Background
The Glasgow Coma Scale (GCS) has been widely used as a measure of neurologic impairment in trauma patients for decades. The scale is made up of three components (eye, verbal, and motor), and its score ranges from a maximum total of 15 in a neurologically intact patient to a minimum total of three in an unresponsive patient. This range helps establish traumatic brain injury (TBI) severity, with scores of 15-13 correlating to mild head injury, 12-9 to moderate head injury, and eight or less to severe head injury.
Changes in a patient’s total GCS score and/or in any of the three components serve as important prognostic factors that dictate medical and surgical management. In the prehospital setting, GCS scoring can help providers decide when to intubate and where to transport. In the hospital, GCS can dictate the need for additional interventions such as obtaining imaging, inserting an external ventricular drain at bedside, or rushing to the operating room.
Despite its wide use, the GCS assessment is often susceptible to human error. Obtaining an accurate score requires providers to not only understand the intricacies of the scale itself but to also take into account patient-specific characteristics, such as medical and social histories, as well as contextual factors, like mechanism of injury.
Some underlying conditions like seizure disorders and substance abuse can transiently affect a patient’s neurologic function, while others, like language barriers and injuries affecting the eyes, can result in erroneous scores altogether. These nuances, as well as differing levels of training and experience, increase the likelihood of inconsistent GCS scoring between healthcare providers.
An instance where inter-provider GCS score discrepancies could be detrimental to patient outcomes is the transition of care between Emergency Medical Services (EMS) and Emergency Department (ED) staff. While multiple factors can contribute to differing EMS and ED GCS assessments, studies have found that EMS scoring is often inaccurate.
In 2002, a small study by Bazarian et al. examined data from 60 TBI patients with GCS scores ranging between 8-13, and found that EMS-GCS was on average two points lower than ED-GCS.1 A few years later, Kerby et al. further explored this topic in a much larger study, dividing scores based on TBI severity.4 This paper found that EMS and ED assessments were least likely to agree in patients with GCS scores between 9-12, corresponding with moderate TBI severity. Bledsoe et al. arrived at a similar conclusion in 2015.7
This group however highlighted that GCS scoring inaccuracies were common among EMS as well as hospital staff, with ED attendings, residents, nurses, and prehospital staff accurately assessing GCS in only one-third of cases. In adults, the motor GCS component was found to be the least accurate,7 while in children it was the verbal component.5
These inaccuracies are significant because improper GCS scoring by EMS and ED personnel can lead to unnecessary interventions or, alternatively, delay care. Therefore, improving GCS assessment accuracy and consistency among healthcare providers is crucial to improving patient outcomes.
Project Aim and Design
This article describes an education project aimed at improving prehospital GCS assessment accuracy among EMS providers. The project was designed as a prospective cohort study, which collected data using a baseline knowledge assessment (pretest), immediate post-lecture retest (posttest), as well as three-month, six-month, and 12-month follow-up posttests. All posttests were identical to the pretest. Participation was completely voluntary and anonymous.
The pretest was a 10-question survey assessing the participants’ baseline knowledge of the topic. Six of those questions focused on pediatric patients, while four focused on adults. Participants were not allowed to use any scoring aids during the pretest. Upon submission, participants did not receive a score and were unable to see the correct and incorrect answers.
The pretest was followed by an educational lecture (approximately 20 minutes in length), either in person or remotely via an online platform, which provided a detailed overview of adult and pediatric GCS components, common pitfalls, and proper score applications. The lecture also reviewed how to use the GCS scoring aid designed by the study team based on the National Trauma Data Standard (Figure 1). Immediately following the lecture, the participants took a posttest to assess short-term lecture efficacy.
Follow-up posttests were distributed via email at three, six, and 12 months following the lecture to assess long-term lecture efficacy. During all of the posttests, participants were allowed to use the GCS scoring aid in Figure 1. Participants were not shown their scores or the correct answers upon completion of the assessments. This project was initiated in collaboration with the Richmond Ambulance Authority (RAA).
