The Glasgow Coma Score: reliable evidence?

Quantitative Electroencephalography Analysis for Improved Assessment of Consciousness Levels in Deep Coma Patients Using a Proposed Stimulus Stage

"Coma" is defined as an inability to obey commands, to speak, or to open the eyes. So, a coma is a state of unarousable unconsciousness. In a clinical setting, the ability to respond to a command is often used to infer consciousness. Evaluation of the patient's level of consciousness (LeOC) is important for neurological evaluation. The Glasgow Coma Scale (GCS) is the most widely used and popular scoring system for neurological evaluation and is used to assess a patient's level of consciousness. The aim of this study is the evaluation of GCSs with an objective approach based on numerical results. So, EEG signals were recorded from 39 patients in a coma state with a new procedure proposed by us in a deep coma state (GCS: between 3 and 8). The EEG signals were divided into four sub-bands as alpha, beta, delta, and theta, and their power spectral density was calculated. As a result of power spectral analysis, 10 different features were extracted from EEG signals in the time and frequency domains. The features were statistically analyzed to differentiate the different LeOC and to relate with the GCS. Additionally, some machine learning algorithms have been used to measure the performance of the features for distinguishing patients with different GCSs in a deep coma. This study demonstrated that GCS 3 and GCS 8 patients were classified from other levels of consciousness in terms of decreased theta activity. To the best of our knowledge, this is the first study to classify patients in a deep coma (GCS between 3 and 8) with 96.44% classification performance.

Those who speak survive: the value of the verbal component of GCS in trauma

Aim

To evaluate the value of the individual components of GCS in predicting the survival of trauma patients in the Emergency Department.

Methods

Trauma patients who were admitted for more than 24 h or died after arrival at Al-Ain Hospital from January 2014 to December 2017 were studied. Children < 16 years, elderly > 80 years, patients with facial injuries, those intubated in the ER, and those with missing primary outcomes were excluded. Demography, vital signs, Glasgow Coma Scale (GCS), GCS components, Injury Severity Score (ISS), head AIS, and death were compared between those who died and those who survived. Factors with a p value of < 0.1 were entered into a backward likelihood logistic regression model to define factors that predict death.

Results

A total of 2548 patients were studied, out of whom 11 (0.4%) died. The verbal component of GCS (p < 0.001) and the ISS (p = 0.047) were the only significant predictors for death in the logistic regression model. The AUC (95% CI) of the GCS-VR was 0.763 (0.58–0.95), p = 0.003. The best point of GCS-VR that predicted survival was 5, having a sensitivity of 97%, a specificity of 54.5%, positive predictive value of 99. 8%, negative predictive value of 7.3%, and likelihood ratio of 2.13.

Conclusion

In general trauma patients, acute trauma care professionals can use GCS-VR to predict survival when clinical condition permits instead of the total GCS score or ISS.

Interobserver Reliability of Glasgow Coma Scale Scores for Intensive Care Unit Patients

BACKGROUND

Intensive care units frequently use the Glasgow Coma Scale to objectively assess patients' levels of consciousness. Interobserver reliability of Glasgow Coma Scale scores is critical in determining the degree of impairment.

OBJECTIVE

To evaluate interobserver reliability of intensive care unit patients' Glasgow Coma Scale scores. Methods This prospective observational study evaluated Glasgow Coma Scale scoring agreement among 21 intensive care unit nurses and 2 independent researchers who assessed 202 patients with neurosurgical or neurological diseases. Each assessment was completed independently and within 1 minute. Participants had no knowledge of the others' assessments.

RESULTS

Agreement between Glasgow Coma Scale component and sum scores recorded by the 2 researchers ranged from 89.5% to 95.9% (P = .001). Significant agreement among nurses and the 2 researchers was found for eye response (73.8%), motor response (75.0%), verbal response (68.1%), and sum scores (62.4%) (all P = .001). Significant agreement among nurses and the 2 researchers (55.2%) was also found for sum scores of patients with sum scores of 10 or less (P = .03).

