Regional diaphragm volume displacement is heterogeneous in dogs
Regional diaphragm volume displacement is heterogeneous in dogs
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DOI：
10.1152/ajpregu.00270.2016
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发表时间：
2017-03-01
影响因子：
2.8
通讯作者：
Boriek, Aladin M.
中科院分区：
文献类型：
--
作者：
Greybeck, Brooke;Lu, Raymond;Boriek, Aladin M.
肌肉缩短和体积位移（VD）是膈肌产生压力能力的关键决定因素。本研究旨在验证横膈膜VD是异质性的假设，VD的分布取决于区域肌肉缩短、姿势和肌肉激活水平。在4只狗的左半膈腹膜表面、背肋区、中肋区和腹肋区沿肌肉束缝合放射不透明标记物。在安静的自发呼吸、被动充气到总肺活量（TLC）和对闭塞气道吸气时，在三个肺容量（功能剩余容量、功能剩余容量+ 1/2吸气容量和俯卧位和仰卧位的TLC）进行双平面视频透视检查。我们的数据显示腹侧肋膈具有最大的VD，与背侧肋部分相比，其贡献了近两倍的总膈VD。此外，腹侧肋膈在俯卧位时贡献了近一半的总VD，而在仰卧位时仅贡献了四分之一的总VD。在对抗气道闭塞和仰卧位时被动充气至TLC时，脚膈移位的体积相当于中肋部分的体积。区域肌肉缩短与区域VD密切匹配。我们得出结论，膈肌的主要动力来源主要是腹肋区对其VD的贡献。
Muscle shortening and volume displacement (VD) are critical determinants of the pressure-generating capacity of the diaphragm. The present study was designed to test the hypothesis that diaphragm VD is heterogeneous and that distribution of VD is dependent on regional muscle shortening, posture, and the level of muscle activation. Radioopaque markers were sutured along muscle bundles of the peritoneal surface of the crural, dorsal costal, midcostal, and ventral costal regions of the left hemidiaphragm in four dogs. The markers were followed by biplanar video fluoroscopy during quiet spontaneous breathing, passive inflation to total lung capacity (TLC), and inspiratory efforts against an occluded airway at three lung volumes spanning the vital capacity [functional residual capacity, functional residual capacity + 1/2 inspiratory capacity, and TLC in both the prone and supine postures]. Our data show the ventral costal diaphragm had the largest VD and contributed nearly two times to the total diaphragm VD compared with the dorsal costal portion. In addition, the ventral costal diaphragm contributed nearly half of the total VD in the prone position, whereas it only contributed a quarter of the total VD in the supine postition. During efforts against an occluded airway and during passive inflation to TLC in the supine position, the crural diaphragm displaced volume equivalent to that of the midcostal portion. Regional muscle shortening closely matched regional VD. We conclude that the primary force generator of the diaphragm is primarily dominated by the contribution of the ventral costal region to its VD.