Meniscus formation during tracheal instillation of surfactant
Meniscus formation during tracheal instillation of surfactant
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DOI：
10.1152/jappl.1998.85.1.266
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发表时间：
1998-07-01
影响因子：
3.3
通讯作者：
Kamm, RD
中科院分区：
文献类型：
--
作者：
Espinosa, FF;Kamm, RD
肺表面活性物质滴注治疗新生儿呼吸窘迫综合征的方法是分娩的一个重要属性，它可能决定治疗的总体疗效。先前的研究主要集中在大剂量的滴注速率上。这些发现表明，快速注射导致更均匀的分布，而缓慢输注相对于重力流入依赖性肺，导致不均匀沉积。这些结果表明，形成弯月面是有益的，由此可以进行更均匀的分散。本研究的目的是制定一个功能标准，半月板形成期间团注。体外实验用于检查表面活性物质滴注的临床设置。检查的物理变量为推注粘度（mu）和密度（rho）、重力（g）、注射速率（Q）、气管相对于重力的方向（θ）、气管尺寸（D）、表面张力（γ）和导管尺寸（d）。除重力和导管尺寸外，所有数量均不同。实验结果表明，当N-St > 0.004Re（1/2）时，弯月面形成，其中N-St为Stokes数，Re为雷诺数，N-St = μ Q/D（4）rhogsin θ，即粘性效应与重力效应之比，Re = rhoQD/d（2）μ，即惯性效应与粘性效应之比。快速注射、高粘度和相对于重力的小倾斜促进弯月面形成。这些结果可用于完善表面活性物质替代治疗的管理指南。
The method of surfactant instillation into the lungs for treatment of neonatal respiratory distress syndrome is an important attribute of delivery, and it may determine the overall efficacy of treatment. Previous studies primarily focused on the rate at which the bolus is instilled. These findings show that rapid injections lead to a more homogenous distribution, whereas slow infusions drain into the dependent lung with respect to gravity, resulting in a heterogeneous deposition. These results suggest that it is beneficial to form a meniscus, from which a more homogenous dispersal can proceed. The objective of the present study was to develop a functional criterion for meniscus formation during bolus injection. An in vitro experiment was used to examine the clinical setting of surfactant instillation. The physical variables examined were the bolus viscosity (mu) and density (rho), gravity (g), injection rate (Q), orientation of the trachea with respect to gravity (theta), tracheal size (D), surface tension (gamma), and catheter size (d). All quantities were varied, except gravity and catheter size. Experimental results show that a meniscus will form when N-St > 0.004Re(1/2), where N-St is Stokes number and Re is Reynolds number, N-St = mu Q/D(4)rho gsin theta, a ratio of viscous effects to gravitational effects, and Re = rho QD/d(2)mu, a ratio of inertial effects to viscous effects. Rapid injections, high viscosity, and small inclination with respect to gravity promote meniscus formation. These results can be used to refine the guidelines for administration of surfactant replacement therapy.