Time to death after withdrawal of treatment in donation after circulatory death (DCD) donors

Deep learning unlocks the true potential of organ donation after circulatory death with accurate prediction of time-to-death

Increasing the number of organ donations after circulatory death (DCD) has been identified as one of the most important ways of addressing the ongoing organ shortage. While recent technological advances in organ transplantation have increased their success rate, a substantial challenge in increasing the number of DCD donations resides in the uncertainty regarding the timing of cardiac death after terminal extubation, impacting the risk of prolonged ischemic organ injury, and negatively affecting post-transplant outcomes. In this study, we trained and externally validated an ODE-RNN model, which combines recurrent neural network with neural ordinary equations and excels in processing irregularly-sampled time series data. The model is designed to predict time-to-death following terminal extubation in the intensive care unit (ICU) using the history of clinical observations. Our model was trained on a cohort of 3,238 patients from Yale New Haven Hospital, and validated on an external cohort of 1,908 patients from six hospitals across Connecticut. The model achieved accuracies of [Formula: see text] and [Formula: see text] for predicting whether death would occur in the first 30 and 60 minutes, respectively, with a calibration error of [Formula: see text]. Heart rate, respiratory rate, mean arterial blood pressure (MAP), oxygen saturation (SpO2), and Glasgow Coma Scale (GCS) scores were identified as the most important predictors. Surpassing existing clinical scores, our model sets the stage for reduced organ acquisition costs and improved post-transplant outcomes.

Predicting Time to Death After Withdrawal of Life-Sustaining Measures Using Vital Sign Variability: Derivation and Validation

To develop a predictive model using vital sign (heart rate and arterial blood pressure) variability to predict time to death after withdrawal of life-supporting measures.

Shifting Paradigms for Suppressing Fibrosis in Kidney Transplants: Supplementing Perfusion Solutions With Anti-fibrotic Drugs

Great efforts have been made toward addressing the demand for donor kidneys. One of the most promising approaches is to use kidneys from donation after circulatory death donors. These kidneys, however, suffer from more severe ischemia and reperfusion injury than those obtained via donation after brain death and are thus more prone to develop interstitial fibrosis and tubular atrophy. Even though machine perfusion is increasingly used to reduce ischemia and reperfusion injury, there are no effective treatments available to ameliorate interstitial fibrosis and tubular atrophy, forcing patients to resume dialysis, undergo re-transplantation, or suffer from premature death. Safe and effective anti-fibrotic therapies are therefore greatly desired. We propose a new therapeutic approach in which machine perfusion solutions are supplemented with anti-fibrotic compounds. This allows the use of higher concentrations than those used in humans whilst eliminating side effects in other organs. To the authors' knowledge, no one has reviewed whether such an approach could reduce interstitial fibrosis and tubular atrophy; we therefore set out to explore its merit. In this review, we first provide background information on ischemia and reperfusion injury as well as interstitial fibrosis and tubular atrophy, after which we describe currently available approaches for preserving donor kidneys. We then present an evaluation of selected compounds. To identify promising compounds, we analyzed publications describing the effects of anti-fibrotic molecules in precision-cut kidneys slices, which are viable explants that can be cultured ex vivo for up to a few days whilst retaining functional and structural features. LY2109761, galunisertib, imatinib, nintedanib, and butaprost were shown to exert anti-fibrotic effects in slices within a relatively short timeframe (<48 h) and are therefore considered to be excellent candidates for follow-up ex vivo machine perfusion studies.

Advances in Hypothermic and Normothermic Perfusion in Kidney Transplantation

Hypothermic and normothermic machine perfusion in kidney transplantation are purported to exert a beneficial effect on post-transplant outcomes compared to the traditionally used method of static cold storage. Kidney perfusion techniques provide a window for organ reconditioning and quality assessment. However, how best to deliver these preservation methods or improve organ quality has not yet been conclusively defined. This review summarises the promising advances in machine perfusion science in recent years, which have the potential to further improve early graft function and prolong graft survival.

Improving the predictability of time to death in controlled donation after circulatory death lung donors

Although the use of donation after circulatory death (DCD) donors has increased lung transplant activity, 25-40% of intended DCD donors do not convert to actual donation because of no progression to asystole in the required time frame after withdrawal of cardiorespiratory support (WCRS). No studies have specifically focussed on DCD lung donor progression. This retrospective study reviewed intended DCD lung donors to make a prediction model of the likelihood of progression to death using logistic regression and classification and regression tree (CART). Between 2014 and 2018, 159 of 334 referred DCD donors were accepted, with 100 progressing to transplant, while 59 (37%) did not progress. In logistic regression, a length of ICU stay ≤ 5 days, severe infra-tentorial brain damage on imaging and use of vasopressin were related with the progression to actual donation. CART modelling of the likelihood of death within 90-minute post-WCRS provided prediction with a sensitivity of 1.00 and positive predictive value of 0.56 in the validation data set. In the nonprogressed DCD group, 26 died within 6 h post-WCRS. Referral received early after ICU admission, with nonspontaneous ventilatory mode, deep coma and severe infra-tentorial damage were relevant predictors. The CART model is useful to exclude DCD donor candidates with low probability of progression.

