Modeling water vapor and heat transfer in the normal and the intubated airways
Modeling water vapor and heat transfer in the normal and the intubated airways
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DOI：
10.1023/b:abme.0000019180.03565.7e
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发表时间：
2004-04-01
影响因子：
3.8
通讯作者：
Hunter, PJ
中科院分区：
文献类型：
--
作者：
Tawhai, MH;Hunter, PJ
人工通气患者的气管内插管绕过鼻腔和口腔通常的调节区域。在这种情况下，空气中热量或水分的任何不足都由肺气道壁的蒸发和热传递来补偿。为了研究气管内的热、水传输动力学，在具有对称几何和解剖几何的气道模型中求解了一个耦合的非线性方程组。气道内热量、水汽和速度的径向分布用幂律方程来描述。随时间变化的方程组的解产生动态气流和粘膜温度和空气湿度。将模型结果与正常和插管气道的两项独立实验研究进行比较，发现在大范围的分钟通气中，模型结果密切相关。使用基于解剖学的模型，展示了一系列空间分布的温度路径，这突出了该模型预测目前无法测量的气道区域热行为的能力。在模拟速率在15到100 l / min（-1）之间的口腔呼吸时，精确表示导气管几何形状是必要的，但对称几何形状对于通常提供给插管患者的低分钟通气和温暖吸入空气条件是足够的。
Intubation of the artificially ventilated patient with an endotracheal tube bypasses the usual conditioning regions of the nose and mouth. In this situation any deficit in heat or moisture in the air is compensated for by evaporation and thermal transfer from the pulmonary airway walls. To study the dynamics of heat and water transport in the intubated airway, a coupled system of nonlinear equations is solved in airway models with symmetric geometry and anatomically based geometry. Radial distribution of heat, water vapor, and velocity in the airway are described by power-law equations. Solution of the time-dependent system of equations yields dynamic airstream and mucosal temperatures and air humidity. Comparison of model results with two independent experimental studies in the normal and intubated airway shows a close correlation over a wide range of minute ventilation. Using the anatomically based model a range of spatially distributed temperature paths is demonstrated, which highlights the model's ability to predict thermal behavior in airway regions currently inaccessible to measurement. Accurate representation of conducting airway geometry is shown to be necessary for simulating mouth-breathing at rates between 15 and 100 l (.) min(-1), but symmetric geometry is adequate for the low minute ventilation and warm inspired air conditions that are generally supplied to the intubated patient.