THE PULMONARY FUNCTION IN LUNG INJURY INDUCED BY SEVERAL CUSES IN AWAKE SHEEP

本实验研究了清醒绵羊几种原因所致肺损伤的肺力学等肺功能变化及病理生理差异。我们通过以下方法确定肺力学。通过右侧开胸术将硅橡胶封套放置在胸膜腔中以测量胸膜压。进行了慢性气管造口术。插入10号Shiley套囊气管切开插管。流量和潮气量（Vt）通过连接到气管切开插管的呼吸速度描记器（Fleish）测量。通过压差传感器（Validyne）测量跨肺压（Ptp）。通过Vt除以Ptp计算动态肺顺应性（Cdyn）。肺阻力（RI.）通过将Ptp除以流量来计算。我们还准备了慢性仪器羊肺淋巴液动力学和肺血流动力学。内毒素血症（ETX）、肺空气栓塞（PE）、百草枯中毒（PA）和左房压（IP）升高对肺淋巴动力学和肺血流动力学的影响不同。ETX、PE和PA可引起肺水肿。内毒素和肺栓塞可引起肺动脉高压，而肺动脉血流动力学无明显变化，百草枯后3小时肺淋巴流量增加。这些结果表明，肺损伤的发展在增加的通透性肺水肿是不同的，根据肺损伤的原因。比较了肿瘤坏死因子（TNF）和内毒素（ETX）致肺损伤时肺力学的变化。两组肺动脉压升高时，Cdyn均降低，R_L均升高。提示TNF和ETX对肺血流动力学和气道的影响基本一致。但TNF组的这些变化开始较ETX组早。

We studied the changes of pulmonary function such as lung mechanics and the differences of pathophysiology in lung injury induced by several causes in awake sheep. We determined lung mechanics by the following method. Silastic envelopes were placed in the pleural space for the measurement of pleural pressure through a right-sided thoracotomy. A chronictracheo stomy was made. A size 10 Shiley cuffed tracheostomy tube was inserted. Flow and tidal volume (Vt) was measured by a pneumotachograph (Fleish) attached to the tracheostomy tube. Transpulmonary pressure (Ptp) was measured by a differential pressure transducer (Validyne). Dynamic lung compliance (Cdyn) was calculated by dividing Vt by Ptp. Lung resistance(RI.) was calculated by dividing Ptp by flow. We also prepared chronically instrumented sheep to measure the lung lymph dynamics and pulmonary hemodynamics. The responses of the lu ng lymph dynamics and pulmonary hemodynamics to endotoxemia(ETX), pulmonary air embolism(PE), paraquat toxicity(PA) and increased left atrial pressure(IP) are different. ETX, PE and PA produced increased permeability pulmonary edema. ETX and PE produced pulmonary hypertension,though pulmonary hemodynamics in PA did not changes.Lung lymph flow increased 3hr after paraquat. These findings suggest that the development of lung injury in increased permeability pulmonary edema is different according to the cause for lung injury. We compared the changes of lung mechanics in TNF(tumor necrosis factor)-induced lung injury with those in ETX-induced lung injury. In both groups, Cdyn decreased and R_L increased, when pulmonary artery pressure was elevated. These findings suggest that TNF and ETX showed the almost same response to the pulmonary hemodynamics and airway. However, the start of these changes was earlier in TNF group than in ETX group.