Brain death: a clinical overview

Brain death/death by neurologic criteria: What you need to know

ABSTRACT

Since the beginning of time, man has been intrigued with the question of when a person is considered dead. Traditionally, death has been considered the cessation of all cardiorespiratory function. At the end of the last century a new definition was introduced into the lexicon surrounding death in addition to cessation of cardiac and respiratory function: Brain Death/Death by Neurologic Criteria (BD/DNC). There are medical, legal, ethical, and even theological controversies that surround this diagnosis. In addition, there is no small amount of confusion among medical practitioners regarding the diagnosis of BD/DNC. For families enduring the devastating development of BD/DNC in their loved one, it is the duty of the principal caregiver to provide a transparent presentation of the clinical situation and clear definitive explanation of what constitutes BD/DNC. In this report, we present a historical outline of the development of BD/DNC as a clinical entity, specifically how one goes about making a determination of BD/DNC, what steps are taken once a diagnosis of BD/DNC is made, a brief discussion of some of the ethical/moral issues surrounding this diagnosis, and finally the caregiver approach to the family of a patient who had been declared with BD/DNC. It is our humble hope that with a greater understanding of the myriad of complicated issues surrounding the diagnosis of BD/DNC that the bedside caregiver can provide needed closure for both the patient and the family enduring this critical time in their life.

Brain death: A review of the latest guidelines

ABSTRACT

The incidence of brain death/death by neurologic criteria (BD/DNC) among all hospital deaths in the US is approximately 2.06% or 15,000-20,000 cases annually. This article reviews the latest guidelines for adult and pediatric BD/DNC. Although there have not been many changes to the guidelines over the years, BD/DNC guideline updates maintain consistency in determining BD/DNC.

Role of Clinical and Multimodality Neuroimaging in the Evaluation of Brain Death/Death by Neurologic Criteria and Recent Highlights from 2023 Updated Guidelines

Purpose of Review: This review aims to provide a comprehensive overview of the diagnosis of brain death/death by neurologic criteria (BD/DNC) by emphasizing the clinical criteria established by the American Academy of Neurology (AAN) in light of their updated guidelines released in 2023. In this review, we will focus on the current implementation of ancillary tests including the catheter cerebral angiogram, nuclear scintigraphy, and transcranial Doppler, which provide support in diagnoses when clinical examination and apnea tests are inconclusive. Finally, we will also provide examples to discuss the implementation of certain imaging studies in the context of diagnosing BD/DNC. Recent Findings: Recent developments in the field of neurology have emphasized the importance of clinical criteria for diagnosing BD/DNC, with the AAN providing clear updated guidelines that include coma, apnea, and the absence of brainstem reflexes. Current ancillary tests, including the catheter cerebral angiogram, nuclear scintigraphy, and transcranial Doppler play a crucial role in confirming BD/DNC when the clinical assessment is limited. The role of commonly used imaging studies including computed tomography and magnetic resonance angiographies of the brain as well as CT/MR perfusion studies will also be discussed in the context of these new guidelines. Summary: BD/DNC represents the permanent cessation of brain functions, including the brainstem. This review article provides the historical context, clinical criteria, and pathophysiology that goes into making this diagnosis. Additionally, it explores the various ancillary tests and selected imaging studies that are currently used to diagnose BD/DNC under the newly updated AAN guidelines. Understanding the evolution of how to effectively use these diagnostic tools is crucial for healthcare professionals who encounter these BD/DNC cases in their practice.

The impact of clinical education on knowledge and attitudes towards brain death among Polish medical students - a cross-sectional study

BACKGROUND

Understanding brain death is essential for progress in organ transplantation; however, it remains a challenging ethical matter. In 2019, Poland revised its legislation on brain death to align with international standards. This study aimed to evaluate the knowledge and worldview concerning brain death among Polish medical students, categorised according to their stage of education.

METHODS

An online questionnaire was administered to 169 medical students from four Polish medical universities. The participants were divided into preclinical (n = 94) and clinical (n = 75) groups. The questionnaire consisted of two parts, with the first part comprising 13 questions focusing on knowledge about brain death and the process of its determination. The second part contained six questions related to the participants' worldview regarding brain death, particularly concerning organ transplantation.

