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

据报道，即使在正常肺中，在机械连续正压通气过程中，肺泡压力的分布也不均匀。调节吸气流量、模式和吸气末停顿（EIP）的持续时间可以产生可变的吸气模式。我们研究了在机械通气过程中哪种吸气方式最适合均匀化肺泡压力的不均匀分布。我们同时进行肺泡压力测量在每个叶动态肺泡胶囊的方法。在正常肺模型的对照研究后，我们试图通过给药白介素-1和肿瘤坏死因子来确定脓毒性肺水肿模型的最佳吸气方式。在正常肺模型中，与缓慢吸气流量相比，EIP模式的加入显著降低了非依赖区（NDZ）和依赖区（DZ）之间的末吸气肺泡压力梯度。EIP压力型表现为NDZ的逐渐减小波和DZ的逐渐增大波。与EIP开始时相比，EIP结束时MDZ的肺泡压明显降低，DZ的肺泡压明显升高。机械通气初始吸气期，NDZ区肺泡压升高，DZ区肺泡压降低。由于肺泡压力从NDZ向DZ重新分布，施加EIP时压力分布更加均匀。在脓毒性肺模型中，由于肺泡分泌增加，用肺泡囊法测量肺泡压力非常困难。我们发现在正常肺模型机械通气时加入EIP，肺泡压力分布更加均匀。添加EIP可以纠正脓毒症肺模型肺泡压力的不均匀分布。在脓毒性肺模型的进一步研究中，有必要改进肺泡压力测量方法。少

It has been reported that a heterogeneous distribution of alveplar pressure occurs during mechanical continuous positive pressure ventilation even in the normal lung. Regulating an inspiratory flow rate, pattern, and a duration of an added end inspiratory pause (EIP) can produse variable inspiratory patterns. We studied which inspiratory pattern is optimal to homogenize the heterogeneous distribution of alveolar pressure during mechanical ventilation. We performed simultaneous alveolar pressure measurements in each of lobes dynamically with an alveolar capsule method. After the control study in normal lung models, we tried to determine an optimal inspiratory pattern in the models with septic pulmonary edema made by administration of interleukin-1 and tumor necrosis factor.In normal lung models, addition of EIP pattern significantly decreased an end inspiratory alveolar pressure gradient between a nondependent zone (NDZ) and a dependent zone (DZ) compared to the slow inspiratory flow pa … More ttern. The EIP pressure patterns showed a gradual decreasing wave in NDZ and a gradual increasing wave in DZ.Alveolar pressures significantly decreased in MDZ and increased in DZ at the end of EIP compared to those at the beginning of EIP.Alveolar pressures were higher in NDZ and lower in DZ at the initial inspiratory phase during mechanical ventilation. Pressure distribution became more homogeneous when EIP was applied due to redistribution of alveolar pressure from NDZ to DZ.In septic lung models, measurements of alveolar pressures with the alveolar capsule method were very difficult by increased secretion from alveoli.We made it clear that the distribution of alveolar pressure becomes more homogeneous when EIP was added during mechanical ventilation in normal lung models. Addition of EIP may correct the heterogeneous distribution of alveolar pressure in septic lung models. It will be necessary to improve the methods to measure alveolar pressures for the additional investigations about septic lung models. Less