Meniscus formation during tracheal instillation of surfactant
| Autor: | Roger D. Kamm, F. F. Espinosa |
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| Předmět: |
Glycerol
medicine.medical_specialty Neonatal respiratory distress syndrome Physiology Meniscus (anatomy) Injections Route of administration Pulmonary surfactant Physiology (medical) medicine Surfactant replacement therapy Bolus injection Respiratory distress Viscosity business.industry Respiratory disease Water Capillary Resistance Pulmonary Surfactants medicine.disease Surgery Trachea medicine.anatomical_structure Anesthesia business Algorithms Gravitation |
| Zdroj: | Europe PubMed Central |
| Popis: | 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 (μ) and density (ρ), gravity ( g), injection rate (Q), orientation of the trachea with respect to gravity (θ), tracheal size ( D), surface tension (γ), and catheter size ( d). All quantities were varied, except gravity and catheter size. Experimental results show that a meniscus will form when NSt> 0.004Re2/3, where NStis Stokes number and Re is Reynolds number, NSt= μQ/ D4ρ gsinθ, a ratio of viscous effects to gravitational effects, and Re = ρQ D/ d2μ, 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. |
| Databáze: | OpenAIRE |
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