Prediction Model for Timing of Death in Potential Donors After Circulatory Death (DCD III): Protocol for a Multicenter Prospective Observational Cohort Study

Background

Controlled donation after circulatory death (cDCD) is a major source of organs for transplantation. A potential cDCD donor poses considerable challenges in terms of identification of those dying within the predefined time frame of warm ischemia after withdrawal of life-sustaining treatment (WLST) to circulatory arrest. Several attempts have been made to develop models predicting the time between treatment withdrawal and circulatory arrest. This time window determines whether organ donation can occur and influences the quality of the donated organs. However, the selected patients used for these models were not always restricted to potential cDCD donors (eg, patients with cancer or severe infections were also included). This severely limits the generalizability of those data.

Objective

The objectives of this study are the following: (1) to develop a model predicting time to death within 60 minutes in potential cDCD patients; (2) to validate and update previous prediction models on time to death after WLST; (3) to determine timing and patient characteristics that are associated with prognostication and the decision-making process that leads to initiating end-of-life care; (4) to evaluate the impact of timing of family approach on organ donation approval; and (5) to assess the influence of variation in WLST processes on postmortem organ donor potential and actual postmortem organ donors.

Methods

In this multicenter observational prospective cohort study, all patients admitted to the intensive care unit of 3 university hospitals and 3 teaching hospitals who met the criteria of the cDCD protocol as defined by the Dutch Transplant Foundation were included. The target of enrolment was set to 400 patients. Previously developed models will be refitted in our data set. To further update previous prediction models, we will apply least absolute shrinkage and selection operator (LASSO) as a tool for efficient variable selection to develop the multivariable logistic regression model.

Results

This protocol was funded in August 2014 by the Dutch Transplant Foundation. We expect to have the results of this study in July 2020. Patient enrolment was completed in July 2018 and data collection was completed in April 2020.

Conclusions

This study will provide a robust multimodal prediction model, based on clinical and physiological parameters, that can predict time to circulatory arrest in cDCD donors. In addition, it will add valuable insight in the process of WLST in cDCD donors and will fill an important knowledge gap in this essential field of health care.

Trial Registration

ClinicalTrials.gov NCT04123275; https://clinicaltrials.gov/ct2/show/NCT04123275

International Registered Report Identifier (IRRID)

DERR1-10.2196/16733

An international comparison of deceased donor kidney utilization: What can the United States and the United Kingdom learn from each other?

In transplant, meaningful international comparisons in organ utilization are needed. This collaborative study between the United Kingdom (UK) and the United States (US) aimed to develop a kidney utilization metric allowing for legitimate intercountry comparisons. Data from the UK and US transplant registries, including all deceased donor kidneys recovered from 2006 to 2017, were analyzed. To identify a potentially comparable kidney utilization rate (UR), several denominators were assessed. We discovered that the proportion of transplanted kidneys from elderly donors in the UK (10.7%) was 18 times greater than that in the US (0.6%). Conversely, en bloc pediatric kidney transplant was more common in the US. Donation after circulatory death utilization has risen in both countries but is twice as prevalent in the UK (39% of transplants) vs the US (20%). In addition, US and UK URs are not directly comparable due to fundamental system differences. However, using a suite of URs revealed practice areas likely to yield the most benefit if improved, such as efforts to increase kidney offer acceptance in the US and to reduce postacceptance discard in the UK. Methods used in this study, including novel intracountry risk-adjusted UR trend logistic regression analyses, can be translated to other international transplant registries in pursuit of further global learning opportunities.

Missed opportunities for DCD kidney donors: Evaluation of warm ischemic time and associated functional warm ischemic time

INTRODUCTION

Many transplant centers utilize a hard cutoff of 2 hours of warm ischemic time (WIT), defined as the time from withdrawal of life-sustaining measures to cold organ flush, to exclude donation after circulatory determination of death (DCD) kidney donation. As a result, almost a quarter of withdrawals to retrieve DCD organs fail to produce kidney transplants in Ontario. In order to assess our ability to increase organ yield, we wanted to characterize WIT and functional WIT (fWIT, time from systolic blood pressure <50 mm Hg to cold organ flush), as well as determine the time at which potential donors eventually die in those that did not become organ donors.

METHODS

A retrospective review of all DCD kidney donors in Ontario was performed utilizing the Trillium Gift of Life Database from April 2013 to February 2018.

RESULTS

Of 350 DCD kidney donors analyzed, 46.9% had < 0.5 hours, 51.7% between 0.5 and 2 hours, and 1.4% >2 hours of WIT. In each of these categories (WIT <0.5 hours, 0.5-2 hours and >2 hours), the percentage of patients with fWIT <30 minutes was 100%, 94.4%, and 100%, respectively (P = NS). There were 106 potential donors who did not end up donating due to WIT >2 hours. Of these, 20.8% died between 2 and 4 hours, 10.4% between 4 and 6 hours, and 68.8% beyond 6 hours.

DISCUSSION

The percentage of donors with fWIT >30 minutes did not increase with increasing WIT in DCD donors that went on to donate organs. These data support assessment of waiting up to 4 hours for DCD kidney donation as long as fWIT remains low.

Onset of Donor Warm Ischemia Time in Donation After Circulatory Death Liver Transplantation: Hypotension or Hypoxia?

