Assessment of Covert Consciousness in the Intensive Care Unit: Clinical and Ethical Considerations

Predictors of Recovering Full Consciousness: Results From a Prospective Multisite Italian Study

BACKGROUND

Improving prognostication in patients with a prolonged disorder of consciousness (pDoC) is among the most challenging issues in neurorehabilitation. The aim of this Italian multisite prospective longitudinal study was to identify valuable predictors of the complete recovery of consciousness (emergence from Minimally Conscious State, eMCS) at 3 months (T1) from the admission in intensive rehabilitation units (IRUs) in pDoC (T0).

METHODS

Patients with Unresponsive Wakefulness Syndrome (UWS) or MCS admitted within 3 months of injury to 4 Italian IRUs were included. Demographic, clinical, and neurophysiological data were collected at T0, and a clinical diagnosis of consciousness (UWS, MCS-, MCS+) was established at T0 and T1 using the Coma Recovery Scale-Revised (CRS-R).

RESULTS

One hundred forty-three patients were initially included and 131 completed follow-ups at T1: (76 males; median age: 69 years [IQR = 23]; VS/UWS: 51, MCS-: 29, MCS+: 51; etiology: 33 traumatic, 14 anoxic, 24 ischemic, 55 hemorrhagic, 5 other; median time post-injury: 40 days [IQR = 23]). At T1, 77 patients were eMCS, and 10 improved their clinical diagnosis. Among the clinical and neurophysiological independent variables, a higher CRS-R visual sub-score and the presence of EEG reactivity to eye opening at T0 were the best independent predictors of eMCS. Out of 77 eMCS, 18 reached a moderate disability (Glasgow Outcome Scale Extended-GOSE > 4), while the others persisted with a severe disability (GOS-E ≤ 4).

CONCLUSIONS

A multimodal assessment can help identify patients who achieve functionally relevant improvements and thus better support clinicians when communicating with caregivers.

TRIAL REGISTRATION

ClinicalTrials.gov registration number: NCT04495192.

Palliative General Anesthesia at Terminal Extubation: "Go Gentle into that Good Night"

Withdrawal of life-sustaining treatments in the intensive care unit most often culminates into the discontinuation of mechanical ventilation and removal of the endotracheal tube or "terminal extubation." Standards of practice call for the appropriate use of analgesia and sedation before, during and after extubation with an explicit goal to relieve suffering but not to hasten death. Patients subjected to this procedure are exposed to variable pharmacologic agents, modes, and doses, without any knowledge or monitoring of what these patients are experiencing. This practice seems to rest on contestable assumptions regarding the reliability of bedside examination, the experiential states of unresponsive patients, and the scope of the doctrine of double effect; instead, I argue for palliative general anesthesia in order to safeguard against potential suffering at the end of life. I employ philosophical notions of harm to justify the normative status of palliative anesthesia, in conjunction with contemporary evidence as it relates to the phenomena of covert consciousness and cognitive-motor dissociation. If this analysis is correct, then it may serve as a valid challenge toward current practice without having engaged into controversial debates over the soundness of the doctrine of double effect, or euthanasia. Primun non nocere offers the strongest justification for general anesthesia when terminal extubation is planned.

Neural Voices of Patients with Severe Brain Injury?

Studies have shown that some covertly conscious brain-injured patients, who are behaviorally unresponsive, can reply to simple questions via neuronal responses. Given the possibility of such neuronal responses, Andrew Peterson et al. have argued that there is warrant for some covertly conscious patients being included in low-stakes medical decisions using neuronal responses, which could protect and enhance their autonomy. The justification for giving credence to alleged neuronal responses must be analyzed from various perspectives, including neurology, bioethics, law, and as we suggest, philosophy of mind. In this article, we analyze the warrant for giving credence to neuronal responses from two different views in philosophy of mind. We consider how nonreductive physicalism's causal exclusion problem elicits doubt about interpreting neural activity as indicating a conscious response. By contrast, such an interpretation is supported by the mind-body powers model of neural correlates of consciousness inspired by hylomorphism.

Medical and surgical treatments in disorders of consciousness

Ever since a 2012 landmark study showed positive effects of amantadine in people with disorders of consciousness (DOC), there has been a shift in research efforts from merely improving diagnostics and prognostication of DOC to also include therapeutic trials, in the quest to improve consciousness recovery after brain injury. Stimulation of residual consciousness in the intensive care unit is critical because failure to do so may lead to unwarranted pessimistic prognosis and premature withdrawal of life-sustaining therapies. Similarly, it is crucial to harvest the potential of chronic DOC patients for late consciousness recovery, which is increasingly reported. To this end, medical and nonpharmacologic, including surgical, treatment strategies are being tested. These include dopaminergic and GABAergic drugs (medical), vagal nerve stimulation (noninvasive or surgical), and deep brain stimulation (surgical). In addition, transcranial magnetic stimulation, transcranial direct current stimulation, and low-intensity ultrasound (nonpharmacologic and nonsurgical) are covered in another chapter in this volume of the Handbook. Although overall, DOC treatment studies are subject to small sample sizes, unblinded protocols, and limited follow-up, this will likely change in the foreseeable future with the advent of adequately powered multicenter studies, randomized, double-blind, placebo-controlled designs, and standardized outcome measures. This chapter discusses the present state and outlooks of the field of medical and surgical options to boost arousal and awareness in patients with DOC, indicating the future of DOC treatment is bright.

Intractable conflicts over end-of-life decisions: A descriptive and ethical analysis of French case-law

CONTEXT

In European and Anglo-Saxon countries, life-sustaining treatment (LST) limitation decisions precede more than 80% of ICU deaths. However, there is now increasing evidence of disagreement and conflict between clinical teams and family members over LST limitation decisions. In some cases, these conflicts are brought to the courts. The aim of this study was to provide a descriptive and qualitative analysis of cases brought to the French courts.

