Clinical Criteria For Brain Death Research Articles

Diagnostic Value of Computed Tomography Angiography in Confirmation of Brain Death

Accurate and on-time confirmation of brain death (BD) is necessary to prevent unnecessary treatments and allow for well-timed organ harvesting for transplantation. While clinical criteria for BD are legally reliable in some countries, others may prefer complementary ancillary tests to assess the brain's electrical activity and/or blood circulation. This study aims to define the sensitivity and specificity of CT-Angiography based on four-, seven-, and ten-score tests compared to the clinical criteria and electroencephalography in patients with BD. A total of 32 patients with a confirmed diagnosis of BD according to their clinical criteria (cases) along with 18 patients with GCS=3 and absent brain stem and papillary reflexes who had spontaneous respiration (controls), all with blood pressure > 90 mmHg, diuresis > 100 ml/h, and CVP > 6-8 mmHg, underwent CT-angiography. The 4-, 6-, and 10-score criteria were used according to the opacity/lack of opacity of the brain vessels in CTA evaluation scales for the diagnosis of BD. The two groups were homogeneous in terms of age, gender distribution, and the etiology of coma. All patients in the control group received zero in 4-, 7-, and 10-scores; while, the average values for 4-score, 7-score, and 10-score in patients with confirmed BD were 3.75±0.67, 6.4±1.36, and 9.06±2.2, respectively. Of patients with BD, 28 (87.5%), 26 (81.25%), and 25 (78.12%) received full 4-, full 7-, and full 10-scores. The sensitivity and specificity as well as negative and positive predictive values for all three scores were found to be 100%. Also, the sensitivities for various cerebral vessels were as: ICV: 100%, GCV: 96.9%, P2: 90.6%, M4: 87.5%, BA: 84.4%, and A3: 84.4%. Also, the specificity of lack of opacification in all these vessels for the diagnosis of BD was 100%. According to our findings, the CTA-based four-point scoring system with 100% specificity can be used along with clinical examinations to confirm BD.

Relationships Between Resting Energy Expenditure and Transcranial Doppler Measurements in Patients With and Without Brain Death.

Introduction Brain metabolism deteriorates during brain death, suggesting that cerebral metabolic measurements could serve as a prognostic factor. The application of transcranial Doppler can be useful in evaluating patients evolving to brain death. Resting energy expenditure is lower than expected in patients with brain death, and this is caused by the decrease in cerebral blood flow and consequently lower oxygen supply. The primary aim of this retrospective study is to investigate the early metabolic changes in patients with clinical criteria of brain death and examine if these changes are related to a gradual decrease in blood flow velocities in the middle cerebral artery. Methods All consecutive patients from 1st June 2018 to 30th April 2022, admitted to the ICU with brain injury and a GCS ≤8, were included retrospectively in the study. Patients were allocated into two groups: Group A, patients without clinical signs of brain death (n = 32), and Group B, patients with brain death (n = 34). In each group, three sets of metabolic measurements were performed concomitantly with cerebral blood flow velocities using transcranial Doppler (a) upon admission to the ICU, (b) once hemodynamic stabilization was obtained, and (c) 48 hours after their hemodynamic stabilization or when brain death was confirmed by clinical criteria. Resting energy expenditure (REE) measurements were performed using a metabolic computer. Cerebral blood flow velocities were measured after a period of 30 min using a 2-MHZ 2D ultrasound probe. Results Brain-dead patients had a significant decrease in their metabolic parameters as the cerebral blood flow velocities recorded with the transcranial Doppler deteriorated, (REE Group A = 1667.65 ± 597 vs Group B = 1376.12 ± 615, p = 0.05 and REE predictedGroup A = 113.19 ± 44.9 vs Group B = 93.29 ± 41.5, p = 0.066 for measurement 1;REE Group A = 1844 ± 530.9 vs Group B = 1219.97 ± 489, p < 0.001 and REE predictedGroup A = 124.38 ± 39 vs Group B = 81.35 ± 30.4, p < 0.001 for measurement 2; REE Group A = 1750.97 ± 414, p < 0.001 and REE predicted Group A = 116.38 ± 19.2 vs Group B = 56.09 ± 19.6, p < 0.001 for measurement 3).Multiple stepwise regression analysis revealed a strong relationship between age, the worsening of the blood flow velocities pattern, and the decrease in REE (multiple R = 0.264, F = 5.55, p = 0.009).Furthermore, a statistically significant correlation was found between temperature and REE (correlation coefficient = 0.500, 0.674, 0.784 for measurements 1, 2, and 3, respectively, and p < 0.001 for all measures). Conclusions In brain-dead patients, the gradual decrease in cerebral blood flow leads to a decrease in REE as well as thermogenetic control. These changes can be detected early after the patient's admission to the ICU.

