Technical aids in the diagnosis of brain death: a comparison of SEP, AEP, EEG, TCD and CT angiography

[Diagnosis of brain death in Germany-Implementation of the guidelines of the German Medical Association]

BACKGROUND

The 4th update of the guidelines of the German Medical Association on the diagnosis of irreversible loss of brain function (brain death, BD) has introduced important new regulations regarding the required qualification of the examiners, approved procedures for ancillary testing, and a clarification regarding the sequencing of diagnostic steps.

OBJECTIVE

Investigation of the implementation and practical effects on the diagnosis of brain death.

METHOD

Descriptive evaluation of the routine documentation of the German Organ Procurement Organization, comparing the periods July 2011-June 2015 (3rd update) and July 2015-June 2019 (4th update).

RESULTS

Patient numbers decreased from 6100 to 5403. The largest decrease affected hospitals without neurosurgery. Children were not affected. With the 4th update, clinical diagnostics were increasingly performed during on-call hours by external neurologists. Of the patients 83.8% now received ancillary tests compared to 80.1% previously. Computed tomography angiography (CTA), first introduced in the 4th update, was applied in 23.2% and established complete loss of cerebral circulation in 89.4%. The time between first documentation of the clinical signs of BD and certification of BD increased from 7.0 ± 12.7 h to 8.2 ± 14.2 h. The diagnosis was slightly less frequent with 95.3% compared to 96.6%.

CONCLUSION

The updated standards were implemented in accordance with the guidelines. The demand for external consulting neurologists and neurosurgeons as well as the time required for BD assessment have increased. Negative effects on pediatric BD diagnostics were not apparent. CTA is widely and successfully used in adults as a new ancillary diagnostic procedure.

[Prospective investigation of extracranial duplex sonography for the detection of cerebral circulatory arrest in patients with irreversible loss of brain function]

BACKGROUND

A broader distribution of bedside color-coded duplex sonography (CCD) for detection of cerebral circulatory arrest (CCA) would be important to improve its use in the diagnosis of irreversible loss of brain function (ILBF-Dx).

QUESTION

Is extracranial compared to the commonly applied transcranial CCD of the brain-supplying vessels (ECCD vs. TCCD) equivalent for the detection of CCA in ILBF-Dx regarding specificity and sensitivity?

MATERIAL AND METHODS

Study period January 2019-June 2022, screening of 136 and inclusion of 114 patients with severe brain lesions > 24 h after onset of fixed and dilated pupils, apnea and completed ILBF-Dx. Exclusion of patients without brainstem areflexia and guideline-conform applicability of CCD. Complementary ECCD (and TCCD, if other method used for irreversibility detection).

RESULTS

Detection of ILBF (ILBF+) in 86.8% (99/114), no ILBF (ILBF-) in 13.2% (15/114). ECCD was fully feasible in all patients; findings matching CCA were found in 94/99 ILBF+ cases (ECCD+) and not in 5 patients (ECCD-). All 15 patients with ILBF- showed ECCD- findings. Thus, the specificity of ECCD was 1.0, and the sensitivity was 0.949. TCCD showed CCA in 56 patients (TCCD+), and ECCD+ was also found in all of them. An inconclusive result of TCCD in ILBF+ was found in 38 cases, with parallel ECCD+ in all of these patients. In 20 cases, TCCD did not show CCA (TCCD-), these also showed ECCD-. Of these patients 15 were ILBF- and 5 were ILBF+.

DISCUSSION

TCCD was not completely feasible or inconclusive in one third of the cases, whereas ECCD was always feasible. ECCD showed high validity with respect to the detection of CCA. Therefore, the possibility of using ECCD alone to detect CCA in ILBF-Dx should be discussed.

Procedures of brain death diagnosis and organ explantation in a tertiary medical centre - a retrospective eight-year cohort study

AIM OF THE STUDY

To assess the frequency and variables associated with the need for ancillary tests to confirm suspected brain death in adult patients, and to assess the time from brain death to organ explantation in donors. We further sought to identify modifiable factors influencing the time between brain death and start of surgery.

METHODS

Medical records and the Swiss organ allocation system registry were screened for all consecutive adult patients diagnosed with brain death at an intensive care unit of a Swiss tertiary medical centre from 2013 to 2020. The frequency and variables associated with the performance of ancillary tests (i.e., transcranial doppler, digital subtraction angiography, and computed tomography angiography) to confirm brain death were primary outcomes; the time from death to organ explantation as well as modifying factors were defined as secondary outcomes.

RESULTS

Among 91 patients with a diagnosis of brain death, 15 were not explanted and did not undergo further ancillary tests. Of the remaining 76 patients, who became organ donors after brain death, ancillary tests were performed in 24%, most frequently in patients with hypoxic-ischaemic encephalopathy. The leading presumed causes of death (not mutually exclusive) were haemorrhagic strokes (49%), hypoxic-ischaemic encephalopathies (33%) and severe traumatic brain injuries (22%). Surgery for organ explantation was started within a median of 16 hours (interquartile range [IQR] 13-18) after death with delay increasing over time (nonparametric test for trend p = 0.05), mainly due to organ allocation procedures. Patients with brain death confirmed during night shifts were explanted earlier (during night shifts 14.3 hours, IQR 11.8-16.8 vs 16.3 hours, IQR 13.5-18.5 during day shifts; p = 0.05).

