Numerical Investigation of Aerosol Deposition at the Eyes When Using a Hood Inhaler for Infants—a 3D Simulation

Abstract

A numerical investigation of a hood inhaler is presented, aiming at the assessment of the amount of aerosol that reaches the eyes of the patient when administering medications with such a device. Using a hood for aerosol therapy for infants was already found to be effective and friendly to handle over the commonly used face mask. Using a hood device may adversely deliver unwanted medications to the eyes of the infant. The current study addresses the extent of aerosol deposition at the infant's eye zone. We describe the development and utilization of a numerical simulation for studying the transport and fate of the aerosol particles within a 3D realistic representation of the hood and the infant's head, with a focus on the eye zone. The governing equations were solved using the commercial software, FLUENT 6.1, which is based on the finite volume method. The computational domain was created using the GAMBIT package. The computational geometry was built separately for each configuration of the hood and the infant. It is shown that under optimal working conditions (i.e., when the infant's head is aligned to the funnel) the percentage of aerosol reaching the eye zone is 0.48%. However, when the funnel is tilted toward the eyes the amount of aerosol reaching the eyes zone is predicted to be 4.7%. In general, the results obtained in this study are in good agreement with available in vitro data. It can be concluded that using the hood for aerosol therapy results in minimal deposition at the infant's eye area.

Hood Nebulization: Effects of Head Direction and Breathing Mode on Particle Inhalability and Deposition in a 7-Month-Old Infant Model

“…(5) Similar results were also reported by Bar-Yishay et al (6) in their pilot study that compared lung function response to bronchodilator nebulization via hood and mask. Numerical modeling and simulation of hood treatment include reports by Amirav et al (7) and Shakked et al, (8,9) who studied related issues such as the carrier airflow, lung delivery efficiency, and eye depositions. Such quantitative evaluations of different scenarios have the potential to improve current practices of hood treatment and to develop new inhalation therapy protocols for infant patients.…”

Reconciling Oxygen and Aerosol Delivery with a Hood on In Vitro Infant and Paediatric Models

“…A disproportionately large facemask can be an irritation to the infant, while only a few facemask sizes are available for various face sizes in infants. In addition, the leaked flow from the gaps between the mask and face can carry the aerosol toward the eyes of the infant through the noise, thus easily irritating the eyes; the external flow at 8 L/min carries the aerosol toward the eyes of an infant patient [25,26].…”