Results
A total of 282 test submissions from 135 EMS providers were analyzed. Participants averaged 12 years of experience in healthcare, with varying degrees of training ranging from Emergency Medical Technician (EMT) students to physicians. Total pretest scores averaged 52% (95% CI, 49-55%, n=135), with pediatric and adult questions averaging 28% (95% CI, 26-30%) and 59% (95% CI, 55-63%), respectively. Immediate posttest improvement was noted with total scores averaging 70% (95% CI, 67-73%, p<0.001, n=122), pediatric 39% (95% CI, 37-41%, p<0.001) and adult 79% (95% CI, 75-83%, p<0.001).
At three months, total accuracy was noted at 66% (95% CI, 52-80% p=0.031, n=13), while pediatric was at 36% (95% CI, 26-46%, p=0.079) and adult at 75% (95% CI, 59-91%, p=0.039). At six months, total accuracy was 81% (95% CI, 75-87%, p<0.001, n=9), pediatric 44% (95% CI, 38-50%, p<0.001) and adult 92% (95% CI, 84-100%, p<0.001). At 12 months, total accuracy was 60% (95% CI, 21-99%, p=0.364, n=3), pediatric 33% (95% CI, 9-57%, p=0.358) and adult 67% (95% CI, 24-110%, p=0.385). Statistically significant differences in scores were determined using p<0.05.
Discussion
The pretest mean scores in this study support prior literature evidence highlighting the need for improved EMS-GCS accuracy. Posttest scores demonstrate the efficacy of the lecture and badge scoring aid in enhancing GCS accuracy in the short term with notable improvement in the long term for both adult and pediatric patients. All posttest scores were significantly higher than pretest scores, except for the pediatric component in the three-month follow-up and all components of the 12-month follow-up.
Several limitations to the study are worth noting. The use of the badge scoring aid during posttests likely contributed to score improvements. With that said, we believe that scoring aids play an important role in improving EMS-GCS assessment in the field. When EMS providers encounter high-acuity clinical situations, they are forced to divide their attention among multiple aspects of patient care. In these scenarios, providers may turn to anecdotal experience for GCS assessment rather than relying on their memory of each GCS component.
By introducing the badge scoring aid during the lecture and using it for the posttests, we hoped to create a sense of familiarity that would in turn encourage participants to utilize the scoring aid during real-life scenarios. Unfortunately, we did not track how often, if at all, providers used the aids during the posttests. Therefore, we are unsure of the scoring aids’ efficacy.
Another important limitation to acknowledge in this study is participant attrition. The decrease in responses is evident throughout each interval testing window, even between the pretest and posttest which occurred merely 30 minutes apart. The small sample sizes decrease the power of the data and increase the risk of false negative results. This could be a possible explanation for the lack of statistical significance in some of the study results at three and 12 months (Figure 2). With that said, decreased material retention could also explain these findings, and could be easily addressed with annual refresher courses.
While the above limitations are important to keep in mind, analysis of the data showed that pediatric GCS scores were consistently lower than adult GCS scores in all tests, regardless of aid use or participant attrition. This observation may be due to the increased complexity of the pediatric GCS verbal component, a known challenge for EMS providers4, due to lack of practice, or both.
Since pediatric patients represent only a small fraction of the EMS patient population2, providers perform pediatric GCS assessments less frequently, especially in clinically acute situations, which could translate into less accurate scoring. To address this challenge, agencies could increase the frequency of pediatric simulations and scenarios included in the training and maintenance of EMS certifications. With greater repetition, pediatric GCS scoring should become simpler and more consistent.
Though this paper focuses on the complete GCS assessment, we wanted to acknowledge the 2021 update to the National Guidelines for the Field Triage of Injured Patients.2 In this update, total GCS is being de-emphasized and the motor component is being used to guide patient triage to trauma centers. More specifically, prior to the update, a total GCS score below 14 designated a patient as high risk for serious injury, necessitating transport to the highest-level trauma center in the area.
