Leuthold R, Spahn D R, Niederer P F, Schmid E R
Institute of Biomedical Engineering and Medical Informatics, University of Zurich, Switzerland.
J Biomed Eng. 1992 Jan;14(1):77-80. doi: 10.1016/0141-5425(92)90040-r.
Gas transport during high-frequency oscillation was investigated in vitro using CO2 elimination from the lung surrogate as a measure of gas transport efficiency. The length of the connecting tube between the piston pump and the three-port connector did not affect gas transport efficiency if the oscillatory volume (VDEL) was constant; inserting an additional tube between the three-port connector and the endotracheal tube decreased gas transport efficiency dramatically. In contradistinction, increasing VDEL caused a steep rise in gas transport efficiency as soon as VDEL surpassed the volume of the tubes connecting the lung surrogate with its surroundings. As gas transport efficiency was found to be very sensitive to the net oscillatory volume, i.e. VDEL minus the volume of the tubes connecting the lung and the surroundings, direct wash-out was considered to be an effective gas transport mechanism during high frequency oscillation. Two preliminary experiments on dogs allowed us to substantiate this hypothesis in vivo.
利用从肺替代物中消除二氧化碳作为气体传输效率的衡量指标，在体外研究了高频振荡期间的气体传输。如果振荡容积（VDEL）恒定，活塞泵与三通连接器之间连接管的长度不会影响气体传输效率；在三通连接器和气管导管之间插入额外的管子会显著降低气体传输效率。相反，一旦VDEL超过连接肺替代物与其周围环境的管子容积，增加VDEL会导致气体传输效率急剧上升。由于发现气体传输效率对净振荡容积（即VDEL减去连接肺与周围环境的管子容积）非常敏感，直接冲洗被认为是高频振荡期间一种有效的气体传输机制。在狗身上进行的两项初步实验使我们能够在体内证实这一假设。