Effectiveness of Interventional Strategies in Modulating Knowledge and Attitude of Health Care Professionals for Promoting Organ Donation: A Study in Tertiary Care Public Hospital of North India.

Objective:To evaluate the impact of interventional “educational module” on knowledge and attitude regarding organ donation amongst resident doctors and nurses in the Institute of National Importance.Study Design:Interventional and prospective.Methods:We devised an interactive educational module covering various aspects of organ donation through a series of audiovisual lectures and information booklets. Resident doctors and nurses posted in those areas of the 1948-bedded Postgraduate Institute of Medical Education and Research (PGIMER), where head injury patients were treated and were subject to intervention using this module. The pre and postinterventional scores of their knowledge and attitude regarding organ donation were compared to find out impact of the intervention.Results:A total of 242 nurses and 87 resident doctors participated in this research. Higher knowledge score was observed preintervention amongst doctors as compared to nurses. Significant improvement was seen in total knowledge scores of both groups postintervention. Doctors had better scores for the “concept of organ donation,” while nurses were more familiar with “procedures and protocols.” Both had low knowledge about “clinical criteria for brain death” and “legal issues” preintervention which improved significantly postintervention. The positive impact of intervention was also observed on attitude in both categories. A significant impact of intervention was observed on overall propensity of doctors and nurses to promote organ donation, for pledging their own organs and for counseling of the patient/attendants on this cause.Conclusion:Scientifically designed educational modules have a promising role in improving awareness and attitude of health care professionals regarding organ donation and their propensity to be prospective donors, effective counselors, and advocates of organ donation.

Editors' note: Variability in reported physician practices for brain death determination

