Positive pressure application of oxygen using Venturi nozzle Corovalve made on a 3D printer. A simple and inexpensive method applicable in emergency conditions on a mass scale

Acute hypoxemic respiratory failure (which occures also with severe course of COVID-19) requires oxygen therapy. The invasiveness and intensity of chosen therapy corresponds with patient's condition and technical means available. If a large number of patients with hypoxic failure suddenly occur, the available equipment and/or human capacity to provide effective oxygen therapy may be greatly strained. The goal of our experiment was to test functionality of a simple device equipped with a Venturi nozzle Corovalve which we designed and printed on a 3D printer. We incorporated the nozzle into a system assembled from parts commonly available in the Czech Republic. We put this device through a static test and a dynamic test performed on ourselves and measured its basic parameters. In our experiment during spontaneous ventilation the device was able to generate positive mean airway pressure. At higher flow rates, the system was able to maintain a slightly positive pressure even during the inspiration, so we can talk about a system that allows, under certain circumstances, spontaneous ventilation at continuous positive airway pressure. The most effective from setting tested was oxygen input of 15 L/min combined with PEEP valve set to 10-15 cm H₂O. Mean airway pressure ranged at 9-12 cm H₂O and oxygen concentration in the inspiration mixture was 40-42%. We therefore conclude that our nozzle Corovalve printed on a 3D printer can be used in a simple device allowing positive pressure oxygen application during spontaneous ventilation EPAP/CPAP. It is economical and easy to provide method and therefore of a rather interesting potential. With a sufficient number of 3D printed nozzles it could be deployed quickly and on a mass scale.

Keywords: COVID-19, oxygen therapy, CPAP, Venturi nozzle, 3D printing, Corovalve.