摘要
目的观察急性呼吸窘迫综合征(ARDS)患者呼气末正压(PEEP)滴定过程中的潮气分布和局部机械能。方法对2018年11月至2019年2月北京协和医院收入的10例接受有创机械通气的ARDS患者进行PEEP滴定(15~0 cmH2O,1 cmH2O=0.098 kPa),该过程中使用电阻抗成像(EIT)技术监测肺内从腹侧到背侧人为划分的4个"感兴趣区(ROI)"(ROI 1~2区代表非重力依赖区,ROI 3~4区代表重力依赖区)的局部潮气比例,并计算局部机械能大小。采用单因素方差分析比较不同PEEP水平下ROI 1~4区通气分布及机械能的差异。结果 (1)随着PEEP从15 cmH2O递减至0 cmH2O,重力依赖区潮气比例下降,非重力依赖区潮气比例增加,且差异均有统计学意义(F=5.611、5.587,P均<0.001),潮气由重力依赖区向非重力依赖区分布。(2)随着PEEP从15 cmH2O递减至0 cmH2O,总机械能降低,且差异有统计学意义(F=19.601,P <0.001);而局部机械能在ROI2~4区降低,且差异均有统计学意义(F=4.130,P=0.003;F=30.690,P <0.001;F=16.744,P <0.005),但在ROI 1区差异无统计学意义(F=0.460,P=0.804)。结论借助EIT技术能够监测ARDS患者PEEP滴定过程中的局部机械能。PEEP递减过程中,总体机械能降低,但局部机械能存在增加的可能性。局部机械能在PEEP设置中可能提供有用的信息。
Objective To investigate regional gas distribution and regional mechanical power during positive end-expiratory pressure(PEEP) titration in acute respiratory distress syndrome(ARDS)patients using electrical impedance tomography(EIT). Methods Ten ARDS patients admitted to Peking Union Medical College Hospital from November 2018 to February 2019 and receiving invasive mechanical ventilation were studied. A descending PEEP trial(15-0 cmH2 O, 1 cm H_2O=0.098 kPa) in 3 cmH_2O steps was monitored by EIT, with lung images divided into four ventral-to-dorsal horizontal regions of interest(ROIs)1 and 2 represent non-dependent areas, while ROIs 3 and 4 represent dependent areas). Gas distributions in the four regions were recorded, with which regional mechanical powers in each region were calculated.Results With PEEP decreasing from 15 cmH2 O to 0 cmH2 O, tidal volumes significantly decreased in dependent areas(F=5.611, P < 0.001), but significantly increased in non-dependent areas(F=5.587,P < 0.001). Ventilation shifted from dorsal regions to ventral regions during the descending PEEP trial. With PEEP decreasing from 15 cmH2 O to 0 cmH2 O, global mechanical power decreased significantly(F=19.601,P < 0.001); mechanical power decreased significantly in ROIs 2-4(F=4.130, P=0.003; F=30.690, P < 0.001;F=16.744, P < 0.005) but did not change significantly in ROI 1(F=0.460, P=0.804). Conclusions Regional mechanical power can be monitored by EIT. Global mechanical power decreases during the descending PEEP trial, while regional mechanical power may increase in some cases, which may help in the selection of PEEP.
引文
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