Donation after circulatory death: the current state and technical approaches to organ procurement. Curr Opin Organ Transplant. 2015;20:127-132. [PMID: 25719900 DOI: 10.1097/mot.0000000000000179]

Antemortem Heparin in Organ Donation After Circulatory Death Determination: A Systematic Review of the Literature

Donation after circulatory death determination frequently involves antemortem heparin administration to mitigate peri-arrest microvascular thrombosis. We systematically reviewed the literature to: (1) describe heparin administration practices and (2) explore the effects on transplant outcomes. We searched MEDLINE and EMBASE for studies reporting donation after circulatory death determination heparin practices including use, dosage, and timing (objective 1). To explore associations between antemortem heparin and transplant outcomes (objective 2), we (1) summarized within-study comparisons and (2) used meta-regression analyses to examine associations between proportions of donors that received heparin and transplant outcomes. We assessed risk of bias using the Newcastle Ottawa Scale and applied the GRADE methodology to determine certainty in the evidence. For objective 1, among 55 eligible studies, 48 reported heparin administration to at least some donors (range: 15.8%-100%) at variable doses (up to 1000 units/kg) and times relative to withdrawal of life-sustaining therapy. For objective 2, 7 studies that directly compared liver transplants with and without antemortem heparin reported lower rates of primary nonfunction, hepatic artery thrombosis, graft failure at 5 y, or recipient mortality (low certainty of evidence). In contrast, meta-regression analysis of 32 liver transplant studies detected no associations between the proportion of donors that received heparin and rates of early allograft dysfunction, primary nonfunction, hepatic artery thrombosis, biliary ischemia, graft failure, retransplantation, or patient survival (very low certainty of evidence). In conclusion, antemortem heparin practices vary substantially with an uncertain effect on transplant outcomes. Given the controversies surrounding antemortem heparin, clinical trials may be warranted.

A retrievable, dual-chamber stent protects against warm ischemia of donor organs in a model of donation after circulatory death

BACKGROUND

Ischemic injury during the agonal period of donation after circulatory death donors remains a significant barrier to increasing abdominal transplants. A major obstacle has been the inability to improve visceral perfusion, while at the same time respecting the ethics of the organ donor. A retrievable dual-chamber stentgraft could potentially isolate the organ perfusion from systemic hypotension and hypoxia, without increasing cardiac work or committing the donor.

METHODS

Retrievable dumbbell-shaped stents were laser welded from nitinol wire and covered with polytetrafluoroethylene. Yorkshire pigs were assigned to either agonal control or dumbbell-shaped dual-chamber stentgraft. A central lumen maintained aortic flow, while an outer visceral chamber was perfused with oxygenated blood. A 1-hour agonal phase of hypoxia and hypotension was simulated. Stents were removed by simple sheath advancement. Cardiac monitoring, labs, and visceral flow were recorded followed by recovery of the animal to a goal of 48 hours.

RESULTS

Cardiac stress did not increase during stent deployment. Visceral pO2 and flow were dramatically improved in stented animal relative to control animals. Five of 7 control animals were killed after renal failure complications, whereas all stent animals survived. Histology confirmed increased ischemic changes among control kidneys compared to stented animals.

CONCLUSION

A dual-chamber stent improved outcomes after a simulated agonal phase. The stent did not increase cardiac work, thus respecting a key ethical consideration. The ability of a dual-chamber stent to prevent ischemia during organ recovery may become a powerful tool to address the critical donor organ shortage.

Machine perfusion of circulatory determined death hearts: A scoping review

BACKGROUND

Ex vivo machine perfusion (EVMP) is reported to can successfully be applied for donor heart preservation. To respond to the organ shortage, some centres also accept hearts from marginal donors such as non-heart beating donors (NHBD) or hearts donated after cardiac death (DCD) for heart transplantation (HTx). Clinical as well as preclinical science on EVMP of DCD hearts seems to be promising but the ideal perfusion practice itself appears unclear.