The 2021 update changed this triage criteria, now classifying all patients with a motor GCS less than six (i.e., not following commands) as high risk.This simplified approach has been found to yield similar outcomes in both adult and pediatric patients.3,6,8 Though easier to teach and certainly easier to implement, this recommendation possibly overlooks the importance of the individual GCS components in dictating management and prognosis for TBI patients.
Additional studies may be needed to further assess these implications as total GCS becomes less emphasized in EMS practice. Furthermore, future studies could shed light on the specific numbers of unnecessary/delayed GCS-based trauma alerts and interventions as well as related costs. Attempting to quantify the economic impact of the discrepancies described in this study and other existing literature could help advocate for stronger education efforts on this topic.
Conclusion
GCS scoring is consistently inaccurate among EMS providers, especially for pediatric patients. A focused educational lecture covering adult and pediatric GCS components and proper clinical applications can improve scoring accuracy in both the short and long term. Adding a badge scoring aid to help providers remember GCS scoring while on duty can solidify these concepts in practice, yielding more accurate assessments in the prehospital setting.
As the EMS field continues to grow and evolve, the role of GCS scoring is uncertain. With that said, agencies should consider offering continuing education opportunities to bridge existing knowledge gaps in order to improve patient outcomes and minimize resource waste.
References
1. Bazarian JJ, Eirich MA, Salhanick SD. The relationship between pre-hospital and emergency department Glasgow Coma Scale Scores. Brain Injury. 2003 Jul;17(7):553–60. doi:10.1080/0269905031000070260
2. Shah MN, Cushman JT, Davis CO, Bazarian JJ, Auinger P, Friedman B. The epidemiology of Emergency Medical Services use by children: An analysis of the National Hospital Ambulatory Medical Care Survey. Prehospital Emergency Care. 2008;12(3):269–76. doi:10.1080/10903120802100167
3. Newgard CD, Fischer PE, Gestring M, Michaels HN, Jurkovich GJ, Lerner EB, et al. National guideline for the field triage of injured patients: Recommendations of the national expert panel on Field Triage, 2021. Journal of Trauma and Acute Care Surgery. 2022 Aug 27;93(2). doi:10.1097/ta.0000000000003627
4. Kerby JD, MacLennan PA, Burton JN, McGwin G, Rue LW. Agreement between Prehospital and emergency department glasgow coma scores. Journal of Trauma: Injury, Infection & Critical Care. 2007 Nov;63(5):1026–31. doi:10.1097/ta.0b013e318157d9e8
5. DiBrito SR, Cerullo M, Goldstein SD, Ziegfeld S, Stewart D, Nasr IW. Reliability of Glasgow Coma Score in Pediatric Trauma Patients. Journal of Pediatric Surgery. 2018 Sept;53(9):1789–94. doi:10.1016/j.jpedsurg.2017.12.027
6. Cicero MX, Cross KP. Predictive value of initial Glasgow Coma Scale score in pediatric trauma patients. Pediatric Emergency Care. 2013 Jan;29(1):43–8. doi:10.1097/pec.0b013e31827b52bf
7. Bledsoe BE, Casey MJ, Feldman J, Johnson L, Diel S, Forred W, et al. Glasgow coma scale scoring is often inaccurate. Prehospital and Disaster Medicine. 2015 Feb;30(1):46–53. doi:10.1017/s1049023x14001289
8. Acker SN, Ross JT, Partrick DA, Nadlonek NA, Bronsert M, Bensard DD. Glasgow Motor Scale Alone is equivalent to Glasgow coma scale at identifying children at risk for serious traumatic brain injury. Journal of Trauma and Acute Care Surgery. 2014 Aug;77(2):304–9. doi:10.1097/ta.0000000000000300
