Synopsis
Recognise lung over-expansion injury and arterial gas embolism after diving, stabilise immediately, and obtain urgent UK diving-medicine and hyperbaric advice.
- Compressed gas expands during ascent, with the greatest proportional volume change near the surface; breath-holding or regional airway trapping can rupture alveoli even after a shallow dive.
- Escaped gas may cause pneumothorax, tension pneumothorax, pneumomediastinum, subcutaneous emphysema or entry into pulmonary veins with arterial gas embolism.
- A stroke-like deficit, seizure, visual change, confusion or loss of consciousness within minutes of surfacing is arterial gas embolism until urgently assessed, even if symptoms improve spontaneously.
- Chest pain, dyspnoea, voice change, neck crepitus or haemoptysis after ascent suggests pulmonary over-expansion injury; normal initial radiography does not exclude small mediastinal gas or gas embolism.
- Give 100% oxygen immediately and call emergency plus diving-medicine services. Oxygen reduces bubble size and improves oxygen delivery; it should continue during transfer whenever safely possible.
- Do not use Trendelenburg positioning, in-water recompression, commercial-air travel or unpressurised altitude transfer unless the diving and retrieval teams explicitly direct the safest option.
- Tension pneumothorax is a resuscitation diagnosis and must be decompressed before hyperbaric chamber treatment because trapped pleural gas can expand and destabilise the patient.
- Do not delay a compelling arterial gas embolism referral for extensive imaging; the hyperbaric specialist should help sequence CT, trauma care and chamber transfer.
- Routine aspirin, anticoagulation, corticosteroid and prophylactic antibiotic treatment is not indicated for gas embolism or uncomplicated pulmonary barotrauma.
- No further diving is permitted until specialist assessment. At-work divers require the HSE return-to-work process; recreational divers need a UKDMC-recognised diving medical opinion.
Key red flags
A rapid or uncontrolled ascent, breath-holding, out-of-air emergency or obstructive lung disease followed immediately by chest symptoms strongly supports barotrauma. It can occur despite apparently compliant computer profiles.
Retrosternal pain, dysphagia, voice change, neck swelling or palpable crepitus after surfacing suggests mediastinal and subcutaneous gas. Haemodynamic stability does not exclude an associated pneumothorax or AGE.
Severe respiratory distress, unilateral reduced air entry, hypotension, tachycardia, increasing ventilatory pressure or peri-arrest physiology after ascent requires immediate decompression without waiting for a radiograph.
Abrupt focal weakness, aphasia, visual loss, vertigo, seizure, confusion or coma during ascent or soon after surfacing is characteristic. Rapid spontaneous improvement does not remove the need for hyperbaric assessment.
Chest pain, dysrhythmia, shock or cardiac arrest immediately after ascent may reflect coronary gas, hypoxia or another cardiac event. Treat standard resuscitation needs while contacting hyperbaric medicine.
Decompression sickness, immersion pulmonary oedema, aspiration, salt-water inhalation, myocardial ischaemia, stroke, seizure, hypoglycaemia and trauma can mimic or coexist; none justifies withholding emergency oxygen or specialist advice.
Investigation priorities
Reconstruct pressure exposure and mechanism without delaying treatment.
Management branches
Any serious chest, neurological or cardiorespiratory symptom during ascent or after surfacing.
- Call 999 or Coastguard at sea, give 100% oxygen by tight-fitting mask, keep the casualty lying horizontally, warm and monitored, and use the live BHA emergency contact.
- Perform ABCDE assessment with glucose and a documented neurological examination, treating arrest, hypoxaemia, seizure, trauma and shock in parallel.
- Preserve the dive computer and record profile, gas and symptom timing, but do not postpone evacuation or oxygen to complete a perfect history.
- Agree destination, imaging and pressure-safe transport with the diving physician; avoid altitude exposure and never attempt in-water recompression.