METHODS

We conducted a retrospective national observational study. All identified cases of emergency recourse to the judge in the context of LST limitation decisions in France between 2005 and 2022 were included.

RESULTS

Seventy-six cases were investigated by the judge, with an increasing number over the years. The LST limitation decisions contested by the relatives were mainly decisions to withdraw treatment (78%) concerning patients with neurological injury (76%). The judge successively assessed the compliance with the legal decision-making process and the characterization of the inappropriateness of treatments. The latter was assessed by the judge using medical and non-medical criteria. In all, the medical decision was upheld in 29 cases (38%) and over-ruled in 20 cases (26%). Thirteen cases (17%) were finally settled out of court, and 14 patients (18%) died before the end of the investigation. The qualitative analysis highlighted opposing moral values and principles put forward by family members and physicians.

CONCLUSION

The growing incidence and deeply intertwined elements of these conflicts call for more policy and research to resolve them before they go to court.

Emerging ethical issues in patients with disorders of consciousness: A clinical guide

Clinicians who manage patients with disorders of consciousness (DoC) commonly encounter challenging ethical issues. Consciousness disorders include the vegetative state, the minimally conscious state, and covert consciousness resulting from cognitive-motor dissociation. The practice landscape of ethical issues encompasses making the correct diagnosis; making and communicating an accurate prognosis despite irreducible uncertainty; conducting effective shared decision-making with a lawful surrogate decision-maker to deliver goal-concordant care; providing optimal medical, rehabilitative, and palliative care across the spectrum of care sites: acute inpatient, neurorehabilitative, chronic, and palliative; respecting the human rights of and advocating for DoC patient, an historically under-served population and, when appropriate, properly participating in decisions to withhold or withdraw life-sustaining therapy. Research and translational issues in DoC patients include the challenges posed by emerging diagnostics and therapeutics and their prudential integration into clinical practice in the service of patients and their families. Our conceptual analysis of these ethical issues and our practical advice to address them comprise the subject material of this chapter.

A scientific approach to diagnosis of disorders of consciousness

Disorder of consciousness (DoC) are the shared clinical manifestation of severe brain injuries resulting from a variety of etiologies. The nosology of DoC, as well as the armamentarium of methods available to diagnose it, has rapidly evolved. As a result, the diagnosis of DoC is complex and dynamic. We offer an evidence-based approach to DoC diagnosis, highlighting the challenges and pitfalls therein. Accordingly, we summarize the contemporary taxonomy of DoC and its development. We discuss the standardized behavioral diagnostic tools that form the foundation of DoC diagnosis, the evidence for their use, and their limitations. We also highlight recent advances in functional MRI (fMRI) and electroencephalography (EEG) techniques to increase the sensitivity and specificity of DoC diagnosis. We discuss the concept of covert consciousness (i.e., cognitive motor dissociation) as a discrete diagnostic category of DoC, as well as its diagnostic implications. Finally, we underscore issues of neuroethics and equity raised by contemporary models of DoC.

Neurocritical Care in 2024: Where are We Headed?

Providing specialized care to critically ill neurology patients has improved outcomes for patients with neurological emergencies; however, there are still some gaps in neurocritical care (NCC) that offer opportunities for improvement. Among these gaps, improving education of the multidisciplinary NCC team, targeting individualized treatments for neurologically critically ill patients, and reducing disparities for undeserved patients as well as disadvantaged areas are priorities to advance the field. This review focuses on the current challenges neurointensivists face, including difficulties in neuroprognostication, ethical challenges in end-of-life care, and neuropalliative care. Challenges also involve providing specific NCC education for the multidisciplinary NCC team, as well as advancing research to provide treatments for critically ill neurological patients. Finally, the authors describe future directions that can take NCC to the next level.

Care of the Patient Nearing the End of Life in the Neurointensive Care Unit

BACKGROUND

Neurologically critically ill patients present with unique disease trajectories, prognostic uncertainties, and challenges to end-of-life (EOL) care. Acute brain injuries place these patients at risk for underrecognized symptoms and unmet EOL management needs, which can negatively affect their quality of care and lead to complicated grief in surviving loved ones. To care for patients nearing the EOL in the neurointensive care unit, health care clinicians must consider neuroanatomic localization, barriers to symptom assessment and management, unique aspects of the dying process, and EOL management needs.

AIM

We aim to define current best practices, barriers, and future directions for EOL care of the neurologically critically ill patient.

Applications of Functional Magnetic Resonance Imaging to the Study of Functional Connectivity and Activation in Neurological Disease: A Scoping Review of the Literature

BACKGROUND

Functional magnetic resonance imaging (fMRI) has transformed our understanding of brain's functional architecture, providing critical insights into neurological diseases. This scoping review synthesizes the current landscape of fMRI applications across various neurological domains, elucidating the evolving role of both task-based and resting-state fMRI in different settings.

METHODS

We conducted a comprehensive scoping review following the Preferred Reporting Items for Systematic Review and Meta-Analyses Extension for Scoping Reviews guidelines. Extensive searches in Medline/PubMed, Embase, and Web of Science were performed, focusing on studies published between 2003 and 2023 that utilized fMRI to explore functional connectivity and regional activation in adult patients with neurological conditions. Studies were selected based on predefined inclusion and exclusion criteria, with data extracted.

