Endoscopic COlorectal Mucosal Evaluation of Oxygen Tension

Anastomosis refers to the surgical connection between two segments of the bowel, typically performed during colon and rectal surgeries to restore the continuity of the digestive tract after a section has been removed. It is necessary that the ends of the tissue at the anastomotic site are healthy (and capable of healing properly) as this will prevent dreaded complications like anastomotic leaks or strictures which can occur in almost a fifth of patients leading to increased hospital length of stay, costs, and mortality. Currently, the most widely used method for assessing tissue viability during anastomosis is indocyanine green fluorescence angiography (ICG-FA). This technique involves injecting a fluorescent dye (indocyanine green) into the bloodstream, which highlights blood flow and tissue perfusion under a special camera. However, ICG-FA has limitations due to allergies and reliability due to the dye's rapid disappearance from the bloodstream. Additionally, the dye cannot be administered repeatedly. This study explores a new method of measuring tissue oxygenation by evaluating mucosal oxygen saturation (StO2) as an alternative to ICG-FA. By evaluating StO2 levels, the research aims to provide a more reliable and repeatable way to assess tissue viability without the drawbacks of using fluorescent dyes. Secondly, any blood supply interruption to the bowel will first lead to mucosal ischemia, which can potentially be reliably captured by measuring mucosal StO2 levels only. In this single-center prospective single-arm study, we will evaluate whether mucosal StO2 levels are associated with or can predict anastomotic complications. This study will not involve any intervention that would affect the standard of care.