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Diving injuries: barotrauma, arterial gas embolism and decompression sickness
Diving injuries come from changes in pressure and gas volume: ear and sinus barotrauma on descent, lung rupture with arterial gas embolism on rapid ascent, and decompression sickness from nitrogen bubbles; treatment of embolism and decompression sickness is 100% oxygen at once and transfer to a recompression chamber.
Why it matters in the exam
Questions describe a diver who ascended quickly after running out of air and within a few minutes develops a sudden neurological deficit or confusion (arterial gas embolism), compared with a diver who, an hour to several hours later, develops joint pain, a rash, leg weakness or urinary retention (decompression sickness). The distinction is mainly in the time of onset, but the treatment of both is the same: 100% oxygen and the chamber.
Practical rules are also tested: the diver is not placed head-down but lies flat; fluids are given; air transfer is only at low altitude or in a pressurised cabin; and flying after routine diving is avoided for about 12 hours after a single dive and about 18 hours after several dives. Middle-ear barotrauma is the most common injury and appears on descent.
Remember the pulmonary complications of a rapid ascent with breath-holding: pneumothorax, air in the mediastinum and under the skin, and arterial gas embolism. A patient with pneumothorax gets a drain before chamber treatment. Type I decompression sickness includes joint pain and rash, and type II nerve injury — mainly of the spinal cord — and lung involvement. Even mild or transient symptoms after a dive require consultation with a hyperbaric medicine centre.
Key points
- Arterial gas embolism — minutes after ascent; decompression sickness — hours later.
- Treatment of both: 100% oxygen, lie flat, fluids and the chamber.
- Middle-ear barotrauma is the most common and appears on descent.
- Pneumothorax — drain before the chamber.
- No flying for about 12 hours after one dive and about 18 hours after several dives.
Summary table
| Injury | Time of onset | Picture | Treatment |
|---|---|---|---|
| Middle-ear barotrauma | On descent | Pain, reduced hearing, blood behind the eardrum | Analgesia, rest from diving |
| Arterial gas embolism | Minutes after ascent (usually under 10) | Stroke-like deficit, confusion, cardiac arrest | 100% oxygen, lie flat, chamber at once |
| Type I decompression sickness | An hour to several hours | Joint pain, rash, itching | 100% oxygen, fluids, chamber |
| Type II decompression sickness | An hour to several hours | Leg weakness, urinary retention, breathlessness | 100% oxygen, fluids, urgent chamber |
| Pulmonary barotrauma | On ascent | Pneumothorax, mediastinal air | Chest drain before the chamber |
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Sources
- Undersea and Hyperbaric Medical Society, Hyperbaric Oxygen Therapy Indications, 15th edition (2023) — Decompression sickness and arterial gas embolism
- Divers Alert Network, Guidelines for flying after diving and first aid for dive injuries, current edition — Oxygen first aid
- Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th edition (2020) — Dysbarism and complications of diving
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.