OBJECTIVES

In accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA), this systematic review scopes all EVMP techniques for human and animal DCD heart preservation and addresses three specific questions, which refer to (a) the perfusion solutions, (b) the perfusion parameters and respective target values and (c) if possible, a direct comparison between cold static storage (CSS) and EVMP.

RESULTS

Search results predominantly consisted of animal studies. Either perfusion with a crystalloid or blood-based solution, each with cardioplegic or non-cardioplegic properties was used. Some perfusates were supplemented with specific pharmacological medication to block pathophysiological pathways, which are involved in ischemia/reperfusion injury or edema formation. Besides normothermic EVMP with oxygenated blood, a wide range of temperature was applied in all approaches, with the lowest temperature at 4 °C. Pressure controlled anterograde Langendorff perfusion was applied mostly. If investigated, crystalloid machine perfusion was presented superior to CSS.

CONCLUSIONS

Only blood based EVMP was introduced into clinical practice. More research, clinical as well as preclinical, is needed to develop the ideal EVMP technique, in terms of blood or crystalloid perfusion.

Criteria to Identify a Potential Deceased Organ Donor: A Systematic Review

OBJECTIVES

To systematically review the global published literature defining a potential deceased organ donor and identifying clinical triggers for deceased organ donation identification and referral.

DATA SOURCES

Medline and Embase databases from January 2006 to September 2017.

STUDY SELECTION

All published studies containing a definition of a potential deceased organ donor and/or clinical triggers for referring a potential deceased organ donor were eligible for inclusion. Dual, independent screening was conducted of 3,857 citations.

DATA EXTRACTION

Data extraction was completed by one team member and verified by a second team member. Thematic content analysis was used to identify clinical criteria for potential deceased organ donation identification from the published definitions and clinical triggers.

DATA SYNTHESIS

One hundred twenty-four articles were included in the review. Criteria fell into four categories: Neurological, Medical Decision, Cardiorespiratory, and Administrative. Distinct and globally consistent sets of clinical criteria by type of deceased organ donation (neurologic death determination, controlled donation after circulatory determination of death, and uncontrolled donation after circulatory determination of death) are reported.

CONCLUSIONS

Use of the clinical criteria sets reported will reduce ambiguity associated with the deceased organ donor identification and the subsequent referral process, potentially reducing the number of missed donors and saving lives globally through increased transplantation.

Organ Donation After Circulatory Death and Before Death: Ethical Questions and Nursing Implications

Scientific advances have enabled thousands of individuals to extend their lives through organ donation. Yet, shortfalls of available organs persist, and individuals in the United States die daily before they receive what might have been lifesaving organs. For years, the legal foundation of organ donation in the United States has been known as the Dead Donor Rule, requiring death to be defined for organ donation purposes by either a cardiac standard (termination of the heartbeat) or a neurological one (cessation of all brain function). In this context, one solution used by an increasing number of health care facilities since 2006 is donation after circulatory death, generally defined as when care is withdrawn from individuals who have known residual brain function. Despite its increased use, donation after circulatory death remains ethically controversial. In addition, some ethicists have advocated forgoing the Dead Donor Rule altogether and allowing donation before or near death in certain circumstances. However, nurses and other health professionals must carefully consider the practical and ethical implications of broadening the Dead Donor Rule-as may be already occurring-or removing it entirely. Such changes could harm both the integrity of the health care system as well as efforts to secure organ donation commitments from the public and are outweighed by the moral and pragmatic cost. Nurses should be prepared to confront the challenge posed by the ongoing scarcity of organs and advocate for ethical alternatives including research on effective care pathways and education regarding organ donation.

Evaluation and reconditioning of donor organs for transplantation through ex vivo lung perfusion

Objective:

To assess the feasibility and impact of ex vivo lung perfusion with hyperoncotic solution (Steen Solution^™) in the utilization of these organs in Brazil.

Methods:

In this prospective study, we subjected five lungs considered to be high risk for transplantation to 4 hours of ex vivo lung perfusion, with evaluation of oxygenation capacity. High-risk donor lungs were defined by specific criteria, including inflammatory infiltrates, pulmonary edema and partial pressure of arterial oxygen less than 300mmHg (inspired oxygen fraction of 100%).

