Weiss D J, Richwagen K, Evanson O A
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
Am J Vet Res. 1996 Mar;57(3):346-50.
To evaluate the contribution of hematocrit and RBC deformability to pulmonary vascular pressures of racehorses.
Pony lungs were isolated and right and left lungs were perfused separately with blood. The effects of changing hematocrit and of pentoxifylline treatment were evaluated.
11 healthy mixed-breed ponies.
Ponies were anesthesized, blood was collected, and lungs were removed and perfused with blood at constant flow rate.
Increasing the hematocrit from 35% to 65% resulted in increases in pulmonary arterial pressure (53%, 45%), capillary shear stress (45%, 32%), and total vascular resistance (92%, 143%) at low (352 +/- 33 ml/min) and high (1,442 +/- 48 ml/min) flow rates, respectively. Pulmonary artery pressures were lower (10%, 11%) when lungs were perfused with blood from pentoxifylline-treated ponies, compared with blood from control ponies with low hematocrit (PCV, 30%) and low-flow rate and with high hematocrit (PCV, 45%) and high flow rate, respectively. Decreases in capillary shear stress and total vascular resistance were also observed for pentoxifylline-treated blood.
Increases in hematocrit equivalent to those occurring during competitive racing activity contribute substantially to pulmonary vascular pressures in horse lungs. Administration of pentoxifylline to ponies reduced RBC deformability and attenuated increases in pulmonary vascular pressures.
Treatment of racehorses with pentoxifylline may reduce exercise-associated increases in pulmonary vacular pressure, thereby attenuating exercise-induced pulmonary hemorrhage.
评估血细胞比容和红细胞变形性对赛马肺血管压力的影响。
分离小马的肺脏，左右肺分别用血液灌注。评估改变血细胞比容和使用己酮可可碱治疗的效果。
11匹健康的杂种小马。
给小马麻醉，采集血液，取出肺脏并以恒定流速用血液灌注。
血细胞比容从35%增至65%时，在低流速（352±33毫升/分钟）和高流速（1442±48毫升/分钟）下，肺动脉压分别升高（53%，45%）、毛细血管切应力分别升高（45%，32%）以及总血管阻力分别升高（92%，143%）。与分别来自血细胞比容低（红细胞压积，30%）且流速低以及血细胞比容高（红细胞压积，45%）且流速高的对照小马的血液相比，用己酮可可碱处理过的小马的血液灌注肺脏时，肺动脉压较低（分别低10%，11%）。对于用己酮可可碱处理过的血液，也观察到毛细血管切应力和总血管阻力降低。
相当于赛马比赛活动期间出现的血细胞比容升高会显著增加马肺的肺血管压力。给小马使用己酮可可碱会降低红细胞变形性，并减弱肺血管压力的升高。
用己酮可可碱治疗赛马可能会降低与运动相关的肺血管压力升高，从而减轻运动性肺出血。
