经鼻导管在无创通气时高效产生和输送气溶胶。
High-efficiency generation and delivery of aerosols through nasal cannula during noninvasive ventilation.
机构信息
1 Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, VA 23284.
出版信息
J Aerosol Med Pulm Drug Deliv. 2013 Oct;26(5):266-79. doi: 10.1089/jamp.2012.1006. Epub 2012 Dec 28.
BACKGROUND
Previous studies have demonstrated the delivery of pharmaceutical aerosols through nasal cannula and the feasibility of enhanced condensational growth (ECG) with a nasal interface. The objectives of this study were to develop a device for generating submicrometer aerosols with minimal depositional loss in the formation process and to improve aerosol delivery efficiencies through nasal cannulas.
METHODS
A combination of in vitro experiments and computational fluid dynamics (CFD) simulations that used the strengths of each method was applied. Aerosols were formed using a conventional mesh nebulizer, mixed with ventilation gas, and heated to produce submicrometer sizes. An improved version of the mixer and heater unit was developed based on CFD simulations, and performance was verified with experiments. Aerosol delivery was considered through a commercial large-bore adult cannula, a divided (D) design for use with ECG, and a divided and streamlined (DS) design.
RESULTS
The improved mixer design reduced the total deposition fraction (DF) of drug within the mixer by a factor of 3 compared with an initial version, had a total DF of approximately 10%, and produced submicrometer aerosols at flow rates of 10 and 15 L/min. Compared with the commercial and D designs for submicrometer aerosols, the DS cannula reduced depositional losses by a factor of 2-3 and retained only approximately 5% or less of the nebulized dose at all flow rates considered. For conventional-sized aerosols (3.9 and 4.7 μm), the DS device provided delivery efficiencies of approximately 80% and above at flow rates of 2-15 L/min.
CONCLUSIONS
Submicrometer aerosols can be formed using a conventional mesh nebulizer and delivered through a nasal cannula with total delivery efficiencies of 80-90%. Streamlining the nasal cannula significantly improved the delivery efficiency of both submicrometer and micrometer aerosols; however, use of submicrometer particles with ECG delivery resulted in overall lower depositional losses.
背景
先前的研究已经证明了通过鼻插管输送药物气溶胶以及使用鼻接口实现增强凝结生长（ECG）的可行性。本研究的目的是开发一种在形成过程中最小化沉积损失的生成亚微米气溶胶的装置，并通过鼻插管提高气溶胶输送效率。
方法
应用了体外实验和计算流体动力学（CFD）模拟的组合，利用了每种方法的优势。使用常规网孔式雾化器形成气溶胶，与通风气体混合，并加热以产生亚微米尺寸。基于 CFD 模拟开发了改进的混合器和加热器单元，并通过实验验证了性能。考虑通过商业大口径成人插管、用于 ECG 的分体式（D）设计和分体式流线型（DS）设计进行气溶胶输送。
结果
与初始版本相比，改进的混合器设计将药物在混合器中的总沉积分数（DF）降低了 3 倍，总 DF 约为 10%，并在 10 和 15 L/min 的流速下产生亚微米气溶胶。与用于亚微米气溶胶的商业和 D 设计相比，DS 插管将沉积损失降低了 2-3 倍，并在考虑的所有流速下保留了不到 5%或更少的雾化剂量。对于常规尺寸的气溶胶（3.9 和 4.7 μm），DS 装置在 2-15 L/min 的流速下提供了约 80%及以上的输送效率。
结论
可以使用常规网孔式雾化器形成亚微米气溶胶，并通过总输送效率为 80-90%的鼻插管输送。鼻插管的流线型设计显著提高了亚微米和微米气溶胶的输送效率；然而，使用 ECG 输送的亚微米颗粒会导致总体沉积损失降低。
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