Tarczy-Hornoch P, Hildebrandt J, Jackson J C
Department of Pediatrics, Box 356320, University of Washington, Seattle, WA 98195-6320, USA.
Respir Physiol. 2000 Apr;120(2):125-38. doi: 10.1016/s0034-5687(00)00097-9.
To estimate regional lung volume during ventilation with liquids (e. g. perfluorochemicals, PFC) we developed a multi-compartment mathematical model of a lung and thorax. The height of the fluid column and the fluid's density determine alveolar pressure (PA). The weight of thoracic contents above any given gravitational plane influences pleural pressure (PPL). Transpulmonary pressure (PTP=PA−PPL) and compliance of the lung and chest wall permit estimation of volumes. The results indicate the lung inflates almost uniformly during total liquid ventilation despite a substantial vertical PA gradient. Inflation uniformity is due to the offsetting vertical PPL gradient created by the added weight of the PFC and sustained by the relative rigidity of the chest wall. During partial liquid ventilation our model indicates that the combination of uniform PA with a large vertical gradient in PPL leads to a vertical PTP gradient and therefore relative over-inflation of the top of the lung. This effect increases with increasing PFC dose and with lung height.
为了估算在液体（如全氟化合物，PFC）通气期间的局部肺容积，我们建立了一个肺和胸廓的多室数学模型。液柱高度和液体密度决定肺泡压力（PA）。任何给定重力平面上方胸廓内容物的重量影响胸膜压力（PPL）。跨肺压（PTP = PA - PPL）以及肺和胸壁的顺应性可用于估算容积。结果表明，在全液体通气期间，尽管存在显著的垂直PA梯度，但肺几乎均匀膨胀。膨胀均匀性是由于PFC附加重量产生的抵消性垂直PPL梯度，并由胸壁的相对刚性维持。在部分液体通气期间，我们的模型表明，均匀PA与PPL中较大垂直梯度的组合会导致垂直PTP梯度，从而导致肺顶部相对过度膨胀。随着PFC剂量增加和肺高度增加，这种效应会增强。