RESULTS

We identified 211 studies, covering a broad spectrum of neurological disorders including mental health, movement disorders, epilepsy, neurodegeneration, traumatic brain injury, cerebrovascular accidents, vascular abnormalities, neurorehabilitation, neuro-critical care, and brain tumors. The majority of studies utilized resting-state fMRI, underscoring its prominence in identifying disease-specific connectivity patterns. Results highlight the potential of fMRI to reveal the underlying pathophysiological mechanisms of various neurological conditions, facilitate diagnostic processes, and potentially guide therapeutic interventions.

CONCLUSIONS

fMRI serves as a powerful tool for elucidating complex neural dynamics and pathologies associated with neurological diseases. Despite the breadth of applications, further research is required to standardize fMRI protocols, improve interpretative methodologies, and enhance the translation of imaging findings to clinical practice. Advances in fMRI technology and analytics hold promise for improving the precision of neurological assessments and interventions.

Covert Consciousness in the ICU

OBJECTIVES

For critically ill patients with acute severe brain injuries, consciousness may reemerge before behavioral responsiveness. The phenomenon of covert consciousness (i.e., cognitive motor dissociation) may be detected by advanced neurotechnologies such as task-based functional MRI (fMRI) and electroencephalography (EEG) in patients who appear unresponsive on the bedside behavioral examination. In this narrative review, we summarize the state-of-the-science in ICU detection of covert consciousness. Further, we consider the prognostic and therapeutic implications of diagnosing covert consciousness in the ICU, as well as its potential to inform discussions about continuation of life-sustaining therapy for patients with severe brain injuries.

DATA SOURCES

We reviewed salient medical literature regarding covert consciousness.

STUDY SELECTION

We included clinical studies investigating the diagnostic performance characteristics and prognostic utility of advanced neurotechnologies such as task-based fMRI and EEG. We focus on clinical guidelines, professional society scientific statements, and neuroethical analyses pertaining to the implementation of advanced neurotechnologies in the ICU to detect covert consciousness.

DATA EXTRACTION AND DATA SYNTHESIS

We extracted study results, guideline recommendations, and society scientific statement recommendations regarding the diagnostic, prognostic, and therapeutic relevance of covert consciousness to the clinical care of ICU patients with severe brain injuries.

CONCLUSIONS

Emerging evidence indicates that covert consciousness is present in approximately 15-20% of ICU patients who appear unresponsive on behavioral examination. Covert consciousness may be detected in patients with traumatic and nontraumatic brain injuries, including patients whose behavioral examination suggests a comatose state. The presence of covert consciousness in the ICU may predict the pace and extent of long-term functional recovery. Professional society guidelines now recommend assessment of covert consciousness using task-based fMRI and EEG. However, the clinical criteria for patient selection for such investigations are uncertain and global access to advanced neurotechnologies is limited.

Detecting awareness after acute brain injury

Advances over the past two decades in functional neuroimaging have provided new diagnostic and prognostic tools for patients with severe brain injury. Some of the most pertinent developments in this area involve the assessment of residual brain function in patients in the intensive care unit during the acute phase of severe injury, when they are at their most vulnerable and prognosis is uncertain. Advanced neuroimaging techniques, such as functional MRI and EEG, have now been used to identify preserved cognitive processing, including covert conscious awareness, and to relate them to outcome in patients who are behaviourally unresponsive. Yet, technical and logistical challenges to clinical integration of these advanced neuroimaging techniques remain, such as the need for specialised expertise to acquire, analyse, and interpret data and to determine the appropriate timing for such assessments. Once these barriers are overcome, advanced functional neuroimaging technologies could improve diagnosis and prognosis for millions of patients worldwide.

Neuroethics, Covert Consciousness, and Disability Rights: What Happens When Artificial Intelligence Meets Cognitive Motor Dissociation?

In this article, we consider the intersection of cognitive motor dissociation (CMD) and artificial intelligence (AI), hence when CMD meets AI. In covert consciousness, there is a discordance between the observed behavior, the traditional bedside mode of assessment, and the response to volitional commands as depicted by neuroimaging or EEG studies. This alphabet soup of acronyms represents both the promise and peril of nascent technology in covert consciousness. On the diagnostic side, there is the complexity and uncertainty of identifying the discordance between cognitive activity and overt behavior. On the therapeutic side, when AI is used to generate speech, there is the possibility of misrepresenting the thoughts and intentions of those who are otherwise voiceless. This concordance of factors makes the application of AI to CMD worthy of deeper consideration. We offer this analysis in the spirit of anticipatory governance, a prudential process by which one plans to prevent or mitigate unintended consequences of novel technology. We first consider the normative challenges posed by CMD for clinical practice, neuroethics, and the law. We then explore the history of covert consciousness and the relationship of severe brain injury to the right-to-die movement, before introducing three biographies of brain injury that highlight the potential impact of disability bias or ableism in clinical practice, assistive technology, and translational research. Subsequently, we explore how AI might give voice to conscious individuals who are unable to communicate and the ethical challenges that this technology must overcome to promote human flourishing drawing upon what Nussbaum and Sen have described as a "capabilities approach" to promote normative reasoning.

Disclosing Results of Tests for Covert Consciousness: A Framework for Ethical Translation

The advent of neurotechnologies including advanced functional magnetic resonance imaging and electroencephalography to detect states of awareness not detectable by traditional bedside neurobehavioral techniques (i.e., covert consciousness) promises to transform neuroscience research and clinical practice for patients with brain injury. As these interventions progress from research tools into actionable, guideline-endorsed clinical tests, ethical guidance for clinicians on how to responsibly communicate the sensitive results they yield is crucial yet remains underdeveloped. Drawing on insights from empirical and theoretical neuroethics research and our clinical experience with advanced neurotechnologies to detect consciousness in behaviorally unresponsive patients, we critically evaluate ethical promises and perils associated with disclosing the results of clinical covert consciousness assessments and describe a semistructured approach to responsible data sharing to mitigate potential risks.