CONCLUSIONS

Although the study showed near-perfect agreement between the 2 researchers' Glasgow Coma Scale scores, agreement among nurses and the 2 researchers was moderate (not near perfect) for subcomponent and sum scores. Accurate Glasgow Coma Scale evaluation requires that intensive care unit nurses have adequate knowledge and skills. Educational strategies such as simulations or orientation practice with a preceptor nurse can help develop such skills.

Factors Influencing the Reliability of the Glasgow Coma Scale: A Systematic Review

BACKGROUND

The Glasgow Coma Scale (GCS) characterizes patients with diminished consciousness. In a recent systematic review, we found overall adequate reliability across different clinical settings, but reliability estimates varied considerably between studies, and methodological quality of studies was overall poor. Identifying and understanding factors that can affect its reliability is important, in order to promote high standards for clinical use of the GCS.

OBJECTIVE

The aim of this systematic review was to identify factors that influence reliability and to provide an evidence base for promoting consistent and reliable application of the GCS.

METHODS

A comprehensive literature search was undertaken in MEDLINE, EMBASE, and CINAHL from 1974 to July 2016. Studies assessing the reliability of the GCS in adults or describing any factor that influences reliability were included. Two reviewers independently screened citations, selected full texts, and undertook data extraction and critical appraisal. Methodological quality of studies was evaluated with the consensus-based standards for the selection of health measurement instruments checklist. Data were synthesized narratively and presented in tables.

RESULTS

Forty-one studies were included for analysis. Factors identified that may influence reliability are education and training, the level of consciousness, and type of stimuli used. Conflicting results were found for experience of the observer, the pathology causing the reduced consciousness, and intubation/sedation. No clear influence was found for the professional background of observers.

CONCLUSION

Reliability of the GCS is influenced by multiple factors and as such is context dependent. This review points to the potential for improvement from training and education and standardization of assessment methods, for which recommendations are presented.

The Glasgow Coma Scale and evidence-informed practice: a critical review of where we are and where we need to be

AIMS AND OBJECTIVES

This paper aims to critically consider the evidence since the Glasgow Coma Scale was first launched, reflecting on how that evidence has shaped practice. It illustrates the lack of clarity and consensus about the use of the tool in practice and draws upon existing evidence to determine the route to clarity for an evidence-informed approach to practice.

BACKGROUND

The Glasgow Coma Scale has permeated and influenced practice for over 40 years, being well-established worldwide as the key tool for assessing level of consciousness. During this time, the tool has been scrutinised, evaluated, challenged and re-launched in a plethora of publications. This has led to an insight into the challenges, and to some extent the opportunities, in using the Glasgow Coma Scale in practice but has also resulted in a lack of clarity.

DESIGN

This is a discursive paper that invites readers to explore and arrive at a more comprehensive understanding of the Glasgow Coma Scale in practice and is based on searches of Scopus, Web of Knowledge, PubMed, Science Direct and CINAHL databases.

RESULTS

While the Glasgow Coma Scale has been rivalled by other tools in an attempt to improve upon it, a shift in practice to those tools has not occurred. The tool has withstood the test of time in this respect, indicating the need for further research into its use and a clear education strategy to standardise implementation in practice.

CONCLUSION

Further exploration is needed into the application of painful stimuli in using the Glasgow Coma Scale to assess level of consciousness. In addition, a robust educational strategy is necessary to maximise consistency in its use in practice.

RELEVANCE TO CLINICAL PRACTICE

The evidence illustrates inconsistency and confusion in the use of the Glasgow Coma Scale in practice; this has the potential to compromise care and clarity around the issues is therefore necessary.

Observations on the Ethical and Social Aspects of Disorders of Consciousness

The care of chronically unconscious patients raises vexing medical, ethical, and social questions concerning diagnosis, prognosis, communication with family members, and decision making, including the withdrawal of life support. We provide updates on major controversies surrounding disorders of consciousness. Issues such as withdrawal of artificial nutrition and hydration – which had been considered “settled” by many in the medical, legal and ethical communities – have resurfaced under the pressure of social groups and religious authorities. Some assumptions about the level of awareness and the prognosis of vegetative state and minimal conscious patients are questioned by advances in clinical care because of insights produced by neuroscience research techniques, particularly functional neuroimaging. Both the clinical and neuroscience dimensions of disorders of consciousness raise complex issues such as resource allocation and high levels of diagnostic inaccuracies (at least, for the vegetative state). We conclude by highlighting areas needing further research and collaboration.

