ICU · Toxicology

Decompression illness and diving emergencies

Also known as Decompression sickness (DCS) · Decompression illness (DCI) · The bends · Arterial gas embolism (AGE) · Pulmonary barotrauma of ascent · The chokes (pulmonary DCS) · The staggers (vestibular DCS) · Skin bends · Hyperbaric oxygen therapy (HBOT) · US Navy Treatment Table 6 · Dysbarism

Decompression illness (DCI) is the umbrella term for the two bubble-mediated injuries of ascent: decompression sickness (DCS — 'the bends', from nitrogen bubble formation in tissues during ascent driven by inert-gas supersaturation and Henry's law) and arterial gas embolism (AGE — alveolar gas forced into arterial circulation from pulmonary barotrauma of ascent). DCS types: Type 1 (mild — musculoskeletal joint pain 'the bends', skin marbling/mottling 'skin bends', lymphatic swelling). Type 2 (serious — neurological: spinal cord involvement is the MOST SERIOUS form with progressive weakness, paraesthesia, sensory level, bladder/bowel dysfunction; cardiopulmonary 'the chokes': substernal chest pain, cough, dyspnoea, haemoptysis; vestibular 'the staggers': vertigo, nystagmus, nausea, tinnitus, hearing loss; cerebral: headache, visual disturbance, confusion, hemiparesis). AGE: stroke-like cerebral symptoms (hemiparesis, aphasia, seizure, coma) DURING or within minutes of surfacing from pulmonary barotrauma — breath-holding or rapid ascent over-expands alveoli → alveolar rupture → gas enters pulmonary veins → left heart → systemic arteries. Onset: AGE within minutes; DCS usually within minutes-to-hours, 98% within 24 h. Management is identical for both: 100% oxygen immediately (denitrogenates tissues — creates maximal gradient for nitrogen washout from bubbles), IV isotonic glucose-free fluids (correct immersion diuresis and dehydration), and DEFINITIVE recompression therapy — hyperbaric oxygen, US Navy Treatment Table 6 (100% oxygen at 2.8 ATA / 18 m / 60 fsw), which shrinks bubbles by Boyle's law (to ~one-third of surface volume), oxygenates ischaemic tissue by Henry's law (~6 vol% dissolved O2 in plasma at 2.8 ATA), and accelerates inert-gas washout. Contact Divers Alert Network (DAN) 24-h hotline for chamber location and retrieval. Early HBOT improves outcomes — recompress as soon as feasible.

low9 referencesUpdated 26 July 202623 min readVerification in progress

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ANY neurological symptom after diving — weakness, paraesthesia, gait ataxia, bladder/bowel dysfunction, vertigo — is presumed SPINAL CORD or CEREBRAL DCS until proven otherwise. This is the MOST SERIOUS form. Give 100% oxygen, IV fluids, retrieve for recompression.
Loss of consciousness, seizure, or focal stroke-like deficit DURING or within minutes of surfacing = ARTERIAL GAS EMBOLISM (AGE) from pulmonary barotrauma until proven otherwise. Treatment is the same: 100% O2 + recompression, NOW.
98% of DCS presents within 24 hours of surfacing. A diver with new symptoms hours after a dive has DCS — never discharge without hyperbaric consultation.
Do NOT use entonox (nitrous oxide) for analgesia — it expands nitrogen bubbles and worsens injury. Use opioids cautiously (avoid respiratory depression pre-chamber).
Drain a pneumothorax BEFORE recompression — trapped gas expands dangerously in the chamber (Boyle's law). Screen any AGE/pulmonary-symptom case with CXR or ultrasound.
Retrieval at sea-level cabin pressure only — avoid unpressurised aircraft above 300 m (1000 ft); further decompression enlarges bubbles.
Contact Divers Alert Network (DAN) 24-h hotline immediately — retrieval logistics dominate outcome.

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