The aim of this study was to investigate the impact of hypoxia and hypotension during the agonal phase of donor warm ischemia time (DWIT) on hepatic ischemia/reperfusion injury (IRI) and complications in donation after circulatory death (DCD) liver transplantation. A retrospective single-center study of 93 DCD liver transplants (Maastricht type III) was performed. DWIT was divided into 2 periods: the agonal phase (from withdrawal of treatment [WoT] until circulatory arrest) and the asystolic phase (circulatory arrest until cold perfusion). A drop to <80% in peripheral oxygenation (SpO₂ ) was considered as hypoxia in the agonal phase (SpO₂ -agonal) and a drop to <50 mm Hg as hypotension in the agonal phase (SBP-agonal). Peak postoperative aspartate transaminase level >3000 U/L was considered as severe hepatic IRI. SpO₂ dropped within 2 minutes after WoT <80%, whereas the systolic blood pressure dropped to <50 mm Hg after 9 minutes, resulting in a longer SpO₂ -agonal (13 minutes) than SBP-agonal (6 minutes). In multiple logistic regression analysis, only duration of SpO₂ -agonal was associated with severe hepatic IRI (P = 0.006) and not SBP-agonal (P = 0.32). Also, recipients with long SpO₂ -agonal (>13 minutes) had more complications with a higher Comprehensive Complication Index during hospital admission (43.0 versus 32.0; P = 0.002) and 90-day graft loss (26% versus 6%; P = 0.01), compared with recipients with a short SpO₂ -agonal (≤13 minutes). Furthermore, Cox proportional hazard modeling identified a long SpO₂ -agonal as a risk factor for longterm graft loss (hazard ratio, 3.30; 95% confidence interval, 1.15-9.48; P = 0.03). In conclusion, the onset of hypoxia during the agonal phase is related to the severity of hepatic IRI and postoperative complications. Therefore, SpO₂ <80% should be considered as the start of functional DWIT in DCD liver transplantation.

DCD donor hemodynamics as predictor of outcome after kidney transplantation

Insufficient hemodynamics during agonal phase-ie, the period between withdrawal of life-sustaining treatment and circulatory arrest-in Maastricht category III circulatory-death donors (DCD) potentially exacerbate ischemia/reperfusion injury. We included 409 Dutch adult recipients of DCD donor kidneys transplanted between 2006 and 2014. Peripheral oxygen saturation (SpO2-with pulse oximetry at the fingertip) and systolic blood pressure (SBP-with arterial catheter) were measured during agonal phase, and were dichotomized into minutes of SpO2 > 60% or SpO2 < 60%, and minutes of SBP > 80 mmHg or SBP < 80 mmHg. Outcome measures were and primary non-function (PNF), delayed graft function (DGF), and three-year graft survival. Primary non-function (PNF) rate was 6.6%, delayed graft function (DGF) rate was 67%, and graft survival at three years was 76%. Longer periods of agonal phase (median 16 min [IQR 11-23]) contributed significantly to an increased risk of DGF (P = .012), but not to PNF (P = .071) and graft failure (P = .528). Multiple logistic regression analysis showed that an increase from 7 to 20 minutes in period of SBP < 80 mmHg was associated with 2.19 times the odds (95% CI 1.08-4.46, P = .030) for DGF. In conclusion, duration of agonal phase is associated with early transplant outcome. SBP < 80 mmHg during agonal phase shows a better discrimination for transplant outcome than SpO2 < 60% does.

First Scandinavian Protocol for Controlled Donation After Circulatory Death Using Normothermic Regional Perfusion

BACKGROUND

Donation after circulatory death (DCD) can increase the pool of available organs for transplantation. This pilot study evaluates the implementation of a controlled DCD (cDCD) protocol using normothermic regional perfusion in Norway.

METHODS

Patients aged 16 to 60 years that are in coma with documented devastating brain injury in need of mechanical ventilation, who would most likely attain cardiac arrest within 60 minutes after extubation, were eligible. With the acceptance from the next of kin and their wish for organ donation, life support was withdrawn and cardiac arrest observed. After a 5-minute no-touch period, extracorporeal membrane oxygenation for post mortem regional normothermic regional perfusion was established. Cerebral and cardiac reperfusion was prevented by an aortic occlusion catheter. Measured glomerular filtration rates 1 year postengraftment were compared between cDCD grafts and age-matched grafts donated after brain death (DBD).

RESULTS

Eight cDCD were performed from 2014 to 2015. Circulation ceased median 12 (range, 6-24) minutes after withdrawal of life-sustaining treatment. Fourteen kidneys and 2 livers were retrieved and subsequently transplanted. Functional warm ischemic time was 26 (20-51) minutes. Regional perfusion was applied for 97 minutes (54-106 minutes). Measured glomerular filtration rate 1 year postengraftment was not significantly different between cDCD and donation after brain death organs, 75 (65-76) vs 60 (37-112) mL/min per 1.73 m2 (P = 0.23). No complications have been observed in the 2 cDCD livers.

CONCLUSION

A protocol for cDCD is successfully established in Norway. Excellent transplant outcomes have encouraged us to continue this work addressing the shortage of organs for transplantation.