Usefulness of full outline of unresponsiveness score to predict extubation failure in intubated critically-ill patients: A pilot study

Objective:

To assess the usefulness of the full outline of unresponsiveness (FOUR) score in predicting extubation failure in critically ill intubated patients admitted with disturbed level of conscious in comparison with the Glasgow coma scale (GCS).

Patients and Methods:

All intubated critically ill patients with a disturbed level of consciousness were assessed using both the FOUR score and the GCS. The FOUR score and the GCS were compared regarding their predictive value for successful extubation at 14 days after intubation as a primary outcome measure. The 28-day mortality and the neurological outcome at 3 months were used as secondary outcome measures.

Results:

Eighty-six patients were included in the study. Median age was 63 (50–77) years. Sex–ratio (M/F) was 1.46. On admission, median GCS was 7 (3–10) while median FOUR score was 8.5 (2.3–11). A GCS ≤ 7 predicted the extubation failure at 14 days after intubation with a sensitivity of 88.5% and specificity of 68.3%, whereas a FOUR score <10 predicted the same outcome with a sensitivity of 80.8% and a specificity of 81.7%. The areas under the curves was significantly higher with the FOUR score than with GCS (respectively 0.867 confidence interval [CI]: 95% [0790–0.944] and 0.832 CI: 95% [0.741–0.923]; P = 0.014). When calculated before extubation, FOUR score <12 predicted extubation failure with a sensitivity of 92.3% and a specificity of 85%, whereas a GCS <12 predicted the same outcome with a sensitivity of 73% and a specificity of 61.7%. Both scores had similar accuracy for predicting 28-day mortality and neurological outcome at 3 months.

Conclusion:

The FOUR score is superior to the GCS for the prediction of successful extubation of intubated critically ill patients.

The reliability of the Glasgow Coma Scale: a systematic review

INTRODUCTION

The Glasgow Coma Scale (GCS) provides a structured method for assessment of the level of consciousness. Its derived sum score is applied in research and adopted in intensive care unit scoring systems. Controversy exists on the reliability of the GCS. The aim of this systematic review was to summarize evidence on the reliability of the GCS.

METHODS

A literature search was undertaken in MEDLINE, EMBASE and CINAHL. Observational studies that assessed the reliability of the GCS, expressed by a statistical measure, were included. Methodological quality was evaluated with the consensus-based standards for the selection of health measurement instruments checklist and its influence on results considered. Reliability estimates were synthesized narratively.

RESULTS

We identified 52 relevant studies that showed significant heterogeneity in the type of reliability estimates used, patients studied, setting and characteristics of observers. Methodological quality was good (n = 7), fair (n = 18) or poor (n = 27). In good quality studies, kappa values were ≥0.6 in 85%, and all intraclass correlation coefficients indicated excellent reliability. Poor quality studies showed lower reliability estimates. Reliability for the GCS components was higher than for the sum score. Factors that may influence reliability include education and training, the level of consciousness and type of stimuli used.

CONCLUSIONS

Only 13% of studies were of good quality and inconsistency in reported reliability estimates was found. Although the reliability was adequate in good quality studies, further improvement is desirable. From a methodological perspective, the quality of reliability studies needs to be improved. From a clinical perspective, a renewed focus on training/education and standardization of assessment is required.

Glasgow Coma Scale flow chart: a beginner's guide

The Glasgow Coma Scale (GCS) has been accepted nationally and internationally as a tool to assess depth and duration of consciousness since it was published in 1974. Although it was intended to be an easy and practical bedside tool for any grade of health professional, it is considered to be ambiguous and confusing for infrequent users. Moreover, there has been increasing concern about the accuracy and effectiveness of the GCS observation carried out by these users, which could result from lack of training and dissemination of benchmarking across non-specialist areas. This paper aims to introduce a GCS flow chart to guide users step by step when assessing a patient's level of consciousness.

