The Relationship of the FOUR Score to Patient Outcome: A Systematic Review

Development of a nomogram for predicting the outcome in patients with prolonged disorders of consciousness based on the multimodal evaluative information

OBJECTIVE

To establish a nomogram prediction model for the patients with prolonged disorders of consciousness (PDOC) caused by brain injury at six months based on behavioral scale scores, neuroelectro-physiological techniques and hypothalamic-pituitary hormone levels.

METHODS

The clinical data of patients with PDOC who were first diagnosed and hospitalized in the Department of Rehabilitation Medicine of The Affiliated Jiangning Hospital of Nanjing Medical University from March 2023 to July 2024 were collected retrospectively. We performed stratified sampling based on etiology and divided into a training set (121 cases) and a validation set (49 cases) in a ratio of 7:3. After a 6-month follow-up, patients were divided into groups with improved consciousness and those without improved consciousness based on changes in CRS-R scores.Clinical behavioral scores, somatosensory evoked potentials, brainstem auditory evoked potentials, and levels of hypothalamic-pituitary hormones were utilized to identify prognostic factors for prolonged disorders of consciousness. Concurrently, a nomogram prediction model was crafted and validated to forecast the prognosis of patients with prolonged disorders of consciousness. Decision curve analysis (DCA) was subsequently employed to appraise the clinical applicability of this predictive model.

RESULTS

The comparison of clinical data between the training and validation cohorts revealed no significant statistical disparities (P > 0.05). Within the training cohort of 121 PDOC patients, 63 (52.1%)PDOC patients exhibited enhanced consciousness levels. Similarly, in the validation cohort of 49 PDOC patients, 25 (51%) PDOC patients showed improvements in consciousness. Utilizing a combination of random forest analysis, LASSO regression, and multivariate Logistic regression, we identified four key predictive variables: CRS-R score (OR = 1.05, 95%CI 1.02-1.08, P = 0.002), BAEP grading(OR = 0.88, 95%CI 0.79-0.98, P = 0.02), N60 classification (OR = 1.22, 95%CI 1.01-1.48, P = 0.02), and Estradiol (OR = 1.01, 95%CI 1.00-1.02, P = 0.01). The area under the curve (AUC) for the predictive model in the training set was 0.919(95%CI 0.87-0.968),while in the validation set, it was 0.888(95%CI 0.796-0.98). The calibration curves demonstrated a high degree of concordance between predicted probabilities and actual results, suggesting that the model possesses strong discriminative power and calibration accuracy. Furthermore, in the context of clinical decision-making, Decision Curve Analysis indicated a superior net benefit for our predictive model.

CONCLUSION

The nomogram model, which integrates CRS-R score, BAEP grading, N60 classification and Estradiol, provides a comprehensive assessment of short-term prognosis in patients with prolonged disorders of consciousness, demonstrating high accuracy.

Comparison of Glasgow Coma Scale and Full Outline of UnResponsiveness score to assess the level of consciousness in patients admitted to intensive care units and emergency departments: A quantitative systematic review

OBJECTIVES

We aimed to investigate the reliability and validity of the Glasgow Coma Scale (GCS) and the Full Outline of UnResponsiveness (FOUR) score used by nurses and physicians to assess the level of consciousness in patients admitted to intensive care units (ICUs) and emergency departments (EDs).

REVIEW METHOD USED

This systematic review was guided by the Cochrane Handbook for Systematic Reviews of Interventions and followed the reporting standards of the Preferred Reporting Items for Systematic Review and Meta-Analysis Statement.

DATA SOURCES

A systematic search was conducted using the following databases: CINAHL, MEDLINE, and EMBASE.

REVIEW METHODS

All authors performed the study selection process, data collection, and assessment of quality. The following psychometric properties were addressed: inter-rater reliability, internal consistency, and construct validity.

RESULTS

Six articles were included. The GCS and the FOUR scores demonstrated excellent reliability and very strong validity when used by nurses and physicians to assess the level of consciousness in patients admitted to the ICU and ED. The FOUR score demonstrated slightly higher overall reliability and validity than the GCS.

CONCLUSION

This systematic review indicates that the FOUR score is especially suitable for assessing the level of consciousness in patients admitted to the ICU and ED. The FOUR score demonstrated higher reliability and validity than the GCS, making it a promising alternative assessment scale, despite the GCS's longstanding use in clinical practice.

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.

