The diagnosis of brain death

Donor Pretreatment With IL-1 Receptor Antagonist Attenuates Inflammation and Improves Functional Potency in Islets From Brain-Dead Nonhuman Primates

Most pancreas and islet grafts are recovered from brain-dead (BD) donors. In this study we characterized the early inflammatory response induced by brain death in pancreata and islets from nonhuman primate donors and evaluated the effect of targeted anti-inflammatory intervention in the protection of pancreatic islets prior to transplantation. BD donors were monitored for 6 h and assigned to three experimental groups: group 1: BD-untreated donors (BD-UT) (n = 7), group 2: BD + donor pretreatment with IL-1ra (n = 6), and group 3: non-BD animals serving as controls (n = 7). We observed an IL-1ra-dependent reduction in the mobilization and activation of neutrophils from bone marrow and a significantly reduced accumulation of CD68(+) leukocytes in the pancreas and islets after brain death induction. Donor treatment with IL-1ra significantly decreased chemokine mRNA expression (MCP-1, IL-8, and MIP-1a) and attenuated the activation of circulating neutrophils and intraislet macrophages as demonstrated by a reduction in intracellular IL-1β, IL-6, MCP-1, and MIP-1α expression. As a result, IL-1ra dramatically improved viability, mitochondrial membrane polarity, and islet engraftment in mice transplanted using a minimal islet mass. These results suggest that early immunomodulation targeting inflammation in the BD donor may represent an effective therapeutic strategy to improve islet quality and function prior to transplantation.

A practical approach to neurologic evaluation in the intensive care unit

Delirium and neurologic impairment are extremely common in the intensive care setting, and their delayed identification is an important contributor to patient morbidity. Even in comatose patients, the clinical neurologic examination remains the most accurate and effective tool in assessing nervous system function. Rapid identification of neurologic deficits with a practical and easily reproducible neurologic examination is a core skill for effectively caring for critically ill patients. The purpose of this tutorial is to discuss techniques of neurologic examination and localization with an emphasis on comatose patients. Commonly encountered cases of encephalopathy and coma along with clinical pearls are presented.

Brain Death: Assessment, Controversy, and Confounding Factors

When brain injury is refractory to aggressive management and is considered nonsurvivable, with loss of consciousness and brain stem reflexes, a brain death protocol may be initiated to determine death according to neurological criteria. Clinical evaluation typically entails 2 consecutive formal neurological examinations to document total loss of consciousness and absence of brain stem reflexes and then apnea testing to evaluate carbon dioxide unresponsiveness within the brain stem. Confounding factors such as use of therapeutic hypothermia, high-dose metabolic suppression, and movements associated with complex spinal reflexes, fasciculations, or cardiogenic ventilator autotriggering may delay initiation or completion of brain death protocols. Neurodiagnostic studies such as 4-vessel cerebral angiography can rapidly document absence of blood flow to the brain and decrease intervals between onset of terminal brain stem herniation and formal declaration of death by neurological criteria. Intracranial pathophysiology leading to brain death must be considered along with clinical assessment, patterns of vital signs, and relevant diagnostic studies.

Brain Death Determination

In the United States, each year 1% to 2% of deaths are brain deaths. Considerable variation in the practice of determining brain death still remains, despite the publication of practice parameters in 1995 and an evidence-based guideline update in 2010. This review is intended to give bedside clinicians an overview of definition, the causes and pitfalls of misdiagnosing brain death, and a focus on the specifics of the brain death determination process.

Incidence of neurologic death among patients with brain injury: a cohort study in a Canadian health region

BACKGROUND

Hospital mortality has decreased over time for critically ill patients with various forms of brain injury. We hypothesized that the proportion of patients who progress to neurologic death may have also decreased.

METHODS

We performed a prospective cohort study involving consecutive adult patients with traumatic brain injury, subarachnoid hemorrhage, intracerebral hemorrhage or anoxic brain injury admitted to regional intensive care units in southern Alberta over a 10.5-year period. We used multivariable logistic regression to adjust for patient age and score on the Glasgow Coma Scale at admission, and to assess whether the proportion of patients who progress to neurologic death has changed over time.