Multimodal approaches supporting the diagnosis, prognosis and investigation of neural correlates of disorders of consciousness: A systematic review

The limits of the standard, behaviour-based clinical assessment of patients with disorders of consciousness (DoC) prompted the employment of functional neuroimaging, neurometabolic, neurophysiological and neurostimulation techniques, to detect brain-based covert markers of awareness. However, uni-modal approaches, consisting in employing just one of those techniques, are usually not sufficient to provide an exhaustive exploration of the neural underpinnings of residual awareness. This systematic review aimed at collecting the evidence from studies employing a multimodal approach, that is, combining more instruments to complement DoC diagnosis, prognosis and better investigating their neural correlates. Following the PRISMA guidelines, records from PubMed, EMBASE and Scopus were screened to select peer-review original articles in which a multi-modal approach was used for the assessment of adult patients with a diagnosis of DoC. Ninety-two observational studies and 32 case reports or case series met the inclusion criteria. Results highlighted a diagnostic and prognostic advantage of multi-modal approaches that involve electroencephalography-based (EEG-based) measurements together with neuroimaging or neurometabolic data or with neurostimulation. Multimodal assessment deepened the knowledge on the neural networks underlying consciousness, by showing correlations between the integrity of the default mode network and the different clinical diagnosis of DoC. However, except for studies using transcranial magnetic stimulation combined with electroencephalography, the integration of more than one technique in most of the cases occurs without an a priori-designed multi-modal diagnostic approach. Our review supports the feasibility and underlines the advantages of a multimodal approach for the diagnosis, prognosis and for the investigation of neural correlates of DoCs.

Disorders of Consciousness Programs: Components, Organization, and Implementation

Rehabilitation of patients with disorders of consciousness (DoC) presents unique challenges requiring comprehensive and specialized care. This article reviews the components, organization, and implementation of an inpatient DoC program under the framework of recent evidence-based practice guidelines and minimum competency recommendations. The evidence and clinical applications of these recommendations are elaborated upon with the goal of offering providers a reference to translate guidelines into clinical practice.

Evaluation and Management of Disorders of Consciousness in the Acute Care Setting

Acute disorders of consciousness (DOC) are impairments in arousal and awareness that occur within 28 days of an initial injury and can result from a variety of insults. These states range from coma, unresponsive wakefulness, covert consciousness, minimal consciousness, to confusional state. It is important to perform thorough, serial examinations with particular emphasis on the level of consciousness, brainstem reflexes, and motor responses. Evaluation of acute DOC includes laboratory tests, imaging, and electrophysiology testing. Prognostication in the acute phase of DOC must be done cautiously, using open, frequent communication with families, and by acknowledging significant multidimensional uncertainty.

Disorders of Consciousness Rehabilitation: Ethical Dimensions and Epistemic Dilemmas

Patients with disorders of consciousness who survive to discharge following severe acute brain injury may face profoundly complex medical, ethical, and psychosocial challenges during their courses of recovery and rehabilitation. Although issues encountered in caring for such patients during acute hospitalization have received substantial attention, ethical challenges that may arise in subacute and chronic phases have been underexplored. Shedding light on these issues, this article explores the landscape of normative issues in the course of treating and facilitating access to care for persons with disorders of consciousness during rehabilitation and examines potential implications for patients, clinicians, family members, and society.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Neuroimaging

BACKGROUND

Over the past 5 decades, advances in neuroimaging have yielded insights into the pathophysiologic mechanisms that cause disorders of consciousness (DoC) in patients with severe brain injuries. Structural, functional, metabolic, and perfusion imaging studies have revealed specific neuroanatomic regions, such as the brainstem tegmentum, thalamus, posterior cingulate cortex, medial prefrontal cortex, and occipital cortex, where lesions correlate with the current or future state of consciousness. Advanced imaging modalities, such as diffusion tensor imaging, resting-state functional magnetic resonance imaging (fMRI), and task-based fMRI, have been used to improve the accuracy of diagnosis and long-term prognosis, culminating in the endorsement of fMRI for the clinical evaluation of patients with DoC in the 2018 US (task-based fMRI) and 2020 European (task-based and resting-state fMRI) guidelines. As diverse neuroimaging techniques are increasingly used for patients with DoC in research and clinical settings, the need for a standardized approach to reporting results is clear. The success of future multicenter collaborations and international trials fundamentally depends on the implementation of a shared nomenclature and infrastructure.

METHODS

To address this need, the Neurocritical Care Society's Curing Coma Campaign convened an international panel of DoC neuroimaging experts to propose common data elements (CDEs) for data collection and reporting in this field.

RESULTS

We report the recommendations of this CDE development panel and disseminate CDEs to be used in neuroimaging studies of patients with DoC.

CONCLUSIONS

These CDEs will support progress in the field of DoC neuroimaging and facilitate international collaboration.

Medical AI, inductive risk and the communication of uncertainty: the case of disorders of consciousness

Some patients, following brain injury, do not outwardly respond to spoken commands, yet show patterns of brain activity that indicate responsiveness. This is 'cognitive-motor dissociation' (CMD). Recent research has used machine learning to diagnose CMD from electroencephalogram recordings. These techniques have high false discovery rates, raising a serious problem of inductive risk. It is no solution to communicate the false discovery rates directly to the patient's family, because this information may confuse, alarm and mislead. Instead, we need a procedure for generating case-specific probabilistic assessments that can be communicated clearly. This article constructs a possible procedure with three key elements: (1) A shift from categorical 'responding or not' assessments to degrees of evidence; (2) The use of patient-centred priors to convert degrees of evidence to probabilistic assessments; and (3) The use of standardised probability yardsticks to convey those assessments as clearly as possible.

