Modeling and simulation of the human respiratory system; Part 1: Computational fluid dynamics simulations and whole lung models

To address the challenges related to lung modeling and creation of digital twins of the human respiratory system, the first Lung Modeling Congress was held in November 2023. This article, together with a second article in an upcoming issue of Inhalation, presents a summary of the current state-of-the-art and future challenges in various research areas and was written by the major experts who attended the Congress.

Computational fluid dynamics (CFD) simulations of the upper respiratory system can be of great value. They can contribute to the design of successful nasal surgeries and facilitate understanding of the impact of lung lobectomies. They can also provide insights for inhaler designers regarding why drug delivery performance is affected by inhaler resistance, orientation of an inhaler and patient posture during administration, and thereby can help improve patient compliance with new pharmaceutical products. Lastly, high-fidelity CFD simulations can help in unraveling details about air flow behavior in distal airways, the importance of the persistence of secondary flows and time fluctuations in the deep airways for aerosol deposition and gas exchange, and how these phenomena can be affected by interstitial and obstructive pathologies modifying air duct elasticity and morphology. Whole lung models aim to predict the spatio-temporal distribution of inhaled aerosols in the whole lungs. In contrast to most CFD simulations, this includes the full airway tree down to the smallest airways, on average to the 16th generation and the respiratory zone/alveolar region. Typically, the final aerosol deposition pattern is the primary parameter of interest because it determines the local effective dose and therefore its therapeutic or harmful effects.

Read Part 2–Modeling and simulation of the human respiratory system; Part 2: Inhaler design, in vitro experiments and imaging