RESULTS

The cohort consisted of 2788 patients. The proportion of patients who progressed to neurologic death was 8.1% at the start of the study period, and the adjusted odds of progressing to neurologic death decreased over the study period (odds ratio [OR] per yr 0.92, 95% confidence interval [CI] 0.87-0.98, p = 0.006). This change was most pronounced among patients with traumatic brain injury (OR per yr 0.87, 95% CI 0.78-0.96, p = 0.005); there was no change among patients with anoxic injury (OR per yr 0.96, 95% CI 0.85-1.09, p = 0.6). A review of the medical records suggests that missed cases of neurologic death were rare (≤ 0.5% of deaths).

INTERPRETATION

The proportion of patients with brain injury who progress to neurologic death has decreased over time, especially among those with head trauma. This finding may reflect positive developments in the prevention and care of brain injury. However, organ donation after neurologic death represents the major source of organs for transplantation. Thus, these findings may help explain the relatively stagnant rates of deceased organ donation in some regions of Canada, which in turn has important implications for the care of patients with end-stage organ failure.

Transcranial Sonography and Cerebral Circulatory Arrest in Adults: A Comprehensive Review

The diagnosis of brain death remains a clinical challenge for intensive care unit physicians. Worldwide regulations in its diagnosis may differ, and the need of ancillary tests after a clinical examination is not uniform. Transcranial sonography is a noninvasive, bedside, and widely available technique that can be used in the diagnosis of the cerebral circulatory arrest that preceeds brain death. In this paper we review the general concepts, the technical requisites, the patterns of Doppler signal confirming cerebral circulatory arrest, the vessels to insonate, and the options in cases with poor acoustic window. Future research perspectives in the field of transcranial sonography are discussed as well.

S100B protein may detect brain death development after severe traumatic brain injury

Despite improvements in the process of organ donation and transplants, the number of organ donors is progressively declining in developed countries. Therefore, the early detection of patients at risk for brain death (BD) is a priority for transplant teams seeking more efficient identification of potential donors. In the extensive literature on S100B as a biomarker for traumatic brain injury (TBI), no evidence appears to exist on its prognostic capacity as a predictor of BD after severe TBI. The objective of this study is to assess the value of including acute S100B levels in standard clinical data as an early screening tool for BD after severe TBI. This prospective study included patients with severe TBI (Glasgow Coma Scale score [GCS] ≤ 8) admitted to our Neurocritical Care Unit over a 30 month period. We collected the following clinical variables: age, gender, GCS score, pupillary alterations at admission, hypotension and pre-hospital desaturation, CT scan results, isolated TBI or other related injuries, Injury Severity Score (ISS), serum S100B levels at admission and 24 h post-admission, and a final diagnosis regarding BD. Of the 140 patients studied, 11.4% developed BD and showed significantly higher S100B concentrations (p<0.001). Multivariate analysis showed that bilateral unresponsive mydriasis at admission and serum S100B at 24 h post-admission had odds ratios (ORs) of 21.35 (p=0.005) and 4.9 (p=0.010), respectively. The same analysis on patients with photomotor reflex in one pupil at admission left only the 24 h S100B sample in the model (OR=15.5; p=0.009). Receiver operating characteristics (ROC) curve analysis on this group showed the highest area under the curve (AUC) (0.86; p=0.001) for 24 h S100B determinations. The cut off was set at 0.372 μg/L (85.7% sensitivity, 79.3% specificity, positive predictive value [PPV]=18.7% and negative predictive value [NPV]=98.9%). This study shows that pupillary responsiveness at admission, as well as 24 h serum S100B levels, could serve as screening tools for the early detection of patients at risk for BD after severe TBI.

The Presence of Relatives during Brainstem Death Testing in an Intensive Care Unit

The issue of allowing relatives to witness brainstem death testing has sparked debate between all members of the multidisciplinary team working in intensive care. A literature search was carried out, highlighting the advantages and disadvantages of relatives observing brainstem death testing. Databases searched were the NHS Knowledge Network, OVID, CINAHL, the Cochrane Library, and Medline. Search items included: brainstem death, brainstem death testing, brain death, intensive care, relatives, families and witnessed cardiopulmonary resuscitation. Articles which were under ten years old were included; however articles which were pertinent to the topic were not excluded if outside this timeframe.

