Powell F L, Hastings R H, Mazzone R W
Am J Physiol. 1985 Jul;249(1 Pt 2):R39-43. doi: 10.1152/ajpregu.1985.249.1.R39.
We measured mean pulmonary arterial pressure (Ppa) during temporary unilateral pulmonary arterial occlusion (TUPAO) in 10 ducks. Ppa increased from 11.4 +/- 0.8 mmHg during control conditions to 18.8 +/- 1.8 during TUPAO. In 5 of the 10 ducks we also measured mean left atrial pressure (Pla) and cardiac output (Q). In these ducks Ppa significantly increased with TUPAO from 13.9 +/- 0.4 to 22.0 +/- 1.2 mmHg, whereas Pla and Q did not change significantly. Pulmonary vascular resistance (PVR) increased from 10.6 +/- 1.3 to 24.1 +/- 5.3 mmHg X min X 1(-1) on TUPAO. By assuming equal vascular resistance in either lung it can be calculated that the vascular resistance in only one lung was 22.5 +/- 3.5 mmHg X min X 1(-1) during control conditions. Thus doubling flow resulted in no significant change in one lung's vascular resistance. A morphometric study of both lungs of a domestic goose that were rapidly frozen during TUPAO indicated very little compliance in pulmonary blood capillaries. The relative volume of exchange tissue occupied by blood capillaries was 0.28 in the occluded lung and 0.36 in the perfused lung. Surface-to-volume ratios of blood capillaries were 12,524 cm-1 in the occluded lung and 11,056 cm-1 in the perfused lung. We conclude that PVR in birds is relatively insensitive to changes in Q, in contrast to mammals.
我们在10只鸭的临时单侧肺动脉闭塞（TUPAO）过程中测量了平均肺动脉压（Ppa）。Ppa在对照条件下为11.4±0.8 mmHg，在TUPAO期间升至18.8±1.8 mmHg。在这10只鸭中的5只，我们还测量了平均左心房压（Pla）和心输出量（Q）。在这些鸭中，Ppa在TUPAO时从13.9±0.4显著升至22.0±1.2 mmHg，而Pla和Q没有显著变化。肺动脉阻力（PVR）在TUPAO时从10.6±1.3升至24.1±5.3 mmHg·min·1⁻¹。假设两侧肺血管阻力相等，可计算出在对照条件下仅一侧肺的血管阻力为22.5±3.5 mmHg·min·1⁻¹。因此，流量加倍并未导致一侧肺血管阻力的显著变化。对一只家鹅在TUPAO期间快速冷冻的双肺进行的形态计量学研究表明，肺血毛细血管的顺应性非常小。闭塞肺中被毛细血管占据的交换组织相对体积为0.28，灌注肺中为0.36。闭塞肺中毛细血管的表面积与体积比为12,524 cm⁻¹，灌注肺中为11,056 cm⁻¹。我们得出结论，与哺乳动物相比，鸟类的PVR对Q的变化相对不敏感。
