Li Jie, Wu Wei, Fink James B
Department of Cardiopulmonary Sciences, Division of Respiratory Care, Rush University Medical Center, 1620 W Harrison St, Tower LL1202, Chicago, IL, 60612, USA.
Department of Critical Care Medicine, Shanghai Zhongshan Hospital, Fu Dan University, Shanghai, China.
Intensive Care Med Exp. 2020 Jan 31;8(1):6. doi: 10.1186/s40635-020-0293-7.
Compared to continuous vibrating mesh nebulizer (VMN), inspiration synchronized VMN has shown increased inhaled dose during noninvasive ventilation; however, its use during aerosol delivery via high-flow nasal cannula (HFNC) is still unknown.
An adult manikin was connected to a dual-chamber model lung, which was driven by a critical care ventilator to simulate spontaneous breathing. A HFNC system was utilized with temperature at 37 ° C while gas flow at 5, 10, 20, 40, and 60 L/min. Inspiration synchronized and continuous aerosol generation were compared at different positions (at the inlet of humidifier vs close to patient). One milliliter of albuterol (2.5 mg/mL) was used in each run (n = 3). Collection filter was placed at the trachea and was removed after each run. Drug was eluted from the filter and assayed with UV spectrophotometry (276 nm).
When nebulizer was placed close to patient, inhaled dose was higher with inspiration synchronized than continuous aerosol generation at all gas flows (p = 0.05) except at 5 L/min. When placed at the inlet of humidifier, compared to continuous, inspiration synchronized aerosol generated higher inhaled dose with gas flow set below 50% of patient inspiratory flow [23.9 (20.6, 28.3)% vs 18.1 (16.7, 19.6)%, p < 0.001], but lower inhaled dose with gas flow set above 50% of patient inspiratory flow [3.5 (2.2, 9.3)% vs 9.9 (8.2, 16.4)%, p = 0.001]. Regardless of breathing pattern, continuous aerosol delivered greater inhaled dose with nebulizer placed at humidifier than close to patient at all gas flows except at 5 L/min.
When the HFNC gas flow was set higher than 50% of patient inspiratory flow, no significant advantage was found in inspiration synchronized over continuous aerosol. However, inspiration synchronized aerosol generated 30% more inhaled dose than continuous with gas flow set below 50% of patient inspiratory flow, regardless of nebulizer placement. Continuous nebulizer needs to be placed at the inlet of humidifier.
与连续振动网式雾化器（VMN）相比，吸气同步VMN在无创通气期间显示吸入剂量增加；然而，其在通过高流量鼻导管（HFNC）进行气溶胶输送期间的应用仍不明确。
将一个成人人体模型连接到一个双腔模型肺，该模型肺由一台重症监护呼吸机驱动以模拟自主呼吸。使用HFNC系统，温度设定为37°C，气体流量分别为5、10、20、40和60L/min。在不同位置（加湿器入口处与靠近患者处）比较吸气同步和气溶胶持续产生的情况。每次运行使用1毫升沙丁胺醇（2.5mg/mL）（n = 3）。在气管处放置收集过滤器，每次运行后取出。从过滤器中洗脱药物并用紫外分光光度法（276nm）进行测定。
当雾化器靠近患者放置时，除5L/min外，在所有气体流量下，吸气同步时的吸入剂量均高于气溶胶持续产生时的吸入剂量（p = 0.05）。当放置在加湿器入口处时，与持续产生相比，吸气同步气溶胶在气体流量设定为患者吸气流量的50%以下时产生更高的吸入剂量[23.9（20.6，28.3）%对18.1（16.7，19.6）%，p < 0.001]，但在气体流量设定为患者吸气流量的50%以上时吸入剂量较低[3.5（2.2，9.3）%对9.9（8.2，16.4）%，p = 0.001]。无论呼吸模式如何，除5L/min外，在所有气体流量下，当雾化器放置在加湿器处时，持续产生的气溶胶输送的吸入剂量均大于靠近患者处。
当HFNC气体流量设定高于患者吸气流量的50%时，吸气同步气溶胶与持续产生的气溶胶相比无显著优势。然而，无论雾化器放置位置如何，当气体流量设定低于患者吸气流量的50%时，吸气同步气溶胶产生的吸入剂量比持续产生的多30%。持续雾化器需放置在加湿器入口处。