Preclinical pulmonary capillary endothelial dysfunction is present in brain dead subjects

Pulmonary endothelium is a major metabolic organ affecting pulmonary and systemic vascular homeostasis. Brain death (BD)-induced physiologic and metabolic derangements in donors’ lungs, in the absence of overt lung pathology, may cause pulmonary dysfunction and compromise post-transplant graft function. To explore the impact of BD on pulmonary endothelium, we estimated pulmonary capillary endothelium-bound (PCEB)-angiotensin converting enzyme (ACE) activity, a direct and quantifiable index of pulmonary endothelial function, in eight brain-dead patients and ten brain-injured mechanically ventilated controls. No subject suffered from acute lung injury or any other overt lung pathology. Applying indicator-dilution type techniques, we measured single-pass transpulmonary percent metabolism (%M) and hydrolysis (v) of the synthetic, biologically inactive, and highly specific for ACE substrate ³H-benzoyl-Phe-Ala-Pro, under first order reaction conditions, and calculated lung functional capillary surface area (FCSA). Substrate %M (35 ± 6.8%) and v (0.49 ± 0.13) in BD patients were decreased as compared to controls (55.9 ± 4.9, P = 0.033 and 0.9 ± 0.15, P = 0.033, respectively), denoting decreased pulmonary endothelial enzyme activity at the capillary level; FCSA, a reflection of endothelial enzyme activity per vascular bed, was also decreased (BD patients: 1,563 ± 562 mL/min vs 4,235 ± 559 in controls; P = 0.003). We conclude that BD is associated with subtle pulmonary endothelial injury, expressed by decreased PCEB-ACE activity. The applied indicator-dilution type technique provides direct and quantifiable indices of pulmonary endothelial function at the bedside that may reveal the existence of preclinical lung pathology in potential lung donors.

Improving incidence of referrals for psychosocial and spiritual transdisciplinary care in a palliative care service: focus on brain death

The goal of this project was to examine the uniformity of the hospital's delivery of psychosocial and spiritual care for the families of patients being evaluated for brain death. A retrospective chart review encompassing one calendar year was conducted. After conferring with physicians and staff, a strategy was developed to capture information on patients who were diagnosed with brain death. Following evaluation of the information gathered, a proposal was introduced and hospital procedure revised. Triggers were put in place to ensure consistent offering of psycho-spiritual transdisciplinary services to the families of patients who are undergoing evaluation for brain death.

Advances in transcranial Doppler US: imaging ahead

Transcranial Doppler ultrasonography (US) is a noninvasive, portable technique for evaluating the intracranial vasculature. It has found its most useful clinical application in the detection of vasospasm involving the cerebral vessels after subarachnoid hemorrhage due to aneurysm rupture. The technique has become an integral part of monitoring and managing patients with subarachnoid hemorrhage in the neurologic intensive care unit. In addition, it has proved useful for evaluating the intracranial vasculature in patients with sickle cell disease, stroke, or brain death. Transcranial US originated as a "blind" nonimaging study in which pulsed Doppler technology was used. Identification of the major intracranial vessels and evaluation of those vessels for vasospasm relied on spectral waveforms obtained in each vessel and was based on the depth of the vessel from the skull, the direction of blood flow, and the orientation of the transducer. Recent advances in US technology allow the use of gray-scale, spectral Doppler, and color Doppler flow imaging to directly visualize intracranial vessels, thereby simplifying flow velocity measurements and enhancing their accuracy for vasospasm detection. In particular, measurements of peak systolic velocity and mean flow velocity and calculation of the Lindegaard ratio facilitate the identification of vessels that may be in vasospasm and help differentiate vasospasm from physiologic conditions such as hyperemia and autoregulation. Thus, gray-scale and color Doppler flow imaging offer many advantages over the original pulsed Doppler technique for evaluating the intracranial vasculature.

S100B Protein as a Post-traumatic Biomarker for Prediction of Brain Death in Association With Patient Outcomes

BACKGROUND

S100B is a calcium-binding protein, belonging to the S100 family proteins which are characterized by their high solubility and, currently, comprises 21 members which are expressed in a cell-specific manner. If we can predict the possibility of definite brain death after brain injury, we will rescue some organs of body to transplant proposes.

OBJECTIVES

In this regard our study focused on the S100B protein value in predicting brain death after head trauma. In this study, the use of serum level of protein S100, 24 hours after trauma has been considered as a reliable index for predicting brain death.

PATIENTS AND METHODS

72 patients (50 male and 22 female) aged 5 - 80 years old (median 40 ± 17.72 years) with severe head traumas (GCS≤8) were recruited in this cross-sectional study. Glasgow Coma Scale (GCS) and computed tomography (CT) scan findings were recorded for all patients, and then a single 5mL blood sample was obtained from each patient on admission, after 48 hours and a week later or after brain death to determine the level of S100B protein.

