflammatory reaction that occurs after brain death (BD) tends to amplify over time, contributing to cardiovascular deterioration and occurrence of cardiac arrest (CA). Our purpose is to evaluate the effect of BD protocol duration (BDPD) on potential donor losses due to CA.

METHODS

This retrospective analysis included potential donors reported during the period from May 2012 to April 2014. The risk of losses due to CA was analyzed to identify the chronological threshold at which the probability of loss due to CA increases.

RESULTS

Three hundred and eighty-four potential donors were analyzed. There was a greater chance of CA after a 30-hour threshold (OR 1.67, 95% CI: 1.38-1.83), and the lowest risk of was identified for the range from 12 to 30 hours (OR 0.32, 95% CI: 0.19-0.52). Multivariate analysis identified the following variables as being associated with lower occurrence of CA: BDPD between 12 and 30 hours, management of a potential donor inside the intensive care unit, and the adherence to a goal-directed protocol.

CONCLUSION

A long duration between the first clinical test for BD diagnosis and the procurement of organs may be an important risk factor for the occurrence of cardiac arrest in deceased potential donors.

The development and current status of Intensive Care Unit management of prospective organ donors

Introduction:

Despite continuous advances in transplant medicine, there is a persistent worldwide shortage of organs available for donation. There is a growing body of research that supports that optimal management of deceased organ donors in Intensive Care Unit can substantially increase the availability of organs for transplant and improve outcomes in transplant recipients.

Methods:

A systematic literature review was performed, comprising a comprehensive search of the PubMed database for relevant terms, as well as individual assessment of references included in large original investigations, and comprehensive society guidelines.

Results:

In addition to overall adherence to catastrophic brain injury guidelines, optimization of physiologic state in accordance with established donor management goals (DMGs), and establishment of system-wide processes for ensuring early referral to organ procurement organizations (OPOs), several specific critical care management strategies have been associated with improved rates and outcomes of renal transplantation from deceased donors. These include vasoactive medication selection, maintenance of euvolemia, avoidance of hydroxyethyl starch, glycemic control, targeted temperature management, and blood transfusions if indicated.

Conclusions:

Management of deceased organ donors should focus first on maintaining adequate perfusion to all organ systems through adherence to standard critical care guidelines, early referral to OPOs, and family support. Furthermore, several specific DMGs and strategies have been recently shown to improve both the rates and outcomes of organ transplantation.

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.

Impact of brain death on ischemia/reperfusion injury in liver transplantation

PURPOSE OF REVIEW

In liver transplantation, the ischemia/reperfusion injury (IRI) is influenced by factors related to graft quality, organ procurement and the transplant procedure itself. However, in brain-dead donors, the process of death itself also thoroughly affects organ damage through breakdown of the autonomous nervous system and subsequent massive cytokine release. This review highlights the actual knowledge on these proinflammatory effects of brain death on IRI in liver transplantation.

RECENT FINDINGS

Brain death affects IRI either through hemodynamical or molecular effects with proinflammatory activation. Immunological effects are mainly mediated through Kupffer cell activation, leading to TNF-α and TLR4 amplification. Proinflammatory cytokines such as interleukin (IL)-6, IL-10, TNF-β and MIP-1α are released, together with activation of the innate immune system via natural killer cells and natural killer T cells, which promote organ damage and activation of fibrosis. Preprocurement treatment regimens attempt to hamper inflammatory response by the application of methylprednisolone or thymoglobulin to the donor. Selective P-selectin antagonism resulted in improved function in marginal liver grafts. Inhaled nitric oxide was found to reduce apoptosis in liver grafts. Other medications like the immunosuppressant tacrolimus produced conflicting results regarding organ protection. Furthermore, improved organ storage after procurement - such as machine perfusion - can diminish effects of IRI in a clinical setting.

SUMMARY

Brain death plays a fundamental role in the regulation of molecular markers triggering inflammation and IRI-related tissue damage in liver transplants. Although several treatment options have reached clinical application, to date, the effects of brain death during donor conditioning and organ procurement remain relevant for organ function and survival.

Repletion of S-nitrosohemoglobin improves organ function and physiological status in swine after brain death

OBJECTIVE

To determine if reduction in nitric oxide bioactivity contributes to the physiological instability that occurs after brain death and, if so, to also determine in this setting whether administration of a renitrosylating agent could improve systemic physiological status.

BACKGROUND

Organ function after brain death is negatively impacted by reduced perfusion and increased inflammation; the magnitude of these responses can impact post-graft function. Perfusion and inflammation are normally regulated by protein S-nitrosylation but systemic assessments of nitric oxide bioactivity after brain death have not been performed.

METHODS

Brain death was induced in instrumented swine by inflation of a balloon catheter placed under the cranium. The subjects were then serially assigned to receive either standard supportive care or care augmented by 20 ppm of the nitrosylating agent, ethyl nitrite, blended into the ventilation circuit.

RESULTS

Circulating nitric oxide bioactivity (in the form of S-nitrosohemoglobin) was markedly diminished 10 hours after induction of brain death-a decline that was obviated by administration of ethyl nitrite. Maintenance of S-nitrosohemoglobin was associated with improvements in tissue blood flow and oxygenation, reductions in markers of immune activation and cellular injury, and preservation of organ function.

CONCLUSIONS

In humans, the parameters monitored in this study are predictive of post-graft function. As such, maintenance of endocrine nitric oxide bioactivity after brain death may provide a novel means to improve the quality of organs available for donation.

