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Chest Trauma

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

Overview

Chest trauma encompasses injuries to the chest wall, lungs, heart, and great vessels from blunt or penetrating mechanisms. The thoracic cavity contains the airway, lungs, heart, and major vessels — all immediately life-threatening structures. Prehospital EMT-B management focuses on identifying the specific injury type, supporting oxygenation and ventilation, and rapid transport.

Life-threatening chest injuries (ATOMS): - Airway obstruction - Tension pneumothorax - Open chest wound (sucking chest wound) - Massive hemothorax - Simple pneumothorax (monitor for progression) - Flail chest, cardiac tamponade, pulmonary contusion (additional)

Key Points

  • Tension pneumothorax is the most immediately life-threatening. See the mechanism section below for the full step-by-step pressure progression. Requires needle decompression (ALS/paramedic scope in NM; EMT-B recognizes and expedites transport).
  • Open chest wound (sucking chest wound): cover with occlusive dressing; tape 3 sides only (acts as flutter valve); 4-sided seal can convert to tension pneumothorax
  • Flail chest: two or more adjacent ribs broken in two or more places; paradoxical chest wall movement (segment moves inward with inspiration, outward with expiration); underlying pulmonary contusion is the real threat; positive pressure ventilation (BVM) provides internal splinting
  • Rib fractures: significant pain causes splinting (guarding) → atelectasis and pneumonia; pain management is important
  • Pulmonary contusion: bruised lung tissue; hypoxia develops over hours; not always apparent prehospital
  • All chest trauma patients: 100% O2 via NRB initially; maintain SpO2 ≥94%

Tension Pneumothorax — Mechanism and Recognition

Concept Link

This is obstructive shock. The mechanism described here maps directly to the obstructive shock section in shock-physiology. Read both pages together.

How Pressure Builds: Step by Step

Tension pneumothorax is not a static injury. It is a progressive, escalating pressure crisis. Understanding each step explains every clinical finding.

Step 1 — Air enters the pleural space. A breach in the lung parenchyma (from a rib fracture puncturing lung tissue) or in the chest wall (from a penetrating wound) allows air to enter the pleural space. Normally the pleural space contains a small amount of fluid that holds the lung against the chest wall by surface tension. When air enters, that negative pressure seal is lost.

Step 2 — The affected lung collapses. As air accumulates in the pleural space, the lung on that side cannot expand against the pressure. It collapses progressively. The clinical finding: decreased or absent breath sounds on the affected side. The patient reports dyspnea and may show increasing respiratory rate and effort.

Step 3 — A one-way valve mechanism develops. In tension pneumothorax, the breach acts as a one-way valve: air enters the pleural space with each breath but cannot exit. With every inspiration, more air accumulates. Pressure in the pleural space rises above atmospheric pressure — it is no longer a passive collection but an actively pressurizing space.

Step 4 — The mediastinum shifts. The rising pressure in the affected hemithorax pushes the mediastinal structures — heart, trachea, great vessels — toward the opposite side. The clinical finding: tracheal deviation away from the affected side (toward the unaffected side). This is a late sign. By the time tracheal deviation is visible, the patient is in extremis. Do not wait for tracheal deviation to suspect tension pneumothorax.

Step 5 — The contralateral lung is compressed. As the mediastinum shifts, it compresses the opposite (unaffected) lung. Now the patient has one collapsed lung and one partially compressed lung. Gas exchange is critically impaired. Hypoxia and hypercapnia accelerate.

Step 6 — Venous return is obstructed. The great veins (superior and inferior vena cava) that return blood to the right heart are compressible. As mediastinal pressure rises, these vessels are compressed. The heart receives less blood — preload drops. The clinical finding: jugular venous distension (JVD). Blood backs up in the venous system because it cannot reach the right heart. (Note: in hypovolemic patients who are volume-depleted, JVD may be absent even with tension pneumothorax — this is a clinical trap.)

Step 7 — Cardiac output drops. With reduced venous return, stroke volume falls. The heart compensates with tachycardia, but output continues to fall. The clinical finding: hypotension and tachycardia. This is obstructive shock — the pump is intact but blood cannot flow through the circuit.

Death from tension pneumothorax occurs when cardiac output falls to the point that perfusion of the brain and heart cease. Without intervention, death follows within minutes.

Clinical Findings Mapped to the Mechanism

Clinical Finding Mechanism
Decreased/absent breath sounds (ipsilateral) Lung collapse from pleural air accumulation
Increasing respiratory rate and distress Hypoxia + failed ventilation of collapsed lung
Tracheal deviation (contralateral) Mediastinal shift from pressure buildup — late sign
JVD Venous return obstruction from mediastinal compression
Hypotension + tachycardia Obstructive shock from reduced cardiac output
Deterioration despite O2 Mechanical obstruction cannot be fixed with oxygen alone

Why Needle Decompression Works

Needle decompression (second intercostal space, midclavicular line, on the affected side) inserts a large-bore needle through the chest wall into the pressurized pleural space. Air rushes out through the needle, immediately equalizing the pressure. This: - Allows the mediastinum to return toward midline - Decompresses the great veins, restoring venous return - Reduces compression of the contralateral lung - Allows the collapsed lung to begin re-expanding

The result is rapid improvement in cardiac output, blood pressure, and oxygenation within seconds to minutes if performed correctly.

