摘要
机械通气作为非生理性的通气方式,会对呼吸力学带来很大影响。人工气道最大的问题是给呼吸通路带来额外的气道阻力,通过欧姆定律可以发现其导致的吸气压力下降损耗与呼气压力释放延迟。对于肺部不同部位来讲,正压通气会造成不同的力学状态;通过设定单位面积的胸部或膈肌部位,采用基本力学的方法,可以发现跨肺压、跨胸壁压、跨肺胸压、跨膈肌压、跨肺膈压、胸腔内压、平台压、驱动压的形成及影响因素。吸气驱动引起的肺部压力梯度,在自主呼吸与机械通气时存在明显区别;根据驱动过程可以发现,生理状态下的自主呼吸,其压力梯度从外周向中心传递,对肺组织起到牵拉作用;无自主呼吸下的正压通气,其压力梯度是从中心向外周传递,对肺组织起到推挤作用;而有自主呼吸的正压通气可以分为两个阶段,第一个阶段为吸气触发努力至触发灵敏度前,与生理状态下的自主吸气相似,这个阶段的压力梯度是自外周向中心,但这个阶段时间极短;第二个阶段为吸气触发达触发灵敏度后呼吸机行正压送气过程,压力梯度是患者自主吸气的牵拉与呼吸机正压通气的推挤共同作用形成的,在压力的分配传递上有一定的互补性,尤其对于非生理状态的正压通气而言。所以,通过这些基本力学分析,临床医务人员可以更系统地理解机械通气对呼吸力学的影响。
As a non-physiological way of ventilation,mechanical ventilation has a great effect on the respiratory mechanics.The biggest problem of artificial airway is that it brings extra airway resistance to the respiratory tract.For different parts of the lung,positive pressure ventilation could cause different mechanic states.We can find the formation and influencing factors of transpulmonary pressure,transchest wall pressure,trans-lung-chest pressure,trans-diaphragmatic pressure,trans-pulmonary-diaphragmatic pressure,intrapleural pressure,plateau pressure and driving pressure,by analyzing the mechanic state in a unit area of the chest or diaphragm position in the way of basic mechanics.It is obviously different in the pulmonary pressure gradient caused by inspiratory driving between in spontaneous breathing and in mechanical ventilation.The pressure is transmitted from the periphery to the center in spontaneous breathing in physiological state,playing a traction role for lung tissue.The pressure is transmitted from the center to the periphery in positive pressure ventilation without spontaneous breathing,playing a pushing role for lung tissue.It can be divided into two stages in positive pressure ventilation with spontaneous breathing.The first stage is from inspiratory trigger effort to trigger sensitivity.It is similar to spontaneous inspiration in physiological state.The pressure gradient in this stage is from the peripheral to center.But the period is very short.The second stage is the positive pressure ventilation progress after the trigger sensitivity.The pressure gradient is caused by the pulling of the patient's spontaneous inhalation and the pushing of the positive pressure ventilation of the ventilator.There is a certain complementarity in the distribution and transmission of pressure,especially for non-physiological positive pressure ventilation.Therefore,through these basic mechanical analysis,clinical medical staff can better understand the impact of mechanical ventilation on respiratory mechanics.
作者
武云珍
盖娜
胡文才
郭海生
Wu Yunzhen;Gai Na;Hu Wencai;Guo Haisheng(Department of Critical Care Medicine,Dongying People's Hospital,Dongying 257091,Shandong,China;Department of Emergency,Dongying Hekou People's Hospital,Dongying 257200,Shandong,China;Department of Respiratory,Dongying Hekou Traditional Chinese Medicine Hospital,Dongying 257200,Shandong,China;Department of Respiratory,Dongying People's Hospital,Dongying 257091,Shandong,China)
出处
《中华危重病急救医学》
CAS
CSCD
北大核心
2021年第11期1405-1408,共4页
Chinese Critical Care Medicine
基金
山东省自然科学基金(ZR2014HM040)。
关键词
机械通气
呼吸力学
自动导管补偿
正压通气
Mechanical ventilation
Respiratory mechanics
Automatic tube compensation
Positive pressure ventilation