CONCLUSIONS

Ancillary tests to confirm brain death are frequently performed, mainly in resuscitated patients. The delay to surgery for organ explantation after confirmed brain death was longer during day shifts, increased over time and was mainly determined by organ allocation procedures.

Brain death in children: is computed tomography angiography reliable as an ancillary test?

BACKGROUND

The diagnosis of brain death is primarily clinical. Sometimes ancillary tests are needed.

OBJECTIVE

This study compared sensitivity and interobserver agreement of the 10-, 7- and 4-point CT angiography scoring systems for the diagnosis of brain death in children.

MATERIALS AND METHODS

CT angiography examinations of 50 pediatric patients with a clinical diagnosis of brain death were evaluated according to 10-, 7- and 4-point scoring systems. Images were evaluated by two radiologists who considered the vessel opacification first in the arterial phase (A₀-V₅₀) and then in the venous phase (A₀-V₅₀). We evaluated interobserver agreement for the assessment of vessel opacification and diagnosis of brain death. We compared the differences among brain death diagnoses between children with craniotomy-craniectomy defects, open fontanelles and preserved bone integrity. We subdivided children into two groups according to age: ≤ 2 years and > 2 years. We calculated sensitivities according to age groups.

RESULTS

Using the clinical exam as the reference standard, we found sensitivities for 10-, 7- and 4-point scoring systems to be 70%, 88% and 92% in the A₀-V₅₀ method and 40%, 82% and 82% in the A₅₀-V₅₀ method, respectively. Percentage agreement between readers was 78% for the 7-point scale using the A₀-V₅₀ method and more than 90% for other scoring systems for both the A₀-V₅₀ method and the A₅₀-V₅₀ method. The sensitivity was much lower in children with open anterior fontanelles compared to the groups with preserved bone integrity and with a craniotomy-craniectomy defect.

CONCLUSION

Just as in adult age groups, in children the 4-point scale appears to be more sensitive than the 10- and 7-point scales for CT angiography-based assessment of brain death. Because the scoring systems have similar sensitivities, they could be used as ancillary tests in pediatric cases.

Exclusive color-coded duplex sonography of extracranial vessels reliably confirms brain death: A prospective study

Background

Transcranial color-coded duplex sonography (TCCD) can be used as an ancillary test for determining irreversible loss of brain function (ILBF) when demonstration of cerebral circulatory arrest (CCA) is required. However, visualization of the intracranial vessels by TCCD is often difficult, or even impossible, in this patient cohort due to elevated intracranial pressure, an insufficient transtemporal bone window, or warped anatomical conditions. Since extracranial color-coded duplex sonography (ECCD) can be performed without restriction in the aforementioned situations, we investigated the feasibility of omitting TCCD altogether, such that the ILBF examination would be simplified, without compromising on its reliability.

Methods

A total of 122 patients were prospectively examined by two experienced neurointensivists for the presence of ILBF from 01/2019-12/2021. Inclusion criteria were (i) the presence of a severe cerebral lesion on cranial CT or MRI, and (ii) brainstem areflexia. Upon standardized clinical examination, 9 patients were excluded due to incomplete brainstem areflexia, and a further 22 due to the presence of factors with a potentially confounding influence on apnea testing, EEG or sonography. A total of 91 patients were enrolled and underwent needle-EEG recording for >30 min (= gold standard), as well as ECCD and TCCD. The sonographer was blinded to the EEG result.

Results

All patients whose ECCD result was consistent with ILBF had this diagnosis confirmed by EEG (n = 77; specificity: 1). Both ECCD and EEG were not consistent with ILBF in a further 12 patients. In the remaining two patients, ECCD detected reperfusion due to long-lasting cerebral hypoxia; however, ILBF was ultimately confirmed by EEG (sensitivity: 0.975). This yielded a positive predictive value (PPV) of one and a negative predictive value of 0.857 for the validity of ECCD in ILBF confirmation. TCCD was not possible/inconclusive in 31 patients (34%).

Conclusions

The use of ECCD for the confirmation of ILBF is associated with high levels of specificity and a high positive predictive value when compared to needle-electrode EEG. This makes ECCD a potential alternative to the ancillary tests currently used in this setting, but confirmation in a multi-center trial is warranted.

Trial registration

https://www.drks.de, DRKS00017803.

Cerebral blood vessels and perfusion in the pediatric brain death: five cases studied by neuroimaging

PURPOSE

To detect the cerebral blood vessels and perfusion using neuroimaging modalities including computed tomography angiography (CTA), computed tomography perfusion (CTP), and arterial spin labeling (ASL) in children with brain death (BD).

METHODS

According to the current children's BD criteria, 5 children (3 males, 2 females, mean age of 5.65 years) with BD were enrolled from January 2019 to December 2020. The imaging features of CTA, CTP, and ASL were evaluated to analyze the visualization of important intracranial blood vessels and the states of the cerebral blood flow (CBF) and cerebral blood volume (CBV) related to the region of interest (ROI) brain tissue during the two clinical assessments for BD.

