Tracking of airway and tissue mechanics during TLC maneuvers in mice
Tracking of airway and tissue mechanics during TLC maneuvers in mice
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DOI：
10.1152/japplphysiol.00104.2003
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发表时间：
2003-10-01
影响因子：
3.3
通讯作者：
Sly, PD
中科院分区：
文献类型：
--
作者：
Hantos, Z;Collins, RA;Sly, PD
在6只麻醉和机械通气的BALB/c小鼠中，开发了一种跟踪阻抗估计技术，以跟踪在缓慢的总肺容量动作期间总呼吸阻抗（Zrs）的变化。在从0 - 20 cmH（2）O的跨呼吸压力充气和随后放气期间，用波管技术和伪随机强迫振荡在4和38 Hz之间的9个频率下测量Zrs，每个持续时间约20 s。对Zrs取0.125 s的平均值，并通过以气道阻力（Raw）和惯性以及组织阻尼和弹性（H）为特征的模型进行拟合。下气道传导率（Glaw）与功能残气量（V）以上的容积在0和75 - 95%最大V之间呈线性相关，平均斜率为dGlaw/dV = 13.6 +/-4.6 cmH（2）O（-1）。s（-1）. Raw和H的相互依赖性的特征在于低容量和高容量区域的两种不同且紧密的线性关系，其在类似于40%最大V处分开。Raw与总呼吸系统的最高频率阻力的比较揭示了组织阻力对总呼吸系统阻力的显著体积依赖性贡献，导致Raw在功能残气量和总肺容量分别高估19 +/-8和163 +/-40%，而最低频率电抗与H成比例;这些发现表明，当组织阻抗发生变化时，单频电阻值可能不适合作为Raw的替代物。
A tracking impedance estimation technique was developed to follow the changes in total respiratory impedance (Zrs) during slow total lung capacity maneuvers in six anesthetized and mechanically ventilated BALB/c mice. Zrs was measured with the wave-tube technique and pseudorandom forced oscillations at nine frequencies between 4 and 38 Hz during inflation from a transrespiratory pressure of 0-20 cmH(2)O and subsequent deflation, each lasting for similar to20 s. Zrs was averaged for 0.125 s and fitted by a model featuring airway resistance ( Raw) and inertance, and tissue damping and elastance ( H). Lower airway conductance (Glaw) was linearly related to volume above functional residual capacity (V) between 0 and 75 - 95% maximum V, with a mean slope of dGlaw/dV = 13.6 +/- 4.6 cmH(2)O(-1) . s(-1). The interdependence of Raw and H was characterized by two distinct and closely linear relationships for the low- and high-volume regions, separated at similar to 40% maximum V. Comparison of Raw with the highest-frequency resistance of the total respiratory system revealed a marked volume-dependent contribution of tissue resistance to total respiratory system resistance, resulting in the overestimation of Raw by 19 +/- 8 and 163 +/- 40% at functional residual capacity and total lung capacity, respectively, whereas the lowest frequency reactance was proportional to H; these findings indicate that single- frequency resistance values may become inappropriate as surrogates of Raw when tissue impedance is changing.