155 Therapeutic Oxygen for Gastrointestinal Atomy (TOGA) Pilot Trial: Management of Acute Colonic Pseudo-Obstruction and Ileus With Oxygen Supplementation

Abstract

INTRODUCTION: Acute intestinal dysmotility can lead to bowel distension, which promotes hypoperfusion and further negates contractility in acute colonic pseudo-obstruction (ACPO) and ileus. Current medical treatment is supportive. When bowel distension worsens, endoscopic decompression or surgical intervention may be necessary to avoid mortality; Interventions are time-consuming and not without risk. New effective and safe management approaches are needed. Manipulation of partial pressures of oxygen trapped within the bowel has been shown in patients with ACPO and ileus to improve clinical and radiographic outcomes. Therapeutic oxygen for gastrointestinal atomy (TOGA) is a pilot study aimed to demonstrate the benefit of a six hour course of 100% oxygen by non-rebreather mask as an adjunctive treatment for patients with ACPO and ileus who have failed to respond to alternative medical therapy after 24 hours. METHODS: Eight patients with ACPO or ileus were enrolled in this pilot study (ClinicalTrials.gov Identifier: NCT03386136) between May 1, 2018 and March 1, 2019 and administered 100% oxygen by non-rebreather mask for 6 hours in conjunction with traditional medical management. Abdominal radiographs were examined before and after treatment. Patient demographics, maximum diameter of bowel lumen distension on radiography, and clinical symptoms were recorded. RESULTS: Of the 8 patients (mean age 53.6 ± 17.4 years; 37.5% female), 87.5% demonstrated clinical improvement of symptoms after 6 hours of 100% oxygen (Table 1). For 7 patients, maximum luminal diameter improved on average by 1.14 ± 0.87 cm, the percentage decrease in luminal diameter on average was 13.8 ± 7.1%. One patient failed to improve but was later determined to have malignant small bowel obstruction. Only one patient suffered a potential adverse event to the oxygen therapy (transient tachycardia). No patients developed complications from their underlying disease, such as ischemia or perforation. Responding patients also reported improvements in abdominal pain, distension, and bowel movements. CONCLUSION: TOGA demonstrates that high concentrations of supplemental oxygen is a feasible and tolerable intervention to improve the clinical status of patients with ACPO and ileus, which may shorten hospitalization and overall morbidity. Further prospective enrollment is needed to extrapolate these promising findings and ensure confidence of its incorporation into common clinical practice.