The impact of meeting donor management goals on the development of delayed graft function in kidney transplant recipients

Many organ procurement organizations (OPOs) utilize preset critical care endpoints as donor management goals (DMGs) in order to standardize care and improve outcomes. The objective of this study was to determine the impact of meeting DMGs on delayed graft function (DGF) in renal transplant recipients. All eight OPOs of the United Network for Organ Sharing Region 5 prospectively implemented nine DMGs in every donor after neurologic determination of death (DNDD). "DMGs met" was defined a priori as achieving any seven of the nine DMGs and this was recorded at the time of consent for donation to reflect donor hospital ICU management, 12-18 h later, and prior to organ recovery. Multivariable analyses were performed to identify independent predictors of DGF (dialysis in the first week after transplantation) with a p<0.05. A total of 722 transplanted kidneys from 492 DNDDs were included. A total of 28% developed DGF. DMGs were met at consent in 14%, 12-18 h in 32% and prior to recovery in 38%. DGF was less common when DMGs were met at consent (17% vs. 30%, p=0.007). Independent predictors of DGF were age, Cr and cold ischemia time, while meeting DMGs at consent was significantly protective. The management of potential organ donors prior to consent affects outcomes and should remain a priority in the intensive care unit.

Impact of donor age on long-term outcomes after delayed graft function: 10-year follow-up

Delayed graft function (DGF) has a negative impact on graft survival in donation after brain death (DBD) but not for donation after cardiac death (DCD) kidneys. However, older donor age is associated with graft loss in DCD transplants. We sought to examine the interaction between donor age and DGF in DBD kidneys. This is a single-center, retrospective review of 657 consecutive DBD recipients transplanted between 1990 and 2005. We stratified the cohort by decades of donor age and studied the association between DGF and graft failure using Cox models. The risk of graft loss associated with DGF was not significantly increased for donor age below 60 years (adjusted hazard ratio [aHR] 1.12, 1.51, and 0.90, respectively, for age <40, 41-50 and 51-60 years) but significantly increased after 60 years (aHR 2.67; P = 0.019). Analysis of death-censored graft failure yielded similar results for donor age below 60 years and showed a substantially increased risk with donors above 60 years (aHR 6.98, P = 0.002). This analysis reveals an unexpectedly high impact of older donor age on the association between DGF and renal transplant outcomes. Further research is needed to determine the best use of kidneys from donors above 60 years old, where DGF is expected.

Delayed graft function in the kidney transplant

Acute kidney injury occurs with kidney transplantation and too frequently progresses to the clinical diagnosis of delayed graft function (DGF). Poor kidney function in the first week of graft life is detrimental to the longevity of the allograft. Challenges to understand the root cause of DGF include several pathologic contributors derived from the donor (ischemic injury, inflammatory signaling) and recipient (reperfusion injury, the innate immune response and the adaptive immune response). Progressive demand for renal allografts has generated new organ categories that continue to carry high risk for DGF for deceased donor organ transplantation. New therapies seek to subdue the inflammatory response in organs with high likelihood to benefit from intervention. Future success in suppressing the development of DGF will require a concerted effort to anticipate and treat tissue injury throughout the arc of the transplantation process.

Functional improvement between brain death declaration and organ harvesting

INTRODUCTION

The quality of harvested organs is crucial for graft survival and for posttransplant evolution. This study sought to investigate the evolution of the functional status of brain death (BD) patients during the period between declaration and organ harvesting (BD duration).

MATERIALS AND METHODS

The study included all BD patients who underwent organ harvesting between January 2006 and June 2009. We compared the functional status regarding hemodynamics, respiration, kidney and liver function, coagulation, water, electrolytes, and acid-base balance evaluated at the moment of BD declaration (P1) and just before organ harvesting (P2). The results of the comparison were expressed as improvement, stable, or aggravation. We calculated mean values of the functional parameters in P1 and P2 and the statistical significance of the differences.

RESULTS

Twelve BD patients were included in the study. The time interval between P1 and P2 was 16.08 +/- 8.54 hours (range, 6-32). The number of patients with vasopressor support was 9/12 at P1 and 0/12 at P2, oxygenation disturbances 1/12 in P1 and 0/12 in P2, renal dysfunction 9/12 in P1 and 2/12 in P2, liver dysfunction 7/12 in P1 and 1/12 in P2, coagulopathy 4/12 in P1 and 0/12 in P2, hypernatremia 8/12 in P1 and 3/12 in P2, and metabolic acidosis 9/12 in P1 and 1/12 in P2. The overall assessment showed improvement in all patients. The most statistically significant improvement was registered in the cardiovascular, respiratory, renal, liver, and acid-base status (P < .05).

CONCLUSION

With early, aggressive, protocolized donor management, functional improvement may be achieved during BD duration.

Donor pretreatment with carbamylated erythropoietin in a brain death model reduces inflammation more effectively than erythropoietin while preserving renal function

OBJECTIVE

We hypothesized that donor treatment of deceased brain dead donors would lead to a decrease in inflammatory responses seen in brain death and lead to a restoration of kidney function.

DESIGN

A standardized slow-induction rat brain death model followed by evaluation of kidney function in an isolated perfused kidney model.

SETTINGS

Surgery Research Laboratory, University Medical Center Groningen, the Netherlands.

SUBJECTS

Male Fisher rats.

INTERVENTIONS

Donor treatment with erythropoietin, carbamylated erythropoietin, which lacks erythropoietic activity, or vehicle.

MEASUREMENTS AND MAIN RESULTS

In brain death, carbamylated erythropoietin and, to a lesser extent, erythropoietin were able to decrease the expression of several proinflammatory genes and to decrease the infiltration of polymorphonuclear cells in the kidney. No effect on tubular injury parameters was seen. Kidney function decreased almost by 50% after brain death but was fully restored after treatment with both carbamylated erythropoietin and erythropoietin.

CONCLUSIONS

Carbamylated erythropoietin can inhibit the inflammatory response caused by brain death more effectively than erythropoietin, whereas both substances can restore kidney function after brain death.