呼吸机波形分析简介（流速-时间曲线）

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                    <section><section powered-by="gulangu"><section><section><p><img src="image/20201019/31ce2126d405394d4c703502c384af3c_1.gif" /></p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>流速-时间曲线</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;流速被定义为气体在一定时间内移动置换的容积。图中纵轴为流速，横轴为时间，在0流速以上的流速为吸气流速，0流速以下的呼气流速。</p></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/6279ae51d53f8fd817a1ac40fa3effee_2.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;吸气时间为吸气开始到呼气开始（A到B）。呼气时间为呼气开始到下一次吸气开始（B到C）。吸气峰流速是吸气时间得到的最高流速。呼气峰流速为呼气时间得到的最高流速。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>判断流速波形形状</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/706fadd6e62972cf97c00cff1f8bf478_3.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;吸气流速的图形因流速波形设置或设置呼吸类型而异。容量控制通气呼吸机输送的气流方式：</p><p>&nbsp; &nbsp; &nbsp; &nbsp;方波图形：设置峰流速，吸气相流速保持不变。方波可以导致较高的峰压。</p><p><br  /></p><p>&nbsp; &nbsp; &nbsp; &nbsp;递减波：呼吸初始输送设置的峰流速，随后流速呈线性下降直至设定的容量输送结束，递减波形能产生较低的峰压但能显著增加吸气时间。</p><p><br  /></p><p>&nbsp; &nbsp; &nbsp; &nbsp;正弦波形：吸气流速逐渐回到零点。这种输送流量的方法可以使病人舒适。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;</p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;流速被定义为气体在一定时间内移动置换的容积。图中纵轴为流速，横轴为时间，在0流速以上的流速为吸气流速，0流速以下的呼气流速。</p><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><p>减速波：吸气初始流速最高，但是在吸气过程中因肺的阻抗特性呈指数递减。减速波产生于压力通气模式，如压力控制减压力支持。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>探查呼吸类型</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/a877972284cc489218dfd257dcce5f9b_4.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;指令呼吸：方波和递减波是容量控制指令呼吸的特征，容量、流速和流速波形设置均由医生设置。在压力控制通气，如果吸气时间设置得足够长，压力通气的减速波形可在呼气末降至为0。</p><p><br  /></p><p>&nbsp; &nbsp; &nbsp; &nbsp;自主呼吸：没有压力支持的自主呼吸会导致正弦波形的吸气流速图形，并且常常显示较低的峰流速。压力支持呼吸表现为减速波形，吸气末时流速不会降至为0。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>检测自动PEEP的存在</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/95c52dd416c2eef7a70f8c89a5f52e07_5.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;AUTO-PEEP或PEEPi是呼气末在肺内存在正压（气体陷闭）。AUTO-PEEP最多见于呼气时间不足时。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;AUTO-PEEP表现为在下一次吸气开始时呼气流速没有回到0点（A）。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;较高的呼气末流速通常反应较高的AUTO-PEEP水平（B）。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;较低的呼气末流速通常反应较低的AUTO-PEEP（C）。</p><p>&nbsp;注：流速-时间曲线虽然能说明AUTO-PEEP的存在和相对水平，但是不能准确测量AUTO-PEEP实际数值。 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>AUTO-PEEP导致的吸气努力失败</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/60e00b8d0b69542c28a1877c0c382c45_6.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;如果病人因为吸气时间太长导致AUTO-PEEP，要求呼气时间也较长，常常导致不能触发呼吸。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;上图病人存在吸气努力但不能触发呼吸。这种情况发生于当病人没能完成呼气就发生了吸气努力时（A）。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;为了触发呼吸，病人必须克服AUTO-PEEP和设置的触发限值才能触发呼吸机。当有明显的AUTO-PEEP时，病人吸气努力弱常不能触发呼吸。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>评价支气管扩张剂的反应</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/a7fa7eabe8eabdbf2895b61b31626053_7.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;图中在使用支气管扩张剂前后的流速-时间曲线。比较呼气峰流速和到达0点的时间（B）。使用支气管扩张剂后呼气峰流速增加，到达0流速的时间减少，潜在地说明了支气管扩张剂治疗有效。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;呼气流速的这种改善也见于给病人吸痰后。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>评估压力控制的吸气时间设置</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/b5f19d65ae77524fa489d16b3742e412_8.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;图中压力控制时，吸气时间在给病人输送流量时的影响。较短的吸气时间可以使用吸气流速达到0之间停止吸气（A）。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;增加吸气时间，吸气流速在转换为呼气之前到达0点（B），可以在没有增加压力的情况下输送较大的潮气量。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;进一步延长吸气时间，超过了0流速点一般不会输送更多的潮气量，但可导致一个压力平台（C），这在某些病例是需要的。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>评估流量触发的泄漏率</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/70b2c91f6c38f02553cc21bc0c282565_9.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;图中流量触发的流速-时间曲线，存在持续漏气（如气管插管气囊未充气、支气管胸膜瘘等）。当流量触发敏感度的设置高于泄漏率时，流速-时间曲线能显示泄漏。泄漏使呼吸机的部分基础流量在呼气相从回路逸出（B）。</p><p>&nbsp; &nbsp; &nbsp; &nbsp;0流速基线（A）和流速曲线B点代表了实际的泄漏率（L/min）</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>评估漏气和调整压力支持的呼气触发敏感度</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/a1199d7afe9f98b8b16a567e934c1892_10.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;图中压力支持呼吸下泄漏是怎样影响吸气时间的。典型表现是，当吸气流速下降至终止限值时，压力支持呼吸转换为呼气。有些呼吸机的吸气终止标准（或称呼气触发敏感度）是固定的数值。该数值为输送吸气峰流速的百分比（如10%、25%）。另外一些呼吸机允许临床医生改变吸气终止标准以补偿泄漏或肺阻抗变化对吸气时间的影响。</p><p><br  /></p><p>&nbsp; &nbsp; &nbsp; &nbsp;漏气常常阻止流速下降至设置的终止限值（A），从而导致长时间的吸气（B），调整呼气触发敏感度水平到较高的峰流速百分比（C）允许吸气较早终止，减少病人的吸气时间，利于恢复人机同步。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>双水平通气</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/0607ede9d28e07d86971c87b8085a1bb_11.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;图中在双水平通气时的吸气流速和呼气流速。在高压时间（B）和低压时间（C）期间，高吸气流速说明为指令通气（A），低吸气流速说明为自主吸气。高的呼气峰流速代表指令呼吸的呼气。</p></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section><section powered-by="gulangu"><section><section><p>双水平模式的气道压力释放通气</p></section></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><img src="image/20201019/6a282375f68ee39a232d2372bf11f434_12.jpg" /></p></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp;图中气道压力释放通气（APRV）的吸气流速和呼气流速。APRV具有典型的较长的高压时间（TIMEH）（A）和短的“释放时间”（B）。高的吸气流速代表指令呼吸的开始，较低的吸气流速代表在TIMEH的自主呼吸。另外注意auto-PEEP的存在，这也是APRV的特征。</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/20201019/36ead841acd8729c5fad059bf0038fa3_13.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>