Emerging Indications for Hyperbaric Oxygen Treatment: Registry Cohort Study
Authors: Tanaka Hideaki L , Rees Judy R , Zhang Ziyin , Ptak Judy A , Hannigan Pamela M , Silverman Elaine M , Peacock Janet L , Buckey Jay C ,   Multicenter Registry for Hyperbaric Oxygen Treatment Consortium
Published: July 2024

Background
Hyperbaric oxygen (HBO2) treatment is used across a range of medical specialties for a variety of applications, particularly where hypoxia and inflammation are important contributors. Because of its hypoxia-relieving and anti-inflammatory effects HBO2 may be useful for new indications not currently approved by the Undersea and Hyperbaric Medical Society. Identifying these new applications for HBO2 is difficult because individual centers may only treat a few cases and not track the outcomes consistently. The web-based International Multicenter Registry for Hyperbaric Oxygen Therapy captures prospective outcome data for patients treated with HBO2 therapy. These data can then be used to identify new potential applications for HBO2, which has relevance for a range of medical specialties.

Objective
Although hyperbaric medicine has established indications, new ones continue to emerge. One objective of this registry study was to identify cases where HBO2 has been used for conditions falling outside of current Undersea and Hyperbaric Medical Society–approved indications and present outcome data for them.

Methods
This descriptive study used data from a web-based, multicenter, international registry of patients treated with HBO2. Participating centers agree to collect data on all patients treated using standard outcome measures, and individual centers send deidentified data to the central registry. HBO2 treatment programs in the United States, the United Kingdom, and Australia participate. Demographic, outcome, complication, and treatment data, including pre- and posttreatment quality of life questionnaires (EQ-5D-5L) were collected for individuals referred for HBO2 treatment.

Results
Out of 9726 patient entries, 378 (3.89%) individuals were treated for 45 emerging indications. Post–COVID-19 condition (PCC; also known as postacute sequelae of COVID-19; 149/378, 39.4%), ulcerative colitis (47/378, 12.4%), and Crohn disease (40/378, 10.6%) accounted for 62.4% (n=236) of the total cases. Calciphylaxis (20/378, 5.3%), frostbite (18/378, 4.8%), and peripheral vascular disease–related wounds (12/378, 3.2%) accounted for a further 13.2% (n=50). Patients with PCC reported significant improvement on the Neurobehavioral Symptom Inventory (NSI score: pretreatment=30.6; posttreatment=14.4; P<.001). Patients with Crohn disease reported significantly improved quality of life (EQ-5D score: pretreatment=53.8; posttreatment=68.8), and 5 (13%) reported closing a fistula. Patients with ulcerative colitis and complete pre- and post-HBO2 data reported improved quality of life and lower scores on a bowel questionnaire examining frequency, blood, pain, and urgency. A subset of patients with calciphylaxis and arterial ulcers also reported improvement.

Conclusions
HBO2 is being used for a wide range of possible applications across various medical specialties for its hypoxia-relieving and anti-inflammatory effects. Results show statistically significant improvements in patient-reported outcomes for inflammatory bowel disease and PCC. HBO2 is also being used for frostbite, pyoderma gangrenosum, pterygium, hypospadias repair, and facial filler procedures. Other indications show evidence for improvement, and the case series for all indications is growing in the registry.

International Registered Report Identifier (IRRID)
RR2-10.2196/18857