The Impact of CPR in High-Risk Donation after Circulatory Death Donors and Extended Criteria Donors for Kidney Transplantation

The demand for organs for kidney transplantation (KTX) compels the use of high-risk donation after circulatory death donors (DCDs) and extended criteria donors (ECDs). Many deceased donors receive prehospital CPR, but the literature does not address CPR as a benefit to graft survival. We hypothesized that donor prehospital CPR correlates with improved graft survival with high-risk DCD/ECD kidneys. We retrospectively analyzed KTX recipients and their donor data from 2008 to 2013. A total of 646 cadaveric donors (498 SCDs, 55 DCDs, and 93 ECDs) facilitated 910 KTX. There were 223 KTX performed from 148 high-risk DCDs/ECDs (31 with CPR and 117 without CPR). The mean age of high-risk DCDs/ECDs with CPR was 44.94 versus 53.45 years without CPR (P = 0.005). The recipients of high-risk DCDs/ECDs revealed no significant difference in body mass index, length of stay, discharge Cr, CIT, or DGF with and without CPR. Graft survival at three years was significant with 0/50 failures from high-risk DCDs/ECDs with CPR versus 16/173 without CPR (P = 0.026). Our findings are limited as a single-center retrospective study; however, the result of significant three-year graft survival in high-risk DCDs/ECDs with CPR suggests that prehospital donor CPR should be further investigated for its contribution to the relative quality of the donor.

Oxygen saturation and haemodynamic changes prior to circulatory arrest: Implications for transplantation and resuscitation

Aims

To describe the progression of oxygen saturations and blood pressure observations prior to death.

Introduction

The progression of physiological changes around death is unknown. This has important implications in organ donation and resuscitation. Donated organs have a maximal warm ischaemic threshold. In hypoxic cardiac arrest, an understanding of pre-cardiac arrest physiology is important in prognosticating and will allow earlier identification of terminal states.

Methods

Data were examined for all regional patients over a two-year period offering organ donation after circulatory death. Frequent observations were taken contemporaneously by the organ donation nurse at the time of and after withdrawal of intensive care.

Results

In all, 82 case notes were examined of patients aged 0 to 76 (median 52, 4 < 18 years). From withdrawal of intensive care to death took a mean of 28.5 min (range 4 to 185). A terminal deterioration in saturations (from an already low baseline) commenced 14 min prior to circulatory arrest, followed by a blood pressure fall commencing 8 min prior to circulatory arrest, and finally a rapid fall in heart rate commencing 4 min prior to circulatory arrest. Two patients had a warm ischaemic time of greater than 30 min; 15 patients had a warm ischaemia time of 10 min or greater; and 53 patients had a warm ischaemia time of 5 min or less. It was observed that 0/82 patients had saturations of less than 40% for more than 3 min prior to cardiac arrest and 74/82 for more than 2 min.

Conclusions

There is a perimortem sequence of hypoxia, then hypotension, and then bradycardia. The heart is extremely resistant to hypoxia. A warm ischaemic time of over 30 min is rare.

External validation of prediction models for time to death in potential donors after circulatory death

Predicting time to death in controlled donation after circulatory death (cDCD) donors following withdrawal of life-sustaining treatment (WLST) is important but poses a major challenge. The aim of this study is to determine factors predicting time to circulatory death within 60 minutes after WSLT and validate previously developed prediction models. In a single-center retrospective study, we used the data of 92 potential cDCD donors. Multivariable regression analysis demonstrated that absent cough-, corneal reflex, lower morphine dosage, and midazolam use were significantly associated with death within 60 minutes (area under the curve [AUC] 0.89; 95% confidenence interval [CI] 0.87-0.91). External validation of the logistic regression models of de Groot et al (AUC 0.86; 95% CI 0.77-0.95), Wind et al (AUC 0.62; 95% CI 0.49-0.76), Davila et al (AUC 0.80; 95% CI 0.708-0.901) and the Cox regression model by Suntharalingam et al (Harrell's c-index 0.63), exhibited good discrimination and could fairly identify which patients died within 60 minutes. Previous prediction models did not incorporate the process of WLST. We believe that future studies should also include the process of WLST as an important predictor.

Harms of unsuccessful donation after circulatory death: An exploratory study

While donation after circulatory death (DCD) has expanded options for organ donation, many who wish to donate are still unable to do so. We conducted face-to-face interviews with family members (N = 15) who had direct experience with unsuccessful DCD and 5 focus groups with professionals involved in the donation process. We used qualitative content analysis to characterize the harms of nondonation as perceived by participants. Participants reported a broad spectrum of harms affecting organ recipients, donors, and donor families. Harms included waste of precious life-giving organs and hospital resources, inability to honor the donor's memory and character, and impaired ability for families to make sense of tragedy and cope with loss. Donor families empathized with the initial hope and ultimate despair of potential recipients who must continue their wait on the transplant list. Focus group members reinforced these findings and highlighted the struggle of families to navigate the uncertainty regarding the timing of death during the donation process. While families reported significant harm, many appreciated the donation attempt. These findings highlight the importance of organ donation to donor families and the difficult experiences associated with current processes that could inform development of alternative donation strategies.

A few realistic questions raised by organ retrieval in the intensive care unit

Organ transplantation saves the lives of many persons who would otherwise die from end-stage organ disease. The increasing demand for donated organs has led to a renewed interest in donation after circulatory determination of death (CDD). In many countries (including France), terminally ill patients who die of circulatory arrest after a planned withdrawal of life support may be considered as organ donors under certain conditions. While having equal responsibility towards the potential donor and the persons awaiting a transplant, caregivers may experience an ethical dilemma between the responsibility to deliver the best care to the dying, and the need to retrieve the organs. Once it has been established that the patient wishes to be a donor, we assume that end-of-life care and organ donation may have convergent goals when they contribute to transforming a comfortable death into a chance of life for others in need.

Use of Lung Allografts From Donation After Cardiac Death Donors: A Single-Center Experience

BACKGROUND

Lung transplantation remains the only treatment for end-stage lung disease. Availability of suitable lungs does not parallel this growing trend. Centers using donation after cardiac death (DCD) donor lungs report comparable outcomes with those from brain-dead donors. Donor assessment protocols and consistent surgical teams have been advocated when considering using the use of DCD donors. We present our experience using lungs from Maastricht category III DCD donors.

