Pison U, López F A, Heidelmeyer C F, Rossaint R, Falke K J
Freie Universität Berlin, Universitätsklinikum Rudolf Virchow, Department of Anesthesiology and Intensive Care Medicine, Germany.
J Appl Physiol (1985). 1993 Mar;74(3):1287-92. doi: 10.1152/jappl.1993.74.3.1287.
Nitric oxide (NO) is an endogenous endothelium-derived relaxing factor that participates in the regulation of vascular tone. We studied the effects of inhaled NO gas on transient hypoxic pulmonary vasoconstriction and normal lungs in mechanically ventilated sheep. We measured hemodynamics and pulmonary gas exchange. For gas exchange measurements we used conventional blood gas analysis and the multiple inert gas elimination technique to estimate ventilation-perfusion heterogeneity. Our hypotheses were 1) inhaled NO reverses hypoxic pulmonary vasoconstriction, 2) the hemodynamic effects of inhaled NO are limited to the pulmonary circulation, and 3) inhaled NO does not impair pulmonary gas exchange and may redistribute blood flow to better ventilated areas of the lungs. Hypoxic pulmonary vasoconstriction was induced by using a hypoxic inspiratory gas mixture. The addition of 20 ppm NO to the hypoxic inspiratory gases returned pulmonary arterial pressure to baseline values. Systemic hemodynamics and gas exchange indexes derived from conventional blood gas analysis remained constant. Gas exchange indexes for ventilation-perfusion ratios and gas dispersions improved. The addition of 20 ppm NO to medical air (21% O2) had no such significant effects on hemodynamics or pulmonary gas exchange. Our findings show that inhaled NO reverses transient hypoxic pulmonary vasoconstriction. The hemodynamic effects of NO are limited to the pulmonary circulation; it does not impair pulmonary gas exchange. Moreover, it redistributes blood flow to better ventilated alveoli. As such, NO has potential in the treatment of lung diseases associated with pulmonary hypertension.
一氧化氮（NO）是一种内源性内皮衍生舒张因子，参与血管张力的调节。我们研究了吸入NO气体对机械通气绵羊的短暂性低氧性肺血管收缩及正常肺的影响。我们测量了血流动力学和肺气体交换情况。对于气体交换测量，我们使用传统血气分析和多惰性气体消除技术来评估通气-灌注不均一性。我们的假设为：1）吸入NO可逆转低氧性肺血管收缩；2）吸入NO的血流动力学效应仅限于肺循环；3）吸入NO不会损害肺气体交换，且可能会将血流重新分配至肺内通气较好的区域。通过使用低氧吸入气体混合物诱导低氧性肺血管收缩。向低氧吸入气体中添加20 ppm的NO可使肺动脉压恢复至基线值。传统血气分析得出的全身血流动力学和气体交换指标保持不变。通气-灌注比和气体弥散的气体交换指标得到改善。向医用空气（21% O2）中添加20 ppm的NO对血流动力学或肺气体交换没有此类显著影响。我们的研究结果表明，吸入NO可逆转短暂性低氧性肺血管收缩。NO的血流动力学效应仅限于肺循环；它不会损害肺气体交换。此外，它会将血流重新分配至通气较好的肺泡。因此，NO在治疗与肺动脉高压相关的肺部疾病方面具有潜力。
