Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
Chemical and Petroleum Engineering Department, University of Pittsburgh, Pittsburgh, Pennsylvania.
Pediatr Pulmonol. 2019 Aug;54(8):1319-1325. doi: 10.1002/ppul.24326. Epub 2019 Apr 1.
Nasal cannulas are used to provide oxygen support for infants and have been considered as a means for delivering aerosols to the lungs. To measure mucociliary clearance in the lungs of infants with congenital heart defects, we delivered radiopharmaceutical aerosols via a nasal cannula. Here we report on the pulmonary and nasal deposition of these aerosols.
A total of 18 infants (median age = 26 days; quartiles = 11-74 days) performed clearance measurements soon before or after corrective cardiac surgery. The regional aerosol deposition was assessed using gamma camera imaging.
Cannula flow rate significantly affected pulmonary dosing. Flow rates useful for oxygen support were associated with low pulmonary deposition (2 L/min; mean, 4.5% of deposited dose; range, 2%-9%; n = 7) and high nasal deposition. Much lower cannula flow rates increased the pulmonary deposition (0.2 L/min; mean, 33.5% of deposited dose; range, 15%-51%; n = 5; P = 0.005 vs 2 L/min). The ratio of nose/lung dosing was approximately 26:1 at 2 L/min and 2:1 at 0.2 L/min. Bench studies demonstrated cannula output rates of 10.2 ± 1.7% (2 L/min) and 3.3 ± 0.4% (0.2 L/min) of the loaded nebulizer dose during a 2-minute delivery. Combining in vitro and in vivo results, we estimate that 0.46% of the loaded nebulizer dose reaches the lungs at 2 L/min vs 1.10% at 0.2 L/min during a 2-minute delivery.
With the delivery system used here, pulmonary aerosol delivery via nasal cannula was very inefficient at the flow rates required to provide oxygen support. Even at low flows, nasal deposition was substantial and local toxicity must be considered.
鼻导管用于为婴儿提供氧气支持，并被认为是将气雾剂输送到肺部的一种手段。为了测量患有先天性心脏缺陷的婴儿的黏液纤毛清除功能，我们通过鼻导管输送放射性药物气雾剂。在此，我们报告这些气雾剂在肺部和鼻腔中的沉积情况。
共有 18 名婴儿（中位数年龄=26 天；四分位数范围=11-74 天）在心脏矫正手术后不久进行了清除测量。使用伽马相机成像评估区域性气雾剂沉积。
导管流量显著影响肺部给药剂量。用于氧气支持的流量与肺部沉积率低（2 L/min；平均为沉积剂量的 4.5%；范围为 2%-9%；n=7）和鼻腔沉积率高相关。较低的导管流量显著增加了肺部沉积率（0.2 L/min；平均为沉积剂量的 33.5%；范围为 15%-51%；n=5；P=0.005 与 2 L/min 相比）。在 2 L/min 时，鼻子/肺部给药的比例约为 26:1，而在 0.2 L/min 时约为 2:1。台架研究表明，在 2 分钟的输送过程中，2 L/min 时的导管输出率为 10.2±1.7%（2 L/min），0.2 L/min 时为 3.3±0.4%。将体外和体内结果相结合，我们估计在 2 分钟的输送过程中，2 L/min 时，0.46%的负载雾化器剂量到达肺部，而 0.2 L/min 时为 1.10%。
使用此处使用的输送系统，在提供氧气支持所需的流速下，通过鼻导管输送肺部气雾剂非常低效。即使在低流速下，鼻腔沉积也很显著，必须考虑局部毒性。
