slow recruitment

The investigators aim to prospectively study the feasibility and clinical impact of hyperbaric oxygen therapy in acute hospitalized moderate to severe ulcerative colitis flares as an adjunct to standard medical treatment. Specifically, we will investigate the impact of hyperbaric oxygen therapy on clinical response/remission and serum and mucosal inflammatory markers. The investigators expect that hyperbaric oxygen therapy will improve patient responsiveness to steroids and avoid progression to second line therapy during hospitalization.

Inclusion Criteria:

• known or newly diagnosed moderate to severe ulcerative colitis with a Mayo score of greater than 6
• Mayo endoscopic sub-score of greater than or equal to 2
• Risk score of greater than or equal to 4 points

Exclusion Criteria:

• Complication requiring urgent surgical intervention (in the opinion of the investigators)

Clinically significant cardiac, renal, neurological, endocrine, respiratory or hepatic impairment in the opinion of the investigator, including but not limited to:

• Pulmonary i. COPD with CO2 retention; Previous/current imaging showing hyperinflation/air trapping/bullous disease/blebs (opinion of investigators) ii. Current pneumothorax or previous spontaneous pneumothorax iii. Bronchogenic cyst(s)
• Cardiac i. Uncontrolled HTN (systolic >160 or diastolic >100) ii. Unstable angina or myocardial infarction within the previous 3 months iii. Ejection fraction < 35% iv. Current or previous amiodarone use v. ICD in place vi. Pacemaker in place not approved for chamber use
• Hematological/Oncological i. Current chemotherapeutic drug use, and past history of bleomycin use. ii. Hereditary Spherocytosis iii. Sickle cell anemia
• Gastrointestinal and Infectious Disease i. Known or suspected Crohn's disease ii. Previous infection with mycobacterium, fungus, HIV, Hepatitis B or C iii. Gastrointestinal or systemic infection including, but not limited to, --Clostridium difficile iv. Current capsule endoscopy or previously non-retrieved capsule Endocrinology i. Uncontrolled hyperthyroidism

Neurological and Psychological i. Vagal or other nerve stimulators

ii. Uncontrolled seizure disorder

iii. Medications or medical conditions that lower seizure threshold (in the opinion of the investigator) iv. Drug or alcohol abuse/dependence v. Current treatment for alcohol cessation with disulfiram vi. Current or recent (within past week) use of baclofen Head and Neck i. Previous middle ear damage, surgery or infection(s) which may increase the risk for needing ear tubes (in the opinion of the investigator) ii. Current or previous retinal detachment or optic neuritis iii. Retinal or vitreous surgery within the past 3 months Miscellaneous i. Implanted devices not on the approved list for use with HBOT

Women who are pregnant or nursing. Women with childbearing potential were required to use effective birth control if not surgically sterile or postmenopausal for >2 years.