In “Variability in reported physician practices for brain death determination,” Braksick et al. reported that a survey of physicians at 3 academic medical centers demonstrated variability in performance of brain death evaluations. For example, many respondents reported that they perform ancillary tests for indications outside those described in the 2010 AAN Practice Parameter, including institutional mandates, protection from liability, and following the observation that a patient breathes during apnea testing. In their comments, Sethi and Machado reinforce their finding that ancillary tests are often ordered for indications outside the AAN Practice Parameter recommendations and note that it is imperative to remember that (1) brain death is a clinical determination and (2) ancillary tests can have both false positives and false negatives. Machado also suggests that the AAN criteria be revised to require an ancillary test to reduce variability in brain death policies. Braksick et al. disagree with this proposal, noting that the value of ancillary tests is “extremely questionable.” Furthermore, with respect to Machado's argument that implementing universal mandatory ancillary testing would reduce variability in brain death policies, in light of the fact that he also noted that only 6.5% of policies mandate ancillary testing, it would clearly be more reasonable for these policies to change to conform to the current AAN Practice Parameter than for the other 93.5% of protocols to start mandating ancillary testing. To reinforce awareness about the indications for ancillary testing, Braksick et al. advocate for formal education about brain death determination for all clinicians performing brain death evaluations. They, unfortunately, found that 76% of respondents did not receive formal training on performance of this evaluation. Accordingly, to decrease variability in brain death determination, the Neurocritical Care Society has recently released a training module on brain death.[1][1] Machado further comments that he recently proposed a new disorder of consciousness, based on the case of Jahi McMath, which exists when a patient meets clinical criteria for brain death but has ancillary tests that conflict with the clinical findings. Further discussion of this interesting case and the questions it generated can be found elsewhere.[2][2] In “Variability in reported physician practices for brain death determination,” Braksick et al. reported that a survey of physicians at 3 academic medical centers demonstrated variability in performance of brain death evaluations. For example, many respondents reported that they perform ancillary tests for indications outside those described in the 2010 AAN Practice Parameter, including institutional mandates, protection from liability, and following the observation that a patient breathes during apnea testing. In their comments, Sethi and Machado reinforce their finding that ancillary tests are often ordered for indications outside the AAN Practice Parameter recommendations and note that it is imperative to remember that (1) brain death is a clinical determination and (2) ancillary tests can have both false positives and false negatives. Machado also suggests that the AAN criteria be revised to require an ancillary test to reduce variability in brain death policies. Braksick et al. disagree with this proposal, noting that the value of ancillary tests is “extremely questionable.” Furthermore, with respect to Machado's argument that implementing universal mandatory ancillary testing would reduce variability in brain death policies, in light of the fact that he also noted that only 6.5% of policies mandate ancillary testing, it would clearly be more reasonable for these policies to change to conform to the current AAN Practice Parameter than for the other 93.5% of protocols to start mandating ancillary testing. To reinforce awareness about the indications for ancillary testing, Braksick et al. advocate for formal education about brain death determination for all clinicians performing brain death evaluations. They, unfortunately, found that 76% of respondents did not receive formal training on performance of this evaluation. Accordingly, to decrease variability in brain death determination, the Neurocritical Care Society has recently released a training module on brain death.1 Machado further comments that he recently proposed a new disorder of consciousness, based on the case of Jahi McMath, which exists when a patient meets clinical criteria for brain death but has ancillary tests that conflict with the clinical findings. Further discussion of this interesting case and the questions it generated can be found elsewhere.2 [1]: #ref-1 [2]: #ref-2

Whole-brain death and integration: realigning the ontological concept with clinical diagnostic tests.

For decades, physicians, philosophers, theologians, lawyers, and the public considered brain death a settled issue. However, a series of recent cases in which individuals were declared brain dead yet physiologically maintained for prolonged periods of time has challenged the status quo. This signals a need for deeper reflection and reexamination of the underlying philosophical, scientific, and clinical issues at stake in defining death. In this paper, I consider four levels of philosophical inquiry regarding death: the ontological basis, actual states of affairs, epistemological standards, and clinical criteria for brain death. I outline several candidates for the states of affairs that may constitute death, arguing that we should strive for a single, unified ontological definition of death as a loss of integrated functioning as a unified organism, while acknowledging that two states of affairs (cardiopulmonary death and whole-brain death) may satisfy this concept. I argue that the clinical criteria for determining whole-brain death should be bolstered to meet the epistemic demand of sufficient certainty in defining death by adding indicators of cerebro-somatic dis-integration to the traditional triad of loss of consciousness, loss of brainstem function, and absence of confounding explanations.

Ancillary testing in brain death.

Despite worldwide acceptance of the concept of brain death, there is marked variability in the use of ancillary testing. In most countries, ancillary tests are used primarily when confounding factors interfere with reliable completion of a clinical assessment, or physiologic instability precludes performance of an apnea test. Alternatively, in some countries, confirmatory ancillary tests are routinely required before brain death can be diagnosed. Ancillary tests assess brain function (e.g., electroencephalography) or blood flow (e.g., cerebral angiography). Evaluation of blood flow is affected less by confounding clinical factors and is now preferred in most jurisdictions. With angiographic techniques, a significant proportion of patients meeting clinical criteria for brain death have some opacification of proximal intracranial arteries. Consequently, the sensitivity of angiography is strongly influenced by the particular criteria that are used to define intracranial circulatory arrest. Lack of enhancement of the great cerebral and internal cerebral veins has the highest sensitivity. Worldwide experience with newer tests, such as computed tomography and magnetic resonance angiography, is growing. Radionuclide imaging has the advantage of not requiring use of potentially nephrotoxic contrast material. Transcranial Doppler ultrasonography can be brought to the bedside to demonstrate lack of brain blood flow. The specificity of imaging techniques in the detection of intracranial circulatory arrest has not been as well studied as their sensitivity.