METHODS

Starting 2007 to July 2016, 73 DCD donors were assessed, 44 provided suitable lungs that resulted in 46 transplants. A 2012 to October 2016 comparative cohort of 379 brain-dead donors were assessed. Recipient and donor characteristics and primary graft dysfunction (PGD) and survival were monitored.

RESULTS

Seventy-three DCD (40% dry run rate) donors assessed yielded 46 transplants (23 double, 6 right, and 17 left). Comparative cohort of 379 brain-dead donors yielded 237 transplants (112 double, 43 right, and 82 left). One- and 3-year recipient survival was 91% and 78% for recipients of DCD lungs and 91% and 75% for recipients of lungs from brain-dead donors, respectively. PGD 2 and 3 in DCD recipients at 72 hours was 4 of 46 (9%) and 6 of 46 (13%), respectively. Comparatively, brain-dead donor recipient cohort at 72 hours with PGD 2 and 3 was 23 of 237 (10%) and 41 of 237 (17%), respectively.

CONCLUSIONS

Our experience reaffirms the use of lungs from DCD donors as a viable source with favorable outcomes. Recipients from DCD donors showed equivalent PGD rate at 72 hours and survival compared with recipients from brain-dead donors.

Prediction of potential for organ donation after circulatory death in neurocritical patients

BACKGROUND

The success or failure of donation after circulatory death depends largely on the functional warm ischemia time, which is closely related to the duration between withdrawal of life-sustaining treatment and circulatory arrest. However, a reliable predictive model for the duration is absent. We aimed to compare the performance of the Chinese Donation after Circulatory Death Nomogram (C-DCD-Nomogram) and 3 other tools in a cohort of potential donors.

METHODS

In this prospective, multicenter, observational study, data were obtained from 219 consecutive neurocritical patients in China. The patients were followed until circulatory death after withdrawal of life-sustaining treatment.

RESULTS

The C-DCD-Nomogram performed well in predicting patient death within 30, 60, 120 and 240 minutes after withdrawal of life-sustaining treatment with c-statistics of 0.87, 0.88, 0.86 and 0.95, respectively. The DCD-N score was a poor predictor of death within 30, 60 and 240 minutes, with c-statistics of 0.63, 0.69 and 0.59, respectively, although it was able to predict patient death within 120 minutes, with a c-statistic of 0.73. Neither the University of Wisconsin DCD evaluation tool (UWDCD) nor the United Network for Organ Sharing (UNOS) criteria was able to predict patient death within 30, 60, 120 and 240 minutes after withdrawal of life-sustaining treatment (UWDCD tool: 0.48, 0.45, 0.49 and 0.57; UNOS criteria: 0.50, 0.53, 0.51 and 0.63).

CONCLUSION

The C-DCD-Nomogram is superior to the other 3 tools for predicting death within a limited duration after withdrawal of life-sustaining treatment in Chinese neurocritical patients. Thus, it appears to be a reliable tool identifying potential donors after circulatory death.

A Rodent Model of Cardiac Donation After Circulatory Death and Novel Biomarkers of Cardiac Viability During Ex Vivo Heart Perfusion

BACKGROUND

Organ donation after circulatory death (DCD) is increasingly being used as a means of addressing the organ supply/demand mismatch in solid organ transplantation. There is reluctance to use DCD hearts, due to an inability to precisely identify hearts that have suffered irreversible injury. We investigated novel biomarkers and clinically relevant endpoints across a spectrum of warm ischemic times, before and during ex vivo heart perfusion (EVHP), to identify features associated with a nonviable cardiac phenotype.

METHODS

Donor rats sustained a hypoxic cardiac arrest, followed by variable acirculatory standoff periods (DCD groups). Left ventricular function, histochemical injury, and differences in left ventricular gene expression were studied before, and during, EVHP.

RESULTS

As warm ischemic time exposure increased in DCD groups, fewer hearts were functional during EVHP, and ventricular function was increasingly impaired. Histochemical assessment identified severely injured hearts during EVHP. A novel gene expression signature identified severely injured hearts during EVHP (upregulation of c-Jun, 3.19 (2.84-3.60); P = 0.0014; HMOX-1, 3.87 (2.72-5.50); P = 0.0037; and Hsp90, 7.66 (6.32-9.27); P < 0.0001 in DCD20), and may be useful in identifying high-risk hearts at the point of harvest (Hsp90).

CONCLUSIONS

We demonstrate that our preclinical model recapitulates the cardio-respiratory decompensation observed in humans, and that EVHP appears necessary to unmask distinguishing features of severely injured DCD hearts. Furthermore, we outline a clinically relevant multimodal approach to assessing candidate DCD hearts. Novel mRNA signatures correlated with elevations in cardiac Troponin-I in severely injured hearts during EVHP, and may also detect injury at the point of harvest.

