Computational fluid dynamics simulations of 3D printed ventilator splitters and restrictors for differential multi-patient ventilation

The global pandemic of novel coronavirus (SARS-CoV-2) has led to global shortages of ventilators and accessories. One solution to this problem is to split ventilators between multiple patients, which poses the difficulty of treating two patients with dissimilar ventilation needs. A proposed solution to this problem is the use of 3D-printed flow splitters and restrictors. There is little data available on the reliability of such devices and how the use of different 3D printing methods might affect their performance.

We performed flow resistance measurements on 30 different 3D-printed restrictor designs produced using a range of fused deposition modelling and stereolithography printers and materials, from consumer grade printers using polylactic acid filament to professional printers using surgical resin. We compared their performance to novel computational fluid dynamics models driven by empirical ventilator flow rate data. This indicates the ideal performance of a part that matches the computer model.

The 3D-printed restrictors varied considerably between printers and materials to a sufficient degree that would make them unsafe for clinical use without individual testing. This occurs because the interior surface of the restrictor is rough and has a reduced nominal average diameter when compared to the computer model. However, we have also shown that with careful calibration it is possible to tune the end-inspiratory (tidal) volume by titrating the inspiratory time on the ventilator.

The 3D-printed restrictors varied considerably between printers and materials to a sufficient degree that would make them unsafe for clinical use without individual testing. This occurs because the interior surface of the restrictor is rough and has a reduced nominal average diameter when compared to the computer model. However, we have also shown that with careful calibration it is possible to tune the end-inspiratory (tidal) volume by titrating the inspiratory time on the ventilator.

This BRIDGES record contains raw empirical data and computer modeling results, including instructions for how other users can use our simulation tools to predict the performance of their own 3D printed designs.

Open Access publication details:

Duke, D.J., Clarke, A.L., Stephens, A.L. et al. A computational fluid dynamics assessment of 3D printed ventilator splitters and restrictors for differential multi-patient ventilation. 3D Print Med 8, 2 (2022). https://doi.org/10.1186/s41205-021-00129-1

Received

11 May 2021

Accepted

18 November 2021

Published

05 January 2022

DOI

https://doi.org/10.1186/s41205-021-00129-1