RESULTS

Primary and the last GCS of patients had a predictive value in determining brain death (P < 0.0005), also there was a significant correlation between GCS and level of S100B protein. There was a significant correlation between CT scan findings and S100B protein only after 48 hours of trauma.

CONCLUSIONS

Changes in S100B protein, especially the levels of this dimer 48 hours after trauma can be used as marker to predict brain death. Alongside other known prognostic factors such as age, GCS and diameters of the pupils, however, this factor individually can not conclusive predict the patient's clinical course and incidence of brain death. However, it is suitable to use GCS, CT scan, clinical symptoms and biomarkers together for a perfect prediction of brain death.

Ventilator auto-cycling from cardiogenic oscillations: case report and review of literature

BACKGROUND

Brain death is the total loss of all brain and brain stem functions, and its diagnosis is often confirmed by an apnoea test, which relies on disconnecting the patient from the ventilator. Auto-triggering or auto-cycling is defined as a ventilator being triggered in the absence of patient effort, intrinsic respiratory drive or inspiratory muscle activity. Ventilator auto-triggering could delay the diagnosis of brain death leading to unnecessary admission for the patient and false hopes of recovery for the family.

METHODS

We report a case of ventilator auto-triggering associated with cardiogenic oscillations in a female patient.

RESULTS

We confirmed the finding of ventilator auto-triggering by changing the patient's position and reassessing the triggering thresholds. Brain death was then confirmed by apnoea test.

CONCLUSION

This case is presented to arouse the awareness of the medical staff and nurses to this phenomenon, which can mimic an intrinsic respiratory effort in patients allegedly diagnosed with brain death. Along with this case report, we review the English language publications for similar cases.

Bispectral Index Scale variations in patients diagnosed with brain death

INTRODUCTION

Brain death (BD) is defined as the total irreversible loss of brain stem function. According to the Greek legislation, BD diagnosis is based on clinical criteria that test brain stem function. Bispectral Index Scale (BIS), a parameter derived from a mathematical analysis of the electroengephalogram depicts brain activity. The aim of our study was to record BIS alterations in brain-dead patients.

METHODS

Thirty-five brain dead patients according to the clinical criteria were included in this study. All patients were hemodynamically stable, normothermic, and normocapnic, free of oxygenation disturbances and electrolyte abnormalities. Continuous BIS monitoring (BIS XP, A-2000, Aspect Medical Systems, Newton, Mass, USA) was performed in all patients for periods ranging from 24 to 36 hours.

RESULTS

BIS values were 0 for the majority of the study period in all patients. However, in 23 patients the BIS value exceeded 30 for more than 30 minutes. This increase could not be attributed to any external stimulation.

CONCLUSION

BIS is a noninvasive, easily interpreted method to monitor cerebral activity. According to our results, BIS could be helpful in BD confirmation but cannot replace the valid clinical tests, which are consistent with Greek legislation for this diagnosis.

Systematic review of attitudes toward donation after cardiac death among healthcare providers and the general public

OBJECTIVE

Organ donation after cardiac death (DCD) is one promising possibility of combating the organ shortage, but it raises ethical issues that differ from those raised in donation after brain death (DBD). Also, DCD may be perceived differently than DBD by medical staff and the public. The aim of this article is to systematically review empirical studies on attitudes of medical personnel and the public toward DCD and to discuss the findings from an ethical perspective. Our study was conducted in accordance with a seven-step approach for systematic reviews of empirical studies in bioethics.

DATA SOURCES

The authors chose PubMed, EMBASE, CINAHL, PSYCINFO, and PSYNDEX, thus attempting to cover biomedical, sociological and ethical articles on the subject.

STUDY SELECTION

A search algorithm using controlled vocabulary of the respective databases (where applicable) was created, and criteria for the relevance assessment of the articles were established. Article quality was assessed using the Critical Appraisal Skills Programme tool.

DATA EXTRACTION AND SYNTHESIS

The authors took an integrative approach to the data, combining it for further analysis. Qualitative data were synthesized by means of thematic analysis, and a spectrum of relevant themes was identified. Then the authors extracted the quantitative data that corresponded with the identified themes. Quantitative data on common subjects were juxtaposed and presented later.

