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

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.

Current challenges in lung transplantation

Lung transplantation remains the definitive treatment for end-stage lung disease, but several critical challenges persist. Key issues include the limited availability of donor organs, ongoing debates over optimal preservation methods, and the controversy surrounding the best intraoperative support systems. Additionally, the efficacy of bridging strategies to transplantation continues to be questioned. This review delves into these pressing topics. This includes a focus on donation after cardiac death as a potential solution to expand the donor pool and recent advancements in hypothermic preservation, including innovative portable devices, and the role of bridging strategies. By addressing these multifaceted challenges, this review highlights the importance of continued advancements in donor management, organ preservation, and perioperative care to ultimately improve outcomes for lung transplant recipients.

Neuroimaging Augments DCD-N Score in Predicting Time from Withdrawal of Life-Sustaining Measures to Death Among Potential Organ Donors

BACKGROUND

Controlled donation after circulatory determination of death (DCD) is feasible only if circulatory arrest occurs soon after withdrawal of life-sustaining measures (WLSM). When organ recovery cannot proceed because this time interval is too long, there are potential negative implications, including perceptions of "secondary loss" for patients' families and significant resource consumption. The DCD-N score is a validated clinical tool for predicting rapid death following WLSM. We hypothesized that neuroimaging evidence of effaced perimesencephalic cisterns improves prediction of time to death compared with the DCD-N score alone.

METHODS

In a retrospective population-based cohort study, DCD-N scores were prospectively determined in patients for whom consent for DCD had been obtained. Perimesencephalic cisterns on last available neuroimaging were assessed in duplicate and classified as normal, partially effaced, or completely effaced. Multivariable logistic regression assessed the capacity of DCD-N score and effaced cisterns to predict death within 1, 2, or 3 h of WLSM.

RESULTS

Of 164 consecutive patients, 49 (30%) progressed to death by neurologic criteria and were excluded. Of the remaining 115 patients, 81 (70%) died within 2 h of WLSM. When perimesencephalic cisterns were patent, this occurred in 48% of patients, compared with 88% and 93%, respectively, of patients with partially and completely effaced cisterns (p < 0.0001). In multivariable analysis, the odds ratio for prediction of death within 2 h was 7.2 (2.8-18.3) for each incremental DCD-N score and 15.4 (4.1-58.1) for the presence of either partially or completely effaced cisterns (c = 0.92 vs. 0.75-0.84 for univariate models). Results were comparable for prediction of death within 1 or 3 h. With patent cisterns, median time to death was 132.5 (21-420) minutes, compared with 23.5 (16-32) and 22 (19-30) minutes, respectively, with partially and completely effaced cisterns (p = 0.0002).

CONCLUSIONS

Cerebral edema with effaced perimesencephalic cisterns predicts rapid death following WLSM in potential DCD organ donors and improves on performance of the DCD-N score alone. Although originally validated for the prediction of death within 1 h, the DCD-N score remains predictive up to 3 h following WLSM.

Consensus Statement: Technical Standards for Thoracoabdominal Normothermic Regional Perfusion

BACKGROUND

Thoracoabdominal normothermic regional perfusion (TA-NRP) has emerged as a powerful technique for optimizing organ procurement from donation after circulatory death donors. Despite its rapid adoption, standardized guidelines for TA-NRP implementation are lacking, prompting the need for consensus recommendations to ensure safe and effective utilization of this technique.

METHODS

A working group composed of members from The American Society of Transplant Surgeons, The International Society of Heart and Lung Transplantation, The Society of Thoracic Surgeons, and The American Association for Thoracic Surgery was convened to develop technical guidelines for TA-NRP. The group systematically reviewed existing literature, consensus statements, and expert opinions to identify key areas requiring standardization, including predonation evaluation, intraoperative management, postdonation procedures, and future research directions.

RESULTS

The working group formulated recommendations encompassing donor evaluation and selection criteria, premortem testing and therapeutic interventions, communication protocols, and procedural guidelines for TA-NRP implementation. These recommendations aim to facilitate coordination among transplant teams, minimize variability in practice, and promote transparency and accountability throughout the TA-NRP process.

CONCLUSIONS

The consensus guidelines presented herein serve as a comprehensive framework for the successful and ethical implementation of TA-NRP programs in organ procurement from donation after circulatory death donors. By providing standardized recommendations and addressing areas of uncertainty, these guidelines aim to enhance the quality, safety, and efficiency of TA-NRP procedures, ultimately contributing to improved outcomes for transplant recipients.

