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Blast Injuries

Category: Trauma Sources: raw/protocols/nm-sop-guidelines-treatment-2022.pdf; UCLA EMT Ultimate Study Guide (2026) Last updated: 2026-05-06

Overview

Blast injuries result from explosions — improvised explosive devices (IEDs), industrial accidents, natural gas leaks, or military ordnance. They produce a unique pattern of injury across four mechanisms. A patient may appear uninjured on the surface while sustaining life-threatening internal injuries from the blast wave itself. High index of suspicion is essential.

The Four Blast Injury Mechanisms

Category Mechanism Injuries Key Point
Primary Direct overpressure wave (blast wave) strikes body Hollow organ injury — ear (tympanic membrane rupture), lung (pulmonary blast injury), bowel, eye No external signs — patient may look fine
Secondary Fragmentation (shrapnel) — debris propelled by explosion Penetrating wounds, lacerations, fractures Multiple penetrating injuries at various sites
Tertiary Body thrown by blast wind — patient impacts surfaces Blunt trauma (TBI, spinal, fractures), traumatic amputation Similar to MVCmechanisms
Quaternary All other blast-related injuries Burns, inhalation injury, crush injuries, toxin exposure, psychological Multiple co-occurring conditions

KEY DIFFERENTIATOR — Primary Blast (Hollow Organs): The blast wave travels through air-filled structures selectively. Hollow organs (ears, lungs, bowel, sinuses) are most vulnerable. Solid organs and bone resist the wave better. A patient who was close to an explosion and "looks fine" may have ruptured eardrums, pulmonary blast injury (blood-filled alveoli), or bowel perforation — all of which can be fatal.

KEY DIFFERENTIATOR — High Index of Suspicion: Blast patients may have NO external signs of injury. If a patient was near an explosion, even if walking and talking, assume significant injury. Transport, monitor, ALS intercept.

Primary Blast Injuries — Detail

Pulmonary Blast Injury (Blast Lung)

  • Most lethal primary blast injury
  • Hemorrhage into alveoli → hypoxia, hemoptysis, pneumothorax, tension pneumothorax
  • May develop minutes to hours after exposure
  • Signs: dyspnea, hemoptysis, decreased breath sounds, hypoxia
  • Treatment: high-flow O2; caution with positive pressure ventilation (may worsen pneumothorax)

Tympanic Membrane Rupture

  • Most common primary blast injury — lower lethal potential but high diagnostic value
  • TM rupture indicates significant blast wave exposure — assume other primary injuries may be present
  • Signs: hearing loss, tinnitus, pain, blood from ear canal
  • Do NOT irrigate or pack the canal

Bowel (Abdominal) Blast Injury

  • Air-fluid interface in bowel absorbs blast wave → perforation, hemorrhage
  • Signs may be delayed; abdominal pain and peritoneal signs develop over hours
  • All blast patients should be evaluated at hospital for delayed abdominal injury

Eye (Ocular) Blast Injury

  • Ocular rupture, traumatic cataract, retinal damage
  • Patient may have excellent visual acuity immediately after blast and lose it later
  • Patch both eyes; transport to ophthalmology

Assessment

Scene assessment: - Safety first — secondary explosive devices are a real risk at blast scenes; do not approach until cleared by law enforcement or hazmat - Number of patients (MCI activation if multiple) - Distance from blast center correlates with injury severity

Patient assessment: - Primary assessment: airway (blast lung, inhalation injury), breathing (pneumothorax), circulation (hemorrhage) - Assume multisystem trauma - Check ears: TM rupture is a marker of significant blast exposure - External wounds may be dramatic (secondary blast shrapnel) but primary blast injuries are the killers

EMT-B Management

  1. Scene safety — secondary devices, structural collapse, hazmat
  2. MCI activation if multiple patients
  3. Primary assessment: airway, breathing (blast lung), circulation (hemorrhage)
  4. Hemorrhage control: tourniquets early for extremity wounds; wound packing for junctional wounds
  5. High-flow O2 — suspected blast lung
  6. Occlusive dressing for open chest wounds (secondary blast)
  7. Monitor for tension pneumothorax (positive pressure ventilation + blast lung = high risk)
  8. Transport to trauma center; ALS intercept
  9. All blast patients require hospital evaluation regardless of apparent severity

NM Context

In New Mexico, blast injuries may result from: - Industrial accidents (mining, oil/gas — Farmington/Aztec corridor) - Meth lab explosions - Propane/natural gas explosions (rural settings) - Military/ordnance (Kirtland AFB, White Sands, reservation areas)

NREMT Relevance

  • Four blast injury mechanisms: Primary (blast wave), Secondary (shrapnel), Tertiary (thrown), Quaternary (other)
  • Primary blast = hollow organ injury — no external signs, high suspicion required
  • TM rupture = marker of significant primary blast exposure; look for other primary injuries
  • Blast lung = most lethal primary blast injury; O2; caution with PPV
  • Scene safety: secondary device threat; do NOT rush in

Sources

  • raw/protocols/nm-sop-guidelines-treatment-2022.pdf — Trauma protocols
  • UCLA EMT Ultimate Study Guide (2026) — Blast Injuries: Primary/Secondary/Tertiary/Quaternary mechanisms