Media and popular culture and controversies in comatose patients

Comatose patients may have irrevocably lost all brain function. This condition has been distinguished from other comatose states by the term brain death. Its assessment has been known as the determination of death by neurologic criteria. The clinical diagnosis of brain death implies that the person has died. When the clinical criteria of brain death are met, it allows organ donation or withdrawal of futile support. Without being unnecessarily hostile to the press, one can argue that the representation of comatose states in the media is concerning. Families confronted with this often unexpected loss of life understand this strictly defined neurological condi¬tion well. Unfortunately, the legal cases are surrounded by misinformation and reluctance to understand the implications of these comatose states. Nevertheless, many legal cases are settled in court without much attention. Exposure to the media may solicit physician opinions, and these cases may easily become a spectacle. Bioethical issues do surface under these circumstances.

Diagnosis of brain death: confirmatory tests after clinical test

Background The brain death confirmation tests occupy a different position in each country's diagnostic criteria (or guideline); the choices of tests are also different. China brain death criteria include clinical judgment and confirmation tests. This study aimed to confirm the preferred confirmatory test and complementary confirmatory tests. Methods We did a clinical brain death determination on deep coma patients, and then divided them into brain death group and non-brain death group. According to the Chinese standards for determining brain death, both the groups accepted confirmatory tests including electroencephalograph (EEG), somatosensory evoked potentials (SEP), and transcranial Doppler (TCD). The sensitivity, specificity, false positive rate, and false negative rate were calculated to evaluate the accuracy of the confirmatory tests. Results Among the 131 cases of patients, 103 patients met the clinical criteria of brain death. Respiratory arrest provocation test was performed on 44 cases and 32 cases (73%) successfully completed and confirmed that they have no spontaneous breathing. Of the three confirmation tests, EEG had the highest completion rate (98%) and good sensitivity (83%) and specificity (97%); TCD had followed completion rate (54%) and not good sensitivity (73%) and specificity (75%); SEP had the lowest completion rate (49%), good sensitivity (100%), and not good specificity (78%). After the combination of SEP or TCD with EEG, the specificity can increase to 100%. Conclusions The completion rate of respiratory arrest provocation test remains a problem in the clinical diagnosis of brain death. If the test cannot be completed, whether to increase a confirmatory test is debatable. SEP had an ideal sensitivity, and the specificity will reach 100% after combining with TCD or EEG. When a confirmed test was uncertain, we suggest increasing another confirmatory test.

Non confirmatory electroencephalography in patients meeting clinical criteria for brain death: Scenario and impact on organ donation