RESULTS

The average score obtained by the respondents was 7.53 (± 2.35; min. 1, max. 13) in knowledge checking part of the developed questionnaire (maximal score:13). Students in the clinical stage of their education achieved significantly higher scores compared to preclinical students (mean 8.84; ± 1.89 vs mean 6.49; ± 2.15; p < 0.001). Significant correlations were found between the results of the knowledge part of the questionnaire and responses to worldview questions.

CONCLUSIONS

The stage of education influenced the knowledge of brain death among medical students, although the overall test scores were unsatisfactory. Higher test scores were associated with worldview responses indicating compliance with the current legislation in Poland and evidence-based medicine.

Brain Death Confirmation by 18F-FDG PET/CT: A Case Series

OBJECTIVES

Brain death is a state of irreversible loss of brain function in the cortex and brainstem. Diagnosis of brain death is established by clinical assessments of cranial nerves and apnea tests. Different conditions can mimic brain death. In addition, confirmatory tests may be falsely positive in some cases. In this study, we aimed to evaluate the role of positron emission tomography-computed tomography scan with 2-deoxy-2[18F]fluoro-D-glucose (18F-FDG-PET/CT) as an ancillary test in diagnosing brain death.

MATERIALS AND METHODS

We analyzed 6 potential brain death donors for the confirmatory diagnosis of brain death using FDG-PET/CT. All 6 donors were brain dead by clinical criteria. All patients had electroencephalogram and brain computed tomography. Other than FDG-PET/CT, transcranial Doppler was performed in 1 patient, with other patients having no confirmatory ancillary imaging tests. Patients had nothing by mouth for 6 hours before imaging. Patients were supine in a semi-dark, noiseless, and odorless room with closed eyes. After 60 minutes of uptake,the brain PET/CT scan was performed with sequential time-of-flight-PET/CT (Discovery 690 PET/CT with 64 slices, GE Healthcare). The PET scan consisted of LYSO (Lu1.8Y0.2 SiO5) crystals with dimensions of 4.2 × 6.3 × 25 mm3. Three-dimension images were with scan duration of 10 minutes.

RESULTS

The PET scan confirmed brain death in 5 of the 6 cases. However, we ruled out brain death using PET/CT in a 3-year-old child, although all clinical tests confirmed brain death.

CONCLUSIONS

A PET scan illustrates a hollow skull phenomenon suggestive of brain death. It can be a powerful diagnostic tool to assess brain death.

Liver Transplantation for Acute Liver Failure- Indication, Prioritization, Timing, and Referral

Acute liver failure (ALF) is a major success story in gastroenterology, with improvements in critical care and liver transplant resulting in significant improvements in patient outcomes in the current era compared to the dismal survival rates in the pretransplant era. However, the ever-increasing list of transplant candidates and limited organ pool makes judicious patient selection and organ use mandatory to achieve good patient outcomes and prevent organ wastage. Several scoring systems exist to facilitate the identification of patients who need a liver transplant and would therefore need an early referral to a specialized liver unit. The timing of the liver transplant is also crucial as transplanting a patient too early would lead to those who would recover spontaneously receiving an organ (wastage), and a late decision might result in the patient becoming unfit for transplant (delisted) or have an advanced disease which would result in poor post-transplant outcomes. The current article reviews the indications and contraindications of liver transplant in ALF patients, the various prognostic scoring systems, etiology-specific outcomes, prioritization and timing of referral.

Standards and Ethics Issues in the Determination of Death: A Position Paper From the American College of Physicians

The determination of a patient's death is of considerable medical and ethical significance. Death is a biological concept with social implications. Acting with honesty, transparency, respect, and integrity is critical to trust in the patient-physician relationship, and the profession, in life and in death. Over time, cases about the determination of death have raised questions that need to be addressed. This American College of Physicians position paper addresses current controversies and supports a clarification to the Uniform Determination of Death Act; maintaining the 2 current independent standards of determining death, cardiorespiratory and neurologic; retaining the whole brain death standard; aligning medical testing with the standards; keeping issues about the determination of death separate from organ transplantation; reaffirming the importance and role of the dead donor rule; and engaging in educational efforts for health professionals, patients, and the public on these issues. Physicians should advocate for policies and practices on the determination of death that are consistent with the profession's fundamental and timeless commitment to individual patients and the public.

