Effect of nitric oxide in children with pulmonary hypertension

1.新生儿持续性肺动脉高压动物模型的建立15头新生仔猪，采用颈内静脉置管连续测量肺动脉压。在这种情况下，给予低浓度氧气（FiO2<15%）以增加肺动脉压。低氧高碳酸血症条件下，新生仔猪出生后48小时内肺动脉压与全身动脉压基本相等，出现右向左分流。在这种情况下，大多数动物模型在7天内死亡（FiO2<15%），主要是由于全身动脉压下降。另一方面，在子宫内给予吲哚美辛的4头新生仔猪，肺动脉压在全身动脉压的60%以内。对先天性心脏病合并肺动脉高压患者吸入低剂量一氧化氮（5-10ppm），测定肺血管阻力变化。将这种效果与高浓度氧的效果进行了比较。此外，研究了不同程度肺动脉高压下一氧化氮的有效性。在严重肺动脉高压如Eisenmenger综合征中，高浓度氧和正常氧伴一氧化氮对血流动力学变量均无影响。中度肺动脉高压患者肺动脉压和肺血管阻力均随高氧和一氧化氮吸入而显著降低，而正常肺动脉压患者无此现象。我们的数据表明，对于合并肺动脉高压的先天性心脏病患者，吸入一氧化氮，即使是低剂量，也是一种有效的选择性肺血管扩张剂。

1.Establishment of a animal moldel of persistent pulmonary hypertension of the newborn In 15 newborn piglets, pulmonary artery pressure was continuously measured by the catheter which was inserted from the internal jugular vein. At this condition, low concentration oxygen (FiO2<15%) was administer to increase the pulmonary pressure. In the condition under the hypooxgenation and hypercapnia, pulmonary arterial pressure of newborn piglet within 48 hours after birth was almost equal to systemic arterial pressure, and right to left shunt was present. Most of all animal model died within 7 days under this condition (FiO2<15%) due to decreasing of systemic arterial pressure. On the other hand, in 4 newborn piglets who were administered indometacin in the uterus, pulmonary artery pressure was within 60% of systemic arterial pressure.2.Evaluation of pulmonary vascular response for inhaled nitric oxide in patients with pulmonary hypertension Low dosage nitric oxide (5-10ppm) was inhaled in patients with congenital heart disease complicated with pulmonary hypertension, and the change of pulmonary vascular resistance was measured. Such effectiveness was compared to that of high concentration oxygen. Additionally, the effectiveness of nitric oxide under the different degree of pulmonary hypertension was investigated. In severe pulmonary hypertension such as Eisenmenger syndrome, both high concentration oxygen and the normal oxygen with nitric oxide showed no affect on the hemodynamical variables. In patients moderate pulmonary hypertension, pulmonary artery pressure and pulmonary vascular resistance both significantly decreased with high oxygen and with the nitric oxide inhalation, but these decreases were not found in patients with normal pulmonary pressure. Our data suggested that inhaled nitric oxide, even in a low dosage, was a potent and selective pulmonary vasodilator in patients with congenital heart disease complicated with pulmonary hypertension.