Definitions, diagnostic criteria, and clinical assessment scales in disorders of consciousness

Disorders of consciousness (DoC) are neurologic conditions characterized by severe alteration in level of consciousness. Categories of DoC may include coma, unresponsive wakefulness syndrome/vegetative state, minimally conscious state (MCS; can be further categorized into MCS+ and MCS- based on the presence or absence of language-related behaviors), emergence from MCS, confusional state or delirium, and cognitive motor dissociation (CMD). CMD is a recently defined condition in which the patient fails to demonstrate observable behavioral responses on bedside assessment but demonstrates covert cognitive processing on functional imaging or EEG studies. Accurate differential diagnosis in DoC is aided by adherence to basic principles of assessment, including use of standardized assessment scales. Clinicians should serially administer standardized assessment tools to ensure valid interpretation of results and optimize diagnostic accuracy. Among standardized scales, the Coma Recovery Scale-Revised is most widely used and has the strongest psychometric validity in assessing DoC. The Neurocritical Care Society's Curing Coma Campaign has proposed a slate of DoC common data elements that is expected to improve the consistency and precision of DoC research.

Traumatic brain injury and disorders of consciousness

Trauma is one of the most common causes of disorders of consciousness (DOC) worldwide. Traumatic brain injury (TBI) leads to heterogeneous, multifocal injury via focal brain damage and diffuse axonal injury, causing an acquired network disorder. Recovery occurs through reemergence of dynamic cortical and subcortical networks. Accurate diagnostic evaluation is essential toward promoting recovery and may be more challenging in traumatic than non-traumatic brain injuries. Standardized neurobehavioral assessment is the cornerstone for assessments in the acute, prolonged, and chronic phases of traumatic DOC, while structural and functional neuroimaging, tractography, nuclear medicine studies, and electrophysiologic techniques assist with differentiation of DOC states and prognostication. Prognosis for recovery is better for patients with TBI than those with non-traumatic brain injuries, and the timeline for recovery is longer. The majority of patients experience improvement in their DOC within the first year post-injury, but recovery can continue for five and even ten years after TBI. Pharmacologic therapy and device-related neuromodulation represent important areas for future research.

Complex auditory regularity processing across levels of consciousness in coma: Stage 1 Registered Report

A key question for the scientific study of consciousness is whether it is possible to identify specific features in brain activity that are uniquely linked to conscious experience. This question has important implications for the development of markers to detect covert consciousness in unresponsive patients. In this regard, many studies have focused on investigating the neural response to complex auditory regularities. One noteworthy example is the local global paradigm, which allows for the investigation of auditory regularity encoding at the 'global' level, based on the repetition of groups of sounds. The inference of global regularities is thought to depend on conscious access to such complex auditory stimuli as mostly shown in chronic stages of disorders of consciousness patients. However, whether global regularity encoding can identify covert consciousness along the consciousness spectrum including earlier stages of these disorders remains controversial. Here, we aim to fill this gap by investigating whether the inference of global auditory regularities can occur in acute coma, in the absence of consciousness, and how this may be modulated by the severity of the patients' clinical condition and consciousness level measured using the Full Outline of UnResponsiveness (FOUR) score. We will acquire 63-channel continuous electroencephalography to measure the neural response to global auditory regularity in comatose patients (N = 30) during the first day after cardiac arrest, when patients are unconscious, sedated and under normothermia, and during the second day (with reduced or absent sedation and body temperature control). We hypothesize that global regularity encoding will persist in the absence of consciousness independent of patient outcome, observed as above chance decoding of the neural response to global regularities using multivariate decoding analyses. We further hypothesize that decoding performance will positively correlate with the FOUR score, which indexes consciousness level, and typically improves between the first and second day after coma onset following cardiac arrest in patients with favourable outcome. In an exploratory analysis, we will also evaluate whether global regularity encoding may be influenced by the patients' clinical management, specifically sedation, also shown to affect global deviance detection. Our results will shed light on the neurophysiological correlates of complex auditory regularity processing in unconscious patients and on the link to residual levels of consciousness during the underexplored state of coma upon the first days after cardiac arrest.

