Haas Carl F, Bauser Kimberly A
University Hospital Respiratory Care, University of Michigan Health System, Ann Arbor, MI, USA.
Crit Care Nurs Q. 2012 Jan-Mar;35(1):27-38. doi: 10.1097/CNQ.0b013e31823b2670.
In addition to improving gas exchange by mechanical ventilation, minimizing iatrogenic lung injury and making the patient comfortable are important goals. This article reviews advanced ventilator modes and techniques that might help to accomplish these goals. Small tidal volumes (VT) and low ventilation pressure minimize ventilator-induced lung injury. Airway pressure release ventilation and high-frequency oscillatory ventilation may provide lung-protective ventilation in certain patients with refractory hypoxemia. Adaptive support ventilation (ASV) automatically adjusts VT and rate on the basis of the patient's respiratory mechanics to provide "safe" settings. When ventilator output does not match patient respiratory center timing, patient-ventilator asynchrony occurs. Proportional assist ventilation and neutrally adjusted ventilatory assist are unique modes of ventilation that provide ventilatory support in direct proportion to patient effort and therefore may be able to better match patient need and improve comfort. Weaning protocols reduce duration of ventilation and intensive care unit stay. Certain ventilator modes purport to automate part of the ventilator discontinuance process. The ASV progressively reduces support as the patient's lung condition improves, while SmartCare/pressure support (Dräger, Lübeck, Germany) reduces support and then initiates a spontaneous breathing trial. Further research is required to determine the proper place these new modes have in the intensive care unit.
除了通过机械通气改善气体交换外，尽量减少医源性肺损伤并使患者感到舒适也是重要目标。本文回顾了可能有助于实现这些目标的先进通气模式和技术。小潮气量（VT）和低通气压力可将呼吸机诱发的肺损伤降至最低。气道压力释放通气和高频振荡通气可为某些难治性低氧血症患者提供肺保护性通气。适应性支持通气（ASV）可根据患者的呼吸力学自动调整潮气量和呼吸频率，以提供“安全”设置。当呼吸机输出与患者呼吸中枢的时间不匹配时，就会出现人机不同步。比例辅助通气和中性调节通气辅助是独特的通气模式，可根据患者的努力程度直接提供通气支持，因此可能能够更好地满足患者需求并提高舒适度。撤机方案可缩短通气时间和重症监护病房住院时间。某些通气模式旨在使呼吸机撤机过程的一部分自动化。随着患者肺部状况改善，ASV会逐渐减少支持，而SmartCare/压力支持（德国吕贝克德尔格公司）则会减少支持，然后启动自主呼吸试验。需要进一步研究以确定这些新模式在重症监护病房中的合适位置。