Pupil evaluation in addition to Glasgow Coma Scale components in prediction of traumatic brain injury and mortality

Background

Early diagnosis and prediction of traumatic brain injury (TBI) is essential for determining treatment strategies and allocating resources. This study evaluated the predictive accuracy of Glasgow Coma Scale (GCS) verbal, motor and eye components alone, or in addition to pupil size and reactivity, for TBI.

Methods

A retrospective cohort analysis of data from 51 425 severely injured patients registered in the Trauma Registry of the German Society for Trauma Surgery from 1993 to 2009 was undertaken. Only directly admitted patients alive on admission and with complete data on GCS, pupil size and pupil reactivity were included. The unadjusted predictive roles of GCS components and pupil parameters, alone or in combination, were modelled using area under the receiver operating characteristic (AUROC) curve analyses and multivariable logistic regression regarding presence of TBI and death.

Results

Some 24 115 patients fulfilled the study inclusion criteria. Best accuracy for outcome prediction was found for pupil reactivity (AUROC 0·770, 95 per cent confidence interval 0·761 to 0·779) and GCS motor component (AUROC 0·797, 0·788 to 0·805), with less accuracy for GCS eye and verbal components. The combination of pupil reactivity and GCS motor component (AUROC 0·822, 0·814 to 0·830) outmatched the predictive accuracy of GCS alone (AUROC 0·808, 0·800 to 0·815). Pupil reactivity and size were significantly correlated (rs = 0·56, P &lt; 0·001). Patients displaying both unequal pupils and fixed pupils were most likely to have TBI (95·1 per cent of 283 patients). Good outcome (Glasgow Outcome Scale score 4 or more) was documented for only 1929 patients (8·0 per cent) showing fixed and bilateral dilated pupils.

Conclusion

The best predictive accuracy for presence of TBI was obtained using the GCS components. Pupil reactivity together with the GCS motor component performed best in predicting death.

Prognostic models for the early care of trauma patients: a systematic review

BACKGROUND

Early identification of major trauma may contribute to timely emergency care and rapid transport to an appropriate health-care facility. Several prognostic trauma models have been developed to improve early clinical decision-making.

METHODS

We systematically reviewed models for the early care of trauma patients that included 2 or more predictors obtained from the evaluation of an adult trauma victim, investigated their quality and described their characteristics.

RESULTS

We screened 4,939 records for eligibility and included 5 studies that derivate 5 prognostic models and 9 studies that validate one or more of these models in external populations. All prognostic models intended to change clinical practice, but none were tested in a randomised clinical trial. The variables and outcomes were valid, but only one model was derived in a low-income population. Systolic blood pressure and level of consciousness were applied as predictors in all models.

CONCLUSIONS

The general impression is that the models perform well in predicting survival. However, there are many areas for improvement, including model development, handling of missing data, analysis of continuous measures, impact and practicality analysis.

Precision and reliability of the Glasgow Coma Scale score among a cohort of Latin American prehospital emergency care providers

INTRODUCTION

The Glasgow Coma Scale (GCS) is the standard measure used to quantify the level of consciousness in patients with head injuries. Rapid and accurate GCS scoring is essential for adequate assessment and treatment of critically sick and injured patients. This study sought out to determine the precision and reliability of the GCS among a cohort of Latin American Critical Care Transport Providers.

METHODS

The study consisted of a cross-sectional design using an Internet-based examination. The evaluation consisted of four focused clinical scenarios with a classification based on severity. For measurement of intra-rater reliability the first and fourth cases were identical. Five minutes were allocated for each scenario. For categorical variables, chi-square testing and Fisher's exact testing were used to assess associations. For all tests, statistical significance was set at the 0.05 level.

