GCS: On The Way Out or Here To Stay?

Robert Katzer MD MBAAssociate Professor, Emergency MedicineUniversity of California, IrvineMedical Director, City of Anaheim Fire and RescueAir Medic, San Bernardino County Sheriff

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Before GCS Brain Injury Patients Were Described As

• Comatose

• Sub-comatose

• Obtundation

• Stupor

• Semi-purposeful

• Posturing

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In The Beginning… there was the Glasgow Coma Scale (and Score)

• When exactly was the beginning?

• The Lancet, 1974

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Summary of that Original Article

Basically….

People have trouble agreeing on unconscious, conscious, and description of levels of coma and brain injury while hospitalized

Impaired brain function, whether structural or organic will manifest it in verbal, motor, and eye opening

These three systems can be measured independently and with good interrater reliabiility (M 6%, V9%, E9%).

The scale is the independent numbers, score is the total

That’s it!

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Early Diagram by GCS Creator Explaining Its Breakdown.

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When did GCS Go Global?

• GCS recommended for use in trauma patients 1980, in the first edition of Advanced Trauma Life Support text book

• Its utilization continued to broaden throughout the 80’s into neuro and critical care as well

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What Was the Initial Intent?

• The background of the development of GCS was: • Primarily to trend progress of brain injury patients• Secondarily as a component in prediction of initial

prognosis• The Scale: Eye Opening(E), Verbal(V), and Motor(M) were

intended to track individual patients.• The Score: E+V+M is intended to evaluate populaitions and

not individuals…

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Are all Created Equal?

• We as Americans stand by the belief that all men are created equal

• Teasdale and Jennett, authors of GCS, do note however believe Eye opening, verbal, and motor are created equal.

• They are/were British. But that is not the major bias against E,V,and M

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From Teasdale’s “Glasgow Coma Scale at 40…” Paper

Reservations about the Glasgow Coma Scale, mainly relate to the sum score and to its calculation. These include the appropriate number of steps in each component scale and the weighting that should be attached to each step. We therefore re-emphasise the distinction between use of the scale to assess impaired consciousness in individual patients and the use of the score for classification and research. Moreover, the score is not an interval scale and the common practice of reporting an average Glasgow Coma Score is not appropriate.

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Not An Interval Scale?

Lets use an example that deals with cash……. Money.

The “bill scale”

• Rules in this example:

• There are three types of bills a person can carry.

• We are using the “bill scale” to determine how much money the person has.

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One Dollar Bills: (W for Washington)

Can hold between 1 and 4 dollar bills

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Twenty Dollar Bills (J for Jackson)

Can hold between one and five twenty dollar bills

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Million Dollar Elvis Bills (E for Elvis)

Can hold between one and six million dollar Elvis bills

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How Much Money do These Two People Have Over Time?

• Danny• Initially a W2 J1 E6 , score of 9• Later a W3 J2 E3, score of 7

• Charlotte• Initially W4 J4 E1, score of 9• Later a W4 J1 E4, score of 9

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Looking at the data and applying it to something that matters ($$$$$$)

• Who started with the most money?• Charlotte

• Whose total money increased between the initial and second score?• Danny

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The Point?

• For an interval scale with different components to be valid, the quantity between each component on the scale must be equivalent.

• Since V5 V4 =does not equal V2V1

• Which does not equal M4 M3

• Then

• E2V2M6, 10 does not equal E4V3M3, 10

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How Does GCS Correlate To Meaningful Clinical Outcomes?

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Figure:Teasdale G, Maas A, et. Al. The

Glascow coma Scale at 40 Years:

Standing the Test of Time. Lancet Neurol

2014; 13: 844–54 .

Data from:MRC CRASH Trial

Collaborators. Predicting outcome after

traumatic brain injury: practical prognostic

models based on large cohort of

international patients. BMJ 2008; 336:

425–29.

