The Department of Gastroenterology plans to conduct a randomized controlled study on the efficacy analysis of hyperbaric oxygen-assisted treatment for acute severe ulcerative colitis and refractory inflammatory bowel disease. The research design is a randomized, controlled study. The objective is to compare the clinical remission rate, clinical response rate, endoscopic remission rate, and endoscopic response rate between patients with acute severe ulcerative colitis (ASUC) and refractory inflammatory bowel disease (IBD) treated with hyperbaric oxygen therapy (HBOT) as an adjuvant and those treated with standard treatment regimens. This study aims to provide clear evidence for the use of HBOT as an adjuvant treatment for ASUC and refractory IBD.

Inclusion Criteria:

• According to the diagnostic criteria for ulcerative colitis in the 2018 national consensus opinion on the diagnosis and treatment of inflammatory bowel disease, it was confirmed as ulcerative colitis;
• According to the Truelove-witts standard, it was diagnosed as acute severe ulcerative colitis: the frequency of bloody stools per day is 6 times or more, and at the same time, one of the following systemic toxic manifestations is present: heart rate of 90 bpm, body temperature greater than 37.8℃, hemoglobin less than 105g/L, and erythrocyte sedimentation rate greater than 30mm/h;
• Age ≥ 18 years old;
• Patients who can and are willing to comply with the research protocol can provide a signed and dated written informed consent form.

Exclusion Criteria:

• Patients who may require immediate surgical treatment;
• Pregnant or lactating mothers;
• Patients with a score of ≥6 years old (TMM30/40/50) and <6 points in the measurement of the Eustachian tube;
• Patients with a lung bulla larger than 2 cm at the lung apex or near the pleura in the chest plain scan;
• Patients with severe liver or kidney dysfunction, heart failure or other serious systemic diseases;
• Any situation that hinders the completion of the study or interferes with the analysis of the research results, including a history of drug or alcohol abuse, a smoker who has not quit, patients with mental illness or poor compliance, those with clear immune system (including HIV infection), blood system or tumor-related diseases;
• Patients who have withdrawn their informed consent;
• Patients who have participated in other clinical trials within 3 months before screening.