Endoscopic measurements of gastric mucosal blood flow in dogs

The feasibility and validity of endoscopic measurements of gastric mucosal blood flow (GMBF) using 3% H2 gas clearance were investigated in the intact stomach of anesthetized dogs. Platinum electrodes were lengthened and modified to permit passage through the instrument channel of a standard gastroscope. In five anesthetized dogs, antral mucosal blood flow (103.2 +/- 5.3 ml/min/100 g tissue) was significantly higher (P less than 0.05) than that in the corpus (66.9 +/- 7.1 ml/min/100 g tissue). Histamine stimulation selectively increased flow in the corpus to 134.5 +/- 7.5 ml/min/100 g tissue. Comparison of endoscopic GMBF measurements in these five dogs on 2 different days revealed a close correlation (r = 0.87, P less than 0.001). Endoscopic H2 clearance measurements obtained in five awake dogs were not significantly different from those obtained during pentobarbitol anesthesia. In 12 dogs, GMBF determined by endoscopic H2 gas clearance showed a good agreement (r = 0.91, P less than 0.001) with that measured by radioactive microspheres. These two methods also demonstrated comparable changes in GMBF induced by intravenous infusion of histamine and vasopressin. It was concluded that 3% H2 gas clearance can be used to accurately and reproducibly measure GMBF through the endoscope, a unique advantage of this method for potential clinical use.