Elsevier

Annals of Emergency Medicine

Volume 68, Issue 6, December 2016, Pages 744-750.e3
Annals of Emergency Medicine

Trauma/original research
Glasgow Coma Scale Motor Component (“Patient Does Not Follow Commands”) Performs Similarly to Total Glasgow Coma Scale in Predicting Severe Injury in Trauma Patients

https://doi.org/10.1016/j.annemergmed.2016.06.017Get rights and content

Study objective

Trauma victims are frequently triaged to a trauma center according to the patient’s calculated Glasgow Coma Scale (GCS) score despite its known inconsistencies. The substitution of a simpler binary assessment of GCS-motor (GCS-m) score less than 6 (ie, “patient does not follow commands”) would simplify field triage. We compare total GCS score to this binary assessment for predicting trauma outcomes.

Methods

This retrospective analysis of a statewide trauma registry includes records from 393,877 patients from 1999 to 2013. Patients with initial GCS score less than or equal to 13 were compared with those with GCS-m score less than 6 for outcomes of Injury Severity Score (ISS) greater than 15, ISS greater than 24, death, ICU admission, need for surgery, or need for craniotomy. We judged a priori that differences less than 5% lack clinical importance.

Results

The relative differences between GCS and GCS-m scores less than 6 were less than 5% and thus clinically unimportant for all outcomes tested, even when statistically significant. For the 6 outcomes, the differences in areas under receiver operating characteristic curves ranged from 0.014 to 0.048. Total GCS score less than or equal to 13 was slightly more sensitive (difference 3.3%; 95% confidence interval 3.2% to 3.4%) and slightly less specific (difference –1.5%; 95% confidence interval –1.6% to –1.5%) than GCS-m score less than 6 for predicting ISS greater than 15, with similar overall accuracy (74.1% versus 74.2%).

Conclusion

Replacement of the total GCS score with a simple binary decision point of GCS-m score less than 6, or a patient who “does not follow commands,” predicts serious injury, as well as the total GCS score, and would simplify out-of-hospital trauma triage.

Introduction

Rapid and accurate assessment of a patient’s condition is essential for trauma triage in the field. Emergency medical services (EMS) providers of all levels must be able to quickly evaluate and classify patients for appropriate transport destination while providing medical care. Avoiding undertriage by transporting patients with potentially serious injuries to an appropriate trauma center reduces mortality, but overtriage causes a strain on resources and is inconvenient for patients.

Editor’s Capsule Summary

What is already known on this topic

The Glasgow Coma Scale (GCS) is widely used as a criterion for field triage of injured patients to trauma centers.

What question this study addressed

Does a single GCS element (GCS motor component score <6 or “patient does not follow commands”) predict trauma outcomes, as well as the widely used threshold of total GCS score less than or equal to 13?

What this study adds to our knowledge

In this analysis of a 393,877-adult statewide trauma registry, the differences observed between the new decision point and GCS score less than or equal to 13 were all below the prespecified 5% threshold of clinical importance for 8 trauma outcomes.

How this is relevant to clinical practice

The full GCS is unnecessarily complicated for out-of-hospital field triage and can be effectively replaced by the single decision point “patient does not follow commands.”

The guidelines for field triage of injured patients were designed for use by EMS providers to identify patients with potentially serious injuries and determine the most appropriate level of care.1, 2 The 2011 version consists of 4 steps to determine the appropriate destination for patients. Step 1 includes physiologic criteria, including assessment of vital signs and the Glasgow Coma Scale (GCS) score, and recommends that a patient with a GCS score of less than or equal to 13 be transported to a trauma center, preferably to the highest level of care within the defined trauma system.

Recent research on step-specific field triage has shown the motor component of the GCS (GCS-m) to be a more specific and simpler tool for patient assessment.3, 4, 5, 6, 7, 8 A calculated GCS score of less than or equal to 13 may be a statistically more sensitive and less specific indicator of serious injury than the GCS-m score, which may lead to overtriaging of patients and thus transporting patients to more distant resources that may not be needed for them. Small differences may not be clinically significant, and field use of GCS-m score may be more reliable than the total calculated GCS score. The GCS score is only 1 parameter of trauma triage; therefore, these relatively small differences in sensitivity have an even smaller influence on overall trauma triage sensitivity. The National Expert Panel on Field Triage considered emerging evidence for the use of GCS-m score during their literature review when developing the 2011 guidelines, but this group ultimately did not include use of the GCS-m score in the current guidelines because of “lack of confirmatory evidence, the long standing use of total GCS and its familiarity among current EMS practitioners, the inclusion of the motor score within the total GCS, and complications because of the difficulty of comparing scoring systems.”1 However, several studies have indicated a significant interobserver variability in tallying the total GCS score, with discrepancies as high as 3 points.9 Even the assessment of the GCS-m score suffers from lack of standardization, with variations based on type of painful stimuli applied to elicit responses and variations because of provider education.10, 11 Gill et al12 studied the interrater differences among emergency physicians in determining the GCS score and found that the agreement percentage for exact total GCS score was 32%, whereas the agreement percentage for the motor component was 72%. It is generally accepted that the motor component of the GCS is the most influential one when a patient’s severity of injury is assessed.

We wished to compare the total GCS score less than or equal to 13 with the GCS-m score less than 6 (“patient does not follow commands”) in predicting trauma-related outcomes.

Section snippets

Study Design and Setting

We retrospectively analyzed the prospectively maintained Pennsylvania Trauma System Foundation’s registry, which included trauma patients admitted to the state’s Level I, II, III, and IV trauma centers from 1999 to 2013. The Pennsylvania Trauma System Foundation registry captures all patients with a diagnosis of trauma who are admitted to a Foundation-accredited Level I, II, III, or IV trauma center and patients presenting to the trauma center dead on arrival. This includes all trauma transfer

Results

We found that the differences between total GCS score less than or equal to 13 and GCS-m score less than 6 were all below our prespecified 5% threshold for clinical importance, ranging from 2.5% to 4.9% for sensitivity and –1.2% to –2.0% for specificity (Table 1). All such differences had 95% confidence intervals that did not overlap zero. We found similar results in our 2 sensitivity analyses.

Differences in areas under receiver operating characteristic curves ranged from 0.014 to 0.048 (Figure

Limitations

This study is from a single state and may not be representative elsewhere, although Pennsylvania includes large urban, suburban, and rural areas. A large proportion of the patients in the registry were victims of blunt trauma. In addition, for analysis the values of total GCS and GCS-m scores, systolic blood pressure and respiratory rate were captured at first report (either in the out-of-hospital setting or at the trauma center). A further limitation is that approximately half of the first

Discussion

Total GCS score has historically been an important physiologic component of field triage used to predict trauma outcomes. This relatively complicated 13-point scale has shown inaccuracy among health care workers, however, putting its reliability in question.9

A simpler assessment of cerebral function is the binary clinical determination of whether a patient “follows commands” (GCS-m score=6) or does not. Although previous studies have shown greater agreement among emergency physicians assessing

References (19)

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Please see page 745 for the Editor’s Capsule Summary of this article.

Supervising editor: Steven M. Green, MD

Author contributions: DFK and EMM conceived and designed the study and obtained institutional review board approval and waiver. AJY obtained the data and provided statistical analysis. All authors analyzed and interpreted the data, drafted the article, and contributed substantially to its revision. DFK takes responsibility for the paper as a whole.

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 authors have stated that no such relationships exist and provided the following details: Dr. Kupas is a member of the board of directors of the Pennsylvania Trauma Systems Foundation.

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