RESULTS

The "4-point scale" scoring system of CTA was applied to evaluate BD and no negative results were detected. The CTP results of the 5 children suggested the cessation of cerebral circulation with 100% positive results. The ranges of CBF and CBV were 0.00-9.52 ml/100 g/min (mean value 4.95 ± 1.69 ml/100 g/min) and 0.00-1.34 ml/100 g (mean value 0.36 ± 0.20 ml/100 g), respectively. One patient also underwent ASL examination, which demonstrated a significant reduction in whole brain perfusion, indicating the absence of cerebral circulation. The CBF values of the brainstem, basal ganglia, and prefrontal lobe were 11.61 ± 1.49 ml/100 g/min, 7.81 ± 2.42 ml/100 g/min, and 9.94 ± 2.01 ml/100 g/min, respectively.

CONCLUSION

Neuroimaging examinations particularly CTA and CTP reveal well the hemodynamic and cerebral blood vessels changes of BD, which can be used as supplementary supportive evidence for the declaration of brain death in children.

Pediatric brain death certification: a narrative review

In the five decades since its inception, brain death has become an accepted medical and legal concept throughout most of the world. There was initial reluctance to apply brain death criteria to children as they are believed more likely to regain neurologic function following injury. In spite of early trepidation, criteria for pediatric brain death certification were first proposed in 1987 by a multidisciplinary committee comprised of experts in the medical and legal communities. Protocols have since been developed to standardize brain death determination, but there remains substantial variability in practice throughout the world. In addition, brain death remains a topic of considerable ethical, philosophical, and legal controversy, and is often misrepresented in the media. In the present article, we discuss the history of brain death and the guidelines for its determination. We provide an overview of past and present challenges to its concept and diagnosis from biophilosophical, ethical and legal perspectives, and highlight differences between adult and pediatric brain death determination. We conclude by anticipating future directions for brain death as related to the emergence of new technologies. It is our position that providers should endorse the criteria for brain death diagnosis in children as proposed by the Society of Critical Care Medicine (SCCM), American Academy of Pediatrics (AAP), and Child Neurology Society (CNS), in order to prevent controversy and subjectivity surrounding what constitutes life versus death.

Advanced Bioelectrical Signal Processing Methods: Past, Present and Future Approach-Part II: Brain Signals

As it was mentioned in the previous part of this work (Part I)-the advanced signal processing methods are one of the quickest and the most dynamically developing scientific areas of biomedical engineering with their increasing usage in current clinical practice. In this paper, which is a Part II work-various innovative methods for the analysis of brain bioelectrical signals were presented and compared. It also describes both classical and advanced approaches for noise contamination removal such as among the others digital adaptive and non-adaptive filtering, signal decomposition methods based on blind source separation, and wavelet transform.

Implementation of Computed Tomography Angiography (CTA) and Computed Tomography Perfusion (CTP) in Polish Guidelines for Determination of Cerebral Circulatory Arrest (CCA) during Brain Death/Death by Neurological Criteria (BD/DNC) Diagnosis Procedure

Background: Brain death/death by neurologic criteria (BD/DNC) guidelines are routinely analyzed, compared and updated in the majority of countries and are later implemented as national criteria. At the same time, extensive works have been conducted in order to unify clinical procedures and to validate and implement new technologies into a panel of ancillary tests. Recently evaluated computed tomography angiography and computed tomography perfusion (CTA/CTP) seem to be superior to traditionally used digital subtraction angiography (DSA), transcranial Doppler (TCD) and cerebral perfusion scintigraphy for diagnosis of cerebral circulatory arrest (CCA). In this narrative review, we would like to demonstrate scientific evidence supporting the implementation of CTA/CTP in Polish guidelines for BD/DNC diagnosis. Research and implementation process: In the first of our base studies concerning the potential usefulness of CTA/CTP for the confirmation of CCA during BD/DNC diagnosis procedures, we showed a sensitivity of 96.3% of CTA in a group of 82 patients. CTA was validated against DSA in this report. In the second study, CTA showed a sensitivity of 86% and CTP showed a sensitivity of 100% in a group of 50 patients. In this study, CTA and CTP were validated against clinical diagnosis of BD/DNC supported by TCD. Additionally, we propose our CCA criteria for CTP test, which are based on ascertainment of cerebral blood flow (CBF) < 10 mL/100 g/min and cerebral blood volume < 1 mL/100 g in regions of interest (ROIs) localized in all brain regions. Based on our research results, CTA/CTP methods were implemented in Polish BD/DNC criteria. To our knowledge, CTP was implemented for the first time in national guidelines. Conclusions: CTA and CTP-derived CTA might be in future the tests of choice for CCA diagnosis, proper and/or Doppler pretest might significantly increase sensitivity of CTA in CCA diagnosis procedures. Whole brain CTP might be decisive in some cases of inconclusive CTA. Implementation of CTA/CTP in the Polish BD/DNC diagnosis guidelines does not show any major obstacles. We believe that in next edition of “The World Brain Death Project” CTA and CTP will be recommended as ancillary tests of choice for CCA confirmation during BD/DNC diagnosis procedures.