Results:

During reperfusion, the mean partial pressure of arterial oxygen (inspired oxygen fraction of 100%) of the lungs did not change significantly (p=0.315). In the first hour, the mean partial pressure of arterial oxygen was 302.7mmHg (±127.66mmHg); in the second hour, 214.2mmHg (±94.12mmHg); in the third hour, 214.4mmHg (±99.70mmHg); and in the fourth hour, 217.7mmHg (±73.93mmHg). Plasma levels of lactate and glucose remained stable during perfusion, with no statistical difference between the moments studied (p=0.216).

Conclusion:

Ex vivo lung perfusion was reproduced in our center and ensured the preservation of lungs during the study period, which was 4 hours. The technique did not provide enough improvement for indicating organs for transplantation; therefore, it did not impact on use of these organs.

"Do not do" recommendations of the working groups of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) for the management of critically ill patients

The project "Commitment to Quality of Scientific Societies", promoted since 2013 by the Spanish Ministry of Health, seeks to reduce unnecessary health interventions that have not proven effective, have little or doubtful effectiveness, or are not cost-effective. The objective is to establish the "do not do" recommendations for the management of critically ill patients. A panel of experts from the 13 working groups (WGs) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) was selected and nominated by virtue of clinical expertise and/or scientific experience to carry out the recommendations. Available scientific literature in the management of adult critically ill patients from 2000 to 2017 was extracted. The clinical evidence was discussed and summarized by the experts in the course of consensus finding of each WG, and was finally approved by the WGs after an extensive internal review process carried out during the first semester of 2017. A total of 65 recommendations were developed, of which 5 corresponded to each of the 13 WGs. These recommendations are based on the opinion of experts and scientific knowledge, and aim to reduce those treatments or procedures that do not add value to the care process; avoid the exposure of critical patients to potential risks; and improve the adequacy of health resources.

Recommendations of the Working Groups from the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) for the management of adult critically ill patients

The standardization of the Intensive Care Medicine may improve the management of the adult critically ill patient. However, these strategies have not been widely applied in the Intensive Care Units (ICUs). The aim is to elaborate the recommendations for the standardization of the treatment of critical patients. A panel of experts from the thirteen working groups (WG) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) was selected and nominated by virtue of clinical expertise and/or scientific experience to carry out the recommendations. Available scientific literature in the management of adult critically ill patients from 2002 to 2016 was extracted. The clinical evidence was discussed and summarised by the experts in the course of a consensus finding of every WG and finally approved by the WGs after an extensive internal review process that was carried out between December 2015 and December 2016. A total of 65 recommendations were developed, of which 5 corresponded to each of the 13 WGs. These recommendations are based on the opinion of experts and scientific knowledge, and are intended as a guide for the intensivists in the management of critical patients.

Lungs donated after circulatory death and prolonged warm ischemia are transplanted successfully after enhanced ex vivo lung perfusion using adenosine A2B receptor antagonism

OBJECTIVE

The current supply of acceptable donor lungs is not sufficient for the number of patients awaiting transplantation. We hypothesized that ex vivo lung perfusion (EVLP) with targeted drug therapy would allow successful rehabilitation and transplantation of donation after circulatory death lungs exposed to 2 hours of warm ischemia.

METHODS

Donor porcine lungs were procured after 2 hours of warm ischemia postcardiac arrest and subjected to 4 hours of cold preservation or EVLP. ATL802, an adenosine A_2B receptor antagonist, was administered to select groups. Four groups (n = 4/group) were randomized: cold preservation (Cold), cold preservation with ATL802 during reperfusion (Cold + ATL802), EVLP (EVLP), and EVLP with ATL802 during ex vivo perfusion (EVLP + ATL802). Lungs subsequently were transplanted, reperfused, and assessed by measuring dynamic lung compliance and oxygenation capacity.