The Predictive Validity of the Full Outline of UnResponsiveness Score Compared to the Glasgow Coma Scale in the Intensive Care Unit: A Systematic Review

The Full Outline of UnResponsiveness (FOUR) score was developed to overcome the limitations of the Glasgow Coma Scale (GCS) when assessing individuals with impaired consciousness. We sought to review the evidence regarding the predictive validity of the GCS and FOUR score in intensive care unit (ICU) settings. This review was prospectively registered in PROSPERO (CRD42023420528). Systematic searches of CINAHL, MEDLINE, and Embase were undertaken. Prospective observational studies were included if both GCS and FOUR score were assessed in adults during ICU admission and if mortality and/or validated functional outcome measure scores were collected. Studies were excluded if they exclusively investigated patients with traumatic brain injury. Screening, data extraction, and quality assessment using the Quality in Prognosis Studies tool were conducted by two reviewers. Twenty studies of poor to moderate quality were included. Many studies only included patients with neurological illness and excluded sedated patients, despite high proportions of intubated patients. The FOUR score achieved higher area under the receiver operating characteristic curve values for mortality prediction compared with the GCS, and the FOUR score achieved significantly higher area under the receiver operating characteristic curve values for predictions of ICU mortality. Both coma scales showed similar accuracy in predicting "unfavorable" functional outcome. The FOUR score appeared to be more responsive than the GCS in the ICU, as most patients with a GCS score of 3 obtained FOUR scores between 1 and 8 due to preserved brainstem function. The FOUR score may be superior to the GCS for predicting mortality in ICU settings. Further adequately powered studies with clear, reliable methods for assessment of index and outcome scores are required to clarify the predictive performance of both coma scales in ICUs. Inclusion of sedated patients may improve generalizability of findings in general ICU populations.

The Glasgow Coma Scale and Full Outline of Unresponsiveness score evaluation to predict patient outcomes with neurological illnesses in intensive care units in West Bank: a prospective cross-sectional study

BACKGROUND

Determining the clinical neurological state of the patient is essential for making decisions and forecasting results. The Glasgow Coma Scale and the Full Outline of Unresponsiveness (FOUR) Scale are commonly used tools for measuring behavioral consciousness. This study aims to compare scales among patients with neurological disorders in intensive care units (ICUs) in the West Bank.

METHODS

A prospective cross-sectional design was employed. All patients admitted to ICUs who met inclusion criteria were involved in this study. Data were collected from from An-Najah National University, Al-Watani, and Rafedia Hospital. Both tools were used to collect data.

RESULTS

A total of 84 patients were assessed, 69.0% of the patients were male, and the average length of stay was 6.4 days. The mean score on the Glasgow Coma scale was 11.2 on admission 11.6 after 48 hours, and 12.2 on discharge. The mean FOUR Scale score was 12.2 on admission, 12.4 after 48 hours, and 12.5 at discharge.

CONCLUSIONS

This study indicates that both the Glasgow Coma Scale and the FOUR scale are effective in predicting outcomes for neurologically deteriorated critically ill patients. However, the FOUR scale proved to be more reliable when assessing outcomes in ICU patients.

Comparison of the Prognostic Accuracy of Full Outline of Unresponsiveness (FOUR) Score with Glasgow Coma Scale (GCS) Score among Patients with Traumatic Brain Injury in a Tertiary Care Center

Objectives  The Glasgow Coma Scale (GCS) is widely used and considered the gold standard in assessing the consciousness of patients with traumatic brain injury. However, some significant limitations, like the considerable variations in interobserver reliability and predictive validity, were the reason for developing the Full Outline of Unresponsiveness (FOUR) score. The current study aims to compare the prognostic accuracy of the FOUR score with the GCS score for in-hospital mortality and morbidity among patients with traumatic brain injury. Materials and Methods  A prospective cohort study was conducted, where 237 participants were selected by consecutive sampling from a tertiary care center. These patients were assessed with the help of GCS and FOUR scores within 6 hours of admission, and other clinical parameters were also noted. The level of consciousness was checked every day with the help of GCS and FOUR scores until their last hospitalization day. Glasgow Outcome Scale was used to assess their outcome on the last day of hospitalization. The GCS and FOUR scores were compared, and data were analyzed by descriptive and inferential statistics. The chi-square test, independent Student's t -test, and receiver operating characteristic analysis were used for inferential analysis. Results  The area under the curve (AUC) for the GCS score at the 6th hour for predicting mortality was 0.865 with a cutoff value of 5.5, and it yields a sensitivity of 87% and a specificity of 64%. The AUC for FOUR scores at the 6th hour for predicting the mortality was 0.893, with a cutoff value of 5.5, and it yields a sensitivity of 87% and a specificity of 73%. Conclusion  The current study shows that, as per the AUC of GCS and FOUR scores, their sensitivity was equal, but specificity was higher in the FOUR score. So, the FOUR score has higher accuracy than the GCS score in the prediction of mortality among traumatic brain injury patients.

