Surfactant supplement for adult respiratory distress

成人呼吸窘迫综合征（ARDS）的病理过程在很大程度上是未知的，死亡率为50-70%。(1)病理过程的研究：将外源性表面活性剂与ARDS患者肺水肿液混合，给予未成熟新生兔肺。当水肿液蛋白与表面活性剂比值从5.6增加到11.2时，动物动态肺顺应性从平均1.08下降到0.43 ml/cmH_2O/kg （P < 0.05）。我们得出结论，急性呼吸窘迫综合征呼吸衰竭的一个原因是肺表面活性物质失活在过程中出现的肺水肿。(2)补充表面活性剂治疗急性呼吸窘迫综合征（ARDS）：大肠杆菌内毒素引起的大鼠呼吸衰竭可通过补充外源性表面活性剂（100 mg/kg）得到很大程度的逆转；PaO_2由106 mmHg（平均）改善至400 mmHg以上（P < 0.05），胸片弥漫性浸润消失。我们认为，表面活性剂的补充可以逆转ARDS患者的呼吸衰竭。(3)补充治疗的人工表面活性剂：将双棕榈酰卵磷脂、不饱和卵磷脂（u-L）、磷脂酰甘油和猪表面活性剂疏水蛋白按不同比例混合。未成熟新生兔肺动态顺应性（平均）为1.24 ml/cmH_2O/kg，对照组肺动态顺应性为0.79 ml/cmH_2O/kg （P < 0.05）。结果表明，u-L是影响表面活性剂活性的重要因素。

Pathological process of adult respiratory distress syndrome (ARDS) is largely unknown with 50-70% mortality.(1) Investigation on the pathological process: An exogenous surfactant was mixed with lung edema fluid sampled from ARDS patients, and administered to the lungs of immature newborn rabbits. When the edema fluid protein-to-surfactant ratio increased from 5.6 to 11.2, the dynamic lung compliance of the animals decreased from 1.08 (mean) to 0.43 ml/cmH_2O/kg (P < 0.05). We conclude that a cause of respiratory failure in ARDS is inactivation of pulmonary surfactant by lung edema that appears during the course.(2) Treatment of ARDS by surfactant supplement: Respiratory failure induced by administration of E. Coli endotoxin in rats was largely reversed by supplementation of an exogenous surfactant (100 mg/kg); PaO_2 improved from 106 mmHg (mean) to above 400 mmHg (P < 0.05), and diffuse infiltrates in the chest radiogram disappeared. We conclude that surfactant supplementation can reverse the respiratory failure in ARDS.(3) Artificial surfactant for the supplement therapy: Dipalmitoyl lecithin, unsaturated lecithin (u-L), phosphatidylglycerol and the hydrophobic proteins of porcine surfactant were mixed with various ratios. Dynamic lung compliance of the immature newborn rabbits receiving the mixture consists of all the components was 1.24 ml/cmH_2O/kg (mean), but the value receiving the mixture without u-L was 0.79 ml/cmH_2O/kg (P < 0.05). We conclude that u-L is an important factor for surfactant activity.