Studies on the optimal inspiratory pattern to correct the heterogeneous distribution of alveolar pressure during pressure support ventilation in septic pulmonary edema

在压力支持通气（PSV）过程中，我们可以通过调节初始流速来调节吸气模式。实际上，在临床治疗中，动态测量肺泡压（PA）对于选择纠正PA不均匀分布的吸气模式是困难的。在每种吸气模式中，10 cm H2O的选定压力上升时间（PRT）：0.025、0.5或0.75秒。我们用肺泡囊法同时动态测量了每一个肺叶的PA。在正常肺模型对照研究的基础上，我们尝试在应用白细胞介素-1（IL-1）和肿瘤坏死因子（TNF）建立的脓毒性肺水肿模型中确定最佳的吸气模式，在正常肺模型中，达到所选压力支持水平越慢，初始吸气时PA阴性值越高。在非依赖区（NDZ）和依赖区（DZ），吸气末PA均以吸气模式最高，PRT均为0.5秒，各PRT之间无差异。由于肺泡分泌物增加，用肺泡囊法测量PA非常困难。我们明确指出，当适当测定PA时，PRT在正常肺无模型的PSV期间进行。适当的PRT可以纠正脓毒症肺模型中PA的不均匀分布。为进一步研究脓毒症肺模型，有必要改进PA的测定方法。

With recent ventilators, we can regulate the initial flow rate to modulate inspiratory patters during pressure support ventilation (PSV). Actually, in clinical treatment, it is difficult to measure alveolar pressure (PA) dynamically for the selection of the inspiratory pattern that correct the heteogeneous distribution of PA.We studied which is the most optimal one among four inspiratory patterns during PVS to homogenize he heterogeneous distribution of PA in dogs. In each inspiratory pattern, 10 cm H2O of the selected pressure rising time (PRT) : 0,025,0.5, or 0.75 second. We performed simultaneous PA measurement in each of lobes dynamically with an alveoar capsule method. After the control study in normal lung models, we tried to determine the optimal inspiratory pattern in the models with septic pulmopnary edema made by administration of interleukin-1 and tumor necrosis factor.In normal lung models, the more slowly the selected pressure support level was reached, the higher was the negative PA in the initial inspiration. End inspiratory PA tended to be highest in the inspiraytory pattern with 0.5 second of he PRT in both nondependent zone (NDZ) and dependent zone (DZ), which had no difference among each PRT.In septic lung models, measurements of PA with the alveolar capsule method were very difficult by increased secretion from alveoil.We made it clear that the transmissions of pressure to alveoli were improved when the adequate determination of he PRT was done during PSV in normal lung modeless. Adequate PRT may correct the heterogeneous distribution of PA in septic lung models. It will be necessary to improve the methods to measure PA for the additional investigations about septic lung models.