RESULTS

A total of 62 providers participated, including 17 physicians and 45 advanced providers (nurses and paramedics). No statistically significant differences were observed between physicians and advanced providers in the correct classification of the individual scenarios. Five of the 17 physicians (29.4%) answered all cases correctly, while none of the 45 advanced providers did (p < 0.001). When evaluating the duplicated cases (Cases 1 and 4), five physicians (29.4%) and 11 advanced providers (24.4%) correctly classified the cases. This difference was not statistically significant.

CONCLUSIONS

This study demonstrated a poor precision and poor reliability in the use of the Glasgow Coma Scale within the study subjects.

Reliability and accuracy of Sequential Organ Failure Assessment (SOFA) scoring

OBJECTIVE

The Sequential Organ Failure Assessment (SOFA) score was developed to quantify the severity of patients' illness, based on the degree of organ dysfunction. This study aimed to evaluate the accuracy and the reliability of SOFA scoring.

DESIGN

Prospective study.

SETTING

Adult intensive care unit (ICU) in a tertiary academic center.

SUBJECTS

Thirty randomly selected patient cases and 20 ICU physicians.

MEASUREMENTS AND MAIN RESULTS

Each physician scored 15 patient cases. The intraclass correlation coefficient was .889 for the total SOFA score. The weighted kappa values were moderate (0.552) for the central nervous system, good (0.634) for the respiratory system, and almost perfect (>0.8) for the other organ systems. To assess accuracy, the physicians' scores were compared with a gold standard based on consensus of two experts. The total SOFA score was correct in 53% (n = 158) of the cases. The mean of the absolute deviations of the recorded total SOFA scores from the gold standard total SOFA scores was 0.82. Common causes of errors were inattention, calculation errors, and misinterpretation of scoring rules.

CONCLUSIONS

The results of this study indicate that the reliability and the accuracy of SOFA scoring among physicians are good. We advise implementation of additional measures to further improve reliability and accuracy of SOFA scoring.

Physician Knowledge of the Glasgow Coma Scale

Appropriate triage is critical to optimizing outcome from battle related injuries. The Glasgow Coma Scale (GCS) is the primary means by which combat casualties, who have suffered head injury, are triaged. For the GCS to be reliable in this critical role, it must be applied accurately. To determine the level of knowledge of the GCS among military physicians with exposure and/or training in the scale we administered a prospective, voluntary, and anonymous survey to physicians of all levels of training at military medical centers with significant patient referral base. The main outcome measures were correct identification of title and categories of the GCS along with appropriate scoring of each category. Overall performance on the survey was marginal. Many were able to identify what "GCS" stands for, but far fewer were able to identify the titles of the specific categories, let alone identify the specific scoring of each category. When evaluated based on medical specialties, those in surgical specialties outperformed those in the medical specialties. When comparing the different levels of training, residents and fellows performed better than attending staff or interns. Finally, those with Advanced Trauma Life Support (ATLS) certification performed significantly better than those without the training. Physician knowledge of the GCS, as demonstrated in this study, is poor, even in a population of individuals with specific training in the use of the scale. It is concluded that, to optimize outcome from combat related head injury, methods for improving accurate quantitation of neurologic state need to be explored.

A comparison of the Glasgow Coma Scale score to simplified alternative scores for the prediction of traumatic brain injury outcomes

STUDY OBJECTIVE

The 15-point Glasgow Coma Scale (GCS) is extensively used in the initial evaluation of traumatic brain injury in emergency department (ED) settings. We hypothesized that the GCS might be unnecessarily complex and that a simpler scoring system might demonstrate similar accuracy in the prediction of traumatic brain injury outcomes.

METHODS

We analyzed a prospectively maintained trauma registry of patients evaluated at our Level I trauma center from 1990 to 2002. We calculated the test performance of ED GCS scores relative to 4 clinically relevant traumatic brain injury outcomes (emergency intubation, neurosurgical intervention, brain injury, and mortality) using areas under their receiver operating characteristic (ROC) curves. We performed similar analyses for each of the 3 GCS components and for 2 simplified 3-point scores (simplified verbal score: oriented=2, confused conversation=1, inappropriate words or less=0; simplified motor score: obeys commands=2, localizes pain=1, withdrawal to pain or less=0). We then compared the test performance of each of these 5 to the total GCS score using a priori thresholds for clinically important differences.

