Barnas G M, Hempleman S C, Harinath P, Baptiste J W
Department of Anesthesiology, University of Maryland, Baltimore 21201.
Respir Physiol. 1991 May;84(2):145-57. doi: 10.1016/0034-5687(91)90113-w.
We evaluated whether the avian respiratory system displays the same fundamental mechanical behavior during external forcing as found in mammals. We measured airway flow and pressures in the trachea, air sacs and thoracoabdominal cavity in 4 anesthetized-paralyzed roosters during sinusoidal volume oscillations at the trachea in the normal range of euthermic breathing frequency, f(0.2 to 1.0 Hz), and tidal volume, VT (10-50 ml). From the pressure and flow waveforms, we calculated resistance (R) and elastance (E) of the total respiratory system and its major compartments (lungs, air sacs and chest wall). E of the chest wall was minimum (147 cmH2O.L-1 +/- 7 SE) at 0.2 Hz-50 ml and was consistently, slightly lower than E of the total respiratory system over the entire range studied. Both elastances showed the same dependence on f and VT, increasing slightly with increasing f and decreasing with increasing VT. R of the chest wall was maximum (35.6 cmH2O.L- 1.sec-1 +/- 2.2 SE) at 0.2 Hz-10 ml and decreased with increasing f and VT, although the VT effect diminished at the higher f. E and R of the air sacs were much smaller than those of the chest wall, but showed similar f and VT dependencies. R of the lungs, due to resistance of the airways, was minimum (6.8 cmH2O.L-1.sec-1 +/- 1.5 SE) at 0.2 Hz-10 ml and increased with both f and VT. Total respiratory R reflected R of the air sacs and chest wall at low f and R of the lungs at high f. The f and VT dependencies of E and R in the chicken were strikingly similar to those measured in various types of mammalian respiratory tissues (Stamenović et al. (1990) J. Appl. Physiol. 69: 973-988. We conclude that, despite important anatomical differences between species, avian and mammalian respiratory tissues exhibit fundamentally similar mechanical behavior.
我们评估了鸟类呼吸系统在外部强迫作用下是否表现出与哺乳动物相同的基本力学行为。我们在4只麻醉致瘫的公鸡身上，测量了在正常体温呼吸频率f（0.2至1.0赫兹）和潮气量VT（10 - 50毫升）范围内，气管进行正弦体积振荡时气管、气囊和胸腹腔内的气道流量和压力。根据压力和流量波形，我们计算了整个呼吸系统及其主要部分（肺、气囊和胸壁）的阻力（R）和弹性（E）。胸壁的E在0.2赫兹 - 50毫升时最小（147厘米水柱·升⁻¹ ± 7标准误），并且在整个研究范围内始终略低于整个呼吸系统的E。两种弹性都表现出对f和VT的相同依赖性，随f增加而略有增加，随VT增加而降低。胸壁的R在0.2赫兹 - 10毫升时最大（35.6厘米水柱·升⁻¹·秒⁻¹ ± 2.2标准误），随f和VT增加而降低，尽管在较高频率时VT的影响减弱。气囊的E和R比胸壁的小得多，但表现出相似的f和VT依赖性。由于气道阻力，肺的R在0.2赫兹 - 10毫升时最小（6.8厘米水柱·升⁻¹·秒⁻¹ ± 1.5标准误），随f和VT增加而增加。总呼吸R在低频时反映气囊和胸壁的R，在高频时反映肺的R。鸡的E和R对f和VT的依赖性与在各种类型的哺乳动物呼吸组织中测量到的依赖性惊人地相似（斯塔梅诺维奇等人（1990年）《应用生理学杂志》69：973 - 988）。我们得出结论，尽管物种之间存在重要的解剖学差异，但鸟类和哺乳动物的呼吸组织表现出基本相似的力学行为。
