	Headline
Etiology	Nitrogen bubbles forced out of solution → gas embolism (arterial and venous). Recall Boyle's law! Escaped gas i.e. nitrogen bubbles entering arterial circulation due to PFO or overwhelmed pulmonary filter
Epidemiology	Risk factors - Deep dive, long dive, missed decompression stops, multiple dives - Age - Exercise during or after a dive - Flying/ ascending to altitude after diving - Obesity - Dehydration - Alcohol use prior to dive
Clinical presentation	Can be very non-specific. Symptoms within 6h of dive. Rash - marbled/mottled appearance Joint pain
Pathogenesis	Nitrogen bubbles
Diagnostic investigations	CXR - pneumothorax or pulmonary oedema
Management	Immediate ED management - FiO2 100% empirically - contact National Diving Accident Helpline (or Divers Alert Network) 07831 151 523 - AVOID NSAIDs and entonox! (Opiates can ↑ risk of oxygen toxicity) - Check for urinary retention Onward transfer - Recompression therapy - requires specialised facility - Hyperbaric oxygen therapy

other diving related injuries

history taking for the non-diver

Dive profile: How deep? For how long? Any missed stops? What was their surface interval between dives? Decompression sickness is more likely with higher nitrogen loads. Nitrogen loads will be higher following long or deep dives.
Multiple dives: How many dives, over how many days and how may consecutive days diving? Multiple dives or multi-day diving increase risk as there is an accumulation of nitrogen.
Closed or open circuit and which gases used? This is explained below
Were there any problems during the dive e.g. Did the diver make a rapid ascent? Arterial gas embolism is more likely following rapid ascent (occurring with pulmonary barotrauma).
copied shamelessly from RCEM