EMA Cited · Pulmonary · Trauma

Tension pneumothorax

Updated Oct 28, 2026Adults · ED management9 sources · 7 in PubMed2 figuresNICE NG39 · 2025 meta-analysis

Bottom line

Decompress before imaging only for hemodynamic instability or severe respiratory compromise. Otherwise, confirm it first.¹
Ventilated patients crash fast. Compared with patients breathing on their own, they had 12.6 times the odds of hypotension and 17.7 times the odds of cardiac arrest, usually within minutes.²
Open thoracostomy over the needle if you have the skills, followed by a chest drain.¹ On imaging, needles failed to reach the pleural space in about a third of cases.³
If you use a needle, use a long one. Each extra centimeter of length lowered the failure rate by about 8 percentage points. A 2025 meta-analysis suggests 7 cm.³
Bedside ultrasound beats the supine chest film: sensitivity 91% vs 47% for traumatic pneumothorax.⁴ A negative eFAST still does not exclude it.¹

Recognize

Breathing on their own: hypoxia was reported in 50% of cases, and 9.3% progressed to respiratory arrest.²
On a ventilator: hypoxia was reported in 91.8%. Odds of hypotension were 12.6 times higher and odds of cardiac arrest 17.7 times higher. In one cohort, 39.6% of ventilated patients had no pulse at diagnosis, against none of those breathing on their own. Of those who became hypotensive or arrested, 70.4% did so within minutes.²
Think of it in a ventilated patient who suddenly deteriorates, and after central line placement.⁵
Classic signs are hard to elicit in a busy resuscitation: reduced breath sounds, a hyper-resonant chest and tracheal deviation.³
A wrong diagnosis has a cost. A needle in a chest without tension can cause a pneumothorax.³ In one prehospital series, at least 39% of decompressed patients had no tension pneumothorax on CT.⁶

Portable AP chest X-ray showing a dark, over-expanded left hemithorax and the mediastinum shifted to the right — FIG 1Left tension pneumothorax on a portable film. The left chest is dark and over-expanded, with widened rib spaces, and the mediastinum is pushed to the right. An unstable patient should be decompressed before any film is taken.¹James Heilman, MD · Wikimedia Commons · CC BY-SA 3.0

First minutes

Unstable or in severe respiratory compromise: decompress now, before imaging.¹
Use open thoracostomy if you have the skills, rather than a needle. In a patient breathing on their own, place the chest drain through the thoracostomy.¹
Stable: confirm first. Use chest X-ray or eFAST in the primary survey for severe respiratory compromise. Consider CT for patients who are stable or responding to resuscitation.¹
Watch for recurrence after decompression.¹
Open chest wound: cover it with a simple occlusive dressing and watch for tension.¹

FIG 2 · Decision flowCited

Suspect tension after chest injury, in a ventilated patient who suddenly deteriorates, or after a central line, with hypoxia or shock.^5,2
On a ventilator?
Yes
Expect a fast crash. Hypotension or arrest often comes within minutes.²
Either way
Hemodynamic instability or severe respiratory compromise?
No
Image first: chest X-ray or eFAST, or CT if stable. A negative eFAST does not exclude pneumothorax.¹
Yes
Decompress now, before imaging
Skills available
Open (finger) thoracostomy, preferred over the needle.¹
Otherwise
Needle with a long (about 7 cm) catheter. On the left, use the 2nd intercostal space, midclavicular line.³
Fails to reach the pleura in about 1 in 3.³
Chest drain next, through the thoracostomy in a patient breathing on their own.¹
Reassess and watch for recurrence. If there is no response, the needle may have missed or the diagnosis may be wrong.^1,3,6

FIG 2Suspected tension pneumothorax. Drawn for this page from NICE NG39 and the studies cited below. Each box carries its own citations.^1,3

Decompression

	ATLS	European Trauma Course	2025 meta-analysis
Site	4th or 5th intercostal space, anterior midaxillary line	2nd intercostal space, midclavicular line	Right: 2nd space midclavicular or 5th space midaxillary. Left: 2nd space midclavicular only
Needle	5 cm for smaller adults, 8 cm for larger adults	14 or 16 gauge "extra-long" cannula	7 cm

Course recommendations as summarized in the 2025 meta-analysis, which made the suggestions in the last column.³

Site (5 cm needle)	Chest wall thickness	Failure rate
2nd intercostal space, midclavicular line	42.8 mm	38%
4th/5th space, midaxillary line	39.9 mm	31%
4th/5th space, anterior axillary line	34.3 mm	13%