ObjectiveTo describe the causes and outcome of adult patients with preserved electroencephalographic activity despite clinical findings suggesting brain death (BD), and its impact on organ donation. MethodsRetrospective study of the clinical and electroencephalography (EEG) data of all adult patients admitted to our hospital between January 2001 and December 2011 in whom a comprehensive clinical diagnosis of BD was reached following absence of brainstem reflexes and confirmatory apnea tests, were obtained. All patients with clinical findings suggesting BD and an EEG showing brain activity were selected for the analysis. We calculated the brain death interval (BDI) as the time between the first complete clinical examination and confirmatory ancillary test, or the time between the first and second complete clinical examination for BD, in order to analyze the impact on family consent for organ donation. ResultsA complete clinical examination and EEG were diagnostic in 289 patients. In 279 (96.5%), the first EEG showed electrocerebral inactivity corroborating the clinical findings of BD. The mean BDI in this group was 4.2±5.8h (median; 1.8[1.0–3.5]). This value was significantly lower than in the group in which only two full clinical evaluations were performed (p<0.0001). In 10 out 289 (3.5%), the first EEG showed at least some brain activity. The mean BDI in this group was 27.2±13.8h (median; 22.9 [19.1−31.2]). In two cases, a third EEG was necessary before obtaining electrocerebral inactivity. A BDI>6h, was positively associated with a family refusal for organ donation (p=0.02). ConclusionsThe rate of EEGs with electrocerebral activity despite clinical findings suggesting BD was only 3.5%. It occurred most frequently with severe brainstem damage. Although in this small percentage of patients, BD diagnosis was notably delayed, in the great majority of cases the use of EEG shortened the BDI. In our series, a BD diagnosis delay >6h negatively affected consent for organ donation. SignificanceThe use of EEG can decrease the time interval for brain death diagnosis.

Pitfalls in Brain Death Diagnosis: A Case Report

Although there are distinct guidelines in nearly all countries, a reliable secure assessment of brain death in cases with open head injury can be challenging. We present a case of a 32-year-old man with severe head injury after intracranial penetration of a grindstone fragment. As the injury led to destruction of nearly the whole greater wing of the right sphenoid bone and parts of the right orbit, the examination of brainstem reflexes and the confirmation of brain death was unfeasible. On day 2, all clinical criteria of brain death (coma, absence of brainstem reflexes, apnea) were fulfilled. In addition, there was an extinction of brainstem auditory (BAEP) and cerebral (N20) components of median nerve somatosensory evoked potentials, while electroencephalogram (EEG) activity was still present. In the following days, a persisting EEG activity was obtained. Thus, an irreversible loss of whole brain functions could not be proved. As the patient had agreed to organ donation in case of brain death several years ago, ancillary methods to test the cessation of cerebral blood flow were mandatory. However, in this patient these methods turned out either to be doubtful or unavailable. For example, values of transcranial Doppler ultrasonography are not reliable in cases with open head injury. Due to a progressive septic state, time was running out to get the radiopharmaceutical agent for a cerebral scintigraphy (delivery time about 7 days, as the radiopharmaceutical agent was not in stock). Referring to the actual German guidelines, we had no legitimating indication for a cerebral angiography. Finally, the patient died of sepsis. We discuss the widening of the German guidelines in assessing brain death with the fast and low-risk method of cerebral computed tomography-angiography (CTA) to confirm diagnosis of brain death.

Brain Death or Brain Dying?