A Study on Knowledge Towards Brain Death among Residents in Indonesia

This research was conducted to evaluate the knowledge and diagnosis of brain death among resident in Indonesia. This study used an observational analytic study with a cross-sectional study design using a questionnaire. The research subjects consisted of 132 level 2 (after 2 years of residency) and level 3 (after 4 years of residency) residents, the total sampling for which was taken from the departments of Neurosurgery, Anesthesiology, and Neurology at Dr. Soetomo Academic Medical Center Hospital, Surabaya, Indonesia. Data were taken from November 2018 to January 2019. A total of 132 residents of Neurosurgery, Neurology, and Anesthesiology participated in this study. From the series of studies, residents’ knowledge of the concept of brain death was in the sufficient category (41.7%), residents’ knowledge of the technical diagnosis of brain death was in the good category (40.2%), residents’ knowledge of brain death examination was in the less category (43.2%), and finally, it was found that the resident's knowledge of brain death was in a good category (35.6%). There were also significant differences in knowledge of brain death between Neurosurgery, Neurology, and Anesthesiologist Resident (P <0.001) and knowledge of brain death between level 2 and level 3 residents (P=0.032). In general, the Indonesian resident doctors’ knowledge of brain death is adequate, but knowledge of the clinical examination of brain death is still lacking. Further research must be carried out to promote knowledge of brain death in residents as well as professional doctors/specialists, so that the number of organ transplants, especially in Indonesia, will increase.

Controversies in Brain Death Declaration: Legal and Ethical Implications in the ICU

Purpose of review

This article provides a brief overview of the history and complexities of brain death determination. We examine a few legal cases that highlight some of the controversies surrounding the validity of brain death tests in light of varying state laws and institutional policy, the appropriateness of making religious accommodations, the dilemma of continuing organ-sustaining support in a pregnant brain-dead patient, and the issue of whether to obtain informed consent from surrogate decision makers before proceeding to testing.

Recent findings

In response to physician concerns about navigating these complex cases, especially with laws that vary from state to state, the American Academy of Neurology has published a position statement in January of 2019 endorsing brain death as the irreversible loss of all functions of the entire brain. It provides positions on the determination of brain death as well as guidance surrounding requests for accommodation.

Summary

Although death by neurologic criteria has been accepted as death medically for over 40 years, legal variance exists throughout the states, especially regarding religious accommodations and in pregnancy. Questions of whether to obtain informed consent from surrogate decision makers prior to brain death testing remain, and there is no guideline regarding obtaining ancillary testing. We expect to see continued cases that cause medical, legal, and ethical controversies in our ICUs. As such, uniform training in proper methodology in performing the brain death examination and appropriate use of ancillary testing is crucial, and there is a need for legal consistency in the acceptance of the medical standard.

Impact of Skull Defects on the Role of CTA for Brain Death Confirmation

BACKGROUND AND PURPOSE

Intracranial pressure modifications caused by a skull defect, such as craniectomy or craniotomy, may change the hemodynamics and decrease the accuracy of CTA to confirm brain death. This study aimed to evaluate the impact of a skull defect and the interpretation criteria of images on this diagnostic test.

MATERIALS AND METHODS

A series of consecutive patients with a clinical diagnosis of brain death underwent CTA (case group), while the control group comprised patients with acute ischemic stroke in the same period. CTA criteria adopted to confirm brain death were the absence of opacification of the M4 branches and internal cerebral veins. The evaluation also included the presence of "stasis filling." Cases were stratified as intact skull, craniotomy, and craniectomy. Three neuroradiologists evaluated all examinations independently.

RESULTS

In the case group, according to the Frampas criteria, the sensitivity of CTA to confirm brain death was 95.5% in patients with intact skull, 87.5% with craniotomy, and 60% with craniectomy. False-negative diagnoses of brain death were 15.6%, related to stasis filling in 71.4% (P < .001). However, according to the "modified Frampas criteria," the sensitivity of CTA to confirm brain death was 100% in patients with intact skull, 93.8% with craniotomy, and 80% with craniectomy. False-negative diagnoses of brain death were found in 6.2% of patients, and there was no stasis filling. CTA showed 100% specificity in the control group. There were no disagreements among observers.

CONCLUSIONS

CTA had a high diagnostic accuracy and reproducibility to confirm brain death in patients with an intact skull. The modified Frampas criteria increased the sensitivity of CTA, particularly in patients with a skull defect. A concurrent skull defect, especially craniectomy, can decrease the sensitivity of CTA to confirm brain death.

How should we use imaging in the determination of brainstem death?

Brainstem death is defined as the "irreversible cessation of brainstem function", either due to primary intracranial events or extracranial factors such as hypoxia. The importance of accurate and timely diagnosis of brainstem death in critical care should not be understated, as it allows the withdrawal of treatment when it is no longer deemed to beneficial. Additionally, it may facilitate the process of organ donation. Overall, the diagnosis of brainstem death has four common principles across the world: (1) neurological criteria based on clinical assessment; (2) evidence of irreversible brain damage from known aetiology; (3) demonstrating an absence of a reversible cause; and (4) the use of ancillary studies. The latter in particular has been a controversial issue, with much debate continuing on how imaging should be used. We discuss three key questions surrounding the role of imaging in the diagnosis of brainstem death as well as important issues the radiology community should consider.

The Role of Neuroimaging in the Determination of Brain Death

BACKGROUND AND PURPOSE

Brain death determination (BDD) is primarily a clinical diagnosis, where death is defined as the permanent loss of brainstem function. In scenarios where clinical examinations are inaccurate, ancillary imaging tests are required. The choice of ancillary imaging test is variable, but the common denominator for all of them is to establish a lack of cerebral blood flow. The purpose of this study was to compare the diagnostic accuracy and interrater reliability of different ancillary imaging tests used for BDD.