Clinical Grading Scales and Neuroprognostication in Acute Brain Injury

Prediction of neurological clinical outcome after acute brain injury is critical because it helps guide discussions with patients and families and informs treatment plans and allocation of resources. Numerous clinical grading scales have been published that aim to support prognostication after acute brain injury. However, the development and validation of clinical scales lack a standardized approach. This in turn makes it difficult for clinicians to rely on prognostic grading scales and to integrate them into clinical practice. In this review, we discuss quality measures of score development and validation and summarize available scales to prognosticate outcomes after acute brain injury. These include scales developed for patients with coma, cardiac arrest, ischemic stroke, nontraumatic intracerebral hemorrhage, subarachnoid hemorrhage, and traumatic brain injury; for each scale, we discuss available validation studies.

Early Shared Decision-Making for Older Adults with Traumatic Brain Injury: Using Time-Limited Trials and Understanding Their Limitations

Older adults account for a disproportionate share of the morbidity and mortality after traumatic brain injury (TBI). Predicting functional and cognitive outcomes for individual older adults after TBI is challenging in the acute phase of injury. Given that neurologic recovery is possible and uncertain, life-sustaining therapy may be pursued initially, even if for some, there is a risk of survival to an undesired level of disability or dependence. Experts recommend early conversations about goals of care after TBI, but evidence-based guidelines for these discussions or for the optimal method for communicating prognosis are limited. The time-limited trial (TLT) model may be an effective strategy for managing prognostic uncertainty after TBI. TLTs can provide a framework for early management: specific treatments or procedures are used for a defined period of time while monitoring for an agreed-upon outcome. Outcome measures, including signs of worsening and improvement, are defined at the outset of the trial. In this Viewpoint article, we discuss the use of TLTs for older adults with TBI, their potential benefits, and current challenges to their application. Three main barriers limit the implementation of TLTs in these scenarios: inadequate models for prognostication; cognitive biases faced by clinicians and surrogate decision-makers, which may contribute to prognostic discordance; and ambiguity regarding appropriate endpoints for the TLT. Further study is needed to understand clinician behaviors and surrogate preferences for prognostic communication and how to optimally integrate TLTs into the care of older adults with TBI.

Comparison of Glasgow Coma Scale and Full Outline of UnResponsiveness score for prediction of in-hospital mortality in traumatic brain injury patients: a systematic review and meta-analysis

BACKGROUND

Currently, Glasgow Coma Scale (GCS) is used to assess patients' level of consciousness. Although this tool is highly popular in clinical settings, it has various limitations that reduce its applicability in certain situations. This had led researchers to look for alternative scoring systems. This study aims to compare the value of GCS and Full Outline of UnResponsiveness (FOUR) score for prediction of mortality in traumatic brain injury (TBI) patients through a systematic review and meta-analysis.

METHOD

Online databases of Medline, Embase, Scopus, and Web of Science were searched until the end of July 2022 for studies that had compared GCS and FOUR score in TBI patients. Interested outcomes were mortality and unfavorable outcome (mortality + disability). Findings are reported as area under the curve (AUC) sensitivity, specificity, and diagnostic odds ratio.

RESULTS

20 articles (comprised of 2083 patients) were included in this study. AUC of GCS and FOUR score for prediction of in-hospital mortality after TBI was 0.92 (95% CI 0.80-0.91) and 0.91 (95% CI 0.88-0.93) respectively. The diagnostic odds ratio of the two scores for prediction of in-hospital mortality after TBI was 44.51 (95% CI 23.58-84.03) for GCS and 45.16 (95% CI 24.25-84.09) for FOUR score. As for prediction of unfavorable outcome after TBI, AUC of GCS and FOUR score were 0.95 (95% CI 0.93 to 0.97) and 0.93 (95% CI 0.91-0.95), respectively. The diagnostic odds ratios for prediction of unfavorable outcome after TBI were 66.31 (95% CI 35.05-125.45) for GCS and 45.39 (95% CI 23.09-89.23) for FOUR score.

CONCLUSION

Moderate level of evidence showed that the value of GCS and FOUR score in the prediction of in-hospital mortality and unfavorable outcome is comparable. The similar performance of these scores in assessment of TBI patients gives the medical staff the option to use either one of them according to the situation at hand.