For the past 50 years, the medical profession has understood ‘‘brain death’’ to represent the endpoint of a neuropathologic vicious cycle. An initial major brain injury sets off a mutually exacerbating cascade of cerebral edema, increased intracranial pressure, and decreased cerebral blood flow, which advances beyond some point-of-no-return to a state of no cerebral blood flow and total brain infarction (death of the brain, or ‘‘brain death’’). This pathophysiology was considered so well established that the Swedish Committee on Defining Death chose that very term—‘‘total brain infarction’’—as its official name for the condition, avoiding the semantic ambiguities inherent in the term ‘‘brain death.’’ Regardless of the name, this endpoint has been traditionally understood to correspond to brain-based statutory definitions of death everywhere in the world. In the United States, virtually all states have adopted some variation on the Uniform Determination of Death Act proposed by the President’s Commission in 1981, namely: ‘‘irreversible cessation of all functions of the entire brain, including the brain stem.’’ In clinical practice, both the irreversibility and totality of nonfunction are considered established by inference from sure knowledge that the neuropathologic vicious cycle has already reached its endpoint of no intracranial blood flow and total brain infarction. The past several decades have witnessed a search for practical clinical criteria to guarantee this inference in individual cases. Most developed countries have standardized protocols, which continue to evolve, although important controversies remain. But reality is rarely as straightforward as theory. In this issue of the Journal of Child Neurology, Suzuki and colleagues present evidence that ‘‘total brain necrosis might not be present in children at the time of clinical diagnosis of brain death.’’ Their hospital routinely follows serial serum levels of neuron-specific enolase, a standard marker of neuronal cell death, in children admitted with acute brain injuries. In a retrospective review spanning 14 years, the authors found 3 children who met clinical criteria for brain death following cardiopulmonary arrest and survived more than 2 months. For comparison, they selected 3 cases with cardiopulmonary arrest and poor outcomes short of brain death. If the vicious cycle ending in total brain infarction universally plays itself out over the course of hours or a few days at most, and if the clinical diagnostic criteria reliably determine that the endpoint has already been reached, then one would expect serum neuron-specific enolase levels to reflect an initial massive outpouring of neuron-specific enolase, followed by rapid exponential decay due to cessation of both intracranial blood flow and cerebrospinal fluid production and flow. The investigators report three findings: two interesting but not surprising, and one very surprising. (1) The children with brain death had higher peak neuron-specific enolase levels than the controls. (2) The time to peak neuron-specific enolase level was not significantly different between the groups (4-10 days vs 5-8 days). (3) Remarkably, all 3 children with brain death had persistent elevation of neuron-specific enolase at 4 weeks (>400 ng/mL) and 8 weeks (>50 ng/mL), in contrast to the two control survivors in the vegetative state, whose neuron-specific enolase decreased to <50 ng/mL within 4 weeks. The authors acknowledge the study’s obvious limitations resulting from its retrospective methodology and the small number of patients that was insufficient for statistical power. They also point out that in the context of brain death, the time course of serum neuron-specific enolase might not exactly reflect that of neuronal cell death. An additional caveat not mentioned in the article is that the patients with chronic brain death they followed may not be (and probably are not) representative of all patients with brain death, particularly those that systemically deteriorate to asystole within a few days despite all therapeutic measures. The study needs to be replicated and extended, although that is much easier said than done. Clearly, this is a wide-open new area for clinical research, for which Japan is uniquely suited, as it is probably the only country where extended intensive care unit support of patients with brain death still occurs, out of respect for traditional societal values. The neuron-specific enolase findings reinforce and contribute a novel temporal dimension to the growing neuropathologic evidence that at the time of fulfillment of clinical brain death criteria, the brain infarction may be far from ‘‘total.’’

Imaging Findings of Brain Death on 3-Tesla MRI

ObjectiveTo demonstrate the usefulness of 3-tesla (3T) magnetic resonance imaging (MRI) including T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), time-of-flight (TOF) magnetic resonance angiography (MRA), T2*-weighted gradient recalled echo (GRE), and susceptibility weighted imaging (SWI) in diagnosing brain death.Materials and MethodsMagnetic resonance imaging findings for 10 patients with clinically verified brain death (group I) and seven patients with comatose or stuporous mentality who did not meet the clinical criteria of brain death (group II) were retrospectively reviewed.ResultsTonsilar herniation and loss of intraarterial flow signal voids (LIFSV) on T2WI were highly sensitive and specific findings for the diagnosis of brain death (p < 0.001 and < 0.001, respectively). DWI, TOF-MRA, and GRE findings were statistically different between the two groups (p = 0.015, 0.029, and 0.003, respectively). However, cortical high signal intensities in T2WI and SWI findings were not statistically different between the two group (p = 0.412 and 1.0, respectively).ConclusionT2-weighted imaging, DWI, and MRA using 3T MRI may be useful for diagnosing brain death. However, SWI findings are not specific due to high false positive findings.