Brain Dead and Pregnant

The presence of pregnancy in a brain-dead woman is a rare circumstance. We present a case of a 31-year-old woman who was 22 weeks pregnant at the time of diagnosis of brain death after intracranial and subarachnoid hemorrhage. After a multidisciplinary approach, the decision was made to continue somatic support to maintain the pregnancy until optimal fetus viability. Cesarean section was performed after 11 weeks (33 weeks gestational age) of brain-death diagnosis with a successful delivery of a live infant. Management of brain-death complications during pregnancy is described.

Posthumous Organ Donation in Islam, Christianity, and Judaism: How Religious Beliefs Shape the Decision to Donate

Evidence indicates that the religious beliefs of patients, potential donors, family members, and healthcare professionals play an important role in deciding to donate an organ. We aim to summarize the religious views of Christians, Muslims, and Jews on organ donation contributing to the decision-making process. Different approaches to this topic worldwide are presented, providing helpful information for medical professionals. A literature review was conducted regarding the view of Israel's leadership of the three largest religions on organ transplantation. This review revealed that all Israeli central religious leaders have a positive view on organ donation. However, various aspects of the transplantation process (such as consent, brain death, and respect for the dead body) must be carried out as each religion prescribes. Thus, understanding the different religious views and regulations on organ donations may help reduce religious concerns about transplantation and narrow the gap between the need and the availability of organ donations.

Evaluation of organ donation process and affecting factors in COVID-19 pandemic

Objectives: More than six million people worldwide are affected by end-stage organ failure and the COVID-19 pandemic has dramatically changed organ and tissue donation. Methods: The data of patients diagnosed with brain death between July 2018-March 2020 (pre-pandemic period) and April 2020-December 2021 (pandemic period) were analyzed retrospectively. Donor characteristics, laboratory levels, time from intensive care admission to determination of brain death, time to family approval, family approval rates and organ types were analyzed. Results: The mean age of 56 patients with pre-pandemic diagnosis of brain death was 61.82 ± 21.39 years, 37 (63%) patients were donors and 53 organs were obtained. Mean age of 39 patients diagnosed with brain death during the pandemic was 58.26 ± 18.02 years and 38 organs were obtained from 21 (52.5%) donors. Between the two periods, there was a decrease of 30.35% in the diagnosis of brain death, 43.24% in the number of donors and 26.41% in the number of organs supplied. The most common cause of brain death was intracranial hemorrhage during both periods. While the time elapsed between family interview and surgery was 9.33 ± 2.19 hours before the pandemic, it was 15.29 ± 4.28 hours during the pandemic period (p = 0.01). There was a significant difference between C-reactive protein levels at the time of diagnosis of brain death (p &lt; 0.05). Staphylococcus haemolyticus was most frequently seen in blood culture. Conclusions: Brain death and organ donation have decreased significantly during the pandemic period compared to previous years, similar to research conducted in different countries and regions. Due to COVID-19, prolonged stays in the intensive care unit (ICU) may pose a risk of infection in ICU donors, and care should be taken in terms of donor loss.

Induced Coma, Death, and Organ Transplantation: A Physiologic, Genetic, and Theological Perspective

In the clinic, the death certificate is issued if brain electrical activity is no longer detectable. However, recent research has shown that in model organisms and humans, gene activity continues for at least 96 h postmortem. The discovery that many genes are still working up to 48 h after death questions our definition of death and has implications for organ transplants and forensics. If genes can be active up to 48 h after death, is the person technically still alive at that point? We discovered a very interesting parallel between genes that were upregulated in the brain after death and genes upregulated in the brains that were subjected to medically-induced coma, including transcripts involved in neurotransmission, proteasomal degradation, apoptosis, inflammation, and most interestingly, cancer. Since these genes are involved in cellular proliferation, their activation after death could represent the cellular reaction to escape mortality and raises the question of organ viability and genetics used for transplantation after death. One factor limiting the organ availability for transplantation is religious belief. However, more recently, organ donation for the benefit of humans in need has been seen as “posthumous giving of organs and tissues can be a manifestation of love spreading also to the other side of death”.

