Abstract
To measure the concentration on of exhaled NO in children, we improved the system of analyzing NOx and estimated the results. The system we used is a chemiluminescence analyzer CLM-500 (SHI-MADZU, JAPAN) sensitive to NO from 0.1 to 5000 parts per billion (ppb, by volume), adapted for an online recorder U-224 (NDKCL Co., Japan). On the hypothesis that expiration velocity influences NO concentrations in expired air, a flow volume regulator of a control capacity from 0 to 3000ml/min was assembled between a mounthpiece and CLM-500, hence NO concentration is measured under a constant expiration flow rate. In our method, the NO concentration on curves show up-hills first, then plateaus and down-hills finally. If the flow rate increased, the curve reached the plateau sooner and the plateau-value in a serial measurement in one patient were statistically constant. On our speculation, the plateau values are the good parameters of NO production in their bronchi.