CONCLUSIONS

Identified themes were the levels of support for DBD vs. DCD, attitudes toward postmortem measures without previous consent, lack of knowledge about DCD, concerns about the Dead Donor Rule, the potential for conflict of interest, making donation happen, and the call for standardized DCD protocols. All of these issues are of ethical relevance and merit further discussion. We conclude that deep-rooted concerns about DCD exist among medical personnel and the general public. These need to be taken seriously in order to maintain or foster trust in the transplantation system.

Clinical variables and neuromonitoring information (intracranial pressure and brain tissue oxygenation) as predictors of brain-death development after severe traumatic brain injury

BACKGROUND AND PURPOSE

The aim of this study was to ascertain the role of clinical variables and neuromonitoring data as predictors of brain death (BD) after severe traumatic brain injury (TBI).

PATIENTS AND METHODS

This prospective observational study involved severe TBI patients admitted to the intensive care unit between October 2009 and May 2011. The following variables were recorded: gender, age, reference Glasgow Coma Scale after resuscitation, pupillary reactivity, prehospital hypotension and desaturation, injury severity score, computed tomography (CT) findings, intracranial hypertension, and low brain tissue oxygenation (Pti02) levels (<16 mm Hg), as well as the final result of BD.

RESULTS

Among 61 patients (86.9% males) who met the inclusion criteria, the average age was 37.69 ± 16.44 years. Traffic accidents were the main cause of TBI (62.3%). The patients at risk of progressing to BD (14.8% of the entire cohort) were those with a mass lesion on CT (odds ratio [OR] 33.6; 95% confidence interval [CI]: 3.75-300.30; P = .002), altered pupillary reaction at admission (OR 25.5; 95% CI: 2.27-285.65; P = .009), as well low Pti02 levels on admission (OR 20.41; 95% CI: 3.52-118.33; P < .001) and during the first 24 hours of neuromonitoring (OR 20; 95% CI: 2.90-137.83; P < .001). Multivariate logistic regression showed that a low Pti02 level on admission was the best independent predictor for BD (OR 20.41; 95% CI: 3.53-118.33; P = .001).

CONCLUSIONS

Clinical variables and neuromonitoring information may identify TBI patients at risk of deterioration to BD.

Semiparametric Bayesian inference for phage display data

We discuss inference for a human phage display experiment with three stages. The data are tripeptide counts by tissue and stage. The primary aim of the experiment is to identify ligands that bind with high affinity to a given tissue. We formalize the research question as inference about the monotonicity of mean counts over stages. The inference goal is then to identify a list of peptide-tissue pairs with significant increase over stages. We use a semiparametric Dirichlet process mixture of Poisson model. The posterior distribution under this model allows the desired inference about the monotonicity of mean counts. However, the desired inference summary as a list of peptide-tissue pairs with significant increase involves a massive multiplicity problem. We consider two alternative approaches to address this multiplicity issue. First we propose an approach based on the control of the posterior expected false discovery rate. We notice that the implied solution ignores the relative size of the increase. This motivates a second approach based on a utility function that includes explicit weights for the size of the increase.

Brain death

The diagnosis of brain death should be based on a simple premise. If every possible confounder has been excluded and all possible treatments have been tried or considered, irreversible loss of brain function is clinically recognized as the absence of brainstem reflexes, verified apnea, loss of vascular tone, invariant heart rate, and, eventually, cardiac standstill. This condition cannot be reversed - not even partly - by medical or surgical intervention, and thus is final. Many countries in the world have introduced laws that acknowledge that a patient can be declared brain-dead by neurologic standards. The U.S. law differs substantially from all other brain death legislation in the world because the U.S. law does not spell out details of the neurologic examination. Evidence-based practice guidelines serve as a standard. In this chapter, I discuss the history of development of the criteria, the current clinical examination, and some of the ethical and legal issues that have emerged. Generally, the concept of brain death has been accepted by all major religions. But patients' families may have different ideas and are mostly influenced by cultural attitudes, traditional customs, and personal beliefs. Suggestions are offered to support these families.

