VCV与PCV通气策略中不同参数调节下雾化治疗对VTi、VTe及Ppeak指标的影响

Effects of Nebulization Therapy on VTi, VTe and Ppeak Indexes Under the Adjustment of Different Parameters in VCV and PCV Ventilation Strategies

目的:探究容量控制通气策略(VCV)和压力控制通气策略(PCV)时不同参数调节的雾化吸入对呼吸力学指标的影响。方法:以随机抽样法为分组依据,将本院抽取的100例机械通气患者分为VCV组(容量控制通气模式)与PCV组(压力控制通气模式)各50例,均于2020年1月—2021年1月期间在本院接受雾化吸入治疗,再将两组根据雾化氧流量参数不同进行分组,其中PCV组雾化氧流量7L/min有23例,9L/min有27例;VCV组雾化氧流量7L/min有26例,9L/min有24例;观察在2种模式下(雾化氧流量分别定为7、9L/min时)在雾化开始之前(雾化氧流量为0)和开始之后10min患者呼吸力学指标[气道峰压(Ppeak)、吸入潮气量(VTi)、呼出潮气量(VTe)]。同时,进行模拟水肺体外实验,观察在不同模式与呼吸机参数条件下雾化10min后(氧流量分别为0、5、7、9L/min)呼吸力学指标的变化。结果:临床研究显示,VCV模式中,患者的VTe、Ppeak随外接雾化氧流量的增加而升高(P<0.05),VTi则没有明显的改变(P>0.05)。PCV模式中,随外接雾化氧流量的增加,患者的VTi降低、VTe升高(P<0.05),Ppeak没有明显改变(P>0.05)。模拟水肺体外实验显示,VCV模式下,不同预设VT各组模拟水肺显示的VT和呼吸机监测的VTe会随着雾化氧流量增加而升高,不同雾化氧流量间差异显著(均P<0.05);而呼吸机监测的VTi无显著变化(P>0.05)。雾化10min后,不同预设VT各组呼吸机监测的VTe在相同雾化氧流量下均明显高于模拟水肺显示的VT,而VTi均显著低于模拟水肺显示的VT(均P<0.05)。PCV模式下,不同预设吸气压力各组呼吸机监测的Ppeak无明显变化(P>0.05);而VTe随着雾化氧流量增加而逐渐升高,VTi逐渐降低,不同雾化氧流量间差异显著(均P<0.05);雾化开始后10min,在相同雾化氧流量下,VTe均明显高于模拟水肺显示的VT,VTi在明显低于模拟水肺显示的VT(均P<0.05)。结论:VCV通气策略下,雾化氧流量的增加会导致患者端的VT升高;PCV通气策略下,患者端的VT、Ppeak无明显变化。在上述两种通气策略下,呼吸机监测的VTi和VTe均无法真实反映患者端的VT。

Objective:To explore the effects of aerosol inhalation adjusted by different parameters on respiratory mechanics indexes during volume-controlled ventilation(VCV)and pressure-controlled ventilation(PCV).Methods:Based on the random sampling method,100 mechanically ventilated patients selected by our hospital were divided into VCV group(volume controlled ventilation mode)and PCV group(pressure controlled ventilation mode)with 50 patients each.Both groups received nebulized inhalation treatment at our hospital from January 2020 to January 2021.The two groups were further divided into groups according to different nebulized oxygen flow parameters,with 23 patients in the PCV group receiving nebulized oxygen flow rate of 7L/min and 27 patients receiving nebulized oxygen flow rate of 9L/min;in the VCV group,there were 26 cases with atomized oxygen flow rate of 7L/min and 24 cases with atomized oxygen flow rate of 9L/min.Observe the respiratory mechanics indicators of patients[peak airway pressure(Ppeak),inhaled tidal volume(VTi),and exhaled tidal volume(VTe)]before and 10 minutes after the start of nebulization(when the nebulized oxygen flow rate is set at 7 and 9L/min,respectively)in two modes.At the same time,a simulated water lung in vitro experiment was conducted to observe the changes in respiratory mechanics indicators after 10 minutes of nebulization(oxygen flow rates of 0,5,7 and 9L/min,respectively)under different modes and ventilator parameters.Results:Clinical studies showed that in VCV mode,patients’VTe and Ppeak increased with the increase of external nebulized oxygen flow(P<0.05),while VTi had no significant change(P>0.05).In PCV mode,with the increase of external nebulized oxygen flow,the patients’VTi decreased and VTe increased(P<0.05),but Ppeak did not change significantly(P>0.05).The simulated scuba in vitro experiment showed that in VCV mode,the VT displayed by the simulated scuba and the VTe monitored by the ventilator in different preset VT groups increased with the increase of the atomized oxygen flow,and the differences between different atomized oxygen flow were significant,but there was no significant change in VTi monitored by ventilator(P>0.05).After nebulization for 10 minutes,the VTe monitored by the ventilator in each preset VT group was significantly higher than the VT displayed by the simulated scuba under the same nebulized oxygen flow,while the VTi was significantly lower than the VT displayed by the simulated scuba(all P<0.05).In PCV mode,the Ppeak monitored by the ventilator in each group with different preset inspiratory pressures did not change significantly(P>0.05);while VTe increased gradually with the increase of nebulized oxygen flow,and VTi gradually decreased,the difference was significant(all P<0.05).10 minutes after the start of atomization,under the same atomized oxygen flow,VTe was significantly higher than the VT displayed by simulated scuba,and VTi was significantly lower than the VT displayed by simulated scuba(all P<0.05).Conclusion:Under the VCV ventilation strategy,the increase of the nebulized oxygen flow would lead to an increase in the VT of the patient;under the PCV ventilation strategy,the VT and Ppeak of the patient did not change significantly.Under the above two ventilation strategies,the VTi and VTe monitored by the ventilator cannot truly reflect the VT on the patient side.