Illness Weakness, Polyneuropathy and Myopathy: Diagnosis, treatment, and long-term outcomes

BACKGROUND

Severe weakness associated with critical illness (CIW) is common. This narrative review summarizes the latest scientific insights and proposes a guide for clinicians to optimize the diagnosis and management of the CIW during the various stages of the disease from the ICU to the community stage.

MAIN BODY

CIW arises as diffuse, symmetrical weakness after ICU admission, which is an important differentiating factor from other diseases causing non-symmetrical muscle weakness or paralysis. In patients with adequate cognitive function, CIW can be easily diagnosed at the bedside using manual muscle testing, which should be routinely conducted until ICU discharge. In patients with delirium or coma or those with prolonged, severe weakness, specific neurophysiological investigations and, in selected cases, muscle biopsy are recommended. With these exams, CIW can be differentiated into critical illness polyneuropathy or myopathy, which often coexist. On the general ward, CIW is seen in patients with prolonged previous ICU treatment, or in those developing a new sepsis. Respiratory muscle weakness can cause neuromuscular respiratory failure, which needs prompt recognition and rapid treatment to avoid life-threatening situations. Active rehabilitation should be reassessed and tailored to the new patient's condition to reduce the risk of disease progression. CIW is associated with long-term physical, cognitive and mental impairments, which emphasizes the need for a multidisciplinary model of care. Follow-up clinics for patients surviving critical illness may serve this purpose by providing direct clinical support to patients, managing referrals to other specialists and general practitioners, and serving as a platform for research to describe the natural history of post-intensive care syndrome and to identify new therapeutic interventions. This surveillance should include an assessment of the activities of daily living, mood, and functional mobility. Finally, nutritional status should be longitudinally assessed in all ICU survivors and incorporated into a patient-centered nutritional approach guided by a dietician.

CONCLUSIONS

Early ICU mobilization combined with the best evidence-based ICU practices can effectively reduce short-term weakness. Multi-professional collaborations are needed to guarantee a multi-dimensional evaluation and unitary community care programs for survivors of critical illnesses.

Functional MRI for Acute Covert Consciousness: Emerging Data and Implementation Case Series

Although research studies have begun to demonstrate relationships between disorders of consciousness and brain network biomarkers, there are limited data on the practical aspects of obtaining such network biomarkers to potentially guide care. As the state of knowledge continues to evolve, guidelines from professional societies such as the American and European Academies of Neurology and many experts have advocated that the risk-benefit ratio for the assessment of network biomarkers has begun to favor their application toward potentially detecting covert consciousness. Given the lack of detailed operationalization guidance and the context of the ethical implications, herein we offer a roadmap based on local institutional experience with the implementation of functional MRI in the neonatal, pediatric, and adult intensive care units of our local government-supported health system. We provide a case-based demonstrative approach intended to review the current literature and to assist with the initiation of such services at other facilities.

Measuring Consciousness in the Intensive Care Unit

Early reemergence of consciousness predicts long-term functional recovery for patients with severe brain injury. However, tools to reliably detect consciousness in the intensive care unit are lacking. Transcranial magnetic stimulation electroencephalography has the potential to detect consciousness in the intensive care unit, predict recovery, and prevent premature withdrawal of life-sustaining therapy.

Multimodal Neuromonitoring and Neurocritical Care in Swine to Enhance Translational Relevance in Brain Trauma Research

Neurocritical care significantly impacts outcomes after moderate-to-severe acquired brain injury, but it is rarely applied in preclinical studies. We created a comprehensive neurointensive care unit (neuroICU) for use in swine to account for the influence of neurocritical care, collect clinically relevant monitoring data, and create a paradigm that is capable of validating therapeutics/diagnostics in the unique neurocritical care space. Our multidisciplinary team of neuroscientists, neurointensivists, and veterinarians adapted/optimized the clinical neuroICU (e.g., multimodal neuromonitoring) and critical care pathways (e.g., managing cerebral perfusion pressure with sedation, ventilation, and hypertonic saline) for use in swine. Moreover, this neurocritical care paradigm enabled the first demonstration of an extended preclinical study period for moderate-to-severe traumatic brain injury with coma beyond 8 h. There are many similarities with humans that make swine an ideal model species for brain injury studies, including a large brain mass, gyrencephalic cortex, high white matter volume, and topography of basal cisterns, amongst other critical factors. Here we describe the neurocritical care techniques we developed and the medical management of swine following subarachnoid hemorrhage and traumatic brain injury with coma. Incorporating neurocritical care in swine studies will reduce the translational gap for therapeutics and diagnostics specifically tailored for moderate-to-severe acquired brain injury.

Functional Neuroimaging as an Assessment Tool in Critically Ill Patients

OBJECTIVE

Little is known about residual cognitive function in the earliest stages of serious brain injury. Functional neuroimaging has yielded valuable diagnostic and prognostic information in chronic disorders of consciousness, such as the vegetative state (also termed unresponsive wakefulness syndrome). The objective of the current study was to determine if functional neuroimaging could be efficacious in the assessment of cognitive function in acute disorders of consciousness, such as coma, where decisions about the withdrawal of life-sustaining therapies are often made.

METHODS

A hierarchical functional magnetic resonance imaging (fMRI) approach assessed sound perception, speech perception, language comprehension, and covert command following in 17 critically ill patients admitted to the intensive care unit (ICU).

