Trauma/editorialCheerio, Laddie! Bidding Farewell to the Glasgow Coma Scale
Introduction
It is time to abandon the Glasgow Coma Scale (GCS). As discussed below, this ubiquitous neurologic scoring system is confusing, unreliable, and unnecessarily complex, and its manner of common clinical use is statistically unsound.
Teasdale and Jennett devised the GCS in 1974 not for acute care, but rather for the “repeated bedside assessment” in a neurosurgical unit to detect “changing states” of consciousness and to measure the “duration of coma.”1 They never intended for its elements to be assigned numeric scores or for its 3 subscales to be merged or totaled. Yet, despite their objections2 both such dubious modifications subsequently proved irresistible to the medical community.
The quantitative GCS subsequently has become the undisputed universal criterion standard for mental status assessment and is thus a fundamental part of the culture of emergency medicine, out-of-hospital care, trauma surgery, and neurosurgery.3, 4, 5, 6, 7 This scale is a core component of prominent trauma and life support courses,4, 5, 6, 7 and in most of the developed world out-of-hospital care providers routinely assess the GCS for each patient with trauma or altered mental status.3, 4, 5 The original GCS article has been cited almost 6,000 times.
This editorial outlines the potent limitations of the GCS and why it should now be considered obsolete within acute care medicine. This scale might be useful, however, for detecting subtle neurologic changes over time in an ICU (as originally envisaged). Curiously, though, it has never been validated for this separate role.
Section snippets
Problems With the GCS
The advantages of the GCS are that it has face validity, wide acceptance, and established statistical associations with adverse neurologic outcomes, including brain injury, neurosurgical intervention, and mortality.3, 8, 9 However, these are offset by several important limitations.
The GCS isn't reliable. To be accurate and useful, a clinical scale must be reproducible. Unfortunately, the GCS contains multiple subjective elements (Figure) and has repeatedly demonstrated surprisingly low
Simpler Scales Perform Just as Well
Do we really need a scale with 13 levels? The GCS predicts mortality well at its extremes and poorly in its midrange,27 and thus most of its predictive capacity is anchored by the endpoints. Accordingly, some of the GCS elements are truly predictive, whereas others are either redundant or simply noise.
What about just using 1 of the 3 GCS subscales in place of the summary score? Indeed, several investigators have demonstrated essentially equivalent test performance for the individual subscales
Why Has the GCS Persisted?
The GCS never began with a sound scientific basis and, as discussed above, fails to meet the standards of modern evidence-based medicine. Why has this sacred cow thrived over the decades? Perhaps the reasons are psychological. The GCS is intellectually appealing to health care providers in that it creates apparent order out of disorder. It ambitiously tackles the enormous complexity of human neurologic response and organizes (oversimplifies) it into a tangible, appealing yardstick that cannot
Conclusion
In 1978, the creators of the GCS said, “We have never recommended using the GCS alone, either as a means of monitoring coma, or to assess the severity of brain damage or predict outcome.”33 Nevertheless, clinicians worldwide persist in using the GCS for all of these things—now despite compelling contrary evidence. The GCS should be abandoned in the ED and out-of-hospital settings altogether. Simple unstructured clinical judgment alone is likely just as accurate; however, if we must satisfy our
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Assessing the level of consciousness in children: a plea for the Glasgow Coma Motor subscore
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Validation of the Simplified Motor Score in the prehospital setting for the prediction of outcomes following traumatic brain injury
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(2006)
International Trauma Life Support for Prehospital Care Providers
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A comparison of five simplified scales to the prehospital Glasgow Coma Scale for the prediction of traumatic brain injury outcomes
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Observer variability in assessing impaired consciousness and coma
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Inter-rater reliability of the Full Outline of Unresponsiveness score and the Glasgow Coma Scale in critically ill patients: a prospective observational study
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Cited by (67)
A Methodological Appraisal of the HEART Score and Its Variants
2021, Annals of Emergency MedicineThe Story of the Development and Adoption of the Glasgow Coma Scale: Part I, The Early Years
2020, World NeurosurgeryCitation Excerpt :Although it has a clear association with prognosis and has played a vital role in research studies, the true value of the GCS lies in the information that it encapsulates about the patient's clinical state, making it possible to record and to communicate such features in a clear and consistent manner. Despite some criticisms, and occasional (premature) farewells,49-51 the inherent qualities of the GCS have led to its enduring popularity as the way to properly systematize communication among health care providers. A strength of this article is the contemporary ‘eye witness’ input of one of the creators of the GCS.
Glasgow Coma Scale Score in Trauma Triage: A Measurement Without Meaning
2018, Annals of Emergency MedicineA Two-Center Validation of “Patient Does Not Follow Commands” and Three Other Simplified Measures to Replace the Glasgow Coma Scale for Field Trauma Triage
2018, Annals of Emergency MedicineCitation Excerpt :Our data corroborate this important finding and confirm that out-of-hospital trauma triage could be simplified by replacing the more complicated GCS with this straightforward, dichotomous measure. Our study builds on previous research, which has consistently indicated that the full GCS is unnecessarily complex for this purpose19-36,38,43,44 and that shorter, less-complicated measures are easier to calculate and apply.2,3,13,15-39 Worldwide, the full GCS is widely required for out-of-hospital trauma assessment because of its inclusion in the National Field Triage Guidelines from the Centers for Disease Control and Prevention.1
How to Measure the Glasgow Coma Scale
2017, Annals of Emergency Medicine
A podcast for this article is available at www.annemergmed.com.
Supervising editor: Michael L. Callaham, MD
Dr. Callaham was the supervising editor on this article. Dr. Green did not participate in the editorial review or decision to publish this article.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The author has stated that no such relationships exist.
Publication date: Available online July 30, 2011.