Our rapidly changing understanding of acute and chronic disorders of consciousness: challenges for neurologists

A number of recent studies suggest that some ‘vegetative state’ patients have been misdiagnosed, judging by their ability to follow commands and in some cases even communicate through brain activity. Such studies highlight the difficulty in forming a diagnosis based only on behavioral assessments. We think that neuroimaging and electrophysiology methods will be used more frequently in clinical settings, integrated with existing behavioral assessments. Such efforts are expected to lead to a more accurate understanding of individual patients’ cognitive abilities or even provide prognostic indicators. In terms of treatment planning (i.e., pain management and end-of-life decision-making), patients with disorders of consciousness are now offered the possibility of expressing their preferences by means of brain–computer interfaces. What remains to be clarified is the degree to which such indirect responses can be considered reliable and of legal representation.

CT perfusion for confirmation of brain death

SUMMARY

For pronouncing brain death, unlike CTP, the 2-phase CTA gives no functional information and is limited by inadvertent delay of the second acquisition, which may give false-negative results. The purpose of our study was to compare CTP and CTA derived from the CTP data with the Dupas and Frampas criteria for confirmation of brain death. A retrospective review of CTP in 11 consecutive patients for confirmation of brain death showed a sensitivity of 72.7% for 7- and 4-point scores, 81.8% for opacification of the ICV, and 100% for CTP scores in the brain stem. CTA obtained from the CTP data showed similar sensitivity in the diagnosis of brain death. This protocol also reduces the iodinated contrast dose and is less operator-dependent. The addition of the functional tools of CTP increased the sensitivity of CTA in the confirmation of brain death.

Subject position affects EEG magnitudes

EEG (electroencephalography) has been used for decades in thousands of research studies and is today a routine clinical tool despite the small magnitude of measured scalp potentials. It is widely accepted that the currents originating in the brain are strongly influenced by the high resistivity of skull bone, but it is less well known that the thin layer of CSF (cerebrospinal fluid) has perhaps an even more important effect on EEG scalp magnitude by spatially blurring the signals. Here it is shown that brain shift and the resulting small changes in CSF layer thickness, induced by changing the subject's position, have a significant effect on EEG signal magnitudes in several standard visual paradigms. For spatially incoherent high-frequency activity the effect produced by switching from prone to supine can be dramatic, increasing occipital signal power by several times for some subjects (on average 80%). MRI measurements showed that the occipital CSF layer between the brain and skull decreases by approximately 30% in thickness when a subject moves from prone to supine position. A multiple dipole model demonstrated that this can indeed lead to occipital EEG signal power increases in the same direction and order of magnitude as those observed here. These results suggest that future EEG studies should control for subjects' posture, and that some studies may consider placing their subjects into the most favorable position for the experiment. These findings also imply that special consideration should be given to EEG measurements from subjects with brain atrophy due to normal aging or neurodegenerative diseases, since the resulting increase in CSF layer thickness could profoundly decrease scalp potential measurements.

Benefit of a single recruitment maneuver after an apnea test for the diagnosis of brain death

Introduction

Many potential lung transplants are lost because of hypoxemia during donor management. We hypothesized that the apnea test, necessary to confirm the diagnosis of brain death in potential lung donors, was involved in the decrease in the ratio of partial pressure of arterial O₂ to fraction of inspired O₂ (PaO₂/FiO₂) and that a single recruitment maneuver performed just after the apnea test can reverse this alteration.

Methods

In this case-control study, we examined the effectiveness of the recruitment maneuver with a comparison cohort of brain dead patients who did not receive the maneuver. Patients were matched one-to-one on the basis of initial PaO₂/FiO₂ and on the duration of mechanical ventilation before the apnea test. PaO₂/FiO₂ was measured before (T1), at the end (T2) and two hours after apnea test (T3).

Results

Twenty-seven patients were included in each group. The apnea test was associated with a significant decrease in PaO₂/FiO₂ from 284 ± 98 to 224 ± 104 mmHg (P < 0.001). The decrease in PaO₂/FiO₂ between T1 and T3 was significantly lower in the recruitment maneuver group than in the control group (-4 (-68-57) vs -61 (-110--18) mmHg, P = 0.02). The number of potential donors with PaO₂/FiO₂ > 300 mmHg decreased by 58% (95% CI: 28-85%) in the control group vs 0% (95% CI: 0-34%) in the recruitment maneuver group (P < 0.001).

Conclusions

The apnea test induced a decrease in PaO₂/FiO₂ in potential lung donors. A single recruitment maneuver performed immediately after the apnea test can reverse this alteration and may prevent the loss of potential lung donors.

