Computational Fluidic Modeling of a Low‐Cost Fluidic Oscillator for Conversion of a CPAP Machine into an Emergency Use Mechanical Ventilator

Dillon, Tom; Ozturk, Caglar; Mendez, Keegan; Rosalia, Luca; Gollob, Samuel Dutra; Kempf, Katharina; Roche, Ellen Tunney

This paper presents the computational fluidic modeling of a fluidic oscillator for the conversion of continuous positive airway pressure (CPAP) machines into emergency pressure support mechanical ventilators by providing a periodic pressure output to patients. The design addresses potential ventilator shortages resulting from the ongoing COVID‐19 pandemic, or future pandemics by converting a positive pressure source into a mechanical ventilator with a part that is (i) inexpensive, (ii) easily manufactured without the need for specialized equipment, (iii) simple to assemble and maintain, (iv) does not require any electronics, and (v) has no moving components that could be prone to failure. A Computational Fluid Dynamics (CFD) model is used to assess flow characteristics of the system, and a prototype is developed and tested with a commercial benchtop respiratory stimulator. The simulations show clinically relevant periodic oscillation with outlet pressures in the range of 8‐20 cmH(2)O and end‐user‐tunable frequencies in the range of 3‐6 seconds (respiratory rate (RR) of 10‐20 breaths per minute). The prototype can respond to disrupted oscillations, an analogue for patient‐initiated breaths. The fluidic oscillator presented here functions at physiologically‐relevant pressures and frequencies, demonstrating potential as a low‐cost, readily deployable means for converting CPAP machines into emergency use ventilators. This article is protected by copyright. All rights reserved.