Measurement of mucosal capillary hemoglobin oxygen saturation in the colon by reflectance spectrophotometry

Background: Advances in optical and computer technology have enabled the development of a device that uses white-light reflectance spectrophotometry to measure capillary hemoglobin saturation in intestinal mucosa during colonoscopy. Methods: Studies were performed with the colon oximeter in anesthetized animals and patients undergoing colonoscopy. Results: Mean (SD) mucosal hemoglobin saturation in the normal colon was 72% (3.5%). In an animal model, ischemia induced by arterial ligation and hypoxemia via hypoxic ventilation each resulted in a decrease of over 40% in the mucosal saturation. In patients with colon polyps, ischemia induced by epinephrine injection, stalk ligation with a loop, or clipping of the polyp stalk each resulted in a decrease of over 40% in the mucosal saturation (p < 0.02). In contrast, saline solution injection did not decrease the mucosal saturation. Conclusions: A novel device for measuring capillary hemoglobin saturation in intestinal mucosa during colonoscopy is capable of providing reproducible measurements in normal patients and clearly detects dramatic decreases in saturation with ischemic and hypoxic insults.