Respiratory Therapy, Neonatal Service Line.
Respir Care. 2014 Mar;59(3):340-4. doi: 10.4187/respcare.01904. Epub 2013 Aug 6.
Nasal CPAP is widely used in neonatal ICUs. Aerosolized medications such as inhaled steroids and β agonists are commonly administered in-line through nasal CPAP, especially to infants with bronchopulmonary dysplasia. We hypothesized that aerosol delivery to the lungs via variable-flow nasal CPAP in an in vitro model would be unreliable, and that the delivery would depend on the position of the aerosol generator within the nasal CPAP circuit.
We used a system that employed a test lung placed in a plastic jar and subjected to negative pressure. Simulated inspiration effort was measured with a heated-wire anemometer. We used technetium-99m-labeled diethylene triamine penta-acetic acid as our aerosol. The nebulizer was placed either close to the humidifier or close to the nasal prongs in the circuit, and patient effort was simulated with a minute ventilation of 0.4 L/min.
Relative aerosol delivery to the infant test lung with the nebulizer close to the humidifier was extremely low (0.3 ± 0.4%), whereas placing the nebulizer close to the nasal prongs resulted in significantly (P < .001) improved delivery (21 ± 11%). Major areas of aerosol deposition with the nebulizer close to the humidifier versus close to the nasal prongs were: nebulizer (10 ± 4% vs 33 ± 13%, P < .001), exhalation limb (9 ± 17% vs 26 ± 30%, P = .23), and generator tubing (21 ± 11% vs 19 ± 20%, P = .86). Placing the nebulizer close to the humidifier resulted in 59 ± 8% of the aerosol being deposited in the inhalation tubing along the heater wire.
Isotope delivery from an aerosol generator placed near the humidifier on variable-flow nasal CPAP was negligible in this in vitro setup; however, such delivery was significantly improved by locating the aerosol generator closer to the nasal CPAP interface.
经鼻持续气道正压通气（CPAP）在新生儿重症监护病房（NICU）中被广泛应用。在 NICU 中，通常通过经鼻 CPAP 在线给予吸入性药物，如吸入性皮质类固醇和β受体激动剂，尤其是用于患有支气管肺发育不良的婴儿。我们假设，在体外模型中，通过变流量经鼻 CPAP 将气雾剂输送到肺部的效果不可靠，而且输送效果取决于气雾剂发生器在经鼻 CPAP 回路中的位置。
我们使用了一种系统，该系统使用放置在塑料罐中并承受负压的测试肺。使用热线风速仪测量模拟吸气努力。我们使用放射性核素 99m 标记的二乙三胺五乙酸作为气雾剂。雾化器放置在加湿器附近或在回路中的鼻塞尖端附近，用每分钟 0.4 L 的分钟通气量模拟患者的努力。
与将雾化器靠近加湿器相比，将雾化器靠近鼻塞尖端放置时，婴儿测试肺的相对气雾剂输送量极低（0.3±0.4%），而将雾化器靠近鼻塞尖端放置时，输送量显著提高（P<0.001，21±11%）。与将雾化器靠近加湿器相比，将雾化器靠近鼻塞尖端放置时，气雾剂的主要沉积区域为：雾化器（10±4%比 33±13%，P<0.001）、呼气支（9±17%比 26±30%，P=0.23）和发生器管（21±11%比 19±20%，P=0.86）。将雾化器靠近加湿器放置时，有 59±8%的气雾剂沉积在沿着热线的吸入管中。
在这种体外设置中，将雾化器放置在靠近加湿器的位置时，从雾化器输送的示踪剂可以忽略不计；然而，通过将气溶胶发生器定位更靠近经鼻 CPAP 接口，可以显著提高输送效果。
