Hyperbaric oxygen therapy (HBOT) is a treatment modality where the patient breathes 100% oxygen in a pressure chamber. In Norway all planned (elective) HBOT is provided by Haukeland University Hospital in Bergen. The major indication for the approximately 200 patients recieving the treatment in Norway is late radiation tissue injury (LRTI). In several other countries, diabetic foot ulcer (DFU) is a more common indication. We have therefore assessed clinical effectiveness of HBOT in patients with LRTI or DFU compared to standard treatment or placebo. We found the assessed studies to indicate that:

• HBOT may contribute to regression or improvement of symptoms associated with LRTI due to radiation of the head and neck region
• no conclusion can be made with regard to HBOT in treatment of LRTI in other body localisations
• HBOT may contribute to more patients with DFU experiencing regression of symptoms or improved healing
• no conclusion can be made with regard to number of amputations due to DFU
• no conclusions can be made with regard to quality of life, number of adverse events or the need for subsequent treatment.

The identified studies are small, with few events and risk of bias. Our confidence in estimates of clinical effectiveness and efficacy is limited. New studies may change the conclusions and the results have to be interpreted with care.