Behavioral assessment scale of consciousness for nonhuman primates: A Delphi study

OBJECTIVE

Nonhuman primates (NHPs) are suitable for being model animals in the study of consciousness and loss of consciousness (LoC) with a similar brain structure and function to humans. However, there is no effective consciousness assessment scale for them. This study aimed to develop a behavioral assessment scale of consciousness for NHPs.

METHODS

We constructed an initial indicator framework based on the clinical consciousness disorder assessment scales and the physiological characteristics, consciousness, and arousal behavior of NHPs. A two-round online Delphi method was conducted by a multidisciplinary expert panel to construct a behavioral assessment scale of consciousness for NHPs. The indicators and descriptions were revised according to the experts' feedback and then sent out for repeated consultations along with a summary of the results of the previous round of consultations. The accepted competencies of indicators were established with mean scores in two scoring criteria (importance and feasibility) ≥4.0, agreement rate with a rating of importance or essential ≥70.0%, and a coefficient of variation ≤0.25, as well as discussions of the research group.

RESULTS

Consensus was achieved after the second round of consultations, which was completed by 28 experts who specialized in rehabilitation, neuroscience, psychology, neurosurgery, and neurology. A new behavioral assessment scale of consciousness for NHPs, including 37 items organized hierarchically within seven dimensions including visual function, auditory function, motor function, orofacial movements, arousal, brainstem reflexes, and respiration, was developed in this study.

CONCLUSIONS

This study has successfully developed a behavioral assessment scale for measuring the conscious state of NHPs or NHP models with LoC. This tool is expected to facilitate future research into the underlying mechanisms of consciousness by providing a detailed and comprehensive means of measurement.

A prediction model of clinical outcomes in prolonged disorders of consciousness: A prospective cohort study

Objective

This study aimed to establish and validate a prediction model for clinical outcomes in patients with prolonged disorders of consciousness (pDOC).

Methods

A total of 170 patients with pDOC enrolled in our rehabilitation unit were included and divided into training (n = 119) and validation sets (n = 51). Independent predictors for improved clinical outcomes were identified by univariate and multivariate logistic regression analyses, and a nomogram model was established. The nomogram performance was quantified using receiver operating curve (ROC) and calibration curves in the training and validated sets. A decision curve analysis (DCA) was performed to evaluate the clinical usefulness of this nomogram model.

Results

Univariate and multivariate logistic regression analyses indicated that age, diagnosis at entry, serum albumin (g/L), and pupillary reflex were the independent prognostic factors that were used to construct the nomogram. The area under the curve in the training and validation sets was 0.845 and 0.801, respectively. This nomogram model showed good calibration with good consistency between the actual and predicted probabilities of improved outcomes. The DCA demonstrated a higher net benefit in clinical decision-making compared to treating all or none.

Conclusion

Several feasible, cost-effective prognostic variables that are widely available in hospitals can provide an efficient and accurate prediction model for improved clinical outcomes and support clinicians to offer suitable clinical care and decision-making to patients with pDOC and their family members.

Relationship between consciousness level and perfusion computed tomography in patients with prolonged disorders of consciousness

PURPOSE

We assessed the relationship between consciousness level and values of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time to peak (TTP) obtained by whole-brain perfusion computed tomography (pCT) in patients with prolonged disorders of consciousness (pDOC).

METHODS

This study included 29 patients in vegetative state (VS), 34 with minimally consciousness state minus (MCS-), and 13 with minimally consciousness state plus (MCS+). All patients were evaluated using the Coma Recovery Scale-Revised (CRS-R), the Glasgow Coma Scale (GCS), and the Full Outline of UnResponsiveness (FOUR). The values of CBF, CBV, MTT, and TTP were obtained from patients who underwent pCT. Differences in CBF, CBV, MTT, and TTP were compared between the three types of pDOC. Correlations between the CRS-R, GCS, and FOUR scores and the pCT results were analyzed.

RESULTS

Among the three groups, patients in VS showed a significantly decreased CBF in the bilateral frontal lobe, thalamus, temporal lobe, occipital lobe, brainstem, and damaged part. CBV was significantly reduced in patients with VS in the bilateral frontal lobe, thalamus, temporal lobe, brainstem, and damaged part. The total CRS-R, GCS, and FOUR scores were positively correlated with CBF, CBV, and TTP in almost all regions of interest.

CONCLUSION

Reductions in CBF and CBV calculated with pCT are associated with impaired consciousness and perfusion CT could be a promising tool in evaluating the conscious level in patients with pDOC.