RESULTS

EVLP + ATL802 significantly improved dynamic lung compliance compared with EVLP (25.0 ± 1.8 vs 17.0 ± 2.4 mL/cmH₂O, P = .04), and compared with cold preservation (Cold: 12.2 ± 1.3, P = .004; Cold + ATL802: 10.6 ± 2.0 mL/cmH₂O, P = .002). Oxygenation capacity was highest in EVLP (440.4 ± 37.0 vs Cold: 174.0 ± 61.3 mm Hg, P = .037). No differences in oxygenation or pulmonary edema were observed between EVLP and EVLP + ATL802. A significant decrease in interleukin-12 expression in tissue and bronchoalveolar lavage was identified between groups EVLP and EVLP + ATL802, along with less neutrophil infiltration.

CONCLUSIONS

Severely injured donation after circulatory death lungs subjected to 2 hours of warm ischemia are transplanted successfully after enhanced EVLP with targeted drug therapy. Increased use of lungs after uncontrolled donor cardiac death and prolonged warm ischemia may be possible and may improve transplant wait list times and mortality.

Ginkgo biloba extract EGb761 attenuates brain death-induced renal injury by inhibiting pro-inflammatory cytokines and the SAPK and JAK-STAT signalings

This study aimed to investigate the protective effects of EGb761, a Ginkgo Biloba extract, against brain death-induced kidney injury. Sixty male Sprague Dawley rats were randomly divided into six groups: sham, brain-death (BD), BD + EGb b48h (48 hours before BD), BD + EGb 2 h (2 hours after BD), BD + EGb 1 h, and BD + EGb 0.5 h. Six hours after BD, serum sample and kidney tissues were collected for analyses. The levels of blood urea nitrogen (BUN) and serum creatinine significantly elevated in the BD group than in sham group. In all the EGb761-treated BD animals except for the BD + Gb 2 h group, the levels of BUN and serum creatinine significantly reduced (all P < 0.01). EGb761 attenuated tubular injury and lowered the histological score. In addition, the longer duration of drug treatment was, the better protective efficacy could be observed. EGb761 significantly reduced IL-1β, IL-6, TNF-α, MCP-1, IP-10 mRNA expression and macrophage infiltration in the kidney. EGb761 treatment at 48 hour before brain death significantly attenuate the levels of p-JNK-MAPK, p-p38-MAPK, and p-STAT3 proteins (all P < 0.05, compared to BD group). In summary, our data showed that EGb761 treatment protected donor kidney from BD-induced damages by blocking SAPK and JAK-STAT signalings. Early administration of EGb761 can provide better protective efficacy.

Donation After Circulatory Death Lungs Transplantable Up to Six Hours After Ex Vivo Lung Perfusion

BACKGROUND

Despite the critical need for donor lungs, logistic and geographic barriers hinder lung utilization. We hypothesized that lungs donated after circulatory death subjected to 6 hours of cold preservation after ex vivo lung perfusion (EVLP) would have similar outcomes after transplantation as lungs transplanted immediately after EVLP, and that both would perform superiorly compared with lungs transplanted immediately after procurement.

METHODS

Donor porcine lungs were procured after circulatory death and 15 minutes of warm ischemia. Three groups (n = 5 per group) were randomized: immediate left lung transplantation (Immediate group), EVLP for 4 hours followed by transplantation (EVLP group), or EVLP for 4 hours followed by 6 hours of cold preservation followed by transplantation (EVLP+Cold group). Lungs were reperfused for 2 hours before obtaining pulmonary vein samples for partial pressure of oxygen/fraction of inspired oxygen ratio calculations, airway pressures for compliance measurements, and wet/dry weight ratios.

RESULTS

The partial pressure of oxygen/fraction of inspired oxygen ratios in the EVLP and EVLP+Cold groups were significantly improved compared with those in the Immediate group (429.7 ± 51.8 and 436.7 ± 48.2 versus 117.4 ± 22.9 mm Hg, respectively). In addition, dynamic compliance was significantly improved in the EVLP and EVLP+Cold groups compared with immediate group (26.2 ± 4.2 and 27.9 ± 3.5 versus 11.1 ± 2.4 mL/cmH₂O, respectively). There were no differences in oxygenation capacity or dynamic compliance between the EVLP and EVLP+Cold groups. Inflammatory cytokine levels were significantly lower in the EVLP and EVLP+Cold groups.

