Daviskas E, Gonda I, Anderson S D
Department of Thoracic Medicine, Royal Prince Alfred Hospital, Camperdown, Australia.
J Appl Physiol (1985). 1990 Jul;69(1):362-72. doi: 10.1152/jappl.1990.69.1.362.
Excessive heat and water losses from the airways are stimuli to asthma. To study heat and water vapor transport in the human respiratory tract, a time-dependent model, based on a single differential equation with an analytical solution, was developed that could predict the intra-airway temperatures and water vapor contents. The key feature is the dependence of the temperature and water vapor along the respiratory tract as a function of the air residence time at each location. The model assumes disturbed laminar flow leading to enhanced transport mechanisms and wall temperature profiles modeled according to experimental data (E. R. McFadden, Jr., B. M. Pichurko, H. F. Bowman, E. Ingenito, S. Burns, N. Dowling, and J. Soloway. J. Appl. Physiol. 58: 564-570, 1985). It predicts that 1) the air equilibrates with the wall before it reaches body conditions (37 degrees C, 99.5% relative humidity); 2) conditioning of the inspired air involves several generations, with the number depending on the respiratory conditions; and 3) the walls of the upper airways are unsaturated, although it is difficult to judge at this state the depth of the respiratory tract affected.
气道中过多的热量和水分流失是引发哮喘的刺激因素。为了研究人体呼吸道中的热和水汽传输，我们开发了一个基于具有解析解的单个微分方程的时间相关模型，该模型可以预测气道内的温度和水汽含量。关键特性是呼吸道沿线的温度和水汽含量取决于空气在每个位置的停留时间。该模型假设层流紊乱会导致传输机制增强，并且根据实验数据（E. R. McFadden, Jr., B. M. Pichurko, H. F. Bowman, E. Ingenito, S. Burns, N. Dowling, and J. Soloway. J. Appl. Physiol. 58: 564 - 570, 1985）对壁温分布进行建模。它预测：1）空气在达到身体条件（37摄氏度，99.5%相对湿度）之前就与壁面达到平衡；2）对吸入空气的调节涉及多个肺段，其数量取决于呼吸条件；3）上呼吸道壁未达到饱和状态，尽管在此状态下难以判断受影响的呼吸道深度。