METHODS

Archival data were retrospectively analyzed for all patients who underwent any ancillary imaging test for BDD at our institution. The results of ancillary imaging tests were compared with, the reference standard, the clinical checklist for declaration of brain death. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of different ancillary imaging tests for BDD were performed. Interobserver agreement between two observers was measured using kappa statistics for each of the imaging modalities.

RESULTS

A total of 74 patients underwent 41 computer tomography perfusion (CTP), 54 CT angiogram, 15 radionuclide scans, 1 cerebral angiogram, 3 magnetic resonance imaging, and 71 nonenhanced CT (NECT) head for BDD. All ancillary tests (except NECT head) showed 100% specificity and PPV. CTP had the highest sensitivity and NPV. All ancillary imaging tests demonstrated very high interrater reliability.

CONCLUSIONS

The uses of ancillary imaging tests for BDD are increasing. Within this study's limitations, CTP followed by radionuclide scan were found to be the most accurate and reliable ancillary imaging test for BDD.

Brain Computed Tomography Angiography as an Ancillary Test in the Confirmation of Brain Death

Introduction

Brain death (BD) is the irreversible termination of the functioning of the brain. The diagnosis should be first made by clinical criteria and confirmed by using paraclinical confirmatory techniques (ancillary tests). While conventional brain angiography remains the standard method of choice, computed tomography angiography (CTA) has emerged as an alternative method. In this study, we tried to evaluate the accuracy of CTA for the diagnosis of BD.

Methods

In this study, we included nine patients with a clinical diagnosis of BD, confirmed by electroencephalography (EEG). CTA was then performed to compare the results.

Results

The most frequent cause for BD was multiple trauma (7/9) in our patients, followed by aneurysm rupture and brain infarct. CTA examination in all patients showed opacification of extracranial arteries and major branches of external carotid artery (ECA), including superficial temporal arteries (STAs), while no opacification was observed in the internal carotid arteries (ICA) including and beyond the cavernous segment, middle cerebral arteries (MCAs), anterior cerebral arteries (ACAs), distal vertebral arteries (VAs), and basilar artery (BA). Moreover, no opacification was observed in the internal cerebral veins (ICVs) or great cerebral vein (GCV).

Conclusion

The accuracy rate of CTA in the detection of intracranial circulatory arrest was 100%. CTA examinations confirmed BD diagnoses in all patients who had clinical and EEG BD diagnoses, and no confliction between CTA findings and clinical diagnoses was observed.

An institutional study of awareness of brain-death declaration among resident doctors for cadaver organ donation

Background and Aims:

Brain death is defined as irreversible and complete cessation of all brain function including that of the brainstem. The aim of this study was to assess the level of knowledge and awareness about brain-death declaration among resident doctors.

Methods:

This was an observational questionnaire-based study conducted in single institute in which 112 junior residents and 46 senior resident doctors in various medical specialities were included by universal sampling method. A prevalidated questionnaire consisting of questions related to knowledge, attitude and performance of brain-death declaration were distributed among residents as per the inclusion criteria to fill in the time limit of 30 min. Statistical tools used were mean and standard deviation, proportion and Chi-square test.

Results:

A total 87 resident doctors consisting of 71.26% males and 28.73% females responded to the questionnaire. About 91.95% correctly defined it as complete cessation of brain activity including brainstem reflexes. Most of the resident doctors (80.45%) knew about the documentation of absence of brainstem reflexes at 6 h intervals and 64.36% were aware about positive apnoea test. When asked about whether there is legal sanction for disconnecting life support in India, 56.32% said no, and 43.67% said yes. Only 12.64% of resident doctors were aware about a panel of 4 physicians are mandatory to declare brain death in India.

Conclusion:

Awareness and attitude towards the identification of brain death and possible deceased donor organ transplantation were lacking amongst resident doctors.

[Determination of irreversibility of clinical brain death. Electroencephalography and evoked potentials]

Principally, in the fourth update of the rules for the procedure to finally determine the irreversible cessation of function of the cerebrum, the cerebellum and the brainstem, the importance of an electroencephalogram (EEG), somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) are confirmed. This paper presents the reliability and validity of the electrophysiological diagnosis, discusses the amendments in the fourth version of the guidelines and introduces the practical application, problems and sources of error.An EEG is the best established supplementary diagnostic method for determining the irreversibility of clinical brain death syndrome. It should be noted that residual brain activity can often persist for many hours after the onset of brain death syndrome, particularly in patients with primary brainstem lesions. The derivation and analysis of an EEG requires a high level of expertise to be able to safely distinguish artefacts from primary brain activity. The registration of EEGs to demonstrate the irreversibility of clinical brain death syndrome is extremely time consuming.The BAEPs can only be used to confirm the irreversibility of brain death syndrome in serial examinations or in the rare cases of a sustained wave I or sustained waves I and II. Very often, an investigation cannot be reliably performed because of existing sound conduction disturbances or failure of all potentials even before the onset of clinical brain death syndrome. This explains why BAEPs are only used in exceptional cases.The SEPs of the median nerve can be very reliably derived, are technically simple and with few sources of error. A serial investigation is not required and the time needed for examination is short. For these reasons SEPs are given preference over EEGs and BAEPs for establishing the irreversibility of clinical brain death syndrome.

