A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

Vaughan, TJ, et al. 2020. A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic. Journal of Open Hardware, 4(1): 3, pp. 1–8. DOI: https://doi.org/10.5334/joh.23

HARDWARE METAPAPER A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic Ted J. Vaughan*, Frank Kirrane†,‡, Kevin M. Moerman*,§, Tara Cahill†,‡, Anthony O’Regan†,‡ and Derek T. O’Keeffe*,†,‡

The COVID-19 pandemic is a public health emergency of unprecedented scale. The surge in clinical cases of patients with severe respiratory illness has overwhelmed the traditional capacity of healthcare systems worldwide. Continuous Positive Airway Pressure (CPAP) delivered through Non-Invasive Ventilation (NIV) has been shown to be useful in caring for patients with COVID-19. In particular patients with early stage milder acute hypoxemic respiratory failure can benefit from NIV CPAP therapy, though there is an acknowledged risk of COVID-19 aerosolization with traditional circuit use. Furthermore, given the surge in clinical care demand, there is an acute global shortage of ventilators, including NIV devices and therefore innovative methods are needed to increase NIV capacity and ameliorate infectious aerosolization. This paper outlines an emergency use modified dual NIV CPAP Circuit that uses a 3D printed splitter designed to work with traditional international NIV CPAP tubing standards and a 3D printed respiratory face mask knuckle to allow for distal expiratory breath exhalation through a viral filter rather than through an open to air proximal valve, which is the traditional NIV CPAP configuration. We expect that this work will increase global NIV CPAP capacity and ameliorate aerosolization of COVID-19 in patients undergoing therapy in an emergency scenario.

Keywords: COVID-19; NIV; 3D Printing; Ventilation; Aerosolization; Respiratory

Metadata Overview • Replication: No other builds known to the authors so • Project repository: https://github.com/3DNIV/3DNIV far. • Archived version DOI: http://doi.org/10.5281/zenodo.3818306 (1) Overview • Licenses: All hardware is licensed under the CERN- Introduction OHL v2 S (CERN Open Hardware Licence Version 2 Coronavirus disease 2019 (COVID-19) is an infectious – Strongly Reciprocal (see also: https://cern-ohl.web. disease caused by a newly discovered coronavirus: SARS- cern.ch/). All project documentation content is li- CoV-2. COVID-19 is an unprecedented global health emer- censed under CC-BY-4.0. The G-code is licensed under gency. In the first half of 2020, over 9 million humans the GNU Affero General Public License. have been infected with over 500,000 deaths (https:// • Target group: medical professionals and biomedical coronavirus.jhu.edu/map.html). The COVID-19 virus pri- engineers marily causes a respiratory infection and is mainly trans- • Skills required: 3D printing – easy; assembly of venti- mitted through aerosolized droplets (e.g. coughs, sneezes, lation circuit and tubing – relatively easy breathing) or contact with contaminated surfaces. About 1:6 people who contract COVID-19 become seriously ill and develop difficulty breathing, requiring hospitalisation * Biomechanics Research Centre (BioMec), Biomedical Engineering, (WHO, 2020). School of Engineering, National University of Ireland Galway, The initial stage of COVID-19 severe acute respiratory Galway, IE infection (SARI) is Type 1 respiratory failure (T1RF), which † School of Medicine, College of Medicine Nursing and Health Sciences, National University of Ireland Galway, Galway, IE is characterised by low blood oxygen levels (hypoxemia, ↓ PO ) with either normal (normocapnia, ↔ PCO ) ‡ Division of Medicine, Galway University Hospital, Galway, IE a 2 a 2 or low levels of blood carbon dioxide (hypocapnia, § Biomechatronics Group, The Media Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts, US ↓ PaCO2). In COVID-19, this T1RF occurs due to inad- Corresponding author: Derek T. O’Keeffe equate gas exchange by the respiratory system due to ([email protected]) lung parenchymal disease causing a diffusion problem for Art. 3, page 2 of 8 Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic oxygen entering the capillaries (WHO, 2020). T1RF usu- Figure 1B, see device A in Table 1) is used to deliver a ally requires respiratory support which includes methods fixed positive pressure of 10 cm H2O (FiO2 0.6) to patients such as High Flow Nasal Cannulae (HFNC) O2 therapy to through a face mask (e.g. Figure 1D, see device B in achieve PaO2 (8-10kPa), SpO2 >90%. Lack of a response Table 1), which is connected through 22mm corrugated to oxygen therapy requires escalation to machine based tubing (e.g. Figure 1C, see component C in Table 1). The Non-invasive Ventilation (NIV) and ultimately Invasive circuit contains an inspiratory viral filter (component D in Mechanical Ventilation (IMV) where required. However, Table 1) at the ventilator connection and an anti-asphyxi- one of the challenges of COVID-19 pandemic has been ation, knuckle vented valve at the tubing – face mask con- the global shortage of ventilators (Truog et al., 2020) and nection, which expires to the room. subsequent rationing of resources due to limited capacity NIV CPAP supplies a constant fixed positive pressure

