阴影成像检测健康志愿者咳嗽的气流动力学：辅助控制气溶胶感染
2012/07/06
摘要
前期研究已经采用多种实验方法对咳嗽的气流动力学进行了检测。本研究采用实时、无创性阴影成像，检测健康志愿者咳嗽气流。20名健康志愿者（10名女性，平均年龄：32.2±12.9岁；10名男性：平均年龄：25.3±2.5）入选，并要求自由进行咳嗽，然后对着袖子进行咳嗽，分析咳嗽气流动力学。对于10名女性，能检测到的最大咳嗽延伸距离为0.16～0.55 m，最大的派生速度为2.2～5.0 m/s，能检测到的最大2-D投射面积为0.010～0.11 m2，最大的派生膨胀率为0.15～0.55 m2/s。对于10名男性，能检测到的最大咳嗽延伸距离为0.31～0.64 m，最大的派生速度为3.2～14 m/s，能检测到的最大2-D投射面积为0.04～0.14 m2，最大的派生膨胀率为0.25～1.4 m2/s。当呼出气流能见度最佳时检测峰值流速，并与前期研究采用其他方法检测的结果进行比较，以便在自然状态下验证前期检测方法。然而，传播距离仅能代表一个下限值，因为一旦温度下降至周围环境温度，阴影检测法不能观察到这些咳嗽气流，这是本研究的一个最大缺陷。志愿者朝袖子咳嗽后进行定量高速影像检测显示，虽然这种方法很少完全阻断咳嗽气流，但能将气流减速、分离和重定向，最终降低其传播。该干预措施的有效性取决于咳嗽时前臂相对于鼻和嘴的最佳位置，但由于该姿势可能弄脏袖子，一些人很难接受。
（陈欣 审校）
PLoS One. 2012;7(4):e34818. Epub 2012 Apr 20.
PLoS One. 2012;7(4):e34818. Epub 2012 Apr 20.
Source
Department of Laboratory Medicine, National University Hospital, Queenstown, Singapore.
Abstract
Cough airflow dynamics have been previously studied using a variety of experimental methods. In this study, real-time, non-invasive shadowgraph imaging was applied to obtain additional analyses of cough airflows produced by healthy volunteers. Twenty healthy volunteers (10 women, mean age 32.2±12.9 years; 10 men, mean age 25.3±2.5 years) were asked to cough freely, then into their sleeves (as per current US CDC recommendations) in this study to analyze cough airflow dynamics. For the 10 females (cases 1-10), their maximum detectable cough propagation distances ranged from 0.16-0.55 m, with maximum derived velocities of 2.2-5.0 m/s, and their maximum detectable 2-D projected areas ranged from 0.010-0.11 m(2), with maximum derived expansion rates of 0.15-0.55 m(2)/s. For the 10 males (cases 11-20), their maximum detectable cough propagation distances ranged from 0.31-0.64 m, with maximum derived velocities of 3.2-14 m/s, and their maximum detectable 2-D projected areas ranged from 0.04-0.14 m(2), with maximum derived expansion rates of 0.25-1.4 m(2)/s. These peak velocities were measured when the visibility of the exhaled airflows was optimal and compare favorably with those reported previously using other methods, and may be seen as a validation of these previous approaches in a more natural setting. However, the propagation distances can only represent a lower limit due to the inability of the shadowgraph method to visualize these cough airflows once their temperature cools to that of the ambient air, which is an important limitation of this methodology. The qualitative high-speed video footage of these volunteers coughing into their sleeves demonstrates that although this method rarely completely blocks the cough airflow, it decelerates, splits and redirects the airflow, eventually reducing its propagation. The effectiveness of this intervention depends on optimum positioning of the arm over the nose and mouth during coughing, though unsightly stains on sleeves may make it unacceptable to some.
PLoS One. 2012;7(4):e34818. Epub 2012 Apr 20.
