Tension pneumothorax.
A tension pneumothorax is a true airway/obstructive emergency that progresses from respiratory distress to obstructive shock to cardiac arrest. Recognize it early, treat it fast.
Early signs
Anxiety, tachypnea, progressive dyspnea, decreased or absent breath sounds on the affected side, chest pain or crepitus after trauma.
Late signs
Hypotension, JVD, tracheal deviation, cyanosis, and pulseless electrical activity from obstructive shock.
Pathophysiology in plain language
Air enters the pleural space but cannot escape — usually through a one-way valve tear in the lung. Pressure rises, collapsing the lung on the injured side and pushing the heart and great vessels toward the other side. Venous return drops, cardiac output crashes, and the patient goes into obstructive shock.
Needle decompression basics
- Confirm the side by auscultation and exam.
- Identify the decompression site per protocol — lateral approach at 4th/5th ICS anterior axillary line is common.
- Clean the site if time permits.
- Insert a 14g catheter-over-needle at the top of the rib (to avoid the neurovascular bundle).
- A rush of air confirms placement. Remove the needle and leave the catheter.
- Reassess; tension can recur if the catheter clots or kinks.
Open pneumothorax (sucking chest wound)
An open chest wound creates a sucking sound because air moves through the chest wall instead of the airway. Seal it with an occlusive dressing taped on three sides (flap valve), or fully seal if the patient is on positive-pressure ventilation. Monitor for tension development after sealing.
NREMT tip
If a trauma patient has hypotension + JVD + unilateral absent breath sounds, the differential narrows to tension pneumothorax vs cardiac tamponade. The side with absent breath sounds points to tension pneumothorax, and the treatment is needle decompression.
FAQ
What are the signs of tension pneumothorax?
Severe respiratory distress, absent or decreased breath sounds on one side, hypotension, jugular venous distention, and tracheal deviation away from the affected side. Tachycardia and cyanosis are common late signs.
Why does the trachea deviate away from the affected side?
Pressure builds on the injured side, pushing the mediastinum — including the trachea — toward the uninjured side. This is a late sign; do not wait for it to act.
How is tension pneumothorax different from cardiac tamponade?
Both cause hypotension and JVD. Tension pneumothorax has unilateral absent breath sounds, hyperresonance, and often a history of chest trauma or positive-pressure ventilation. Tamponade has muffled heart sounds and a history of chest trauma or cardiac procedure.
Where is needle decompression performed?
Traditional teaching is the second intercostal space at the midclavicular line on the affected side. Many systems have moved to the fourth or fifth intercostal space at the anterior axillary line (lateral approach) because of better success and fewer complications. Follow your local protocol.
What size needle is used for decompression?
A large-bore catheter-over-needle, typically 14 gauge × 3.25 inches for adults in the lateral approach, and sometimes longer for larger patients. The traditional anterior approach may be shorter but less reliable.