Clark A R, Burrowes K S, Tawhai M H
Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand.
J Appl Physiol (1985). 2010 May;108(5):1116-26. doi: 10.1152/japplphysiol.01177.2009. Epub 2010 Jan 28.
This study presents a theoretical model of combined series and parallel perfusion in the human pulmonary acinus that maintains computational simplicity while capturing some important features of acinar structure. The model provides a transition between existing models of perfusion in the large pulmonary blood vessels and the pulmonary microcirculation. Arterioles and venules are represented as distinct elastic vessels that follow the branching structure of the acinar airways. These vessels are assumed to be joined at each generation by capillary sheets that cover the alveoli present at that generation, forming a "ladderlike" structure. Compared with a model structure in which capillary beds connect only the most distal blood vessels in the acinus, the model with combined serial and parallel perfusion provides greater capacity for increased blood flow in the lung via capillary recruitment when the blood pressure is elevated. Stratification of acinar perfusion emerges in the model, with red blood cell transit time significantly larger in the distal portion of the acinus compared with the proximal portion. This proximal-to-distal pattern of perfusion may act in concert with diffusional screening to optimize the potential for gas exchange.
本研究提出了一种人体肺腺泡串联和并联灌注的理论模型，该模型在保持计算简单性的同时，捕捉了腺泡结构的一些重要特征。该模型在大型肺血管灌注模型和肺微循环模型之间提供了一种过渡。小动脉和小静脉被表示为不同的弹性血管，它们遵循腺泡气道的分支结构。假设这些血管在每一代都通过覆盖该代存在的肺泡的毛细血管片连接，形成一种“阶梯状”结构。与仅在腺泡最远端血管连接毛细血管床的模型结构相比，串联和并联灌注相结合的模型在血压升高时，通过毛细血管募集增加肺部血流的能力更强。模型中出现了腺泡灌注分层，与近端部分相比，腺泡远端部分红细胞通过时间明显更长。这种从近端到远端的灌注模式可能与扩散筛选协同作用，以优化气体交换的潜力。