Prolonged Elevation of Serum Neuron-Specific Enolase in Children After Clinical Diagnosis of Brain Death

To elucidate the time course of neuronal cell death after the clinical criteria for brain death are met, the authors reviewed serial changes of serum neuron-specific enolase levels in 3 children (age range, 3-15 years) clinically diagnosed as brain dead due to cardiopulmonary arrest. All patients survived for more than 2 months after brain death. Children with brain death had higher peak neuron-specific enolase values (1069-2849 ng/mL) than did 3 control children (256-1800 ng/mL) who did not become brain dead but had poor neurological outcome (1 death, 2 vegetative state) after cardiopulmonary arrest. A major finding is that children with brain death showed persistent elevation of neuron-specific enolase at 4 weeks (>400 ng/mL) and 8 weeks (>50 ng/mL) after cardiopulmonary arrest, in comparison with 2 surviving patients without brain death (<50 ng/mL at 4 weeks). This prolonged elevation of neuron-specific enolase suggests that total brain necrosis might not be present at the time of clinical diagnosis of brain death.

Diffusion-weighted imaging findings in brain death

The purpose of the present study was to determine the role of diffusion-weighted imaging (DWI) and to investigate the use of DWI in the diagnosis of brain death (BD). We prospectively evaluated 22 patients diagnosed with clinical BD (9 women, 13 men; mean age, 39.63 ± 15.1years; age range, 9-66years). All clinical criteria for BD were present in all 22 patients before magnetic resonance imaging, including a positive apnea test. For all cases, DW images, T2-weighted images, and fluid-attenuated inversion recovery were obtained. Thirteen distinct neuroanatomical structures were selected for analysis in all the cases. For each region of interest, the mean, standard deviation, and range of the average apparent diffusion coefficient (ADCav) values were obtained. For BD patients, ADC values in all neuroanatomical structures were significantly lower than those for control subjects. We determined how ADC values in all structures were related to the diagnostic condition as well as the appropriate threshold ADC values to classify a subject as BD or control. The sensitivity, specificity, positive and negative predictive values, and correct classification rate of ADC cutoff values to distinguish BD from control groups were 100%. DWI might be used as a noninvasive confirmatory test for the diagnosis of BD in the future.

The case against confirmatory tests for determining brain death in adults

The determination of brain death is based on a comprehensive clinical assessment. A confirmatory test-at least, in adult patients in the United States-is not mandatory, but it typically is used as a safeguard or added when findings on clinical examination are unwontedly incomplete. In other countries, confirmatory tests are mandatory; in many, they are optional. These tests can be divided into those that test the brain's electrical function and those that test cerebral blood flow. A false-positive result (i.e., the test result suggests brain death, but clinically the patient does not meet the criteria) is not common but has been described for tests frequently used to determine brain death. A false-negative result (i.e., the test result suggests intact brain function, but clinically the patient meets the criteria) in one test may result in more confirmatory tests and no resolution when the test results diverge. Also, pathologic studies have shown that considerable areas of viable brain tissue may remain in patients who meet the clinical criteria of brain death, a fact that makes these tests less diagnostic. Confirmatory tests are residua from earlier days of refining comatose states. A comprehensive clinical examination, when performed by skilled examiners, should have perfect diagnostic accuracy.

Evidence-based guideline update: Determining brain death in adults: Report of the Quality Standards Subcommittee of the American Academy of Neurology

Objective: To provide an update of the 1995 American Academy of Neurology guideline with regard to the following questions: Are there patients who fulfill the clinical criteria of brain death who recover neurologic function? What is an adequate observation period to ensure that cessation of neurologic function is permanent? Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? What is the comparative safety of techniques for determining apnea? Are there new ancillary tests that accurately identify patients with brain death? Methods: A systematic literature search was conducted and included a review of MEDLINE and EMBASE from January 1996 to May 2009. Studies were limited to adults (aged 18 years and older). Results and recommendations: In adults, there are no published reports of recovery of neurologic function after a diagnosis of brain death using the criteria reviewed in the 1995 American Academy of Neurology practice parameter. Complex-spontaneous motor movements and falsepositive triggering of the ventilator may occur in patients who are brain dead. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly. Apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing. There is insufficient evidence to determine if newer ancillary tests accurately confirm the cessation of function of the entire brain. Neurology ® 2010;74:1911–1918

