原发性肺动脉高压(PPH)病人肺泡—动脉氧分压梯度增大,在疾病进展阶段,心排血量下降时,可发生低氧血症。用重复的惰性气体清除技术研究,对这些病人气体交换异常的机制得到较多的了解,特别说明了药物性肺血管张力降低使肺泡通气/灌注(V A/Q)比值恶化的关系。这种肺血管扩张的潜在有害作用,在新近有关PPH用血管扩张剂治疗的报告中, In patients with primary pulmonary hypertension (PPH), the alveolar-arterial oxygen partial pressure gradient increases. Hypoxemia may occur during the progression of the disease and cardiac output decreases. Repeated studies of inert gas scavenging techniques have gained a better understanding of the mechanisms of abnormal gas exchange in these patients and have demonstrated, inter alia, the relationship between reduced pulmonary vascular tone and deteriorated alveolar ventilation / perfusion (V A / Q) ratios. This potentially deleterious effect of pulmonary vasodilation, in a recent report on the treatment of PPH with vasodilators,