Mortality of GCS 4 > That of GCS 3

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GCS Changes- 2014

Some modification of terminology was completed

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1 2 3 4 5 6

1974 Eye Opening None To Pain To Sound Spontaneous ** **

2014 Eye Opening None To Pressure To Speech Spontaneous ** **

1974 Verbal Response None Incomprehensible sounds

Innapropriatewords

Confused Conversation

Oriented **

2014 Verbal Response None Sounds Words Confused Oriented **

1974 Motor Response None Extending Abnormal Flexion

Withdrawing Localizing Pain

Following Commands

2014 Motor Response None Extension Abnormal Flexion

Normal Flexion

(Withdrawal)

Localizing Pain

Following Commands

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GCS Changes: GCS-40

Last year as part of the 40 year and beyond celebration of GCS, Teasdale and colleagues recommended adding a pupillary component.

GCS-P Score (Range from 1-15)

Poor pupillary light response subtracts point.

This increased the specificity, decreased the sensitivity

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Unreactive Pupil Points Subtracted

Both Pupils 2

One Pupil 1

No pupils 0

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Challenges Raised About GCS

• Disagreement on GCS score between two providers

• Research on reliability between different clinicians determining GCS is all over the place

• Some studies say people are consistent

• Other studies say people are not consistent

• Requires a lot of different tasks to obtain a score

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Where to Go From Here?

• Can fewer than all the components reliably predict severity of injury?

• Can a single component or other characteristic predict severity of injury? i.e. AVPU

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GCS-Motor Only Compared to GCS

• Acker Et al.: Motor component only vs. total GCS in identifying TBI in children• No difference

• Chou et al.: Motor component only vs. total GCS in identifying patients with serious traumatic Injuries• Total GCS performs a little better on total mortality

• Total GCS performs a little better on injury severity

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• Primary study question: Does a binary function tool function as well as the 13 point GCS in predicting several clinically relevant outcomes?

• Binary function tool: Does patient follow commands? == Motor GCS < 6

• Compared to all GCS combinations < 13

• Data from all trauma cases of two trauma centers. Data collected from 6 years of one of the centers and 12 years of data from the other.

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Clinical Outcomes Measured

• Emergency intubation

• Clinically significant brain injury

• Need for neurosurgical intervention

• Injury Severity Score (ISS) > 15

• Mortality

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Study Results

• 47,973 trauma patients were included in the analysis

• “Patient does not follow commands” performed as well as GCS <= 13 in predicting:• Emergency Intubation• Clinically significant brain injury• Need for neurosurgery• Injury Severity Score (ISS) > 15• Mortality

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What the future holds?

• More complex GCS?• In the Field?• In the hospital only?

• Or simplified assessment for initial field triage?• Motor component only?• Does not follow commands?

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References

1.Teasdale G, Jennett B. Assessment of Coma and Impaired Consciousness. A practical Scale. The Lancet 1974 81-83

2. Teasdale G, Jennett B. Assessment and Prognosis of Coma After Head Injury. Acta Neurochirugica. 34, 45-55 (1976)3. Hopkins E, Green SM. A Two-Center Validation of "Patient Does Not Follow Commands" and Three Other Simplified Measures to Replace the Glasgow Coma Scale for Field Trauma Triage. Ann Emerg Med. 2018 Sep;72(3):259-2694. Americal College of Surgeons Website, http://bulletin.facs.org/2018/06/atls-10th-edition-offers-new-insights-into-managing-trauma-patients/, accessed 2/15/195. https://www.ncbi.nlm.nih.gov/books/NBK513298/6.. Teasdale G, Maas A, et. Al. The Glascow coma Scale at 40 Years: Standing the Test of Time. Lancet Neurol 2014; 13: 844–54 7. Reith F, Van den Brande R, et al. The reliability of the glascow Coma Scale: A Systemic Review. Intensive Care Med (2016) 42:3–15 8. Chou R, Totten AM, Carney N, et al. Predictive Utility of the Total Glasgow Coma Scale Versus the Motor Component of the Glasgow Coma Scale for Identification of Patients With Serious TraumaticInjuries. Ann Emerg Med. 2017 Aug;70(2):143-157.Brennan P, Murray G, Teasdale G. Simplifying the use of prognostic information in traumatic brain injury. Part 1: The GCS-Pupils score: an extended index of clinical severity. J Neurosurgery, 2018;128(6):1612-20Murray G, Brennan P, Teasdale G. Simplifying the use of prognostic information in traumatic brain injury. Part 2: Graphical presentation of probabilities. J Neurosurgery, 2018;128(6):1621-34

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