RESULTS

Preserved auditory function was observed in 15 patients (88%), whereas 5 (29%) also had preserved higher-order language comprehension. Notably, one patient could willfully modulate his brain activity when instructed to do so, suggesting a level of covert conscious awareness that was entirely inconsistent with his clinical diagnosis at the time of the scan. Across patients, a positive relationship was also observed between fMRI responsivity and the level of functional recovery, such that patients with the greatest functional recovery had neural responses most similar to those observed in healthy control participants.

INTERPRETATION

These results suggest that fMRI may provide important diagnostic and prognostic information beyond standard clinical assessment in acutely unresponsive patients, which may aid discussions surrounding the continuation or removal of life-sustaining therapies during the early post-injury period. ANN NEUROL 2023;93:131-141.

End-Of-Life Care in the Potential Donor after Circulatory Death: A Systematic Review

Background

Donation after circulatory death (DCD) is becoming increasingly common, yet little is known about the way potential donors receive end-of-life care.

Purpose

The aims of this systematic review are to describe the current practice in end-of-life care for potential donors and identify metrics that are being used to assess discomfort among these patients.

Research design and Study Sample

This review encompasses published literature between June 1, 2000 and June 31, 2020 of end-of-life care received by potential DCD patients. The population of interest was defined as patients eligible for Maastracht classification III donation after circulatory death for a solid organ transplantation. Outcomes examined included: analgesic or palliative protocols, and surrogates of discomfort (eg dyspnea, agitation).

Results

Among 141 unique articles, 27 studies were included for full review. The primary reason for exclusion was lack of protocol description, or lack of reporting on analgesic medications. No primary research studies specifically examined distress in the DCD eligible population. Numerous professional guidelines were identified. Surveys of critical care practitioners identified concerns regarding the impact of symptom management on hastening the dying process in the DCD population as a potential barrier to end-of-life palliative treatment.

Conclusions

There is a paucity of empirical evidence for end-of-life symptom assessment and management for DCD patients. Key evidence gaps identified for DCD include the need for: i) a multidisciplinary structure of treatment teams and preferred environment for DCD, ii) objective tools for monitoring of distress in this patient population, and iii) evidence guiding the administration of analgesic medications following withdrawal of life sustaining therapy.

Neuroprognostication: a conceptual framework

Neuroprognostication, or the prediction of recovery from disorders of consciousness caused by severe brain injury, is as critical as it is complex. With profound implications for mortality and quality of life, neuroprognostication draws upon an intricate set of biomedical, probabilistic, psychosocial and ethical factors. However, the clinical approach to neuroprognostication is often unsystematic, and consequently, variable among clinicians and prone to error. Here, we offer a stepwise conceptual framework for reasoning through neuroprognostic determinations - including an evaluation of neurological function, estimation of a recovery trajectory, definition of goals of care and consideration of patient values - culminating in a clinically actionable formula for weighing the risks and benefits of life-sustaining treatment. Although the complexity of neuroprognostication might never be fully reducible to arithmetic, this systematic approach provides structure and guidance to supplement clinical judgement and direct future investigation.

Conventional and Investigational Approaches Leveraging Clinical EEG for Prognosis in Acute Disorders of Consciousness

Prediction of recovery of consciousness after severe brain injury is difficult and limited by a lack of reliable, standardized biomarkers. Multiple approaches for analysis of clinical electroencephalography (EEG) that shed light on prognosis in acute severe brain injury have emerged in recent years. These approaches fall into two major categories: conventional characterization of EEG background and quantitative measurement of resting state or stimulus-induced EEG activity. Additionally, a small number of studies have associated the presence of electrophysiologic sleep features with prognosis in the acute phase of severe brain injury. In this review, we focus on approaches for the analysis of clinical EEG that have prognostic significance and that could be readily implemented with minimal additional equipment in clinical settings, such as intensive care and intensive rehabilitation units, for patients with acute disorders of consciousness.

Psychophysiological Effects of Biographical Interventions in People With Unresponsive Wakefulness Syndrome and Minimally Conscious State

Background

Various music interventions can evoke favorable behavioral responses or physiological reactions in people with disorders of consciousness (DOC), such as coma, unresponsive wakefulness syndrome (UWS), and minimally conscious state (MCS). However, it appears that no study thus far has investigated the effects of music on the endocrine system of people with DOC.

Objective

This explorative study aimed to investigate the effects of biographical music and biographical language on the physiological and endocrine systems of people with UWS and MCS.

Method

A cohort of 20 people with DOC (10 women, 10 men; age range 19–77) received 20 min of biographical music and biographical language. Before and afterward, they were exposed to silence. Physiological and hormonal measurements were conducted before, during, and after the interventions.

Results

Paired t-tests showed a significant decrease of salivary cortisol in the condition with biographical language interventions.

Conclusion

Biographical interventions can modulate reactions in the endocrine system in people with DOC. Further studies are needed to establish whether and how individuals living with DOC show psychoneuroendocrine responses to music and other arts-based interventions.

Ethical Considerations in Clinical Trials for Disorders of Consciousness

As the clinical trial landscape for patients with disorders of consciousness (DoC) expands, consideration of associated ethical challenges and opportunities is of ever-increasing importance. Responsible conduct of research in the vulnerable population of persons with DoC, including those with coma, vegetative state/unresponsive wakefulness syndrome (VS/UWS), minimally conscious state (MCS), covert cortical processing (CCP), and cognitive motor dissociation (CMD), demands proactive deliberation of unique ethical issues that may arise and the adoption of robust protections to safeguard patients, surrogates, and other key stakeholders. Here we identify and critically evaluate four central categories of ethical considerations in clinical trials involving participants with DoC: (1) autonomy, respect for persons and informed consent of individuals with liminal consciousness; (2) balancing unknown benefits and risks, especially considering the epistemological gap between behavior and consciousness that complicates ordinary ascription of subjective states; (3) disclosure to surrogates and clinical teams of investigational results pertaining to consciousness; and (4) justice considerations, including equitable access to clinical trial enrollment across communities and geographies. We outline guiding principles and research opportunities for clinicians, neuroethicists, and researchers engaged in DoC clinical trials to advance ethical study design and deployment in this complex yet crucial area of investigation.

