Biofluid Mechanics Laboratory, Charité - Universitätsmedizin Berlin, Germany.
J Biomech. 2010 Apr 19;43(6):1202-7. doi: 10.1016/j.jbiomech.2009.11.025. Epub 2009 Dec 23.
Alveolar recruitment is a central strategy in the ventilation of patients with acute lung injury and other lung diseases associated with alveolar collapse and atelectasis. However, biomechanical insights into the opening and collapse of individual alveoli are still limited. A better understanding of alveolar recruitment and the interaction between alveoli in intact and injured lungs is of crucial relevance for the evaluation of the potential efficacy of ventilation strategies. We simulated human alveolar biomechanics in normal and injured lungs. We used a basic simulation model for the biomechanical behavior of virtual single alveoli to compute parameterized pressure-volume curves. Based on these curves, we analyzed the interaction and stability in a system composed of two alveoli. We introduced different values for surface tension and tissue properties to simulate different forms of lung injury. The data obtained predict that alveoli with identical properties can coexist with both different volumes and with equal volumes depending on the pressure. Alveoli in injured lungs with increased surface tension will collapse at normal breathing pressures. However, recruitment maneuvers and positive endexpiratory pressure can stabilize those alveoli, but coexisting unaffected alveoli might be overdistended. In injured alveoli with reduced compliance collapse is less likely, alveoli are expected to remain open, but with a smaller volume. Expanding them to normal size would overdistend coexisting unaffected alveoli. The present simulation model yields novel insights into the interaction between alveoli and may thus increase our understanding of the prospects of recruitment maneuvers in different forms of lung injury.
肺泡复张是治疗急性肺损伤和其他与肺泡塌陷和肺不张相关疾病的重要策略。然而，对于单个肺泡的开放和塌陷的生物力学机制仍知之甚少。深入了解正常和受损肺中的肺泡复张以及肺泡之间的相互作用，对于评估通气策略的潜在疗效至关重要。我们模拟了正常和受损肺中的肺泡生物力学。我们使用了一个虚拟单肺泡生物力学行为的基本模拟模型来计算参数化的压力-容积曲线。基于这些曲线，我们分析了由两个肺泡组成的系统中的相互作用和稳定性。我们引入了不同的表面张力和组织特性值来模拟不同形式的肺损伤。所得数据表明，具有相同特性的肺泡可以共存于不同的容积或相同的容积，具体取决于压力。表面张力增加的受损肺中的肺泡在正常呼吸压力下会塌陷。然而，复张手法和呼气末正压可以稳定这些肺泡，但共存的未受损肺泡可能会过度膨胀。顺应性降低的受损肺泡塌陷的可能性较小，预计肺泡将保持开放状态，但容积较小。将其扩张至正常大小会过度膨胀共存的未受损肺泡。该模拟模型提供了对肺泡相互作用的新见解，从而可能增加我们对不同形式肺损伤中复张手法的前景的理解。
