Optimal delivery of aerosols to infants during mechanical ventilation.
Optimal delivery of aerosols to infants during mechanical ventilation.
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DOI：
10.1089/jamp.2013.1077
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发表时间：
2014-09
影响因子：
3.4
通讯作者：
P. Longest;Mandana Azimi;M. Hindle
中科院分区：
文献类型：
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作者：
P. Longest;Mandana Azimi;M. Hindle
本研究的目的是通过评估气雾剂颗粒大小、新型Y形连接器和气雾剂输送时机的影响，确定接受有创机械通气的足月（3.6 kg）婴儿的最佳气雾剂输送条件。方法体外实验使用振动网孔式雾化器，并通过包含商业（CM）或新型流线型（SL）Y形连接器和3 mm气管内导管（ETT）的通气回路评价药物沉积分数和发射剂量，用于质量中值空气动力学直径为880 nm、1.78 μm和4.9 μm的气雾剂。气雾剂在整个吸入周期（T1输送）或吸入的前半部分（T2输送）释放到回路中。使用经验证的计算流体动力学（CFD）模拟和全肺模型预测来评估循环通气期间的肺沉积和呼出剂量。结果在体外实验中，在5 L/min的稳态气管流速下，ETT对880 nm和1.78 μm气溶胶的透过率为80-90%。基于循环通气的CFD模拟，与CM器械相比，SL Y形设计将Y形中的沉积损失减少了约2-4倍，并将肺输送效率提高了约2倍。与T1输送相比，在吸气周期的前半部分（T2）输送气雾剂使通气回路的呼出剂量减少了4倍。使用SL Y形连接器和T2输送实现了最佳肺沉积，对于最佳多分散（≤ 1.78 μm）和单分散（≤ 2.5 μm）粒径，分别实现了45%和60%的肺沉积。结论：优化选定的因素和使用新的SL Y形连接器可以显著提高医用气雾剂对婴儿的肺部输送效率，从目前的<1-10%提高到45- 60%。
PURPOSE The objective of this study was to determine optimal aerosol delivery conditions for a full-term (3.6 kg) infant receiving invasive mechanical ventilation by evaluating the effects of aerosol particle size, a new wye connector, and timing of aerosol delivery. METHODS In vitro experiments used a vibrating mesh nebulizer and evaluated drug deposition fraction and emitted dose through ventilation circuits containing either a commercial (CM) or new streamlined (SL) wye connector and 3-mm endotracheal tube (ETT) for aerosols with mass median aerodynamic diameters of 880 nm, 1.78 μm, and 4.9 μm. The aerosol was released into the circuit either over the full inhalation cycle (T1 delivery) or over the first half of inhalation (T2 delivery). Validated computational fluid dynamics (CFD) simulations and whole-lung model predictions were used to assess lung deposition and exhaled dose during cyclic ventilation. RESULTS In vitro experiments at a steady-state tracheal flow rate of 5 L/min resulted in 80-90% transmission of the 880-nm and 1.78-μm aerosols from the ETT. Based on CFD simulations with cyclic ventilation, the SL wye design reduced depositional losses in the wye by a factor of approximately 2-4 and improved lung delivery efficiencies by a factor of approximately 2 compared with the CM device. Delivery of the aerosol over the first half of the inspiratory cycle (T2) reduced exhaled dose from the ventilation circuit by a factor of 4 compared with T1 delivery. Optimal lung deposition was achieved with the SL wye connector and T2 delivery, resulting in 45% and 60% lung deposition for optimal polydisperse (∼1.78 μm) and monodisperse (∼2.5 μm) particle sizes, respectively. CONCLUSIONS Optimization of selected factors and use of a new SL wye connector can substantially increase the lung delivery efficiency of medical aerosols to infants from current values of <1-10% to a range of 45-60%.