Steroids can reduce warm ischemic reperfusion injury in a porcine donation after circulatory death model with ex vivo lung perfusion evaluation

Donation after circulatory death (DCD) is being used to increase the number of transplantable organs. The role and timing of steroids in DCD donation and ex vivo lung perfusion (EVLP) has not been thoroughly investigated. In this study, we investigated the effect of steroids on warm ischemic injury in a porcine model (n = 6/group). Following cardiac arrest, grafts were left untouched in the donor (90-min warm ischemia). Graft function was assessed after 6 h of EVLP. In the MP group, 500 mg methylprednisolone was given prior to cardiac arrest and during EVLP. In the CONTR group, no steroids were added. Median lung compliance (13 ml/cmH₂ 0) was significantly better preserved in the CONTR group than in the MP group (30.5 ml/cmH₂ 0). Also, median wet-to-dry weight (6.11 vs. 6.94) and CT density (182.5 vs. 352.9 g/l) were significantly better in the MP group than in the CONTR group, respectively. There was no difference in oxygenation and pulmonary vascular resistance. Perfusate cytokine analysis showed a significant reduction in IL-1β, IL-8, IFN-α, IL-10, TNF-α, and IFN-γ in MP. Cytokines in bronchoalveolar lavage were not decreased except for IFN-gamma. We demonstrated that warm ischemic injury in DCD donation can be attenuated by steroids when given prior to warm ischemia and during EVLP. Ethical context of donor preconditioning should be discussed further.

Safety and Outcomes in 100 Consecutive Donation After Circulatory Death Liver Transplants Using a Protocol That Includes Thrombolytic Therapy

Donation after circulatory death (DCD) liver transplantation (LT) reportedly yields inferior survival and increased complication rates compared with donation after brain death (DBD). We compare 100 consecutive DCD LT using a protocol that includes thrombolytic therapy (late DCD group) to an historical DCD group (early DCD group n = 38) and a cohort of DBD LT recipients (DBD group n = 435). Late DCD LT recipients had better 1- and 3-year graft survival rates than early DCD LT recipients (92% vs. 76.3%, p = 0.03 and 91.4% vs. 73.7%, p = 0.01). Late DCD graft survival rates were comparable to those of the DBD group (92% vs. 93.3%, p = 0.24 and 91.4% vs. 88.2%, p = 0.62). Re-transplantation occurred in 18.4% versus 1% for the early and late DCD groups, respectively (p = 0.001). Patient survival was similar in all three groups. Ischemic-type biliary lesions (ITBL) occurred in 5%, 3%, and 0.2% for early DCD, late DCD, and DBD groups, respectively, but unlike in the early DCD group, in the late DCD group ITBL was endoscopically managed and resolved in each case. Using a protocol that includes a thrombolytic therapy, DCD LT yielded patient and graft survival rates comparable to DBD LT.

Does DCD Donor Time-to-Death Affect Recipient Outcomes? Implications of Time-to-Death at a High-Volume Center in the United States

For donation after circulatory death (DCD), many centers allow 1 h after treatment withdrawal to donor death for kidneys. Our center has consistently allowed 2 h. We hypothesized that waiting longer would be associated with worse outcome. A single-center, retrospective analysis of DCD kidneys transplanted between 2008 and 2013 as well as a nationwide survey of organ procurement organization DCD practices were conducted. We identified 296 DCD kidneys, of which 247 (83.4%) were transplanted and 49 (16.6%) were discarded. Of the 247 recipients, 225 (group 1; 91.1%) received kidneys with a time to death (TTD) of 0-1 h; 22 (group 2; 8.9%) received grafts with a TTD of 1-2 h. Five-year patient survival was 88.8% for group 1, and 83.9% for group 2 (p = 0.667); Graft survival was also similar, with 5-year survival of 74.1% for group 1, and 83.9% for group 2 (p = 0.507). The delayed graft function rate was the same in both groups (50.2% vs. 50.0%, p = 0.984). TTD was not predictive of graft failure. Nationally, the average maximum wait-time for DCD kidneys was 77.2 min. By waiting 2 h for DCD kidneys, we performed 9.8% more transplants without worse outcomes. Nationally, this practice would allow for hundreds of additional kidney transplants, annually.

Variations in the Operational Process of Withdrawal of Life-Sustaining Therapy

OBJECTIVE

The process of withdrawal of life-sustaining therapy remains poorly described in the current literature despite its importance for patient comfort and optimal end-of-life care. We conducted a structured review of the published literature to summarize patterns of withdrawal of life-sustaining therapy processes in adult ICUs.

DATA SOURCES

Electronic journal databases were searched from date of first issue until April 2014.

STUDY SELECTION

Original research articles describing processes of life-support therapy withdrawal in North American, European, and Australian ICUs were included.

DATA EXTRACTION

From each article, we extracted definitions of withdrawal of life-sustaining therapy, descriptions and order of interventions withdrawn, drugs administered, and timing from withdrawal of life-sustaining therapy until death.

DATA SYNTHESIS

Fifteen articles met inclusion criteria. Definitions of withdrawal of life-sustaining therapy varied and focused on withdrawal of mechanical ventilation; two studies did not present operational definitions. All studies described different aspects of process of life-support therapy withdrawal and measured different time periods prior to death. Staggered patterns of withdrawal of life-support therapy were reported in all studies describing order of interventions withdrawn, with vasoactive drugs withdrawn first followed by gradual withdrawal of mechanical ventilation. Processes of withdrawal of life-sustaining therapy did not seem to influence time to death.

CONCLUSIONS

Further description of the operational processes of life-sustaining therapy withdrawal in a more structured manner with standardized definitions and regular inclusion of measures of patient comfort and family satisfaction with care is needed to identify which patterns and processes are associated with greatest perceived patient comfort and family satisfaction with care.

