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Syncope

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

Overview

Syncope (fainting) is a transient loss of consciousness with loss of postural tone, typically abrupt in onset and resolving quickly. EMS providers commonly arrive after the event, finding a patient who may be alert and apparently normal. Despite the benign appearance, syncope can represent serious underlying pathology — all syncope patients require hospital-level evaluation.

Key Points

  • Syncope = LOC + loss of postural tone (both required; just feeling dizzy is presyncope)
  • Typically abrupt onset and equally abrupt resolution
  • EMS commonly arrives after event; patient may be alert and oriented
  • All syncope patients deserve hospital evaluation — even those who appear normal
  • Prehospital providers have a unique advantage: they are closest to the event, the scene, and circumstances — this information is valuable and must be transmitted to receiving providers
  • Differential is wide: vasovagal (benign), cardiac dysrhythmia (dangerous), structural cardiac, orthostatic hypotension, neurologic, metabolic (hypoglycemia)
  • Cardiac syncope: often exertional, preceded by palpitations or without warning, in elderly patients
  • Vasovagal syncope: typically preceded by prodrome (nausea, diaphoresis, tunnel vision), triggered by pain/emotional stress, in younger patients

Assessment Relevance

History (history-taking): - Circumstances: what was patient doing? Exertion? Position change? Stress? Dehydration? Heat? - Prodrome: warning symptoms before LOC? (nausea, diaphoresis, graying vision = vasovagal) - Duration of unconsciousness (witnessed?) - Injury from fall? - Last known normal: rule out TIA/seizure (seizure has tonic-clonic activity + postictal phase) - Associated chest pain, palpitations, dyspnea (cardiac etiology) - Recent illness, poor oral intake (dehydration/orthostatic) - Medications: antihypertensives, diuretics, insulin, antidysrhythmics - Prior episodes; any cardiac history

Physical exam (secondary-assessment): - Vital signs: orthostatic changes (BP supine vs. sitting vs. standing); HR - SpO2 - Cardiac monitor - Blood glucose - Neuro exam: focal deficits (TIA/stroke), postictal phase (seizure) - Evidence of trauma from fall: head injury, fractures - Signs of hemorrhage (GI bleed, ectopic pregnancy)

Procedures

  1. Scene size-up (scene-size-up): any trauma from the fall? MOI assessment
  2. Primary assessment (primary-assessment): ABCs; any ongoing LOC or altered mental status?
  3. Check blood glucose — treat if hypoglycemic per diabetic-emergencies
  4. Evaluate for hemorrhage; treat for shock if indicated
  5. Evaluate for trauma; consider spinal immobilization if indicated
  6. Supplemental oxygen only if SpO2 <94%; titrate to ≥94%
  7. Cardiac monitor if available; treat dysrhythmias if present
  8. Transport to appropriate medical facility
  9. Document circumstances, prodrome, duration, recovery for receiving providers

NM Protocol Notes

From NM EMS Treatment Guidelines (2022):

EMT-B scope: - Primary assessment; airway, breathing, circulation management - History including conditions leading to the event; physical exam; vital signs - Rule out and treat specific causes per individual guidelines: - Diabetic emergency - Poisoning/overdose - Cardiac emergency - Stroke/TIA - Head injury - Bleeding/hemorrhage - Dehydration - Seizure - Provide oxygen only if SpO2 <94%; titrate to >94% - Evaluate for hemorrhage; treat for shock if indicated - Evaluate for trauma; consider spinal immobilization if indicated - Blood glucose: obtain and treat per hypoglycemia/hyperglycemia guideline as indicated - Transport to appropriate medical facility - Cardiac monitor; treat dysrhythmias if present per appropriate guideline - 12-lead EKG

ALS scope only (EMT-I/P): IV/IO isotonic solution at flow rate to maintain adequate vital signs

Key NM note: "By being most proximate to the scene and to the patient's presentation, EMS providers are commonly in a unique position to identify the cause of syncope. Consideration of potential causes, ongoing monitoring of vitals and cardiac rhythm, as well as detailed exam and history are essential pieces of information to pass onto hospital providers."

All syncope patients deserve hospital-level evaluation, even if appearing normal with few complaints on scene.

NREMT Relevance

  • Syncope definition: LOC + loss of postural tone
  • Must rule out: cardiac dysrhythmia, hemorrhage, hypoglycemia, stroke, seizure
  • Vasovagal signs: prodrome (nausea, diaphoresis, tunnel vision), triggered by pain/stress
  • Cardiac syncope: exertional, no warning, palpitations — higher-risk
  • All syncope: transport for evaluation
  • Don't miss: hypoglycemia (check BGL), TIA (neuro deficit), occult hemorrhage (GI, ectopic pregnancy)

Sources

  • raw/protocols/nm-sop-guidelines-treatment-2022.pdf — Syncope protocol (p. 46)