This study is a non invasive study to see if 100% oxygen therapy will help to resolve an intestinal obstruction.

TOGA involves the provision of a 6- hour treatment with 100% oxygen via non breather mask to hospitalized patients with ileus, small bowel obstruction and/or colonic pseudo-obstruction will be a useful supplemental therapy, decreasing the diameter of the intestinal lumen and enhancing resolution of ileus/pseudo-obstruction

Inclusion Criteria:

• patient or health proxy has been adequately informed of risks and benefits and agrees to his/her participation in the study.
• patient is a hospitalized inpatient diagnosed with ileus, bowel obstruction or colonic pseudo-obstruction [clinician interpretation or small bowel diameter ≥3.5 cm, cecal diameter ≥ 9 cm, sigmoid colon diameter ≥ 6 cm].
• patient is clinically and hemodynamically stable
• patient does not require supplemental oxygen greater than 2 liters per minute via nasal cannula
• patient does not have any respiratory contraindications to 100% oxygen
• failure to respond to non-surgical/non-endoscopic therapy for at least 24 hours, therapy at discretion of treating physician [to eliminate patients with trivial ileus not requiring advanced intervention]

Exclusion Criteria:

• patient is not expected to survive in the short term.
• patient is a pregnant or lactating woman.
• patient presents with severe or unstable psychiatric disorders.
• patient is participating in concomitant research studies that would interfere with this study.
• patient is an alcohol or drug abuser.
• respirator support required.
• unable to tolerate 100% oxygen for respiratory reasons or any other reasons.
• perforation of the viscus.
• inability to obtain informed consent.
• hypoxemia, as in room air oxygen saturation less than 90%.