Bixler T J, Gott V L, Gardner T J
J Thorac Cardiovasc Surg. 1981 Apr;81(4):537-45.
Pulmonary vascular resistance may be elevated by the use of vasoconstrictive agents or by alveolar hypoxia. The present study was designed to determine the precise vasoconstrictive effects of the two inotropic agents, dopamine and epinephrine, as well as the effects of alveolar hypoxia on the pulmonary vascular system. In addition, the vasoactive effects of a known vasodilator, nitroprusside, were studied. A canine pulmonary lobar preparation was isolated in situ with its pulmonary artery and bronchus selectively cannulated in order to maintain a constant lobar pulmonary blood flow and in order to vary the inspired oxygen concentration from 95% to 0%. Pulmonary vascular pressures were determined by direct measurements and pulmonary vascular resistance units (PVRU) were calculated. Dopamine, epinephrine, and nitroprusside were infused into the isolated pulmonary artery singly and in combination, and the inspired oxygen concentration was varied during each drug infusion. The results of the study demonstrate that dopamine, epinephrine, and alveolar hypoxia all significantly elevate pulmonary vascular resistance. When these two drugs are used together in the presence of hypoxia, the effect on pulmonary resistance is additive. Furthermore, nitroprusside prevents the elevation of pulmonary vascular resistance caused by alveolar hypoxia, and when used with dopamine or epinephrine in the presence of hypoxia, nitroprusside reduces pulmonary vascular resistance toward normal.
使用血管收缩剂或肺泡低氧可使肺血管阻力升高。本研究旨在确定两种正性肌力药物多巴胺和肾上腺素的确切血管收缩作用，以及肺泡低氧对肺血管系统的影响。此外，还研究了一种已知血管扩张剂硝普钠的血管活性作用。采用犬肺叶原位分离制备，选择性地插管肺动脉和支气管，以维持肺叶恒定的肺血流量，并将吸入氧浓度从95% 变化至0%。通过直接测量确定肺血管压力，并计算肺血管阻力单位（PVRU）。将多巴胺、肾上腺素和硝普钠单独及联合注入分离的肺动脉，并在每次药物输注期间改变吸入氧浓度。研究结果表明，多巴胺、肾上腺素和肺泡低氧均显著升高肺血管阻力。当这两种药物在低氧情况下联合使用时，对肺阻力的影响是相加的。此外，硝普钠可防止肺泡低氧引起的肺血管阻力升高，并且在低氧情况下与多巴胺或肾上腺素合用时，硝普钠可使肺血管阻力降至正常水平。
