The role of hyperbaric oxygen therapy in patients with carbon monoxide poisoning is controversial. Hyperbaric oxygen provides tissue oxygenation by dissolving oxygen in plasma, shortens the half-life of carboxyhemoglobin from 240-320 minutes to 20 minutes, and dissociates carbon monoxide from cytochrome c oxidase. Results in clinical studies have been conflicting, but benefits may be seen in patients with severe acute symptoms, loss of consciousness or neurological abnormality.