Thermographic assessment of intestinal viability following ischemic damage

Reactive hyperemia has been shown to be a characteristic of viable ischemic tissue that has been revascularized. A segment of small bowel was made ischemic by arterial occlusion and the ischemia maintained for 2 1/2 hrs (ischemic, viable bowel) or 8 hrs (ischemic, nonviable bowel) before circulation was restored. Thermograms and surface temperature measurements of exposed ischemic and non-ischemic bowel segments were obtained before and every five minutes after revascularization. Thermograms of segments revascularized after 2 1/2 hrs of ischemia demonstrated reactive hyperemia and a one to four degree increase in surface temperature compared to normal surrounding bowel. No hyperemic response was seen in bowel segments that were ischemic for 8 hrs. Our results indicate that thermograms can document reactive hyperemia of an exposed ischemic bowel that has been successfully revascularized and may be an important aid in assessing bowel viability during surgery.