Consensus Statement: Technical Standards for Thoracoabdominal Normothermic Regional Perfusion

BACKGROUND

Thoracoabdominal normothermic regional perfusion (TA-NRP) has emerged as a powerful technique for optimizing organ procurement from donation after circulatory death donors. Despite its rapid adoption, standardized guidelines for TA-NRP implementation are lacking, prompting the need for consensus recommendations to ensure safe and effective utilization of this technique.

METHODS

A working group composed of members from The American Society of Transplant Surgeons, The International Society of Heart and Lung Transplantation, The Society of Thoracic Surgeons, and The American Association for Thoracic Surgery was convened to develop technical guidelines for TA-NRP. The group systematically reviewed existing literature, consensus statements, and expert opinions to identify key areas requiring standardization, including predonation evaluation, intraoperative management, postdonation procedures, and future research directions.

RESULTS

The working group formulated recommendations encompassing donor evaluation and selection criteria, premortem testing and therapeutic interventions, communication protocols, and procedural guidelines for TA-NRP implementation. These recommendations aim to facilitate coordination among transplant teams, minimize variability in practice, and promote transparency and accountability throughout the TA-NRP process.

CONCLUSIONS

The consensus guidelines presented herein serve as a comprehensive framework for the successful and ethical implementation of TA-NRP programs in organ procurement from donation after circulatory death donors. By providing standardized recommendations and addressing areas of uncertainty, these guidelines aim to enhance the quality, safety, and efficiency of TA-NRP procedures, ultimately contributing to improved outcomes for transplant recipients.

Predicting time to asystole following withdrawal of life-sustaining treatment: a systematic review

The planned withdrawal of life-sustaining treatment is a common practice in the intensive care unit for patients where ongoing organ support is recognised to be futile. Predicting the time to asystole following withdrawal of life-sustaining treatment is crucial for setting expectations, resource utilisation and identifying patients suitable for organ donation after circulatory death. This systematic review evaluates the literature for variables associated with, and predictive models for, time to asystole in patients managed on intensive care units. We conducted a comprehensive structured search of the MEDLINE and Embase databases. Studies evaluating patients managed on adult intensive care units undergoing withdrawal of life-sustaining treatment with recorded time to asystole were included. Data extraction and PROBAST quality assessment were performed and a narrative summary of the literature was provided. Twenty-three studies (7387 patients) met the inclusion criteria. Variables associated with imminent asystole (<60 min) included: deteriorating oxygenation; absence of corneal reflexes; absence of a cough reflex; blood pressure; use of vasopressors; and use of comfort medications. We identified a total of 20 unique predictive models using a wide range of variables and techniques. Many of these models also underwent secondary validation in further studies or were adapted to develop new models. This review identifies variables associated with time to asystole following withdrawal of life-sustaining treatment and summarises existing predictive models. Although several predictive models have been developed, their generalisability and performance varied. Further research and validation are needed to improve the accuracy and widespread adoption of predictive models for patients managed in intensive care units who may be eligible to donate organs following their diagnosis of death by circulatory criteria.

Predicting Time to Death After Withdrawal of Life-Sustaining Treatment in Children

Accurately predicting time to death after withdrawal of life-sustaining treatment is valuable for family counseling and for identifying candidates for organ donation after cardiac death. This topic has been well studied in adults, but literature is scant in pediatrics. The purpose of this report is to assess the performance and clinical utility of the available tools for predicting time to death after treatment withdrawal in children.

Predicting the occurrence of early seizures after cerebral venous thrombosis using a comprehensive nomogram

BACKGROUND

Seizure is a common clinical manifestation of cerebral venous thrombosis (CVT). The mortality rate of patients with CVT with seizure is three times higher than that of patients without seizure. The aim of this study was to develop a nomogram to predict the individual probability of acute seizure events in patients with CVT.

METHOD

This was a single-center, retrospective cohort study. We analyzed and compared demographic variables, epidemiological risk factors, clinical presentation, laboratory results and imaging data in a cohort of 142 patients who were diagnosed with CVT in our hospital from January 2013 to December 2018. A nomogram was constructed to predict the risk of early seizure (ES) in these patients according to the multivariable logistic regression analysis results. The concordance index, GiViTi calibration belt and decision curve analysis (DCA) were used to assess nomogram performance.