[Angiographic procedures for determination of cessation of cerebral circulation]

In several European countries catheter angiography is permitted as a confirmatory procedure for the determination of irreversible loss of brain function (brain death). In Germany catheter angiography requires the possibility of a therapeutic implication as a prerequisite. In the updated German guidelines computed tomography angiography (CTA) has been accredited as a new confirmatory procedure if a standardized protocol and predefined assessment parameters are adhered to. The CTA can be performed within a few minutes, even in situations with unstable intensive care patients. Magnetic resonance (MR) angiography has not yet been adequately validated and is not permitted in Germany as a confirmatory procedure for the determination of irreversible loss of brain function.

Revised CT angiography venous score with consideration of infratentorial circulation value for diagnosing brain death

BACKGROUND

Computed tomography angiography (CTA) is largely performed in European countries as an ancillary test for diagnosing brain death. However, CTA suffers from a lack of sensitivity, especially in patients who have previously undergone decompressive craniectomy. The aim of this study was to assess the performance of a revised four-point venous CTA score, including non-opacification of the infratentorial venous circulation, for diagnosing brain death.

METHODS

A preliminary study of 43 control patients with normal CTAs confirmed that the infratentorial superior petrosal vein (SPV) was consistently visible. Therefore, 76 patients (including ten with decompressive craniectomy) who were investigated with 83 CTAs to confirm clinical brain death were consecutively enrolled between July 2011 and July 2013 at a university centre. The image analysis consisted of recording non-opacification of the cortical segment of the middle cerebral artery and internal cerebral vein (ICV), which were used as the reference CTA score, as well as non-opacification of the SPV. The diagnostic performance of the revised four-point venous CTA score based on the non-opacification of both the ICV and SPV was assessed and compared with that of the reference CTA score.

RESULTS

The revised four-point venous CTA score showed a sensitivity of 95 % for confirming clinical brain death versus a sensitivity of 88 % with the reference CTA score. Non-opacification of the SPV was observed in 95 % of the patients. In the decompressive craniectomy group, the revised four-point CTA score showed a sensitivity of 100 % compared with a sensitivity of 80 % using the reference CTA score.

CONCLUSION

Compared with the reference CTA score, the revised four-point venous CTA score based on ICV and SPV non-opacification showed superior diagnostic performance for confirming brain death, including for patients with decompressive craniectomy.

Brain death and care of the organ donor

Brain death has specific implications for organ donation with the potential for saving several lives. Awareness on maintenance of the brain dead has increased over the last decade with the progress in the field of transplant. The diagnosis of brain death is clinical and can be confirmed by apnea testing. Ancillary tests can be considered when the apnea test cannot be completed or is inconclusive. Reflexes of spinal origin may be present and should not be confused against the diagnosis of brain death. Adequate care for the donor targeting hemodynamic indices and lung protective ventilator strategies can improve graft quality for donation. Hormone supplementation using thyroxine, antidiuretic hormone, corticosteroid and insulin has shown to improve outcomes following transplant. India still ranks low compared to the rest of the world in deceased donation. The formation of organ sharing networks supported by state governments has shown a substantial increase in the numbers of deceased donors primarily by creating awareness and ensuring protocols in caring for the donor. This review describes the steps in the establishment of brain death and the management of the organ donor. Material for the review was collected through a Medline search, and the search terms included were brain death and organ donation.

Diagnostic Accuracy of Transcranial Doppler for Brain Death Confirmation: Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Transcranial Doppler is a useful ancillary test for brain death confirmation because it is safe, noninvasive, and done at the bedside. Transcranial Doppler confirms brain death by evaluating cerebral circulatory arrest. Case series studies have generally reported good correlations between transcranial Doppler confirmation of cerebral circulatory arrest and clinical confirmation of brain death. The purpose of this study is to evaluate the utility of transcranial Doppler as an ancillary test in brain death confirmation.

MATERIALS AND METHODS

We conducted a systematic review of the literature and a diagnostic test accuracy meta-analysis to compare the sensitivity and specificity of transcranial Doppler confirmation of cerebral circulatory arrest, by using clinical confirmation of brain death as the criterion standard.

RESULTS

We identified 22 eligible studies (1671 patients total), dating from 1987 to 2014. Pooled sensitivity and specificity estimates from 12 study protocols that reported data for the calculation of both values were 0.90 (95% CI, 0.87-0.92) and 0.98 (95% CI, 0.96-0.99), respectively. Between-study differences in the diagnostic performance of transcranial Doppler were found for both sensitivity (I(2) = 76%; P < .001) and specificity (I(2) = 74.3%; P < .001). The threshold effect was not significant (Spearman r = -0.173; P = .612). The area under the curve with the corresponding standard error (SE) was 0.964 ± 0.018, while index Q test ± SE was estimated at 0.910 ± 0.028.

CONCLUSIONS

The results of this meta-analysis suggest that transcranial Doppler is a highly accurate ancillary test for brain death confirmation. However, transcranial Doppler evaluates cerebral circulatory arrest rather than brain stem function, and this limitation needs to be taken into account when interpreting the results of this meta-analysis.