The neuroethics of disorders of consciousness: a brief history of evolving ideas

Neuroethical questions raised by recent advances in the diagnosis and treatment of disorders of consciousness are rapidly expanding, increasingly relevant and yet underexplored. The aim of this thematic review is to provide a clinically applicable framework for understanding the current taxonomy of disorders of consciousness and to propose an approach to identifying and critically evaluating actionable neuroethical issues that are frequently encountered in research and clinical care for this vulnerable population. Increased awareness of these issues and clarity about opportunities for optimizing ethically responsible care in this domain are especially timely given recent surges in critically ill patients with prolonged disorders of consciousness associated with coronavirus disease 2019 around the world. We begin with an overview of the field of neuroethics: what it is, its history and evolution in the context of biomedical ethics at large. We then explore nomenclature used in disorders of consciousness, covering categories proposed by the American Academy of Neurology, the American Congress of Rehabilitation Medicine and the National Institute on Disability, Independent Living and Rehabilitation Research, including definitions of terms such as coma, the vegetative state, unresponsive wakefulness syndrome, minimally conscious state, covert consciousness and the confusional state. We discuss why these definitions matter, and why there has been such evolution in this nosology over the years, from Jennett and Plum in 1972 to the Multi-Society Task Force in 1994, the Aspen Working Group in 2002 and the 2018 American and 2020 European Disorders of Consciousness guidelines. We then move to a discussion of clinical aspects of disorders of consciousness, the natural history of recovery and ethical issues that arise within the context of caring for people with disorders of consciousness. We conclude with a discussion of key challenges associated with assessing residual consciousness in disorders of consciousness, potential solutions and future directions, including integration of crucial disability rights perspectives.

Electrocerebral Signature of Cardiac Death

BACKGROUND

Electroencephalography (EEG) findings following cardiovascular collapse in death are uncertain. We aimed to characterize EEG changes immediately preceding and following cardiac death.

METHODS

We retrospectively analyzed EEGs of patients who died from cardiac arrest while undergoing standard EEG monitoring in an intensive care unit. Patients with brain death preceding cardiac death were excluded. Three events during fatal cardiovascular failure were investigated: (1) last recorded QRS complex on electrocardiogram (QRS₀), (2) cessation of cerebral blood flow (CBF₀) estimated as the time that blood pressure and heart rate dropped below set thresholds, and (3) electrocerebral silence on EEG (EEG₀). We evaluated EEG spectral power, coherence, and permutation entropy at these time points.

RESULTS

Among 19 patients who died while undergoing EEG monitoring, seven (37%) had a comfort-measures-only status and 18 (95%) had a do-not-resuscitate status in place at the time of death. EEG₀ occurred at the time of QRS₀ in five patients and after QRS₀ in two patients (cohort median - 2.0, interquartile range - 8.0 to 0.0), whereas EEG₀ was seen at the time of CBF₀ in six patients and following CBF₀ in 11 patients (cohort median 2.0 min, interquartile range - 1.5 to 6.0). After CBF₀, full-spectrum log power (p < 0.001) and coherence (p < 0.001) decreased on EEG, whereas delta (p = 0.007) and theta (p < 0.001) permutation entropy increased.

CONCLUSIONS

Rarely may patients have transient electrocerebral activity following the last recorded QRS (less than 5 min) and estimated cessation of cerebral blood flow. These results may have implications for discussions around cardiopulmonary resuscitation and organ donation.

Structural and functional connectivity of the ascending arousal network for prediction of outcome in patients with acute disorders of consciousness

To determine the role of early acquisition of blood oxygen level-dependent (BOLD) signals and diffusion tensor imaging (DTI) for analysis of the connectivity of the ascending arousal network (AAN) in predicting neurological outcomes after acute traumatic brain injury (TBI), cardiopulmonary arrest (CPA), or stroke. A prospective analysis of 50 comatose patients was performed during their ICU stay. Image processing was conducted to assess structural and functional connectivity of the AAN. Outcomes were evaluated after 3 and 6 months. Nineteen patients (38%) had stroke, 18 (36%) CPA, and 13 (26%) TBI. Twenty-three patients were comatose (44%), 11 were in a minimally conscious state (20%), and 16 had unresponsive wakefulness syndrome (32%). Univariate analysis demonstrated that measurements of diffusivity, functional connectivity, and numbers of fibers in the gray matter, white matter, whole brain, midbrain reticular formation, and pontis oralis nucleus may serve as predictive biomarkers of outcome depending on the diagnosis. Multivariate analysis demonstrated a correlation of the predicted value and the real outcome for each separate diagnosis and for all the etiologies together. Findings suggest that the above imaging biomarkers may have a predictive role for the outcome of comatose patients after acute TBI, CPA, or stroke.

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.

Caring for an Unconscious Transgender Patient at the End of Life: Ethical Considerations and Implications

Individuals who identify as transgender (trans) or other gender-diverse identities are highly marginalized populations within the United States health care system. Transgender individuals experience a broad range of health disparities leading to devastating health outcomes. Experiences with discrimination and biased care often result in a lack of trust in providers and reduced care seeking, yet providers frequently rely on communication with trans patients to build competence. Consequently, when a trans patient has restricted communication, whether due to biological or psychological reasons, their care can be further disrupted. The nursing code of ethics compels the provision of competent care to all patients, regardless of demographics or gender identity, including individuals with serious illness and injury. This article describes an approach to the provision of affirmative, trans-inclusive care in a palliative nursing context that integrates cultural humility and self-reflection into an established patient care framework. The approach is then applied to identify ethical dilemmas present in the case of a trans patient who arrived at a hospital in an unconscious state following serious injury. Nurses' use of the ethical approach when caring for seriously ill trans patients would represent important progress toward fostering a health care system that provides affirmative, trans-inclusive care.