Functional NIRS to detect covert consciousness in neurocritical patients

OBJECTIVE

This pilot study assesses the feasibility to detect covert consciousness in clinically unresponsive patients by means of functional near infrared spectroscopy (fNIRS) in a real intensive care unit setting. We aimed to verify if the hemodynamic response to familiar music measured with fNIRS varies according to the level consciousness of the patients.

METHODS

22 neurocritical patients and 6 healthy controls were included. The experiment consisted in 3 subsequent blocks including a first resting state recording, a period of music playback and a second resting state recording. fNIRS measurement were performed on each subject with two optodes on the forehead. Main oscillatory frequencies of oxyhemoglobin signal were analyzed. Spectral changes of low frequency oscillations (LFO) between subsequent experimental blocks were used as a marker of cortical response. Cortical response was compared to the level of consciousness of the patients and their functional outcome, through validated clinical scores.

RESULTS

Cortical hemodynamic response to music on the left prefrontal brain was associated with the level of consciousness of the patients and with their clinical outcome after three months.

CONCLUSIONS

Variations in LFO spectral power measured with fNIRS may be a new marker of cortical responsiveness to detect covert consciousness in neurocritical patients. Left prefrontal cortex may play an important role in the perception of familiar music.

SIGNIFICANCE

We showed the feasibility of a simple fNIRS approach to detect cortical response in the real setting of an intensive care unit.

Behavioral Assessment of Patients with Disorders of Consciousness

Severe brain injury is associated with a period of impaired level of consciousness that can last from days to months and results in chronic impairment. Systematic assessment of level of function in patients with disorders of consciousness (DoC) is critical for diagnosis, prognostication, and evaluation of treatment efficacy. Approximately 40% of patients who are thought to be unconscious based on clinical bedside behavioral assessment demonstrate some signs of consciousness on standardized behavioral assessment. This finding, in addition to a growing body of literature demonstrating the advantages of standardized behavioral assessment of DoC, has led multiple professional societies and clinical guidelines to recommend standardized assessment over routine clinical evaluation of consciousness. Nevertheless, even standardized assessment is susceptible to biases and misdiagnosis, and examiners should consider factors, such as fluctuating arousal and aphasia, that may confound evaluation. We review approaches to behavioral assessment of consciousness, recent clinical guideline recommendations for use of specific measures to evaluate patients with DoC, and strategies for mitigating common biases that may confound the examination.

A Comparison of Full Outline of UnResponsiveness Score with Glasgow Coma Scale Score in predicting Outcomes among Patients with Altered Mental Status admitted to the Critical Care Unit

Aim

Comparison of the Full Outline of UnResponsiveness (FOUR) score with the Glasgow Coma Scale (GCS) score to find the better scoring system for predicting outcomes among altered sensorium patients in the critical care unit.

Materials and methods

This is a prospective observational study. It included 100 patients of altered sensorium, whose GCS and FOUR scores were calculated at admission and followed up till death or discharge to note the outcome. Individual demographics and diagnosis were recorded, and the results were analyzed statistically.

Results

The correlation between the two scores was excellent, with the Spearman's correlation coefficient of 0.88. Discrimination ability of the two scoring systems, as assessed by the area under the receiver operating characteristic curve, was 0.778 for GCS score and 0.883 for FOUR score (p <0.001). When area under the curve (AUC) was calculated exclusively in stroke cases, it was 0.836 for GCS score and 0.944 for FOUR score. Among nonstroke cases, the AUC was 0.756 and 0.859, respectively. However, the 95% confidence limits were overlapping among the corresponding scores.

Conclusion

The above study concludes that there is a good correlation between GCS and FOUR scores in predicting outcomes. Superiority of FOUR score could not be established statistically in view of overlapping confidence limits. However, it performed at par with GCS in prognosticating mortality among patients with altered sensorium.

Clinical significance

In critically ill patients with altered sensorium, explaining the prognosis to the attendants is a challenge for the physician. The commonly used GCS score has several shortcomings, especially in intubated patients. Use of the FOUR score can overcome these shortcomings and help in prognostication of these patients. In view of its good correlation with GCS score and equal efficacy in predicting outcomes in varied etiologies, it can be used as a good alternative to the GCS score.

How to cite this article

Javvaji PK, Nagatham P, Venkata RR, Puttam H, John SK, Karavalla H, et al. A Comparison of Full Outline of UnResponsiveness Score with Glasgow Coma Scale Score in Predicting Outcomes among Patients with Altered Mental Status Admitted to the Critical Care Unit. Indian J Crit Care Med 2022;26(2):210–215.

