基于主动模拟肺平台的经鼻高流量氧疗时实际FiO2的影响因素研究

Influencing factors of actual-FiO2 difference during high-flow nasal cannula therapy based on the active servo respiratory simulation lung

目的探讨不同经鼻高流量氧疗（HFNC）设备、设置氧浓度、设置流量、吸气峰流速和潮气量对HFNC时吸入气氧浓度（FiO2）的影响。方法使用主动模拟肺（ASL5000）模拟患者的自主呼吸，调节参数模拟不同潮气量和吸气峰流速的组合，[潮气量（Vt）=400ml和峰流速（PIF）：40L／min、Vt=400ml和PIF=80L／min，Vt=500ml和PIF=50L／min，Vt=500ml和PIF=100L／mini，设置流量分别为20、40和60L／min时，设置氧浓度分别为30％、50％和70％。利用放置在吸气回路的氧浓度测量仪记录吸入气氧浓度。结果单因素方差分析显示，设备A和B对实际FiO2无显著的影响（P〉0.05）；相同潮气量时，吸气峰流速对实际FiO2都有显著的影响（P〈0．05）；设置流量对实际FiO2都有显著的影响（P〈0．05）。当设置氧浓度为30％、50％和70％，实际FiO2变化率分别为（8．23±2．31）％、（14．11±3．71）％和（16．01±4．31）％。当设置流量为20、40和60L／min时，实际FiO2变化率分别为（22．56±6．42）％、（13．22±4．52）％和（11．35±5．19）％。潮气量400ml时，吸气峰流速40L／min和80L／min，实际FiO2变化率分别为（6．51土2．41）％和（12．12±3．59）％；潮气量500ml时，吸气峰流速50L／min和100L／min，实际FiO2变化率分别为（8．21±2．65）％和（14．67±3．81）％。结论设置流量增加，实际FiO2变化率显著下降，设置氧浓度和吸气峰流速增加，实际FiO2变化率显著增加。

Objective To investigate the effect of different nasal high flow oxygen therapy （HFNC） devices, set-FiO2, set-flow, peak inspiratory flow （PIF） and tidal volume （Vt） on actual-FiO2 during HFNC. Methods The patient＇s spontaneous breathing was simulated using an active simulated lung （ASL5000） and the parameters were adjusted to simulate combinations of different tidal volume and peak inspiratory flow （Vt=400 ml and PIF=40 L/min, Vt=400 ml and PIF=500 ml and PIF=50 L/ min, Vt= 500 ml, and PIF= 100 L/min）, and set-FiO2 were adjusted to 30 %, 50% and 70%, and set flow were adjusted to 20, 40 and 60 L/min, respectively. The actual-FiO2 was recorded by an oxygen sensor placed in the inspiratory circuit. Results One-way analysis of variance showed that devices A and B had no significant effect on the actual FiO2 （ P 〉 0.05）. Under same Vt, peak inspiratory flow had significant effects on actual-FiO2 （ P d0.05）, and set-flow also had significant effects on actual-FiO2 （ P 〈0.05）. When Set-FiO2 were set at 30, 50% and 700%, the actual-FiO2 change rates were （8.23 ±2.31 ） %, （ 14.11 ± 3.71） % and （16. 01±4.31） %, respectively. The actual-FiO2 change rates were （22. 56±6.42）%, （13.22±4.52）% and （11.35±5.19）% when Set-flow were set at 20,40 and 60 L/min, respectively. When tidal volume was equal to 500 ml, peak inspiratory flow was set at 40 L/min and 80 L/min, and the actual-FiO2 change rates were （6.51 ± 2.41 ）% and （ 12.12 ± 3.59 ）% respectively. When the tidal volume was 500 ml, the inspiratory peak flow was 50 L/min and 100 L/min, the actual FiO2 change rates were （8.21 2.65）% and （14.67±3.81）%,respectively.Conclusions Set-flow increased,the actual-FiO2 change rates decreased significantly, Set-FiO2 and peak inspiratory flow increased, the actual-FiO2 change rates increased significantly.