Burst lung, medically called pulmonary barotrauma, happens when air trapped in a diver’s lungs expands during ascent and stretches the delicate lung tissue until it tears. The danger comes from where the escaped air goes. It can collect around the lung, track into the chest and neck, or enter the bloodstream and travel to the brain. A diver who holds their breath during ascent, or who has an airway that traps air, is at the greatest risk. Burst lung is a medical emergency, and early first aid makes a real difference.
How Burst Lung Happens
Air takes up more space as pressure falls, so a breath taken at depth expands as the diver rises. If that expanding air cannot leave the lungs, because the diver is holding their breath, panicking or has a blockage in a small airway, the lungs overstretch and can rupture. This can happen even during a rise of only a few metres in shallow water.
Symptoms of Burst Lung
- Chest pain, often sharp and worse on breathing in
- Difficulty breathing or breathlessness
- Coughing, sometimes with frothy or blood-stained sputum
- Blue colour of the lips and skin
- A change in the voice
- Difficulty swallowing, and a crackling feeling under the skin of the neck or upper chest when pressed
Symptoms such as sudden collapse, confusion, weakness on one side, vision loss or unconsciousness soon after surfacing suggest that air has entered the bloodstream, which is an extreme emergency.
Burst Lung First Aid Steps
- Assess DRABC. Remove the diver from the water safely and check danger, response, airway, breathing and circulation using the DRABC primary survey.
- Call the emergency number and ask for advice from a diving medical service as well.
- Give oxygen if you are trained. Provide 100 per cent oxygen by demand valve or high-flow mask and continue it until the ambulance arrives.
- Position for comfort. A conscious diver with breathing difficulty usually breathes best sitting or semi-reclined. If there are signs of air in the bloodstream, such as collapse or stroke-like symptoms, follow medical advice, which often favours lying flat.
- Keep the diver calm and warm, and do not allow them to exert themselves.
- Monitor continuously. Check breathing rate, pulse and alertness regularly and record them, as described in our vital signs observations guide.
- Be ready to resuscitate. If the diver stops breathing, give breaths and compressions as in CPR for adults.
- Record the dive details, gas used and time of onset for the receiving doctors.
Burst Lung and Decompression Illness
The two conditions can occur together and share some features, including breathlessness and neurological symptoms. First aid is therefore very similar: oxygen, positioning, specialist advice and transfer. See our guide to decompression illness first aid for the full recognition list.
Avoiding Burst Lung
The golden rule of scuba is never to hold your breath. Breathe continuously, ascend at the rate your training specifies, and avoid diving with a chest infection, asthma that is not under control or other conditions that your dive doctor has advised against. Divers who make a rapid emergency ascent should exhale steadily all the way to the surface and seek a medical check afterwards, even if they feel fine.
Frequently Asked Questions
Can burst lung happen in shallow water?
Yes. Pressure changes are proportionally greatest near the surface, so even a short ascent while holding the breath can cause injury.
Is burst lung always obvious?
No. Symptoms may be subtle or delayed. Any diver with chest pain, breathlessness or unusual neurological symptoms after a dive should be assessed urgently.
Do all divers with burst lung need a chamber?
Not all, but doctors will decide. The first aid priorities are oxygen, monitoring and rapid transport to medical care.
References and Further Reading
- American Heart Association and American Red Cross, Guidelines for First Aid
- Divers Alert Network (DAN)
Last updated: October 2026
Prepared by: EHS Guidelines Editorial Team
This article is general educational information and is not a substitute for accredited first aid training or professional medical care. In an emergency, call your local emergency number immediately. Emergency numbers, medicines and protocols differ between countries, so follow local guidance.
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