A model for determining alveolar and small airway dimensions from aerosol recovery data.
A model for determining alveolar and small airway dimensions from aerosol recovery data.
复制标题
用于根据气溶胶回收数据确定肺泡和小气道尺寸的模型。
DOI：
10.1152/jappl.1985.58.2.582
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Rosenthal,FS
中科院分区：
文献类型：
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作者：
Rosenthal,FS
一个数学模型，允许从一系列的气溶胶恢复测量在不同的吸气量进行肺泡和小气道尺寸的确定。该模型假设1）对称的二分肺，2）将气道和肺泡表示为直管集合，以及3）气雾剂团的高斯分散。使用由Weibel给出的尺寸用该模型进行的计算显示出与Palmes等人（J.Appl.Physiol.34：356-360，1973）获得的六个人类受试者的实验数据大体一致。通过改变描述肺泡大小和气道大小的两个参数以获得最佳拟合，发现接近一致。由此产生的估计的大小几乎是独立的分散系数的选择，然而，肺泡大小的估计是相当依赖于在屏气期间假设的沉降形式。在搅拌沉降的假设下确定的六名受试者的肺泡直径值范围为0.13至0.33 mm，而在仍然沉降的假设下，范围为0.24-0.65 mm。（第18-24代）尺寸范围为0.41至0.66 mm（静止沉降假设）和0.39至0.63 mm（搅拌沉降假设）。假设中间（部分搅拌）形式的沉降，6名受试者的肺泡直径为0.28 +/- 0.02 mm，与其他研究者的形态测量结果非常一致。部分搅拌形式的沉降也与恢复与屏气时间的模型预测一致，并且与肺中的心源性气体混合一致。
A mathematical model is presented that allows the determination of alveolar and small airway dimensions from a series of aerosol recovery measurements performed at different inspiration volumes. The model assumes 1) a symmetric dichotomous lung, 2) representation of airway and alveoli as ensembles of straight tubes, and 3) Gaussian dispersion of the aerosol bolus. Calculations with this model using dimensions given by Weibel show general agreement with experimental data on six human subjects obtained by Palmes et al. (J. Appl. Physiol. 34: 356–360, 1973). Close agreement is found by varying two parameters describing alveolar size and airway size to obtain the best fit. The resulting estimates of size are almost independent of the choice of the dispersion coefficient; however, the estimate of alveolar size is quite dependent on the form of settling assumed during breath holding. The values of alveolar diameter in the six subjects, determined under the assumption of stirred settling, ranged from 0.13 to 0.33 mm, whereas under the assumption of still settling the range was 0.24–0.65 mm. Small airway (generations 18–24) dimensions ranged from 0.41 to 0.66 mm under the still-settling assumption and 0.39 to 0.63 mm under the stirred-settling assumption. With the assumption of an intermediate (partially stirred) form of settling, the alveolar diameter in the six subjects is 0.28 +/- 0.02 mm, in close agreement with morphometric measurements by other investigators. A partially stirred form of settling is also consistent with model predictions of recovery vs. breath-holding time and with cardiogenic gas mixing in the lung.