Computed Tomography Angiography (CTA) in Selected Scenarios with Risk of Possible False-Positive or False-Negative Conclusions in Diagnosing Brain Death

It is widely accepted that brain death (BD) is a diagnosis based on clinical examination. However, false-positive and false-negative evaluation results may be serious limitations. Ancillary tests are used when there is uncertainty about the reliability of the neurologic examination. Computed tomography angiography (CTA) is an ancillary test that tends to have the lowest false-positive rates. However, there are various influencing factors that can have an unfavorable effect on the validity of the examination method. There are inconsistent protocols regarding the evaluation criteria such as scoring systems. Among the most widely used different scoring systems the 4-point CTA-scoring system has been accepted as the most reliable method. Appropriate timing and/or Doppler pre-testing could reduce the number of possible premature examinations and increase the sensitivity of CTA in diagnosing cerebral circulatory arrest (CCA). In some cases of inconclusive CTA, the whole brain computed tomography perfusion (CTP) could be a crucial adjunct. Due to the increasing significance of CTA/CTP in determining BD, the methodology (including benefits and limitations) should also be conveyed via innovative electronic training tools, such as the BRAINDEXweb teaching tool based on an expert system.

Brain death/death by neurologic criteria determination: an update

PURPOSE OF REVIEW

Brain death, also known as death by neurologic criteria (DNC), is a well-established concept. In this article, we present a short history of the concept and give an overview of recent changes and a practical update on diagnosis and definitions of brain death/DNC. Unresolved issues will be discussed.

RECENT FINDINGS

There is variability in brain death/DNC determination worldwide. In recent years, successful attempts have been made to harmonize these criteria and, consequently, to improve public trust in the process and diagnosis. An international multidisciplinary collaboration has been created and it has published minimum criteria, provided guidance for professionals and encouragement to revise or develop guidelines on brain death/DNC worldwide.

SUMMARY

There are two sets of criteria for declaration of death. First, if there is neither cardiac output nor respiratory effort, then cardiopulmonary criteria are used. Second, if both the cerebrum and brainstem have completely and permanently lost all functions, and there is a persistent coma, absent brainstem reflexes and no spontaneous respiratory effort, death can be declared on the basis of brain death/DNC. Although attempts to formulate uniform criteria are ongoing, consensus has been reached on the minimum criteria. Some inconsistencies and questions remain.

AC, da Cruz Jr. LCH. The role of neuroimaging in the determination of brain death

Brain death is the irreversible cessation of all brain function. Although protocols for its determination vary among countries, the concept of brain death is widely accepted, despite ethical and religious issues. The pathophysiology of brain death is related to hypoxia and ischemia in the setting of extensive brain injury. It is also related to the effects of brain edema, which increases intracranial pressure, leading to cerebral circulatory arrest. Although the diagnosis of brain death is based on clinical parameters, the use of neuroimaging to demonstrate diffuse brain injury as the cause of coma prior to definitive clinical examination is a prerequisite. Brain computed tomography (CT) and magnetic resonance imaging (MRI) demonstrate diffuse edema, as well as ventricular and sulcal effacement, together with brain herniation. Angiography (by CT or MRI) demonstrates the absence of intracranial arterial and venous flow. In some countries, electroencephalography, cerebral digital subtraction angiography, transcranial Doppler ultrasound, or scintigraphy/single-photon emission CT are currently used for the definitive diagnosis of brain death. Although the definition of brain death relies on clinical features, radiologists could play an important role in the early recognition of global hypoxic-ischemic injury and the absence of cerebral vascular perfusion.