Tension Pneumothorax: Recognition and Management for Students

Lachlan Baillie, Registered Paramedic

3 days ago

4 min read

Tension pneumothorax is one of the few conditions that can kill a patient within minutes and be reversed almost as quickly. It sits on every list of immediately life threatening chest injuries, and it is a favourite in OSCEs and scenario assessments for good reason. The diagnosis is clinical, the window is short, and the patient cannot wait for an X ray. For paramedic and nursing students, the skill is recognising it early and knowing why it becomes so dangerous so fast.

Pathophysiology

From pneumothorax to tension

A pneumothorax is air in the pleural space, the thin space between the lung and the chest wall. Normally the pressure in this space is slightly negative, which keeps the lung expanded against the chest wall. When air enters, the lung on that side partially collapses.

A tension pneumothorax develops when the injury acts as a one way valve. Air enters the pleural space with each breath but cannot escape. Pressure on the affected side keeps rising, the lung collapses completely, and the mediastinum, which contains the heart and great vessels, is pushed towards the opposite side.

Why it causes shock

The real danger is circulatory, not just respiratory. Rising intrathoracic pressure compresses and kinks the great veins, so less blood returns to the heart. With less venous return, cardiac output falls, blood pressure drops and the patient develops obstructive shock. Left untreated, this progresses to cardiac arrest, often with pulseless electrical activity.

Tension pneumothorax kills by stopping blood getting back to the heart, not just by stopping air getting into the lung.

Who gets it

Trauma is the classic cause, from both blunt and penetrating chest injuries, particularly when there are rib fractures. It can also develop from a spontaneous pneumothorax, in patients with lung disease such as asthma or COPD, and after procedures such as central line insertion. Patients receiving positive pressure ventilation are at particular risk, because each assisted breath forces more air into the pleural space.

Assessment and Treatment

Recognising it

Think of tension pneumothorax in any patient with chest trauma or a known pneumothorax who suddenly deteriorates. Signs to look for include:

Increasing respiratory distress, tachypnoea and falling oxygen saturation.
Reduced or absent breath sounds on the affected side.
Reduced chest movement on the affected side, which may look hyperexpanded.
Hyperresonance to percussion on the affected side.
Tachycardia and hypotension, a sign that cardiac output is falling.
Distended neck veins, although these may be absent in a patient who has lost blood.
Agitation, a falling level of consciousness and cyanosis as it progresses.

Tracheal deviation away from the affected side is the sign everyone remembers, but it is a late sign and is often difficult to see or feel. Do not wait for it. Presentation also differs between patients. A systematic review found that ventilated patients were far more likely to present with low oxygen levels, hypotension and cardiac arrest, and often deteriorated within minutes, whereas patients breathing on their own tended to show progressive respiratory distress first.

In practice: a ventilated trauma patient whose airway pressures climb, whose oxygen saturation drops and whose blood pressure falls after transfer is a tension pneumothorax until proven otherwise. Think about it before you think about anything else.

Treatment priorities

Tension pneumothorax is a clinical diagnosis and should be treated immediately. Imaging delays treatment, although point of care ultrasound can support the diagnosis in hospital when it does not slow things down. Priorities include:

Manage the airway, give high flow oxygen and call for help early.
Decompress the chest according to your clinical practice guidelines and scope of practice. Options include needle decompression and, for appropriately trained clinicians, finger thoracostomy.
Be aware that recommended needle sites vary between guidelines. The traditional site is the second intercostal space in the midclavicular line, while many trauma guidelines now prefer the fourth or fifth intercostal space just anterior to the midaxillary line in adults, where the chest wall is usually thinner.
Reassess after every intervention. Needles can kink, block or dislodge, and the tension can return.
Follow decompression with definitive management, usually a chest drain in hospital, and notify the receiving hospital early.

Needle decompression can fail if the needle is too short to reach the pleural space, which is more likely in patients with a thicker chest wall. Ongoing deterioration after decompression should prompt reassessment, not reassurance.

Conclusion

Tension pneumothorax is a time critical cause of obstructive shock. Suspect it in any patient with chest trauma, lung disease or positive pressure ventilation who suddenly deteriorates, look for falling saturation, absent breath sounds and falling blood pressure, and do not wait for tracheal deviation or an X ray. Decompress according to your guidelines, reassess constantly and expect it to come back.

References

Tension Pneumothorax. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK559090/

Roberts DJ, Leigh-Smith S, Faris PD, et al. Clinical presentation of patients with tension pneumothorax: a systematic review. Ann Surg. 2015;261(6):1068. https://pubmed.ncbi.nlm.nih.gov/25563887/

Leigh-Smith S, Harris T. Tension pneumothorax: time for a re-think? Emerg Med J. 2005;22(1):8.

American College of Surgeons Committee on Trauma. Advanced Trauma Life Support (ATLS) Student Course Manual. 10th ed. Chicago: American College of Surgeons; 2018.

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