CONCLUSIONS

Lungs donated after circulatory death can be successfully transplanted as much as 6 hours after EVLP. Cold preservation of lungs after ex vivo assessment and rehabilitation may improve organ allocation, even to distant recipients, without compromising allograft function.

Dual chamber stent prevents organ malperfusion in a model of donation after cardiac death

BACKGROUND

The paradigm for donation after cardiac death subjects donor organs to ischemic injury. A dual-chamber organ perfusion stent would maintain organ perfusion without affecting natural cardiac death. A center lumen allows uninterrupted cardiac blood flow, while an external chamber delivers oxygenated blood to the visceral vessels.

METHODS

A prototype organ perfusion stent was constructed from commercial stents. In a porcine model, the organ perfusion stent was deployed, followed by a simulated agonal period. Oxygenated blood perfused the external stent chamber. Organ perfusion was compared between controls (n = 3) and organ perfusion stent (n = 6). Finally, a custom, nitinol, dual chamber organ perfusion stent was fabricated using a retrievable "petal and stem" design.

RESULTS

Endovascular organ perfusion stent deployment achieved visceral isolation without adverse impact on cardiac parameters. Visceral oxygen delivery was 4.8-fold greater compared with controls. During the agonal period, organs in organ perfusion stent-treated animals appeared well perfused in contrast with the malperfused controls. A custom nitinol and polyurethane organ perfusion stent was recaptured easily with simple sheath advancement.

CONCLUSION

An organ perfusion stent maintained organ perfusion during the agonal phase in a porcine model of donation after cardiac death organ donation without adversely affecting cardiac function. Ultimately, the custom retrievable design of this study may help resolve the critical shortage of donor organs for transplant.

Validation of a pediatric bedside tool to predict time to death after withdrawal of life support

AIM: To evaluate the accuracy of a tool developed to predict timing of death following withdrawal of life support in children.

METHODS: Pertinent variables for all pediatric deaths (age ≤ 21 years) from 1/2009 to 6/2014 in our pediatric intensive care unit (PICU) were extracted through a detailed review of the medical records. As originally described, a recently developed tool that predicts timing of death in children following withdrawal of life support (dallas predictor tool [DPT]) was used to calculate individual scores for each patient. Individual scores were calculated for prediction of death within 30 min (DPT30) and within 60 min (DPT60). For various resulting DPT30 and DPT60 scores, sensitivity, specificity and area under the receiver operating characteristic curve were calculated.

RESULTS: There were 8829 PICU admissions resulting in 132 (1.5%) deaths. Death followed withdrawal of life support in 70 patients (53%). After excluding subjects with insufficient data to calculate DPT scores, 62 subjects were analyzed. Average age of patients was 5.3 years (SD: 6.9), median time to death after withdrawal of life support was 25 min (range; 7 min to 16 h 54 min). Respiratory failure, shock and sepsis were the most common diagnoses. Thirty-seven patients (59.6%) died within 30 min of withdrawal of life support and 52 (83.8%) died within 60 min. DPT30 scores ranged from -17 to 16. A DPT30 score ≥ -3 was most predictive of death within that time period, with sensitivity = 0.76, specificity = 0.52, AUC = 0.69 and an overall classification accuracy = 66.1%. DPT60 scores ranged from -21 to 28. A DPT60 score ≥ -9 was most predictive of death within that time period, with sensitivity = 0.75, specificity = 0.80, AUC = 0.85 and an overall classification accuracy = 75.8%.

CONCLUSION: In this external cohort, the DPT is clinically relevant in predicting time from withdrawal of life support to death. In our patients, the DPT is more useful in predicting death within 60 min of withdrawal of life support than within 30 min. Furthermore, our analysis suggests optimal cut-off scores. Additional calibration and modifications of this important tool could help guide the intensive care team and families considering DCD.