[Ancillary procedures in the diagnostics of brain death. Utilization, results and consequences in northeastern Germany]

BACKGROUND

According to the German Medical Council guidelines, the proof of irreversible brain death can be carried out using clinical investigations alone or can necessitate the use of ancillary tests (ATs), depending on the patient age and type of brain injury.

METHODS

Retrospective evaluation of the diagnostics of irreversible brain death, which were carried out using ATs according to the third edition of the guidelines between January 2001 and December 2010 in Berlin, Brandenburg and Mecklenburg-Western Pomerania and were registered at the German National Foundation for Organ Transplantation.

RESULTS

In 1401 patients (aged 0-94 years) a total of 1636 ATs were carried out. The most frequently used additional procedure for the first AT was an electroencephalogram (EEG) in 71.7 %. Confirmatory results regarding irreversibility were reported for 93.6 % of the initial ATs. Negative results of ATs were less common with primary supratentorial brain lesions (2.9 %) compared to infratentorial lesions (13.7 %), secondary hypoxic brain damage (8.1 %) and children younger than 2 years old (18.5 %). Regardless of the AT results, a return of clinical brain function was never documented. The timing, type and repetition of ATs were variable. In most cases the diagnostic process was clearly accelerated by the use of ATs but was significantly delayed in 10.1 % compared to a purely clinical proof of irreversible brain death.

CONCLUSION

ATs by themselves do not provide evidence of the cessation of all brain functions. Instead, they are used to prove the irreversibility of the clinically defined syndrome. For patients over 2 years old and in the absence of primary brainstem lesions, clinical re-assessment and ATs are considered to be equally accurate in demonstrating irreversibility. A standardization of diagnostic procedures between hospitals would be desirable.

Role of Transcranial Doppler Sonography in Diagnosis of Brain Death: A Single Center Study

BACKGROUND

Diagnosis of brain death relies on clinical and electroencephalographic (EEG) criteria. Waiting for 24 hours is mandatory to make definitive diagnosis of the condition in the Iranian protocol. Although it has been previously shown that oscillatory or spiked systolic or reversed diastolic flow patterns in transcranial Doppler sonography (TCD) are associated with faster brain death confirmation, it has not yet been approved in our protocol. Thus, the aim of this study was to assess the applicability of this method to our organ donation system.

MATERIALS AND METHODS

This study was performed in Masih Daneshvari Organ Procurement Unit from July to December 2009. TCD from the middle cerebral and basilar arteries was attempted in 35 patients who fulfilled the clinical and EEG criteria for brain death. Extensive skull defects and hypotension (blood pressure < 80 mmHg) were the exclusion criteria. Examinations were made for about 30 minutes via temporal and occipital windows as soon as possible after diagnosis of brain death.

RESULTS

The mean age of cases was 31.9±14.78 years and 18 (51.4%) were males. The most prevalent cause of brain death was trauma (in 19 or 54.2% of cases). We were unable to detect any intracranial artery in 2 (5.7%) cases. There were no false negative or false positive results in the remaining ones. Detected ultrasonic patterns of cerebral vascular flow were systolic spike and oscillating signal in 29 (87.9%) and 4 (12.1%) donors, respectively.

CONCLUSION

Our study showed that TCD results in brain dead cases were concordant with clinical and EEG criteria. Therefore, TCD, as a confirmatory test, can be applied for rapid diagnosis of brain death.

[Not Available]

CT-angiography (CTA) has been accredited as an additional technical method for the detection of the cessation of cerebral blood circulation in the updated German guidelines for the determination of irreversible loss of brain function. A standardized CTA protocol was defined. The evaluation of the CTA has to be done by radiologists with several years of experience in neuroradiology, preferably by radiologists certified as neuroradiologists. The so-called "stasis filling", a slow progressive spread of contrast media into the cerebral arteries despite cessation of cerebral blood circulation, has to be considered.

Renaissance of criticism on the concept of brain death--the role of legal medicine in the context of the interdisciplinary discussion

BACKGROUND

In the practice of legal medicine in Germany, the assessment of brain death is of minor importance and attracts little attention. However, since several years, international criticism on the concept of brain death has culminated. By reviewing literature and the results of a questionnaire distributed among the participants of the 93rd Annual Congress of the Germany Society of Legal Medicine, the state of knowledge and the current views on brain death were evaluated.

MATERIALS AND METHODS

Literature search of recent publications regarding brain death was performed (PubMed database, references of legal medicine, Report of the President's Council on Bioethics, USA 2008). A questionnaire was developed and distributed among the participants of the Congress.

RESULTS

The assumption that individual and brain death are synonymous is criticized. Internationally, there are trends to harmonize the very different clinical criteria to assess brain death. The diagnostic advantage of novel techniques such as CT angiography is controversially discussed. It becomes apparent that procedures which record the blood flow and perfusion of the brain will be applied more in the future. Regrettably, these developments are not described in the literature of legal medicine. Moreover, among German forensic scientists, different views concerning brain death exist. The majority favors its equivalent treatment with individual death. The thanatological background can be improved concerning certain aspects of brain death as well as its legal implications.

CONCLUSION

Teaching and research in legal medicine should include the subject brain death. Expertise in forensic science may contribute to the interdisciplinary discussion on brain death. The transfer of actual knowledge, also on disputed ethical aspects of thanatology, to physicians of all disciplines is of great importance.