Usefulness of Addition of CT Perfusion to CT Angiography for Brain Death Diagnosis in a Child

CT perfusion is a new technique that is rapid, available and minimally invasive which provides functional vascular information and can be made after conventional CT and CT angiography at the same imaging session. CT perfusion applications have focused on ischemic stroke with only a short series of applications to brain death diagnosis. Instead, CT angiography is frequently performed as a confirmatory test of brain death, but it has not been completely validated yet. Hence CT perfusion may help in supporting the diagnosis of brain death. We present the case of a 12-year-old child with clinical criteria for brain death who required a confirmatory test. CT angiography and CT perfusion were performed. Both revealed the absence of any intracranial blood flow which supported the clinical diagnosis of brain death.

The case against confirmatory tests for determining brain death in adults

The determination of brain death is based on a comprehensive clinical assessment. A confirmatory test-at least, in adult patients in the United States-is not mandatory, but it typically is used as a safeguard or added when findings on clinical examination are unwontedly incomplete. In other countries, confirmatory tests are mandatory; in many, they are optional. These tests can be divided into those that test the brain's electrical function and those that test cerebral blood flow. A false-positive result (i.e., the test result suggests brain death, but clinically the patient does not meet the criteria) is not common but has been described for tests frequently used to determine brain death. A false-negative result (i.e., the test result suggests intact brain function, but clinically the patient meets the criteria) in one test may result in more confirmatory tests and no resolution when the test results diverge. Also, pathologic studies have shown that considerable areas of viable brain tissue may remain in patients who meet the clinical criteria of brain death, a fact that makes these tests less diagnostic. Confirmatory tests are residua from earlier days of refining comatose states. A comprehensive clinical examination, when performed by skilled examiners, should have perfect diagnostic accuracy.

Evidence-based guideline update: Determining brain death in adults

To provide an update of the 1995 American Academy of Neurology guideline with regard to the following questions: Are there patients who fulfill the clinical criteria of brain death who recover neurologic function? What is an adequate observation period to ensure that cessation of neurologic function is permanent? Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? What is the comparative safety of techniques for determining apnea? Are there new ancillary tests that accurately identify patients with brain death? A systematic literature search was conducted and included a review of MEDLINE and EMBASE from January 1996 to May 2009. Studies were limited to adults. In adults, there are no published reports of recovery of neurologic function after a diagnosis of brain death using the criteria reviewed in the 1995 American Academy of Neurology practice parameter. Complex-spontaneous motor movements and false-positive triggering of the ventilator may occur in patients who are brain dead. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly. Apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing. There is insufficient evidence to determine if newer ancillary tests accurately confirm the cessation of function of the entire brain.

Contrast-Enhanced Transcranial Color Sonography in the Diagnosis of Cerebral Circulatory Arrest

Objective We sought to determine the utility of constrat-enhanced transcranial color sonography (TCCS) in the diagnosis of cerebral circulatory arrest in cases of difficult acoustic window. Materials and Methods From January 2007 to July 2008, we prospectively studied 50 patients who fulfilled clinical criteria of brain death. In all cases, we performed TCCS aiming to insonate both middle cerebral arteries (MCA) and the basilar artery (BA). In those case in which insonation of any vessel was not possible, we repeated the exploration after injecting a 2.5-mL bolus of sulphurhexafluoridedispersion. Afterward, we compared the rate of insonation of the vessels and the number of conclusive studies. Results The mean patient age was 53.2 ± 15.9 years. Thirty-two were men (64%). The most frequent neurologic injury was hemorrhagic stroke and traumatic brain injury. Contrast-enhanced TCCS resulted in an increased rate of insonation in both MCA and in BA, and in the number of conclusive studies. Conclusions Contrast-enhanced TCCS increased the number of conclusive studies with cerebral circulatory arrest, which minimized the importance of a previous study in cases with a poor acoustic window.