Persistent cerebral blood flow by transcranial Doppler ultrasonography in an asphyxiated newborn meeting brain death diagnosis: case report and review of the literature

We want to illustrate the difficulty of establishing a brain death diagnosis in newborn children and how an easy and useful tool, the transcranial Doppler ultrasonography, can leave an unexpected result that complicates the process despite the rest of the diagnostic tests. We describe a 36-week gestation newborn male who was diagnosed of brain death after asphyxiated and offered for donation. After initial stabilization at admission, we established brain death diagnosis by checking and meeting every criterion. The donation process was complicated because of persistent blood flow on transcranial Doppler ultrasonography. Transcranial Doppler ultrasonography is a very useful method to assess cerebral blood flow. However, caution and individualization are needed when interpreting this complementary exam, especially in highly conflictive situations like brain death diagnosis.

Reduction in inter-hemispheric connectivity in disorders of consciousness

Clinical diagnosis of disorders of consciousness (DOC) caused by brain injury poses great challenges since patients are often behaviorally unresponsive. A promising new approach towards objective DOC diagnosis may be offered by the analysis of ultra-slow (<0.1 Hz) spontaneous brain activity fluctuations measured with functional magnetic resonance imaging (fMRI) during the resting-state. Previous work has shown reduced functional connectivity within the “default network”, a subset of regions known to be deactivated during engaging tasks, which correlated with the degree of consciousness impairment. However, it remains unclear whether the breakdown of connectivity is restricted to the “default network”, and to what degree changes in functional connectivity can be observed at the single subject level. Here, we analyzed resting-state inter-hemispheric connectivity in three homotopic regions of interest, which could reliably be identified based on distinct anatomical landmarks, and were part of the “Extrinsic” (externally oriented, task positive) network (pre- and postcentral gyrus, and intraparietal sulcus). Resting-state fMRI data were acquired for a group of 11 healthy subjects and 8 DOC patients. At the group level, our results indicate decreased inter-hemispheric functional connectivity in subjects with impaired awareness as compared to subjects with intact awareness. Individual connectivity scores significantly correlated with the degree of consciousness. Furthermore, a single-case statistic indicated a significant deviation from the healthy sample in 5/8 patients. Importantly, of the three patients whose connectivity indices were comparable to the healthy sample, one was diagnosed as locked-in. Taken together, our results further highlight the clinical potential of resting-state connectivity analysis and might guide the way towards a connectivity measure complementing existing DOC diagnosis.

Confounding factors in brain death: cardiogenic ventilator autotriggering and implications for organ transplantation

Brain death is characterised by a flaccid, areflexic neurological examination; fixed, dilated and midpoint pupils and total absence of intrinsic respiratory drive. A non-reversible clinical state or brain lesion must also be identified. Integral to brain death diagnosis is loss of respiratory drive. Following terminal brainstem herniation, a cardiovascular hyperdynamic state often occurs. This hyperdynamic state causes cyclical volume displacement within the chest in phase with the cardiac cycle, causing oscillations in gas flow patterns and may be reflected in ventilator airway pressure and flow waveforms. When these flow/pressure waveform oscillations meet or exceed ventilator flow or pressure trigger sensitivity, ventilator breaths may be triggered in the total absence of intrinsic respiratory drive. In a patient with no apparent neurological function who is still triggering ventilator breaths, detailed analysis of ventilator pressure/flow waveforms in context with neurological assessment findings can identify cardiac autotriggering in a brain-dead patient. Undetected, cardiogenic ventilator autotriggering results in prolonged ICU stay and potential loss of transplantable organs. Collaborative practice and aggressive surveillance to determine loss of all neurologic function and evaluate possible autotriggering in this population is paramount and can minimise ICU stay, reduce costs of care, decrease family stress and facilitate recovery of transplantable organs.

Attitudes towards end-of-life decisions and the subjective concepts of consciousness: an empirical analysis

Background

People have fought for their civil rights, primarily the right to live in dignity. At present, the development of technology in medicine and healthcare led to an apparent paradox: many people are fighting for the right to die. This study was aimed at testing whether different moral principles are associated with different attitudes towards end-of-life decisions for patients with a severe brain damage.

Methodology

We focused on the ethical decisions about withdrawing life-sustaining treatments in patients with severe brain damage. 202 undergraduate students at the University of Padova were given one description drawn from four profiles describing different pathological states: the permanent vegetative state, the minimally conscious state, the locked-in syndrome, and the terminal illness. Participants were asked to evaluate how dead or how alive the patient was, and how appropriate it was to satisfy the patient's desire.

