¹³³Xe洗い出し曲線のシミュレーションモデルによる解析と graphical analysis の比較検討

抄録

A comparison of two different analytical approaches for xenon-133 washout curves was made. To estimate regional ventilation from the xenon-133 washout curve, a mathematical approach was made with a model lung which has a common dead space and regional wellventilated (fast) and poorly ventilated (slow) spaces. For the convenience of analysis a backward projection method has generally been used instead of the simulation model. An attempt was made to clarify the difference in values obtained by the two methods from the standpoint of respiratory physiology.
Experimental data showed that regional tidal ventilation values (computed V_Ti) obtained mathematically using the simulation model were always larger than those (manual V_Ti) obtained from the backward projection method in both fast and slow spaces.
Assuming computed V_Ti to be the sum of two valves; regional alveolar ventilation(corrected V_Ti) and regional dead space ventilation(V_Dsi), corrected V_Ti was compared with manual V_Ti. In fast space corrected V_Ti and manual V_Ti were almost equal and in slow space, corrected V_Ti tended to be slightly smaller than manual V_Ti. Manual V_Ti, calculated by analytical methods used heretofore, approximates ventilation values obtained from the simulation model when the volume of common dead space is omitted.