Understanding MARCH - The Relevance of Respiratory Assessment

From the MARCH Mnemonic Series – Tactical Trauma Care for EMS Providers

After controlling Massive Hemorrhage and ensuring a patent airway, the next priority in the MARCH sequence is Respiration.

Effective breathing is critical for oxygen delivery and carbon dioxide removal. When trauma impairs the chest wall or lungs, hypoxia and shock can develop rapidly – even when the airway is clear.

In tactical or prehospital settings, respiratory compromise is often caused by thoracic injury, such as a gunshot, stab wound, or blast trauma.

These injuries can lead to life-threatening conditions like tension pneumothorax or open chest wounds, both of which are preventable causes of death when identified and treated early.

This article – the third in a five-part series – will focus on that next critical step:

R – Respiration

Respiration refers to the body’s ability to move air into and out of the lungs and to exchange gases at the alveolar level.

Any disruption – mechanical, anatomical, or physiological – can cause hypoxia and threaten survival.

The responder’s task is to rapidly assess, seal, decompress, and support breathing as needed.

Principles of Respiratory Management

Assess the Casualty’s Breathing
Begin by evaluating rate, depth, and effort of respirations. Look, listen, and feel for:
- Asymmetrical chest rise or movement
- Difficulty speaking, gasping, or labored breathing
- Cyanosis around lips or fingertips
- Tracheal deviation, jugular venous distention, or subcutaneous emphysema
- Penetrating trauma to the chest or upper abdomen
If you’re operating in a tactical environment, conduct this assessment as efficiently as safety allows—rapid but systematic.
Expose and Inspect for Chest Injuries
Visually inspect the anterior, lateral, and posterior thorax for entry and exit wounds, contusions, or deformities. In low-light or confined spaces, gloved hands may detect what the eyes can’t.
- Sucking chest wounds (open pneumothorax) occur when air enters the pleural space through a chest wall defect.
- These must be sealed immediately with a vented or occlusive chest seal to prevent the progression to tension pneumothorax.
Modern products like the HyFin® Vent Chest Seal or FoxSeal™ are designed for field reliability and are standard in most tactical trauma kits.
Manage a Tension Pneumothorax
A tension pneumothorax occurs when air becomes trapped in the pleural space and cannot escape, collapsing the lung and compressing the heart and great vessels.
Signs may include:
- Severe respiratory distress
- Decreased or absent breath sounds on one side
- Hypotension and tachycardia
- Tracheal deviation (a late sign)
Intervention:
If tension pneumothorax is suspected and equipment/training allow, perform needle decompression:
- Use a 14-gauge, 3.25-inch (8.25 cm) needle or catheter.
- Insert into the 5th intercostal space, anterior axillary line (or 2nd intercostal space, midclavicular line if indicated).
- Listen for escaping air and observe for improvement in breathing and perfusion.
Always reassess, if symptoms recur, repeat decompression or prepare for chest tube insertion at higher care levels.
Support Oxygenation and Ventilation
If available and appropriate, administer supplemental oxygen to maintain SpO₂ above 94%.
For inadequate respirations, assist with bag-valve-mask (BVM) ventilation while maintaining airway alignment. In prolonged field care, consider monitoring SpO₂ and ETCO₂, if resources allow, to guide ongoing management.
Continue Monitoring and Reassessment
The chest is dynamic, bleeding, air leakage, or mechanical disruption can recur with movement or time. Reassess chest rise, breath sounds, and patient condition frequently during evacuation.

Key Takeaway for EMS and Tactical Providers

Thoracic trauma demands vigilance. While hemorrhage and airway compromise often draw attention first, unrecognized respiratory failure can kill just as quickly. The tactical provider must be proficient in identifying chest injuries, applying chest seals, and performing needle decompression when indicated.
In short: find the holes, seal the leaks, relieve the pressure, and keep the oxygen moving.

Coming Next: Part Four – Circulation

Once bleeding is controlled, the airway is secure, and breathing is restored, it’s time to assess circulation—the body’s ability to perfuse vital organs.

In Part Four of our MARCH series, we’ll explore recognition and management of shock, fluid resuscitation strategies, and maintaining perfusion in both field and tactical environments.

Because after oxygen, the mission is to keep it flowing where it matters most.

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Understanding MARCH – The Relevance of Respiratory Assessment