低水平辅助通气与T管法对机械通气患者撤机时呼吸力学的影响比较

Comparison of the effects between low-level assisted ventilation and T-piece method on respiratory mechanics during weaning of mechanically ventilated patients

目的有创机械通气患者在拔管前3 d内进行自主呼吸试验(SBT)时应用低水平辅助通气与T管法对呼吸力学差异的比较。方法采用回顾性观察性研究方法。纳入2018年12月至2020年6月广州医科大学附属第一医院重症医学科收治的有创机械通气时间超过72 h、病情稳定且进入撤机阶段的25例困难撤机或延迟撤机患者作为研究对象,共收集到119例次呼吸力学指标,根据数据收集时使用的通气模式分为低水平辅助通气组和T管组。比较两组不同通气模式相关呼吸力学指标如食道压(Pes)、胃内压(Pga)、跨膈压(Pdi)、最大跨膈压(Pdimax)、Pdi/Pdimax比值、食道压-时间乘积(PTPes)、胃内压-时间乘积(PTPga)、跨膈压-时间乘积(PTPdi)、膈肌肌电(EMGdi)、膈肌肌电最大值(EMGdimax)、PTPdi/PTPes比值、Pes/Pdi比值、吸气时间(Ti)、呼气时间(Te)、呼吸周期(Ttot)的差异。结果与T管组比较,低水平辅助通气组有更高的Pes、PTPes、PTPdi/PTPes比值、Pes/Pdi比值和Te〔Pes(cmH_(2)O,1 cmH_(2)O=0.098 kPa):2.84(-1.80,5.83)比-0.94(-8.50,2.06),PTPes(cmH_(2)O·s·min^(-1)):1.87(-2.50,5.93)比-0.95(-971,2.56),PTPdi/PTPes比值:0.07(-1.74,1.65)比-1.82(-4.15,-1.25),Pes/Pdi比值:0.17(-0.43,0.64)比-0.47(-0.65,-0.11),Te(s):1.65(1.36,2.18)比1.33(1.05,1.75),均P<0.05〕;而T管组与低水平辅助通气组Pga、Pdi、Pdimax、Pdi/Pdimax比值、PTPga、PTPdi、EMGdi、EMGdimax、Ti、Ttot比较差异均无统计学意义〔Pga(cmH_(2)O):6.96(3.54,7.60)比7.74(4.37,11.30),Pdi(cmH_(2)O):9.24(4.58,17.31)比6.18(2.98,11.96),Pdimax(cmH_(2)O):47.20(20.60,52.30)比29.95(21.50,47.20),Pdi/Pdimax比值:0.25(0.01,0.34)比0.25(0.12,0.41),PTPga(cmH_(2)O·s·min^(-1)):7.20(2.54,9.97)比7.97(5.74,13.07),PTPdi(cmH_(2)O·s·min^(-1)):12.15(2.95,19.86)比6.87(2.50,12.63),EMGdi(μV):0.05(0.03,0.07)比0.04(0.02,0.06),EMGdimax(μV):0.07(0.05,0.09)比0.07(0.04,0.09),Ti(s):1.20(0.95,1.33)比1.07(0.95,1.33),Ttot(s):2.59(2.22,3.09)比2.77(2.35,3.24),均P>0.05〕。结论机械通气患者撤机行SBT时使用T管法较低水平辅助通气法增加了呼吸作功,因此行SBT过程中应避免长时间使用T管。

Objective To compare the difference of low-level assisted ventilation and T-piece method on respiratory mechanics of patients with invasive mechanical ventilation during spontaneous breathing trial(SBT)within 3 days before extubation.Methods A retrospective observational study was conducted.Twenty-five patients with difficulty in weaning or delayed weaning from invasive mechanical ventilation who were admitted to department of critical care medicine of the First Affiliated Hospital of Guangzhou Medical University from December 2018 to June 2020,and were in stable condition and entered the weaning stage after more than 72 hours of invasive mechanical ventilation were studied.A total of 119 cases of respiratory mechanical indexes were collected,which were divided into the low-level assisted ventilation group and the T-piece group according to the ventilator method and parameters used during the data collection.The different ventilation modes related respiratory mechanics indexes such as the esophageal pressure(Pes),the gastric pressure(Pga),the transdiaphragmatic pressure(Pdi),the maximum Pdi(Pdimax),Pdi/Pdimax ratio,the esophageal pressure-time product(PTPes),the gastric pressure-time product(PTPga),the transdiaphragmatic pressure-time product(PTPdi),the diaphragmatic electromyography(EMGdi),the maximum diaphragmatic electromyography(EMGdimax),PTPdi/PTPes ratio,Pes/Pdi ratio,the inspiratory time(Ti),the expiratory time(Te)and the total time respiratory cycle(Ttot)at the end of monitoring were recorded and compared between the two groups.Results Compared with the T-piece group,Pes,PTPes,PTPdi/PTPes ratio,Pes/Pdi ratio and Te were higher in low-level assisted ventilation group[Pes(cmH_(2)O,1 cmH_(2)O=0.098 kPa):2.84(-1.80,5.83)vs.-0.94(-8.50,2.06),PTPes(cmH_(2)O·s·min^(-1)):1.87(-2.50,5.93)vs.-0.95(-9.71,2.56),PTPdi/PTPes ratio:0.07(-1.74,1.65)vs.-1.82(-4.15,-1.25),Pes/Pdi ratio:0.17(-0.43,0.64)vs.-0.47(-0.65,-0.11),Te(s):1.65(1.36,2.18)vs.1.33(1.05,1.75),all P<0.05],there were no significant differences in Pga,Pdi,Pdimax,Pdi/Pdimax ratio,PTPga,PTPdi,EMGdi,EMGdimax,Ti and Ttot between the T-piece group and the low-level assisted pressure ventilation group[Pga(cmH_(2)O):6.96(3.54,7.60)vs.7.74(4.37,11.30),Pdi(cmH_(2)O):9.24(4.58,17.31)vs.6.18(2.98,11.96),Pdimax(cmH_(2)O):47.20(20.60,52.30)vs.29.95(21.50,47.20),Pdi/Pdimax ratio:0.25(0.01,0.34)vs.0.25(0.12,0.41),PTPga(cmH_(2)O·s·min^(-1)):7.20(2.54,9.97)vs.7.97(5.74,13.07),PTPdi(cmH_(2)O·s·min^(-1)):12.15(2.95,19.86)vs.6.87(2.50,12.63),EMGdi(μV):0.05(0.03,0.07)vs.0.04(0.02,0.06),EMGdimax(μV):0.07(0.05,0.09)vs.0.07(0.04,0.09),Ti(s):1.20(0.95,1.33)vs.1.07(0.95,1.33),Ttot(s):2.59(2.22,3.09)vs.2.77(2.35,3.24),all P>0.05].Conclusions When mechanically ventilated patients undergo SBT,the use of T-piece method increases the work of breathing compared with low-level assisted ventilation method.Therefore,long-term use of T-piece should be avoided during SBT.