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Glasgow Coma Scale (GCS)

Category: Concepts Sources: raw/protocols/nm-sop-guidelines-treatment-2022.pdf, raw/nremt/psychomotor-skills.md Last updated: 2026-04-05

Overview

The Glasgow Coma Scale is a standardized neurological scoring tool that quantifies level of consciousness across three independent components: eye opening, verbal response, and motor response. Scores range from 3 (no response in any category) to 15 (fully awake, oriented, following commands). It gives you a number you can trend — more useful than "patient seems worse" when handing off to ALS or the ER.

GCS is used alongside AVPU for rapid field assessment. AVPU is faster (4 categories); GCS is more granular and is the standard for documenting TBI severity.

The Scale

Eye Opening (E) — max 4

Score Response
4 Spontaneous — opens eyes without any stimulus
3 To voice — opens eyes when you speak to them
2 To pain — opens eyes only to painful stimulus
1 None — no eye opening to any stimulus

Verbal Response (V) — max 5

Score Response
5 Oriented — knows person, place, time, event
4 Confused — speaks in sentences but is disoriented
3 Inappropriate words — random words, no conversation
2 Incomprehensible sounds — moaning, groaning, no words
1 None — no verbal response

Motor Response (M) — max 6

Score Response
6 Obeys commands — follows a 2-step command ("squeeze my hand")
5 Localizes pain — moves hand toward painful stimulus
4 Withdraws — pulls away from pain (normal flexion)
3 Flexion — abnormal flexion, wrists curl inward (decorticate posturing)
2 Extension — arms extend and rotate outward (decerebrate posturing)
1 None — no motor response

Memory trick for motor: "Old Ladies Can't Flex Enough" — Obeys, Localizes, withdraws (Curls), Flexion, Extension, nothing (Empty)

Interpreting the Score

Total Severity Clinical Picture
13–15 Mild TBI Alert to slightly confused; may have normal conversation
9–12 Moderate TBI Significant confusion, may not follow commands reliably
≤8 Severe TBI Cannot follow commands; airway at risk; triggers advanced management
3 No response Worst possible score; does not mean dead

GCS ≤8 = consider advanced airway and hyperventilation only if herniation signs present.

A GCS of 15 does not rule out significant injury — a patient can have a subdural hematoma and walk into the ER at GCS 15. Serial trending matters more than a single value.

How to Document

Write it as a breakdown, not just the total:

GCS 10: E3 V3 M4

This tells the receiving team which components are impaired. A score of 10 from E2V3M5 (eye problem) is very different from E3V2M5 (verbal problem) clinically.

Change Significance
Drop of 2+ points Significant deterioration — reassess, upgrade priority, call ALS
Improving from scene to transport Good sign — document both scores
Fluctuating May suggest seizure activity, hypoglycemia, or intermittent airway compromise

Always document GCS at scene and again at handoff. "GCS 14 on scene, 11 on arrival" tells the ER exactly what happened en route.

GCS vs. AVPU

AVPU Approximate GCS
Alert 14–15
Voice 10–13
Pain 6–9
Unresponsive 3–5

Use AVPU for speed in the primary assessment. Use GCS when you have 30 seconds and want a documented, trendable number — particularly for any head trauma or altered LOC patient.

Common Mistakes

  • Scoring the intubated patient — no verbal score possible; document as "V1T" (T = intubated). Total is E + M + 1T, but mark it clearly.
  • Pain stimulus technique — use supraorbital ridge pressure or trapezius pinch, not sternal rub (sternal rub leaves bruises and doesn't differentiate localization from withdrawal well).
  • Reporting only the total — "GCS 9" is less useful than "E2V3M4." Always break it down.
  • Equating GCS 3 with death — GCS 3 means no observed response. Reversible causes (hypothermia, overdose, postictal state) can produce GCS 3. Document; don't conclude.
  • Skipping it because the patient "seems fine" — baseline GCS 15 on scene is important data if they deteriorate en route.

NM Protocol Notes

NM EMS Treatment Guidelines (2022) specify GCS use in head injury:

  • Document initial GCS on scene for all moderate/severe TBI (GCS ≤13 or P/U on AVPU)
  • Serial reassessment with any change in mentation
  • GCS ≤8 or Unresponsive on AVPU: hyperventilate to EtCO2 30–35 mmHg (herniation protocol) — this is ALS scope; EMT-B ventilates manually at protocol-directed rate
  • Elevated head of bed 30 degrees for GCS ≤8
  • Pediatric GCS exists (modified verbal component for pre-verbal children) — consult protocol for children under 2

NREMT Relevance

Consistently tested on the cognitive exam:

  • Know all three components and all scoring levels (especially motor — most complex)
  • GCS ≤8 = severe TBI, advanced airway consideration
  • Distinguish decorticate (flexion, M3) from decerebrate (extension, M2) — both are ominous; decerebrate is worse
  • Know that GCS is a trend tool — one score is less meaningful than two
  • Herniation triad (Cushing's): bradycardia + hypertension + irregular respirations — not part of GCS but occurs concurrently with rapid GCS deterioration

Sources

  • raw/protocols/nm-sop-guidelines-treatment-2022.pdf — Head Injury/TBI protocol