Measurement of local blood flow of the intestine by hydrogen clearance method; experimental study

Local blood flow of the bowel wall was measured by hydrogen clearance method both in the muscular and submucosal layers in the mongrel dog, separately and concurrently. A platinum wire electrode with a bare tip of 0.5 mm in length and 0.2 mm in diameter was inserted into the each layer. About 10 per cent hydrogen gas was inhalated directly through the side hole attached to the endotracheal tube for 1-2 minutes and the obtained clearance curves were plotted on the semi-logarithmic scale, which was almost monoexponential. The results obtained were as follows: 1) Mean basal perfusion rate of the muscular layer of the intestine was 0.81-0.92 ml/min/gm, whereas that of the submucosal layer was 1.29-1.31 ml/min/gm, respectively. There was little difference of perfusion rates between the small and the large intestine. The results showed good correlationship with those reported by other authors. 2) The effect of vasoactive substances such as vasoconstrictor and vasodilator on the local blood flow in the bowel wall was confirmed. 3) This method is repeatedly applicable for measurement and also renders the information on the distribution of blood flow in the splanchnic area.