Clinical Application: Endoscopy
Using T-Stat in the Diagnosis of Gastrointestinal Ischemia.
Early visual signs of ischemia are unreliable. Non-invasive measures such as Doppler flow, pulsatility, and capillary refill are imperfect predictors of outcome, while invasive tests (such as lactate) respond slowly and may not change significantly in cases of regional ischemia. Venous saturation is well correlated with clinical outcome, … yet until now, Svo2 could not be locally measured at specific end-organs, and thus was not available for assessment during endoscopic procedures.
What do tissue saturation readings mean?
Normal mucosa has been found to have a capillary hemoglobin oxygen saturation of 60‐80% in the esophagus, stomach, small intestine, colon and rectum.
Significant decreases in capillary oxygen saturation were observed in patients with chronic mesenteric ischemia, with capillary saturations of 20‐40% in severe cases. Capillary oxygen saturation was also found to be significantly lower than normal in ischemic colitis and in advanced gastrointestinal neoplasms. In contrast, capillary oxygen saturation was found to be normal in most cases of chronic radiation proctopathy and peptic ulcer.
In cases of low capillary saturations due to mesenteric ischemia, capillary saturation has been shown to normalize following percutaneous stenting of the affected arteries.
The T‐Stat 1.5 mm catheter can be used through the instrument channel of most endoscopes – including double‐balloon endoscopes – and has been shown to have a high specificity for the diagnosis of mesenteric ischemia.