Protocol to assess performance of crisis standards of care guidelines for clinical triage

During the COVID-19 pandemic, US states developed Crisis Standards of Care (CSC) algorithms to triage allocation of scarce resources to maximize population-wide benefit. While CSC algorithms were developed by ethical debate, this protocol guides their quantitative assessment. For CSC algorithms, this protocol addresses (1) adapting algorithms for empirical study, (2) quantifying predictive accuracy, and (3) simulating clinical decision-making. This protocol provides a framework for healthcare systems and governments to test the performance of CSC algorithms to ensure they meet their stated ethical goals.

For complete details on the use and execution of this protocol, please refer to Jezmir et al. (2021).

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Scoring with Crisis Standards of Care (CSC) triage algorithms

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Assessing the predictive accuracy of triage algorithms

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Simulating clinical decision-making by triage algorithms

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Troubleshooting disease severity, comorbidity scoring, and ties

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.

Early abolition of cough reflex predicts mortality in deeply sedated brain-injured patients

Background

Deep sedation may hamper the detection of neurological deterioration in brain-injured patients. Impaired brainstem reflexes within the first 24 h of deep sedation are associated with increased mortality in non-brain-injured patients. Our objective was to confirm this association in brain-injured patients.

Methods

This was an observational prospective multicenter cohort study involving four neuro-intensive care units. We included acute brain-injured patients requiring deep sedation, defined by a Richmond Assessment Sedation Scale (RASS) < −3. Neurological assessment was performed at day 1 and included pupillary diameter, pupillary light, corneal and cough reflexes, and grimace and motor response to noxious stimuli. Pre-sedation Glasgow Coma Scale (GCS) and Simplified Acute Physiology Score (SAPS-II) were collected, as well as the cause of death in the Intensive Care Unit (ICU).

Results

A total of 137 brain-injured patients were recruited, including 70 (51%) traumatic brain-injured patients, 40 (29%) vascular (subarachnoid hemorrhage or intracerebral hemorrhage). Thirty patients (22%) died in the ICU. At day 1, the corneal (OR 2.69, p = 0.034) and cough reflexes (OR 5.12, p = 0.0003) were more frequently abolished in patients that died in the ICU. In a multivariate analysis, abolished cough reflex was associated with ICU mortality after adjustment to pre-sedation GCS, SAPS-II, RASS (OR: 5.19, 95% CI [1.92–14.1], p = 0.001) or dose of sedatives (OR: 8.89, 95% CI [2.64–30.0], p = 0.0004).

Conclusion

Early (day 1) cough reflex abolition is an independent predictor of mortality in deeply sedated brain-injured patients. Abolished cough reflex likely reflects a brainstem dysfunction that might result from the combination of primary and secondary neuro-inflammatory cerebral insults revealed and/or worsened by sedation.

Automated pupillometry and the FOUR score - what is the diagnostic benefit in neurointensive care?

Introduction

The Glasgow Coma Scale (GCS) and visual inspection of pupillary function are routine measures to monitor patients with impaired consciousness and predict their outcome in the neurointensive care unit (neuro-ICU). Our aim was to compare more recent measures, i.e. FOUR score and automated pupillometry, to standard monitoring with the GCS and visual inspection of pupils.

Methods

Supervised trained nursing staff examined a consecutive sample of patients admitted to the neuro-ICU of a tertiary referral centre using GCS and FOUR score and assessing pupillary function first by visual inspection and then by automated pupillometry. Clinical outcome was evaluated 6 months after admission using the Glasgow Outcome Scale-Extended.

Results

Fifty-six consecutive patients (median age 63 years) were assessed a total of 234 times. Of the 36 patients with at least one GCS score of 3, 13 had a favourable outcome. All seven patients with at least one FOUR score of ≤ 3 had an unfavourable outcome, which was best predicted by a low “brainstem” sub-score. Compared to automated pupillometry, visual assessment underestimated pupillary diameters (median difference, 0.4 mm; P = 0.006). Automated pupillometry detected a preserved pupillary light reflex in 10 patients, in whom visual inspection had missed pupillary constriction.

Discussion

Training of nursing staff to implement frequent monitoring of patients in the neuro-ICU with FOUR score and automated pupillometry is feasible. Both measures provide additional clinical information compared to the GCS and visual assessment of pupillary function, most importantly a more granular classification of patients with low levels of consciousness by the FOUR score.