This is ALS (paramedic) scope in New Mexico. The EMT-B's role is to: 1. Recognize the clinical picture early — before all the classic signs develop 2. Call for ALS intercept immediately 3. Initiate transport — do not wait for ALS to arrive if it will significantly delay transport to a trauma center 4. Provide high-flow O2 and support ventilation 5. Reassess continuously — tension pneumothorax can develop or recur

Do not let waiting for tracheal deviation delay your ALS call. The full triad (absent breath sounds + JVD + tracheal deviation + hypotension) is a pre-arrest picture. Act on absent breath sounds + increasing distress + deteriorating vitals after a significant chest injury.

Assessment Relevance

History (history-taking): - MOI: Blunt (MVC, fall, blunt strike) vs. penetrating (GSW, stab wound); velocity and energy; seat belt use; airbag deployment - Symptoms: chest pain (localized = rib fracture; diffuse = tension/contusion), dyspnea, hemoptysis - Time of injury

Physical exam (secondary-assessment): - Inspection: paradoxical movement (flail), open wounds, contusions, deformity, penetrating entry/exit - Palpation: crepitus (rib fractures, subcutaneous emphysema), tenderness - Auscultation: bilateral breath sounds — unilateral absent or decreased = pneumothorax/hemothorax - Tracheal position: deviation away from affected side in tension pneumothorax (late sign) - JVD: present in tension pneumothorax and cardiac tamponade - Neck veins: absent in hemothorax/hypovolemia - BP and pulse: hypotension indicates tension pneumothorax, massive hemothorax, or tamponade - SpO2

Procedures

All chest trauma: 1. Scene size-up (scene-size-up): MOI, hazards; c-spine consideration 2. Primary assessment (primary-assessment): airway, breathing (rate, effort, breath sounds bilaterally), circulation 3. 100% O2 via NRB — oxygen-administration; SpO2 ≥94% 4. Transport to trauma center; request ALS/ALS intercept for all significant chest trauma

Open chest wound (sucking chest wound): 1. Apply occlusive dressing (commercial chest seal or plastic) 2. Tape 3 sides only — creates flutter valve 3. If fully occlusive seal: monitor closely for development of tension pneumothorax 4. If tension pneumothorax develops after sealing: release the seal momentarily to allow air to escape, then re-seal

Flail chest: 1. 100% O2; manual positive pressure ventilation (BVM) if respiratory failure — BVM provides internal pneumatic splinting 2. Positive pressure ventilation for severe chest wall instability causing inadequate ventilatory volume 3. Pain management (ALS scope): Morphine 4–10 mg slow IV/IO or Fentanyl 25–100 mcg slow IV/IO

Tension pneumothorax (recognized by EMT-B; intervention is ALS): - Signs: decreased/absent breath sounds unilateral, tracheal deviation, JVD, hypotension, increasing respiratory distress - EMT-B: high-flow O2, transport immediately, ALS intercept - Paramedic: needle decompression (2nd intercostal space, midclavicular line)

NM Protocol Notes

From NM EMS Treatment Guidelines (2022):

All chest injuries — EMT-B scope: - 100% O2 via NRB face mask; maintain SpO2 ≥94% - Transport to closest available trauma center; consider ALS intercept - Primary assessment; manage as indicated

Flail Chest: - All patients: 100% O2 via NRB; SpO2 ≥94% - Intubation and mechanical ventilation rarely indicated for chest wall injury alone (usually needed for hypoxia from underlying pulmonary contusion) - Positive pressure ventilation for severe chest wall instability causing inadequate ventilatory volume - Pain management if no contraindications: - Morphine: Adult 4–10 mg slow IV/IO (2–4 mg every 10 min; max 10 mg without Medical Control); Pediatric 0.05–0.1 mg/kg slow IV/IO - Fentanyl: Adult 25–100 mcg slow IV/IO every 5 min (max 100 mcg single dose, 300 mcg total); Pediatric 0.5–1 mcg/kg IV/IO or IM (max 2.0 mcg/kg) - (ALS scope for IV analgesics)

Simple Pneumothorax: - 100% O2 via NRB; SpO2 ≥94% - Observe for progression to tension pneumothorax

Tension Pneumothorax: - 100% O2 via NRB; SpO2 ≥94% - Needle decompression — EMT-P only

Open Chest Wound: - 100% O2 via NRB; SpO2 ≥94% - Apply fully occlusive chest seal (commercial) or occlusive dressing taped 3 sides (flutter valve) - Monitor closely for development of tension pneumothorax

Barotrauma (diving/CBRNE events): - 100% O2 via NRB; SpO2 ≥94% - Monitor for pneumothorax development - Caution: positive pressure ventilation and CPAP may cause or exacerbate underlying pneumothorax — use with caution - Administer bronchodilators if bronchospasm or wheezing - IV/IO isotonic fluid to maintain vital signs

NREMT Relevance

High-priority NREMT topic: - Open chest wound: occlusive dressing, taped 3 sides (flutter valve) — NOT 4 sides - Flail chest: paradoxical breathing; BVM provides positive pressure splinting - Tension pneumothorax signs: absent breath sounds unilateral + tracheal deviation + JVD + hypotension - Needle decompression: ALS (paramedic) scope — EMT-B recognizes and expedites transport - All chest trauma: 100% O2 initially

Sources

  • raw/protocols/nm-sop-guidelines-treatment-2022.pdf — Chest Injuries protocol (p. 72–73); General Trauma Guidelines (p. 59–60)