Pooled from observational studies in a 2016 meta-analysis.⁷

Sources disagree

Where to put the needle. The 2016 meta-analysis found the lowest predicted failure at the 4th/5th space in the anterior axillary line.⁷ The 2025 meta-analysis found no significant difference between sites once needle length was matched (p = 0.052). On the left, the risk of heart injury at the 5th space rose with needle length, so it suggests the 2nd space in the midclavicular line on that side.³ In a CT review, an 8 cm catheter at the 5th space in the anterior axillary line put the heart at risk in 42% of patients.⁶

Needles fail often. On imaging, 32.8% failed to enter the pleural space (24 studies, 8,046 patients). Clinical improvement failed in about half.³
In one prehospital CT review, 39% to 76% of needles at the 2nd space failed to reach the pleura, depending on the method. Injured chest walls were thicker than uninjured ones.⁶
Finger or needle? Studies of paramedic decompression were mostly retrospective, with no randomized trials. Complications were reported in 13.7% after needle and 4.8% after finger thoracostomy. Mortality ranges were too wide to compare.⁸
NICE prefers open thoracostomy when the expertise is there.¹ REBEL EM argues finger thoracostomy is faster and more reliable than the needle.⁵

Imaging

Test for pneumothorax	Sensitivity	Specificity	Source
Chest ultrasound, trauma	91%	99%	Cochrane, 9 studies, 1,271 patients⁴
Supine chest X-ray, trauma	47%	100%	Cochrane⁴
Chest ultrasound, all settings	78.6%	98.4%	13 studies⁹
Chest X-ray, all settings	39.8%	99.3%	13 studies⁹

Ultrasound signs used in these studies were lung sliding, comet tails and the lung point.⁹
A negative eFAST does not exclude a pneumothorax.¹
In trauma, consider chest X-ray or eFAST in the primary survey for severe respiratory compromise, and CT for stable adults.¹

Pitfalls

Waiting for a chest film in an unstable patient.¹
Trusting a short needle at the 2nd intercostal space in a thick chest wall.^7,3
Placing a long needle low on the left, near the heart.^3,6
Assuming a needle that "worked" has fixed the problem. Place a drain and watch for recurrence.¹
Calling it tension when it isn't. At least 39% of one prehospital series had no tension pneumothorax.⁶
Forgetting it in a ventilated patient who suddenly becomes hypotensive.^2,5

How strong is the evidence?

Weak and observational. In the 2025 meta-analysis, 50 of 51 studies were level IV evidence, and heterogeneity was extreme (I² > 99%).³ The review of paramedic decompression found no randomized trials.⁸ What we know about the clinical picture comes from 5 cohort studies and 156 case reports and series.² The NICE recommendations were published in 2016.¹

On-shift teaching

Questions to ask a learner at the bedside. Tap a question to see the answer. Every answer uses facts cited above.

Q1Why is tension pneumothorax more dangerous in a ventilated patient?

Ventilated patients had 12.6 times the odds of hypotension and 17.7 times the odds of arrest. In one cohort, 39.6% had no pulse at diagnosis, and most who crashed did so within minutes.²

Q2When do you decompress before imaging?

Only for hemodynamic instability or severe respiratory compromise.¹

Q3Why do needles at the 2nd intercostal space fail?

The chest wall is thickest there (42.8 mm on average), and a 5 cm needle failed in 38%.⁷ Each extra centimeter of needle lowered the failure rate by about 8 percentage points.³

Q4Left-sided tension and only a long needle: where do you put it?

The 2025 meta-analysis suggests the 2nd intercostal space, midclavicular line, because heart injury risk at the 5th space rose with needle length.³ An 8 cm catheter at the left 5th space put the heart at risk in 42% of one CT series.⁶

Q5How does bedside ultrasound compare with a supine chest X-ray for traumatic pneumothorax?

Sensitivity 91% vs 47%, with similar specificity (99% vs 100%).⁴

Q6You've done a finger thoracostomy. What next?

Place a chest drain through the thoracostomy if the patient is breathing on their own, and watch for recurrence.¹

References

Evidence base

What this page is built on

9 sources, cited 62 times. Dots are sources, filled by how far each was read; stronger color means a larger share of the citations. Tap a tier to see its sources.

Read in full · 3Abstract read · 6Record only · 0Link checked · 0

Checked by the writer, not a physician. The dots show how each source was read, not that anyone has confirmed the claims.

Not for clinical use

AI-generated draft. Not reviewed by a physician. This page is for education only and may contain errors, including in doses. Do not use it to diagnose, treat or make decisions about any patient. Rely on your own clinical judgment, your institution's protocols and current drug labeling. Reading this page does not create a physician-patient relationship. Full terms