RESULTS

Each of the 3 GCS components alone and the 2 simplified 3-point scores demonstrated ROC areas within 9% of that of the GCS score for the 4 outcomes, with a median difference of 3.0% (interquartile range 1.6% to 4.5%). These differences were all below our a priori definitions of clinical importance.

CONCLUSION

The 3 individual GCS components alone and two 3-point simplified scores demonstrated test performance similar to the total GCS score for the prediction of 4 clinically relevant traumatic brain injury outcomes. Despite the widespread use of the GCS for the initial evaluation of traumatic brain injury, this score may be unnecessarily complex for this indication.

Respiratory Rate as a Prehospital Triage Tool in Rural Trauma

BACKGROUND

Where trauma systems do not exist, such as in low-income countries, the aim of prehospital triage is identification of trauma victims with high priority for forward resuscitation. The present pilot study explored the accuracy of simple prehospital triage tools in the hands of nongraduate trauma care providers in the minefields of North Iraq and Cambodia.

METHODS

Prehospital prediction of trauma death and major trauma victims (Injury Severity Score > 15) was studied in 737 adult patients with penetrating injuries and long evacuation times (mean, 6.1 hours).

RESULTS

Both the respiratory rate and the full Physiologic Severity Score predicted trauma death with high accuracy (area under the curve for receiver-operating characteristic plots at 0.9) and significantly better than other physiologic indicators. The accuracy in major trauma victim identification was moderate for all physiologic indicators (area under the receiver-operating characteristic curve, 0.7-0.8).

CONCLUSION

Respiratory rate > 25 breaths/min may be a useful triage tool for nongraduate trauma care providers where the scene is chaotic and evacuations long. Further studies on larger cohorts are necessary to validate the results.

Effectiveness of a Glasgow Coma Scale instructional video for EMS providers

INTRODUCTION

The Glasgow Coma Scale (GCS) is the standard measure used to quantify the level of consciousness of patients who have sustained head injuries. Rapid and accurate GCS scoring is essential.

OBJECTIVE

To evaluate the effectiveness of a GCS teaching video shown to prehospital emergency medical services (EMS) providers.

METHODS

Participants and setting--United States, Mid-Atlantic region EMS providers. Intervention--Each participant scored all of the three components of the GCS for each of four scenarios provided before and after viewing a video-tape recording containing four scenarios. Design--Before-and-after single (Phase I) and parallel Cohort (Phase II). Analysis--Proportions of correct scores were compared using chi-square, and relative risk was calculated to measure the strength of the association.

RESULTS

75 participants were included in Phase I. In Phase II, 46 participants participated in a parallel cohort design: 20 used GCS reference cards and 26 did not use the cards. Before observing the instructional video, only 14.7% score all of the scenarios correctly, where as after viewing the video, 64.0% scored the scenarios results were observed after viewing the video for those who used the GCS cards (p = 0.001; RR = 2.0; 95% CI = 1.29 to 3.10) than for those not using the cards (p < 0.0001; RR = 10.0; 95% CI = 2.60 to 38.50).

CONCLUSIONS

Post-video viewing scores were better than those observed before the video presentation. Ongoing evaluations include analysis of long-term skill retention and scoring accuracy in the clinical environment.

Scoring systems in trauma

BACKGROUND

Trauma is a major cause of mortality and morbidity worldwide. Methods of assessing outcome have evolved with management of trauma victims.

RESULTS AND DISCUSSION

The wide variety of scoring instruments available to assess the injured patient may be divided into three groups: anatomical, physiological and combined systems. Anatomical systems depend on an accurate description of the injuries sustained. Physiological systems measure the effects of injury on the patient's physiological reserves. Combined systems contain elements of both anatomical and physiological scores. Prospectively, scoring systems help in description, triage, treatment decisions and estimating outcome. Retrospective scoring is helpful in audit, in quality control, in comparing treatment methods or centres, and in identifying unexpected outcomes. Limitations may be inherent in the system or may reflect inaccurate or incomplete data collection.