Computed tomography angiography in the diagnosis of brain death: a systematic review and meta-analysis

BACKGROUND

Physiological instability and confounding factors may interfere with the clinical diagnosis of brain death. Computed tomography angiography (CTA) has been suggested as a potential ancillary test for confirmation of brain death, but its diagnostic accuracy remains unclear.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL for studies comparing CTA with other accepted methods of diagnosing brain death (clinical or radiographic). Summary estimates of diagnostic accuracy were computed using random effects models. Subgroup analyses and meta-regression were performed to assess associations between CTA sensitivity and study or patient characteristics.

RESULTS

Twelve studies, involving 541 patients, were included. If the CTA criterion for brain death was complete lack of opacification of intracranial vessels, then the pooled sensitivity was 62 % (50-74 %) for venous phase and 84 % (75-94 %) for arterial phase imaging. The sensitivity of CTA was higher when the criterion for brain death involved absence of opacification of internal cerebral veins, either alone (99 %, 97-100 %) or in combination with lack of flow to the distal middle cerebral artery branches (85 %, 77-93 %). CTA sensitivity was not influenced by different reference standards (clinical vs. radiographic) or predominant diagnostic category (stroke vs. brain trauma). Specificity of CTA could not be adequately determined from the existing data.

CONCLUSION

Many patients who progress to brain death by accepted clinical or radiographic criteria have persistent opacification of proximal intracranial vessels when CTA is performed. The specificity of CTA in the diagnosis of brain death has not been adequately assessed. Routine use of CTA as an ancillary test in the diagnosis of brain death is therefore not recommended until diagnostic criteria have undergone further refinement and prospective validation. Absence of opacification of the internal cerebral veins appears to be the most promising angiographic criterion.

Cerebral and brainstem electrophysiologic activity during euthanasia with pentobarbital sodium in horses

Background

An overdose of pentobarbital sodium administered IV is the most commonly used method of euthanasia in veterinary medicine. Determining death after the infusion relies on the observation of physical variables. However, it is unknown when cortical electrical activity and brainstem function are lost in a sequence of events before death.

Hypothesis/Objectives

To examine changes in the electrical activity of the cerebral cortex and brainstem during an overdose of pentobarbital sodium solution for euthanasia. Our testing hypothesis is that isoelectric pattern of the brain in support of brain death occurs before absence of electrocardiogram (ECG) activity.

Animals

Fifteen horses requiring euthanasia.

Methods

Prospective observational study. Horses with neurologic, orthopedic, and cardiac illnesses were selected and instrumented for recording of electroencephalogram, electrooculogram, brainstem auditory evoked response (BAER), and ECG. Physical and neurologic (brainstem reflexes) variables were monitored.

Results

Loss of cortical electrical activity occurred during or within 52 seconds after the infusion of euthanasia solution. Cessation of brainstem function as evidenced by a lack of brainstem reflexes and disappearance of the BAER happened subsequently. Despite undetectable heart sounds, palpable arterial pulse, and mean arterial pressure, recordable ECG was the last variable to be lost after the infusion (5.5–16 minutes after end of the infusion).

Conclusions and Clinical Importance

Overdose of pentobarbital sodium solution administered IV is an effective, fast, and humane method of euthanasia. Brain death occurs within 73–261 seconds of the infusion. Although absence of ECG activity takes longer to occur, brain death has already occurred.

Gadolinium-enhanced magnetic resonance angiography in brain death

Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

Brain death scintigraphy and pathology results in a rat model

OBJECTIVES

Brain scintigraphy with Tc-99m-labeled diethylenetriaminopenta-acetic acid is a sensitive diagnostic method showing loss of cerebral blood flow that occurs after brain death. Cerebral blood flow can be quantitatively estimated by this method. The aim of this study was to compare histopathologic changes occurring with the decrease of cerebral blood flow (as shown by Tc-99m-labeled diethylenetriaminopenta-acetic acid brain death scintigraphy) after brain death in an experimental model.

MATERIALS AND METHODS

The study included examination of cerebral blood flow by Tc-99m-labeled diethylenetriaminopenta-acetic acid brain scintigraphy in the 20 rats, 1 day before brain death, after producing brain death in 11 surviving rats. Tc-99m-labeled diethylenetriaminopenta-acetic acid brain scintigraphy was performed under intubation and monitored. The Mann-Whitney U test was performed to compare groups (scintigraphic quantification results before and after brain death).

RESULTS

In the time activity curves generated from the analysis of the scintigraphies, decreases in counts in the brain death group were obtained in the arterial phase (P < .01). Decreases of the cerebral blood flow between the first and the sixth minutes were statistically significant (P < .05). Common principal histopathologic changes of the brain death (ie, autolysis and color loss in the nerve cells, diffuse edema, petechial hemorrhage in the brain tissues) were observed in all subjects.

CONCLUSIONS

Quantitative findings of the brain scintigraphy by Tc-99m-labeled diethylenetriaminopenta-acetic acid was related with the histopathologic findings seen during the early brain death, with significant decreases of the cerebral blood flow. Quantification of Tc-99m-labeled diethylenetriaminopenta-acetic acid brain death scintigraphy as an easier and less-expensive scintigraphic method of cerebral blood flow might indicate a definite diagnosis of brain death and thus, potential donors can be determined earlier, leaving to increased transplant rates.