Effect of small flow reversals on aerosol mixing in the alveolar region of the human lung.
Effect of small flow reversals on aerosol mixing in the alveolar region of the human lung.
复制标题
小流量反转对人肺肺泡区域气溶胶混合的影响。
DOI：
10.1152/japplphysiol.00588.2004
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Prisk,GKim
中科院分区：
文献类型：
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作者：
Darquenne,Chantal;Prisk,GKim
有人认为，肺泡流的不可逆性与流线的拉伸和折叠模式相结合，可导致肺中混合的突然增加。为了确定这种现象是否在体内人肺中起作用，我们用设计用于诱导复杂折叠模式的方案进行了一系列团注研究。在美国国家航空航天局微重力研究飞机上，8名受试者在短时间的微重力状态下吸入了直径为0.5和1微米的颗粒，穿透量分别为300和1，200毫升。吸气是从残气量到1升1 G以上的功能残气量。随后是10秒的屏气，在此期间，在Vp= 300 ml时施加多达7个100 ml的血流反向（FR），在Vp= 1，200 ml时施加多达4个500 ml的FR，并呼气至剩余容量。通过在口部连续监测的气溶胶浓度和流速计算团注分散和沉积。随着FR的增加，分散和沉积没有显著增加，除了在Vp= 300 ml时0和7 FR之间的分散，直径为0.5 μ m的颗粒，这种增加很小。这表明伸展和折叠现象在我们进行的FR次数内没有发生，或者在基本动作中包括的一个呼吸周期内已经发生。我们推测，这种现象发生在基本机动过程中，这与以前在微重力下观察到的高度分散和沉积是一致的。
It has been suggested that irreversibility of alveolar flow combined with a stretched and folded pattern of streamlines can lead to a sudden increase in mixing in the lung. To determine whether this phenomenon is operative in the human lung in vivo, we performed a series of bolus studies with a protocol designed to induce complex folding patterns. Boli of 0.5- and 1-μm-diameter particles were inhaled at penetration volumes (Vp) of 300 and 1,200 ml in eight subjects during short periods of microgravity aboard the National Aeronautics and Space Administration Microgravity Research Aircraft. Inspiration was from residual volume to 1 liter above 1 G functional residual capacity. This was followed by a 10-s breathhold, during which up to seven 100-ml flow reversals (FR) were imposed at Vp= 300 ml and up to four 500-ml FR at Vp= 1,200 ml, and by an expiration to residual volume. Bolus dispersion and deposition were calculated from aerosol concentration and flow rate continuously monitored at the mouth. There was no significant increase in dispersion and deposition with increasing FR except for dispersion between 0 and 7 FR at Vp= 300 ml with 0.5-μm-diameter particles, and this increase was small. This suggested that either the phenomenon of stretch and fold did not occur within the number of FR we performed or that it had already occurred during the one breathing cycle included in the basic maneuver. We speculate that the phenomenon occurred during the basic maneuver, which is consistent with the high degree of dispersion and deposition observed previously in microgravity.