RESULTS

Forty-three (30.28%) patients experienced seizure within 2 weeks after a CVT diagnosis. Multivariate analysis identified focal neurologic deficit, Glasgow Coma Scale (GCS) scores ≤ 8 on admission, hemorrhagic lesions, superior sagittal sinus thrombosis (SSST) and frontal lobe lesions as independent predictive factors for ES occurrence after CVT. A nomogram was generated based on these predictive factors with the concordance index reaching 0.82, indicating that the clinical tool was well calibrated. DCA showed that the model was useful with a threshold probability in the range of 0-77%.

CONCLUSIONS

We developed the first nomogram that could predict the risk of ES in CVT patients. This effective and convenient tool has shown promising clinical benefit and will assist clinicians in making treatment decisions.

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.

Distinctive egg-laying patterns in terminal versus non-terminal periods in three fruit fly species

The specific objective of this study was to use a logistic regression model for determining the degree to which egg laying patterns of individual females at the end of life (i.e., terminal segments) in each of three different fruit fly species could be distinguished from the egg-laying patterns over a similar period in midlife (i.e., non-terminal segments). Extracting data from large-scale databases for 11-day terminal and 11-day non-terminal segments in the vinegar fly (Drosophila melanogaster), the Mexican fruit fly (Anastrepha ludens) and the Mediterranean fruit fly (Ceratitis capitata) and organizing the model's results in a 2 × 2 contingency table, we found that: (1) daily egg-laying patterns in fruit flies can be used to distinguish terminal from non-terminal periods; (2) the overall performance metrics such as precision, accuracy, false positives and true negatives depended heavily on species; (3) differentiating between terminal and non-terminal segments is more difficult when flies die at younger ages; and (4) among the three species the best performing metrics including accuracy and precision were those produced using data on D. melanogaster. We conclude that, although the reliability of the prediction of whether a segment occurred at the end of life is relatively high for most species, it does not follow precisely predicting remaining life will also be highly reliable since classifying an end of life period is a fundamentally different challenge than is predicting an exact day of death.

Donation after circulatory determination of death in western Canada: a multicentre study of donor characteristics and critical care practices

PURPOSE

Donation after circulatory determination of death (DCD) has been performed in Canada since 2006. Numerous aspects of donor management remain controversial.

METHODS

We performed a multicentre cohort study involving potential DCD donors in western Canada (2008-2017), as well as recipients of their organs, to describe donor characteristics and critical care practices, and their relation to one-year recipient and graft survival.

RESULTS

There were 257 patients in four provinces that underwent withdrawal of life-sustaining therapies (WLST) in anticipation of possible DCD. The proportion of patients that died within two hours of WLST ranged from 67% to 88% across provinces (P = 0.06), and was predicted by deeper coma (P = 0.01), loss of pupillary light or corneal reflexes (P = 0.02), and vasopressor use (P = 0.01). There were significant differences between provinces in time intervals from onset of hypotension to death (9-11 min; P = 0.02) and death to vascular cannulation (7-10 min; P < 0.001). There was inconsistency in pre-mortem heparin administration (82-96%; P = 0.03), including timing (before vs after WLST; P < 0.001) and dose (≥ 300 vs < 300 units·kg-1; P < 0.001). Donation after circulatory death provided organs for 321 kidney, 81 liver, and 50 lung transplants. One-year recipient and graft survival did not differ among provinces (range 85-90%, P = 0.45). Predictors of death or graft failure included older recipient age (odds ratio [OR] per year, 1.04; 95% confidence interval [CI],1.01 to 1.07) and male donor sex (OR, 3.35; 95% CI, 1.39 to 8.09), but not time intervals between WLST and cannulation or practices related to heparin use.

CONCLUSION

There is significant variability in critical care DCD practices in western Canada, but this has not resulted in significant differences in recipient or graft survival. Further research is required to guide optimal management of potential DCD donors.

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.

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.

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.

Organ donation protocols

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

ICU Management of the Potential Organ Donor: State of the Art

End-organ failure is associated with high mortality and morbidity, in addition to increased health care costs. Organ transplantation is the only definitive treatment that can improve survival and quality of life in such patients; however, due to the persistent mismatch between organ supply and demand, waiting lists continue to grow across the world. Careful intensive care management of the potential organ donor with goal-directed therapy has the potential to optimize organ function and improve donation yield.