Nomogram for Predicting Time to Death After Withdrawal of Life-Sustaining Treatment in Patients With Devastating Neurological Injury

Reliable prediction of time of death after withdrawal of life-sustaining treatment in patients with devastating neurological injury is crucial to successful donation after cardiac death. Herein, we conducted a study of 419 neurocritical patients who underwent life support withdrawal at four neurosurgical centers in China. Based on a retrospective cohort, we used multivariate Cox regression analysis to identify prognostic factors for patient death, which were then integrated into a nomogram. The model was calibrated and validated using data from an external retrospective cohort and a prospective cohort. We identified 10 variables that were incorporated into a nomogram. The C-indexes for predicting the 60-min death probability in the training, external validation and prospective validation cohorts were 0.96 (0.93-0.98), 0.94 (0.91-0.97), and 0.99 (0.97-1.00), respectively. The calibration plots after WLST showed an optimal agreement between the prediction of time to death by the nomogram and the actual observation for all cohorts. Then we identified 22, 26 and 37 as cut-points for risk stratification into four groups. Kaplan-Meier curves indicated distinct prognoses between patients in the different risk groups (p < 0.001). In conclusion, we have developed and validated a nomogram to accurately identify potential cardiac death donors in neurocritical patients in a Chinese population.

Kidney donation after circulatory death (DCD): state of the art

The use of kidneys from controlled donation after circulatory death (DCD) donors has the potential to markedly increase kidney transplants performed. However, this potential is not being realized because of concerns that DCD kidneys are inferior to those from donation after brain-death (DBD) donors. The United Kingdom has developed a large and successful controlled DCD kidney transplant program that has allowed for a substantial increase in kidney transplant numbers. Here we describe recent trends in DCD kidney donor activity in the United Kingdom, outline aspects of the donation process, and describe donor selection and allocation of DCD kidneys. Previous UK Transplant Registry analyses have shown that while DCD kidneys are more susceptible to cold ischemic injury and have a higher incidence of delayed graft function, short- and medium-term transplant outcomes are similar in recipients of kidneys from DCD and DBD donors. We present an updated, extended UK registry analysis showing that longer-term transplant outcomes in DCD donor kidneys are also similar to those for DBD donor kidneys, and that transplant outcomes for kidneys from expanded-criteria DCD donors are no less favorable than for expanded-criteria DBD donors. Accordingly, the selection criteria for use of kidneys from DCD donors should be the same as those used for DBD donors. The UK experience suggests that wider international development of DCD kidney transplantation programs will help address the global shortage of deceased donor kidneys for transplantation.

Kidney donation after circulatory death (DCD): state of the art

Ischemia–reperfusion (IR) injury to the kidney occurs in a range of clinically important scenarios including hypotension, sepsis and in surgical procedures such as cardiac bypass surgery and kidney transplantation, leading to acute kidney injury (AKI). Mitochondrial oxidative damage is a significant contributor to the early phases of IR injury and may initiate a damaging inflammatory response. Here we assessed whether the mitochondria targeted antioxidant MitoQ could decrease oxidative damage during IR injury and thereby protect kidney function. To do this we exposed kidneys in mice to in vivo ischemia by bilaterally occluding the renal vessels followed by reperfusion for up to 24 h. This caused renal dysfunction, measured by decreased creatinine clearance, and increased markers of oxidative damage. Administering MitoQ to the mice intravenously 15 min prior to ischemia protected the kidney from damage and dysfunction. These data indicate that mitochondrial oxidative damage contributes to kidney IR injury and that mitochondria targeted antioxidants such as MitoQ are potential therapies for renal dysfunction due to IR injury.

Exploration of Withdrawal of Life-Sustaining Therapy in Canadian Intensive Care Units

OBJECTIVE

The process of controlled donation after circulatory death (cDCD) is strongly connected with the process of withdrawal of life-sustaining therapy. In addition to impacting cDCD success, actions comprising withdrawal of life-sustaining therapy have implications for quality of palliative care. We examined pilot study data from Canadian intensive care units to explore current practices of life-sustaining therapy withdrawal in nondonor patients and described variability in standard practice.

DESIGN

Secondary analysis of observational data collected for Determination of Death Practices in Intensive Care pilot study.

SETTING

Four Canadian adult intensive care units.

PATIENTS

Patients ≥18 years in whom a decision to withdraw life-sustaining therapy was made and substitute decision makers consented to study participation. Organ donors were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Prospective observational data on interventions withdrawn, drugs administered, and timing of life-sustaining therapy withdrawal was available for 36 patients who participated in the pilot study. Of the patients, 42% died in ≤1 hour; median length of time to death varied between intensive care units (39-390 minutes). Withdrawal of life-sustaining therapy processes appeared to follow a general pattern of vasoactive drug withdrawal followed by withdrawal of mechanical ventilation and extubation in most sites but specific steps varied. Approaches to extubation and weaning of vasoactive drugs were not consistent. Protocols detailing the process of life-sustaining therapy withdrawal were available for 3 of 4 sites and also exhibited differences across sites.

CONCLUSIONS

Standard practice of life-sustaining therapy withdrawal appears to differ between selected Canadian sites. Variability in withdrawal of life-sustaining therapy may have a potential impact both on rates of cDCD success and quality of palliative care.