Resting-State NIRS-EEG in Unresponsive Patients with Acute Brain Injury: A Proof-of-Concept Study

BACKGROUND

Neurovascular-based imaging techniques such as functional MRI (fMRI) may reveal signs of consciousness in clinically unresponsive patients but are often subject to logistical challenges in the intensive care unit (ICU). Near-infrared spectroscopy (NIRS) is another neurovascular imaging technique but low cost, can be performed serially at the bedside, and may be combined with electroencephalography (EEG), which are important advantages compared to fMRI. Combined NIRS-EEG, however, has never been evaluated for the assessment of neurovascular coupling and consciousness in acute brain injury.

METHODS

We explored resting-state oscillations in eight-channel NIRS oxyhemoglobin and eight-channel EEG band-power signals to assess neurovascular coupling, the prerequisite for neurovascular-based imaging detection of consciousness, in patients with acute brain injury in the ICU (n = 9). Conscious neurological patients from step-down units and wards served as controls (n = 14). Unsupervised adaptive mixture-independent component analysis (AMICA) was used to correlate NIRS-EEG data with levels of consciousness and clinical outcome.

RESULTS

Neurovascular coupling between NIRS oxyhemoglobin (0.07-0.13 Hz) and EEG band-power (1-12 Hz) signals at frontal areas was sensitive and prognostic to changing consciousness levels. AMICA revealed a mixture of five models from EEG data, with the relative probabilities of these models reflecting levels of consciousness over multiple days, although the accuracy was less than 85%. However, when combined with two channels of bilateral frontal neurovascular coupling, weighted k-nearest neighbor classification of AMICA probabilities distinguished unresponsive patients from conscious controls with > 90% accuracy (positive predictive value 93%, false discovery rate 7%) and, additionally, identified patients who subsequently failed to recover consciousness with > 99% accuracy.

DISCUSSION

We suggest that NIRS-EEG for monitoring of acute brain injury in the ICU is worthy of further exploration. Normalization of neurovascular coupling may herald recovery of consciousness after acute brain injury.

Brainstem dysfunction in critically ill patients

The brainstem conveys sensory and motor inputs between the spinal cord and the brain, and contains nuclei of the cranial nerves. It controls the sleep-wake cycle and vital functions via the ascending reticular activating system and the autonomic nuclei, respectively. Brainstem dysfunction may lead to sensory and motor deficits, cranial nerve palsies, impairment of consciousness, dysautonomia, and respiratory failure. The brainstem is prone to various primary and secondary insults, resulting in acute or chronic dysfunction. Of particular importance for characterizing brainstem dysfunction and identifying the underlying etiology are a detailed clinical examination, MRI, neurophysiologic tests such as brainstem auditory evoked potentials, and an analysis of the cerebrospinal fluid. Detection of brainstem dysfunction is challenging but of utmost importance in comatose and deeply sedated patients both to guide therapy and to support outcome prediction. In the present review, we summarize the neuroanatomy, clinical syndromes, and diagnostic techniques of critical illness-associated brainstem dysfunction for the critical care setting.

The current significance of the FOUR score: A systematic review and critical analysis of the literature

BACKGROUND

The Full Outline of Un-Responsiveness Score (FOURs) is a scale for clinical assessment of consciousness that was introduced to overcome disadvantages of the widely accepted Glasgow Coma Scale (GCS).

OBJECTIVE

To carry out a systematic review and critical analysis of the available literature on the clinical application of FOURs and perform a comparison to GCS, in terms of reliability and predictive value.

METHODS

Initial search retrieved a total of 147 papers. After applying strict inclusion criteria and further article selection to overcome data heterogeneity, a statistical comparison of inter-rater reliability, in-hospital mortality and long-term outcome prediction between the two scales in the adult and pediatric population was done.

RESULTS

Even though FOURs is more complicated than GCS, its application remains quite simple. Its reliability, validity and predictive value have been supported by an increasing number of studies, especially in critical care. A statistically significant difference (p = .034) in predicting in-hospital mortality in adults, in favor of FOURs when compared to GCS, was found. However, whether it poses a clinically significant advantage in detecting patients' deterioration and outcome prediction, compared to other scaling systems, remains unclear.

CONCLUSIONS

Further studies are needed to discern the FOURs' clinical usefulness, especially in patients in non-critical condition, with milder disorders of consciousness.