Oxygen therapy at greater than atmospheric pressure, usually 2-3 atmospheres, increases the amount of dissolved O₂ in the blood according to Henry’s law.  In 100 ml blood, 0.3 ml O₂ dissolves at a PO₂ of 13.3 kPa (100 mmHg).  Thus, for 100% O₂ at 3 atmospheres, dissolved O₂ = 5.7 ml. 

Conditions that may be treated with hyperbaric oxygen

 Air or gas embolism  
Carbon monoxide poisoning
 Carbon monoxide poisoning complicated by cyanide poisoning  
 Clostridial myositis and myonecrosis (gas gangrene)  
 Crush injury, compartment syndrome and other acute traumatic ischaemias  
 Decompression sickness  
 Enhancement of healing in selected problem wounds  
 Exceptional blood loss (anaemia)  
 Intracranial abscess  
 Necrotising soft tissue infections  
 Osteomyelitis (refractory)  
 Delayed radiation injury (soft tissue and bony necrosis)  
 Skin grafts and flaps (compromised)  
 Thermal burns