Lewis R M
Respir Care. 1982 Jun;27(6):675-81.
The response of a time-cycled, continuous-flow, pressure-limited infant ventilator to changes in lung compliance was assessed by use of a variable-compliance test lung. A 50% reduction in lung compliance produced an automatic increase in mean airway pressure (MAP). Increases in MAP averaged 17% over baseline values. Factors that favored a large increase in MAP when lung compliance was reduced were a high original lung compliance, a low ventilator compliance, a high I:E, and ventilation with a triangular inspiratory pressure wave. The increase in MAP was accompanied by a change in the inspiratory pressure wave from triangular to square. Increases in MAP were not seen when the pressure wave was initially square. Automatic increases in MAP when lung compliance decreases may help to minimize decreases in PaO2; however, pulmonary barotrauma and increases in intracranial pressure could also result. The factors that allow for automatic MAP increases may also allow for automatic decreases in MAP as lung compliance improves. The advantages and disadvantages of automatic changes in MAP merit further study.
使用可变顺应性测试肺评估了时间切换、持续气流、压力限制型婴儿呼吸机对肺顺应性变化的反应。肺顺应性降低50%会导致平均气道压（MAP）自动升高。MAP升高值比基线值平均高出17%。当肺顺应性降低时，有利于MAP大幅升高的因素包括初始肺顺应性高、呼吸机顺应性低、吸呼比（I:E）高以及采用三角形吸气压力波进行通气。MAP升高伴随着吸气压力波从三角形变为方形。当压力波最初为方形时，未观察到MAP升高。肺顺应性降低时MAP自动升高可能有助于将动脉血氧分压（PaO2）的降低降至最低；然而，也可能导致肺气压伤和颅内压升高。随着肺顺应性改善，允许MAP自动升高的因素也可能导致MAP自动降低。MAP自动变化的优缺点值得进一步研究。
