Research of the Effects of New Ventilatory Therapy Using the Combination of PLV and NO to Neonates

全氟碳（PFC）部分液体通气（PVL）改善呼吸窘迫综合征（RDS）患者肺部气体交换。一氧化氮（NO）是一种气体形式的内皮衍生的松弛因子。当低浓度吸入时，可使收缩的肺血管平滑肌松弛。我们假设PVL和NO联合使用比PVL或NO单独使用对RDS患者更有效。因此，我们进行了动物实验来验证这一假设。采用温生理盐水肺灌洗法制备新生仔猪RDS动物模型。首先，研究了PFC的最佳容积，动物的功能残量（FRC）在灌洗前为26 ml，灌洗后为14 ml。肺顺应性随着PFC体积从5ml /kg增加到30ml /kg，以5ml为单位增加。而PFC在25 ml/kg和30 ml/kg时，氧合和CO2消除恶化，因此我们认为15-20 ml/kg的PFC剂量非常接近FRC，可能是RDS患者的最佳剂量。其次，我们比较了常规机械通气（CMV）和高频振荡通气（HFOV）两种不同通气方式对PLV的影响。在CMV期间，PLV能够保持良好的氧合和通气。然而，一旦CMV变为HFOV，动脉血气值恶化。当动物经HFOV通气后再次转为CMV时，血气值有所改善，由此我们得出HFOV不是适合PLV的通气方式。第三，我们进行了另一项实验，研究了NO和PLV的相互作用。与单用PLV相比，PLV和NO联合使用显著提高了仔猪的氧合水平。然而，由于实验数量不够，因此无法得出明确的结论。

Partial liquid ventilation (PVL) with perfluorocarbon (PFC) improves pulmonary gas exchange in the respiratory distress syndrome (RDS). Nitric oxide (NO) is an endothelium-derived relaxing factor in a gaseous form. When inhaled at low concentrations, it may relax constricted pulmonary vascular smooth muscle. We hypothesized the combination of PVL and NO can be more effective to the patients with RDS than when PVL or NO is used alone. Therefore, we conducted animal experiments to investigate this hypothesis. We made RDS animal model using newborn piglets by lung lavage with warm saline.First, the optimal volume of PFC was investigated, Functional residual capacity (FRC) of the animals were 26 ml before lavage and 14 ml after lavage. Lung compliance improved as the volume of PFC was increased from 5 ml/kg to 30 ml/kg in 5 ml increments. However, oxygenation and CO2 elimination worsened at the volume of 25 ml/kg and 30 ml/kg of PFC.These results led us to conclude 15-20 ml/kg, that is very close to FRC, maybe optimal dose of PFC to the patients with RDS.Second, we compared the effects of two different ventilation mode with PLV, which were conventional mechanical ventilation (CMV) and high-frequency oscillatory ventilation (HFOV). During CMV, PLV was able to keep good oxygenation and ventilation. However, once CMV was changed to HFOV, arterial blood gas value worsened. And when animals were changed to CMV again after ventilated by HFOV, blood gas value showed improvement, From these results, we conclude that HFOV is not adequate ventilation mode for PLV.Third, we conducted the another experiment that investigated the mutual effects of the combination of NO and PLV.Oxygenation of piglets remarkably improved during the combination of PLV and NO compared with PLV only. However, we could not performed sufficient number of experiments, therefore, definitive conclusion was not able to be demonstrated here.