Principal Findings

We found that the moral principles in which people believe affect not only people's judgments concerning the appropriateness of the withdrawal of life support, but also the perception of the death status of patients with severe brain injury. In particular, we found that the supporters of the Free Choice (FC) principle perceived the death status of the patients with different pathologies differently: the more people believe in the FC, the more they perceived patients as dead in pathologies where conscious awareness is severely impaired. By contrast, participants who agree with the Sanctity of Life (SL) principle did not show differences across pathologies.

Conclusions

These results may shed light on the complex aspects of moral consensus for supporting or rejecting end-of-life decisions.

Donation after cardiac death lung transplantation outcomes

PURPOSE OF REVIEW

Lung transplantation is now a well established treatment option for several end-stage respiratory diseases. Survival after lung transplantation has significantly improved over the last decade. The primary limitation to increased utilization of lung transplantation remains donor scarcity. Suitable allografts have been procured from donors after determination of neurologic death and from donors after determination of cardiac death (DDCD or DCD). Historically, the first human lung transplantation performed, utilized an allograft procured after cardiovascular death, also referred to as nonheart-beating donor.The experience at University of Wisconsin in 1993 reintroduced DCD lung transplantation with the first successful clinical case.

RECENT FINDINGS

A potential additional lung allograft source, DCD lung transplantation has been established with very acceptable outcomes observed by several centers. We provide the relevant background for the rationale of donor allograft expansion to include DCD lungs from controlled (Maastricht category III donors).

SUMMARY

This review considers the available evidence for DCD lung transplantation and compares reported primary graft dysfunction rates and current survival data available.

"Any possible restoration of function could not occur": Harvey Cushing and the early description of brain death

OBJECTIVES

To describe a case from 1908 of apparent brain death after operative intervention by Harvey Cushing at the Johns Hopkins Hospital.

METHODS

After institutional review board approval, which waived the requirement of informed consent from patients, and through the courtesy of the Alan Mason Chesney Archives, we reviewed the Johns Hopkins Hospital surgical files from 1896 to 1912.

RESULTS

We selected a single adult patient operated upon by Cushing, whose respirations ceased in the operating room and who was maintained by the use of artificial respiration via a tracheostomy during a 36-hour period, whereas further surgical interventions were performed in an attempt to improve his condition. The patient's condition remained unimproved; artificial respirations were discontinued and the "cessation of all cardiac activity" was observed.

CONCLUSIONS

Brain death is a concept that presents unique challenges to the practicing physician. Although recent advances have allowed for better diagnosis of brain death, the topic remains fraught with controversy. The case described here documents Harvey Cushing's struggles with the ethics of maintaining vital organ function with artificial respiration, despite clear evidence of irreversible ischemic brain damage. This case predates the earliest descriptions of brain death by more than 50 years and illustrates the dilemmas facing clinicians at the turn of the twentieth century.

Brain death--think twice before labeling a patient

Brain death is defined as the cessation of cerebral and brainstem function. A 12-year-old boy presented with alleged history of snake bite. He was brain dead with Glasgow Coma Score of 3 and absent corneal reflexes. However, it was only neuroparalytic effect of the venom, which improved in due course of time with antivenoms. This case highlights the occurrence of both internal and external ophthalmoplegia, which would mimic brain death in many ways, thus prompting an intensivist to consider withdrawing ventilatory support, which would be disastrous.

Diffusion-weighted imaging findings in brain death

INTRODUCTION

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).

METHODS

We prospectively evaluated 22 patients diagnosed with clinical BD (9 women, 13 men; mean age, 39.63 ± 15.1 years; age range, 9-66 years). 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.

RESULTS

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%.

CONCLUSIONS

DWI might be used as a noninvasive confirmatory test for the diagnosis of BD in the future.

Organ Donation : Intensive Care Issues in Managing Brain Dead

Organ donation and transplantation is one of the most powerful and dramatic practices in modern medicine. It is the pinnacle of centuries of dreams, massive amounts of accrued knowledge and impressive technical developments. One organ donor has the potential of saving more than five lives and impacting the quality of life of many others via tissue donation. The clinical team has a responsibility to the donor families and the recipient patient to do everything possible to provide best practices supported by the best evidence. These standardized best practices should come from the published evidence which is adapted for use in the specific environment, culture, and infrastructure of the institution.