[Eligibility to a Maastricht III - type organ donation according to the protocol proposed by the French organ procurement organization (Agence de la biomedicine) among patients in a medico surgical intensive care unit]

OBJECTIVE

Because of graft shortages, an experimental programme of organ donation after Maastricht 3-type circulatory death (M3) has been proposed by the French organ procurement organization (Agence de la biomedicine: ABM). The aim of the study was to estimate how many potential patients were eligible for an M3-type organ donation, amongst deceased patients who have had life-support withdrawn.

PATIENTS AND METHODS

We conducted a retrospective study looking at the notes of deceased patients in a French general intensive care unit (ICU), where organ donation is arranged in DBD donors.

RESULTS

Over the year 2013, 1475 patients were admitted in ICU and 215 died. One hundred and one patients were brain-injured and 26 of them died following a decision to withdrawn life-support and without contraindication to organ donation. Among them, 2 patients (8%) met the criteria for the French M3-type organ donation protocol. A 12.5% increase in organ donation activity of our team and five organ transplantations could have been considered.

CONCLUSION

If M3 organ donation is considered, a significant increase in transplantation would be expected.

Eligibility for organ donation following end-of-life decisions: a study performed in 43 French intensive care units

PURPOSE

A persistent shortage of available organs for transplantation has driven French medical authorities to focus on organ retrieval from patients who die following the withdrawal of life-sustaining therapy. This study was designed to assess the theoretical eligibility of patients who have died in French intensive care units (ICUs) after a decision to withhold or withdraw life-sustaining therapy to organ donation.

METHODS

This was an observational multi-center study in which data were collected on all consecutive patients admitted to any of the 43 participating ICUs during the study period who qualified for a withholding/withdrawal procedure according to French law. The theoretical organ donor eligibility of the patients once deceased was determined a posteriori according to current medical criteria for graft selection, as well as according to the withholding/withdrawal measures implemented and their impact on the time of death.

RESULTS

A total of 5,589 patients were admitted to the ICU during the study period, of whom 777 (14 %) underwent withholding/withdrawal measures. Of the 557 patients who died following a foreseeable circulatory arrest, 278 (50 %) presented a contraindication ruling out organ retrieval. Of the 279 patients who would have been eligible as organ donors regardless of measures implemented, cardiopulmonary support was withdrawn in only 154 of these patients, 70 of whom died within 120 min of the withdrawal of life-sustaining treatment. Brain-injured patients accounted for 29 % of all patients who qualified for the withholding/withdrawal of treatment, and 57 % of those died within 120 min of the withdrawal/withholding of treatment.

CONCLUSION

A significant number of patients who died during the study period in French ICUs under withholding/withdrawal conditions would have been eligible for organ donation. Brain-injured patients were more likely to die in circumstances which would have been compatible with such practice.

The M3 from the international point of view

Deciding to cease treatment in intensive care unit patients whose prognosis is hopeless allows programming the moment of death, and hence, post mortem transplantable organ donation. Such organ donations are more frequent in Anglo-Saxon countries. In the context of growing organ needs, they have significantly increased the number of organs that are available for transplant. Progressive experience has shown that crystal-clear procedures must be set up in order to avoid lack of understanding, opposition, or even conflict between involved medical teams and immediate relatives of potential donors. The decision of organ transplantation must totally be separated from the decision of treatment cessation. Supportive treatment cessation must be done according to previously established procedures. Medications that are compatible with organ transplantation must be listed. Finally, the needs of patient relatives must be met.

Eligibility of patients withheld or withdrawn from life-sustaining treatment to organ donation after circulatory arrest death: epidemiological feasibility study in a French Intensive Care Unit

Background

Transplantation brings sustainably improved quality of life to patients with end-stage organ failure. Persisting shortfall in available organs prompted French authorities and practitioners to focus on organ retrieval in patients withdrawn from life-sustaining treatment and awaiting cardiac arrest (Maastricht classification category III). The purpose of this study was to assess the theoretical eligibility of non-heart-beating donors dying in the intensive care unit (ICU) after a decision to withhold or withdraw life-sustaining treatment (WoWt).

Methods

We collected the clinical and biological characteristics of all consecutive patients admitted to our ICU and qualified for a WoWt procedure under the terms of the French Leonetti law governing end-of-life care during a 12-month period. The theoretical organ donor eligibility (for kidney, liver, or lung retrieval) of deceased patients was determined a posteriori 1) according to routine medical criteria for graft selection and 2) according to the WoWt measures implemented and their impact on organ viability.

Results

A total of 596 patients (mean age: 67 ± 16 yr; gender ratio M/F: 1.6; mean SAPS (Simplified Acute Physiology Score) II: 54 ± 24) was admitted to the ICU, of which 84 patients (mean age: 71 ± 14 yr, 14% of admissions, gender ratio M/F: 3.2) underwent WoWt measures. Eight patients left the unit alive. Forty-four patients presented a contraindication ruling out organ retrieval either preexisting admission (n = 20) or emerged during hospitalization (n = 24). Thirty-two patients would have been eligible as kidney (n = 23), liver (n = 22), or lung donors (n = 2). Cardiopulmonary support was withdrawn in only five of these patients, and three died within 120 minutes after withdrawal (the maximum delay compatible with organ viability for donor grafts).

Conclusions

In this pilot study, a significant number of patients deceased under WoWt conditions theoretically would have been eligible for organ retrieval. However, the WoWt measures implemented in our unit seems incompatible with donor organ viability. A French multicenter survey of end-of-life practices in ICU may help to identify potential appropriate organ donors and to interpret nation-specific considerations of the related professional, legal, and ethical frameworks.