呼吸机辅助自主呼吸通气模式及其临床应用

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                    <section><section powered-by="gulangu"><section><section><p><img src="image/20201019/e5e7e34f8d69e7d33c5e008e02e20732_1.gif" /></p></section></section></section><section powered-by="gulangu"><section><section><p>辅助自主呼吸（assisted spontaneous breathing，ASB）</p></section> <p><img src="image/20201019/1c47c68127b0851bae70497f93a615ca_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;在患者吸气时由呼吸机给予一定的压力送气，帮助克服启动吸气活瓣阻力和胸肺弹性回缩力，减少自主吸气做功称为ASB。这一通气模式实际上是CPAP和压力切换通气的结合，既保持自主呼吸的优点，又有利于克服自主呼吸能力与通气要求的差别。</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;应用ASB时，应预先设定触发压力和支持压力水平，患者吸气引起气道压力降低到触发水平后，呼吸机即按照预先设定的支持压力通气，当吸气流量低于峰值25%时，停止送气。</p><p>&nbsp; &nbsp; &nbsp; &nbsp; ASB 将在下列情形下被终止：</p><p>&nbsp; &nbsp; &nbsp; &nbsp; 在吸气I相，当吸气流速降至零。如病人呼气或人机对抗。</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;在吸气II 相，当吸气流速降至峰流速的某个值。成人：25％；小儿：25％</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;若上述标准未达到，吸气时间超过4秒，在小儿通气1.5秒。</p></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/4ee1624d909d981a89c95799077a4c43_3.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>临床应用</p></section> <p><img src="image/20201019/1c47c68127b0851bae70497f93a615ca_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;ASB最主要的优点是其提供的气流形式能适应于患者的呼吸力学，调整支持压力代替患者完成适当的呼吸功，同步性能好，患者易耐受。此外允许自主呼吸，气体在肺内分布更加均匀。患者可自主调节通气量变化，气道压力为所预设压力，相对较低。与控制通气比较，可降低气道峰压，减少气压伤和机械通气对血流动力学的不利影响，也有利于预防呼吸肌废用性萎缩和帮助停机。常用于ARDS患者以及脱机时的模式之一，因此同样适用于SARS患者。</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;最佳的支持压力应相当于克服气道阻力的压力，然后观察有无呼吸困难或过度通气进行相应调整。存在呼吸辅助肌参与呼吸时，常提示支持压力较低，出现抽搐时则提示通气过度，CO2排出过多引起呼吸性碱中毒。只有Pa<span>CO2</span>和Pa<span>O2</span>均处于正常范围内才提示调节得当。如果Pa<span>CO2</span>过高，应进一步增加支持压力，反之亦然。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section> <section powered-by="gulangu"><section><section><p>欢</p></section></section></section> </section><section> <section powered-by="gulangu"><section><section><p>迎</p></section></section></section> </section><section> <section powered-by="gulangu"><section><section><p>关</p></section></section></section> </section><section> <section powered-by="gulangu"><section><section><p>注</p></section></section></section> </section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section> <section powered-by="gulangu"><section><section><p><img src="image/20201019/49692c66e805e7714887253296dfca5f_5.jpg" /></p></section></section></section> </section><section> <section powered-by="gulangu"><section><section> </section></section></section> </section><section> <section powered-by="gulangu"><section><section><p>关注我们</p><p>一起涨姿势！</p></section></section></section> </section></section></section></section>