Assessment of mucosal hemodynamics in normal human colon and patients with inflammatory bowel disease.

Reflectance spectrophotometry measures indices of mucosal hemoglobin concentration (IHB) and oxygen saturation (ISO2). In the rat colon, characteristic patterns of IHB and ISO2 are associated with ischemia with congestion (increased IHB and decreased ISO2) and ischemia without congestion (decreased IHB and decreased ISO2). Endoscopic measurements with acceptable interobserver variability was demonstrated in the canine stomach. In eight healthy subjects, endoscopic measurement in different areas of the colon and rectum revealed significantly lower IHB values in the splenic flexure. These observations are compatible with reduced flow and increased susceptibility to ischemic damage in this watershed area. The endoscopic measurements in 13 patients with active inflammatory bowel disease revealed an increase in IHB and ISO2 values in the involved areas, indicating an increase in mucosal blood flow. In six patients restudied when the disease remitted, these values returned to normal.