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Stroke / TIA

Category: Medical Sources: raw/protocols/nm-sop-guidelines-treatment-2022.pdf Last updated: 2026-04-03

Overview

A stroke (cerebrovascular accident, CVA) is caused by either ischemia (clot blocking cerebral blood flow — 85% of cases) or hemorrhage (rupture of a cerebral blood vessel). Transient ischemic attack (TIA) presents identically but resolves within 24 hours (usually minutes) without infarction. Both require urgent evaluation.

Prehospital priorities: recognize stroke using a validated tool (Cincinnati, FAST), establish "last known well" time precisely, transport to a Stroke Center with advance notification. The time window for IV thrombolytics (tPA) is typically 3–4.5 hours from symptom onset — early notification is critical. Large vessel occlusion (LVO) strokes may benefit from mechanical thrombectomy with a wider time window.

Key Points

  • Time is brain — every minute of stroke = 1.9 million neurons lost
  • "Last known well" (last time patient was at their neurological baseline) is THE most important history element — not just symptom onset time
  • Do NOT treat hypertension in the prehospital setting for stroke — BP elevation may be compensatory
  • Do NOT give aspirin for suspected stroke — hemorrhagic stroke contraindicates anticoagulants
  • Hypoglycemia can mimic stroke — always check blood glucose
  • LVO scales (RACE, C-STAT, LAMS) identify patients who may benefit from thrombectomy — NM protocols direct use of these
  • Bypass non-stroke-capable facility to transport to Stroke Center when possible

Assessment Relevance

Stroke screening tools:

Cincinnati Prehospital Stroke Scale (3 items) — see cincinnati-stroke-scale for full testing protocol, sensitivity/specificity, and last known well guidance: - Facial droop: ask patient to smile — one side droops - Arm drift: arms outstretched eyes closed 10 seconds — one arm drifts down - Speech: "You can't teach an old dog new tricks" — slurred, wrong words, or mute - Any ONE abnormal = 72% probability of stroke

FAST mnemonic: Face, Arms, Speech, Time

LVO scales (identify large vessel occlusion for thrombectomy candidacy): - RACE: facial palsy, arm motor, leg motor, head/gaze deviation, agnosia/aphasia - Higher score = higher likelihood of LVO requiring mechanical thrombectomy

History (history-taking): - Last known well — exact time patient was last at neurological baseline - Symptom onset timeline - Blood glucose check — mandatory - Blood thinner medications (especially NOACs, warfarin, clopidogrel — affects tPA eligibility) - Prior stroke/TIA history - Headache (sudden severe "thunderclap" headache = hemorrhagic stroke until proven otherwise)

Physical exam (secondary-assessment): - Neuro: LOC (AVPU), pupil equality, focal deficits (unilateral weakness, facial droop) - Vital signs: BP (typically elevated), pulse, SpO2 - Blood glucose: hypoglycemia can mimic stroke

Procedures

  1. Scene size-up (scene-size-up): medical NOI; consider fall trauma if patient was found down
  2. Primary assessment (primary-assessment): airway (LOC-impaired patients may not protect airway), breathing (SpO2), circulation; determine priority
  3. Perform Cincinnati or FAST stroke screen
  4. Establish "last known well" time — question family/bystanders aggressively
  5. Perform LVO scale if trained (RACE, C-STAT, LAMS)
  6. Check blood glucose — treat hypoglycemia if present
  7. Apply oxygen ONLY if SpO2 <94%; titrate to maintain 94–99%
  8. Transport to Stroke Center with advance notification — do NOT delay on scene
  9. Reassessment en route (reassessment) — serial neuro checks; watch for airway compromise

NM Protocol Notes

From NM EMS Treatment Guidelines (2022):

EMT-B scope: - Provide oxygen only if SpO2 <94%; titrate to maintain >94% — do not hyperoxidize - Perform serial prehospital stroke assessments: Cincinnati, Los Angeles, or FAST scales - Perform LVO scale: RACE, C-STAT, or LAMS - Establish timeline: last known well, last seen at baseline, blood glucose level - Document blood thinner usage (especially beyond aspirin/clopidogrel — affects hospital treatment options) - If seizure activity present, refer to Seizure guideline - Transport to nearest Stroke Center or acute stroke-ready hospital; early notification is essential - Consider bypassing non-stroke-capable facility - Consider ALS intercept or aeromedical resources for symptomatic stroke - Do NOT treat hypertension in the prehospital setting - IV access (EMT-I/P only); avoid multiple IV attempts — do not delay transport for IV access

NM note on destination: Patients with stroke signs should be transported to the nearest stroke center or, if unavailable, to an acute stroke-ready hospital. The time savings from bypassing a non-capable facility and the hospital's preparation time are both critical factors.

NREMT Relevance

High-frequency NREMT topic: - Cincinnati Prehospital Stroke Scale components and interpretation (any ONE positive = suspect stroke) - "Last known well" vs. "symptom onset" — distinguish these; both are asked on NREMT - Do NOT give aspirin for stroke (hemorrhagic risk) - Do NOT treat hypertension prehospital for stroke - Hypoglycemia mimics stroke — check BGL is a standard NREMT question - Transport destination: Stroke Center, with advance notification - "Thunderclap headache" = hemorrhagic stroke red flag

Sources

  • raw/protocols/nm-sop-guidelines-treatment-2022.pdf — Suspected Stroke/TIA protocol (p. 45)