Some ventilator settings can double airway stress

Mechanical ventilation saves lives, but the airflow it produces inside an intubated airway can also shape conditions linked to complications during long-term support. In a recent study, SUNY Polytechnic Institute faculty Dr. Aarthi Sekaran (Assistant Professor of Mechanical Engineering) and Dr. Ahmed Abdelaal (Assistant Professor of Mechanical Engineering Technology) examined how two practical factors—endotracheal tube (ETT) cuff design and ventilator mode—change airflow behavior inside the human trachea.

Their paper, “Computational and Experimental Characterization of Flow in an Intubated Human Trachea”, recently published in a special issue of Fluids on respiratory flows, focuses on the region near the ETT cuff, where secondary issues such as infection can originate.

The team compared two cuff geometries commonly used in clinical devices, Taperguard-style and Microcuff-type, and evaluated them under two ventilation strategies: Pressure-Controlled Ventilation (PCV) and Assisted Volume-Controlled Ventilation (VCV).

To capture realistic, time-varying flow physics, Sekaran and Abdelaal combined 3D unsteady computational fluid dynamics (URANS CFD) with experimental validation, using flow measurements and visualization to confirm key behaviors. This blended approach allowed them to quantify changes in flow asymmetry, secondary flow structures, and wall shear stress, metrics that matter because they influence how strongly air “drags” along airway surfaces and how transport occurs near the cuff.

A central finding is that ventilator mode and cuff geometry interact: the Taperguard configuration under PCV produced substantially higher wall shear stress, reaching nearly double what was observed for the same cuff under VCV. In contrast, the Microcuff + VCV combination produced lower velocities and reduced shear, with peak levels around 80% of those seen in the Taperguard case.

Overall, the study provides a validated, engineering-based lens for understanding how device design and ventilation strategy can meaningfully reshape tracheal airflow, insights that can inform both future ETT design and clinical decision-making.