Research Needs for Prognostic Modeling and Trajectory Analysis in Patients with Disorders of Consciousness

BACKGROUND

The current state of the science regarding the care and prognosis of patients with disorders of consciousness is limited. Scientific advances are needed to improve the accuracy, relevance, and approach to prognostication, thereby providing the foundation to develop meaningful and effective interventions.

METHODS

To address this need, an interdisciplinary expert panel was created as part of the Coma Science Working Group of the Neurocritical Care Society Curing Coma Campaign.

RESULTS

The panel performed a gap analysis which identified seven research needs for prognostic modeling and trajectory analysis ("recovery science") in patients with disorders of consciousness: (1) to define the variables that predict outcomes; (2) to define meaningful intermediate outcomes at specific time points for different endotypes; (3) to describe recovery trajectories in the absence of limitations to care; (4) to harness big data and develop analytic methods to prognosticate more accurately; (5) to identify key elements and processes for communicating prognostic uncertainty over time; (6) to identify health care delivery models that facilitate recovery and recovery science; and (7) to advocate for changes in the health care delivery system needed to advance recovery science and implement already-known best practices.

CONCLUSION

This report summarizes the current research available to inform the proposed research needs, articulates key elements within each area, and discusses the goals and advances in recovery science and care anticipated by successfully addressing these needs.

Proceedings of the First Curing Coma Campaign NIH Symposium: Challenging the Future of Research for Coma and Disorders of Consciousness

Coma and disorders of consciousness (DoC) are highly prevalent and constitute a burden for patients, families, and society worldwide. As part of the Curing Coma Campaign, the Neurocritical Care Society partnered with the National Institutes of Health to organize a symposium bringing together experts from all over the world to develop research targets for DoC. The conference was structured along six domains: (1) defining endotype/phenotypes, (2) biomarkers, (3) proof-of-concept clinical trials, (4) neuroprognostication, (5) long-term recovery, and (6) large datasets. This proceedings paper presents actionable research targets based on the presentations and discussions that occurred at the conference. We summarize the background, main research gaps, overall goals, the panel discussion of the approach, limitations and challenges, and deliverables that were identified.

Recovery from disorders of consciousness: mechanisms, prognosis and emerging therapies

Substantial progress has been made over the past two decades in detecting, predicting and promoting recovery of consciousness in patients with disorders of consciousness (DoC) caused by severe brain injuries. Advanced neuroimaging and electrophysiological techniques have revealed new insights into the biological mechanisms underlying recovery of consciousness and have enabled the identification of preserved brain networks in patients who seem unresponsive, thus raising hope for more accurate diagnosis and prognosis. Emerging evidence suggests that covert consciousness, or cognitive motor dissociation (CMD), is present in up to 15-20% of patients with DoC and that detection of CMD in the intensive care unit can predict functional recovery at 1 year post injury. Although fundamental questions remain about which patients with DoC have the potential for recovery, novel pharmacological and electrophysiological therapies have shown the potential to reactivate injured neural networks and promote re-emergence of consciousness. In this Review, we focus on mechanisms of recovery from DoC in the acute and subacute-to-chronic stages, and we discuss recent progress in detecting and predicting recovery of consciousness. We also describe the developments in pharmacological and electrophysiological therapies that are creating new opportunities to improve the lives of patients with DoC.

Cortical Function in Acute Severe Traumatic Brain Injury and at Recovery: A Longitudinal fMRI Case Study

Differences in the functional integrity of the brain from acute severe brain injury to subsequent recovery of consciousness have not been well documented. Functional magnetic resonance imaging (fMRI) may elucidate this issue as it allows for the objective measurement of brain function both at rest and in response to stimuli. Here, we report the cortical function of a patient with a severe traumatic brain injury (TBI) in a critically ill state and at subsequent functional recovery 9-months post injury. A series of fMRI paradigms were employed to assess sound and speech perception, command following, and resting state connectivity. The patient retained sound perception and speech perception acutely, as indexed by his fMRI responses. Command following was absent acutely, but was present at recovery. Increases in functional connectivity across multiple resting state networks were observed at recovery. We demonstrate the clinical utility of fMRI in assessing cortical function in a patient with severe TBI. We suggest that hallmarks of the recovery of consciousness are associated with neural activity to higher-order cognitive tasks and increased resting state connectivity.

From Awareness to Prognosis: Ethical Implications of Uncovering Hidden Awareness in Behaviorally Nonresponsive Patients

Long-term patient outcomes after severe brain injury are highly variable, and reliable prognostic indicators are urgently needed to guide treatment decisions. Functional neuroimaging is a highly sensitive method of uncovering covert cognition and awareness in patients with prolonged disorders of consciousness, and there has been increased interest in using it as a research tool in acutely brain injured patients. When covert awareness is detected in a research context, this may impact surrogate decisionmaking-including decisions about life-sustaining treatment-even though the prognostic value of covert consciousness is currently unknown. This paper provides guidance to clinicians and families in incorporating individual research results of unknown prognostic value into surrogate decisionmaking, focusing on three potential issues: (1) Surrogate decisionmakers may misinterpret results; (2) Results may create false hope about the prospects of recovery; (3) There may be disagreement about the meaningfulness or relevance of results, and appropriateness of continued care.