(FDA, 2020). NIV CPAP has emerged as preferred form of airflow at 10 cm H2O (FiO2 0.6) to stent the airways open NIV support in the management of the hypoxaemic for in patients who are breathing spontaneously. It is impor- COVID-19 patients outside of ICU, with some data sug- tant to note that CPAP systems do not cycle, but instead gesting that it can result in the avoidance of IMV (McEnery provide a positive pressure throughout inspiration and et al., 2020). expiration respiratory phases. Patients must initiate A system-level diagram of a standard NIV CPAP circuit their own breaths and CPAP systems do not provide pres- that would typically be found in a hospital setting is shown sures above the level of the set CPAP level (NIH, 2020). in Figure 1A. A pressure-control ventilator machine (e.g. In March 2020, the US Food and Drug Administration

Figure 1: A system-level schematic of the standard NIV CPAP configuration (A), a standard NIV machine (B), a standard NIV 22mm tubing circuit (C), and a standard (22mm) NIV face mask with expiratory knuckle valve (D). Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Art. 3, page 3 of 8 Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

Table 1: Required standard/commercial devices and components.

ID Device/component # Product, manufacturer A Ventilator 1 Philips Respironics Trilogy 202, Koninklijke Philips N.V. B Face mask 2 BiTac MaxShield, Pulmodyne C Respirator tubing 1 BiTrac Circuit, Pulmodyne D Inspiratory filter 2 Servo Duo Guard, Maquet Getinge E Expiratory filter 2 VIROBAC II viral/bacterial filter, 20801, King Systems F Disinfectant 1 Actichlor Plus, Ecolab G Test lungs 2 Adult 190 (1 Liter) 6006832, Maquet Getinge

(FDA) recommended the use of CPAP for patients with IMV initiatives in that we identified that as well as IMV, COVID-19, cautioning the importance of continuous there is also a clinical need for, but a corresponding simi- patient vitals monitoring and the risk of virus aerosoliza- lar shortage of NIV CPAP devices. Therefore we focused tion (FDA, 2020). Similarly, in April 2020, NHS advocated our project efforts on doubling capacity of these respira- CPAP rather than HFNC as the preferred form of NIV sup- tory NIV machines through open source 3D printing of port in the management of the hypoxemic patient with an NIV splitter. In addition, the use of a traditional NIV COVID-19 (NIH, 2020). However, the America Association CPAP device circuit involves the use of a mask mounted of Anaesthesiologists have highlighted the potential risk expiratory valve which vents to the surrounding room, of increased infectious transmission using traditional NIV thereby presenting an infection control risk. Therefore we systems, since they have an anti-asphyxiation valve on the designed an open source 3D printed solution to overcome face mask that is open to room air, to allow the patient this limitation, hence increasing CPAP utility in COVID-19. to expire against CPAP (ASA, 2020). Therefore, patients with COVID-19 requiring NIV should ideally be managed Overall implementation and design in a negative pressure room, or be cohorted together to The modified Dual NIV CPAP circuit prevent infectious transmission. In addition, other meth- A system-level diagram of the modified Dual NIV CPAP cir- ods use NIV hoods or modifying standard NIV circuits to cuit is shown below in Figure 2. This circuit introduces include a filter at the exhalation port or vent (McEnery et two novel components: 1) a single 3D printed T-piece al., 2020) to prevent transmission. There is a global short- splitter with dual inspiratory viral filters at the ventilator age of ventilators, including NIV devices, and therefore end, and 2) a modified 3D printed non-vented knuckle innovative methods are needed to increase NIV capacity at the tubing – face mask interface. Instead of having an and ameliorate infectious aerosolization. anti-asphyxiation valve, the knuckle connects to the tub- This work outlines the development of an innovative ing through an expiratory viral filter to prevent harmful Dual NIV CPAP circuit using 3D printing technology that aerosolised particles being transmitted to the outer envi- (i) increases CPAP capacity by reconfiguring to a dual ronment. circuit configuration and (ii) prevents infectious viral We proposed to use our open source 3D printed split- aerosolization of COVID-19 during operation through a ter and respiratory knuckle in any globalised standard NIV modified exhalation port. This approach may be required CPAP circuit, thereby allowing maximum impact of our when regular medical supply chains fail or in under proposal. Currently only the 3D printed components are resourced healthcare settings. Please note that this circuit designed and provided open source. Combined with the design should only be used in an extreme emergency sce- commercial/standard (non-open source) clinical hardware nario when you cannot source regular medical supplies they provide a rapid solution to increase capacity in the and used under registered clinician control with frequent emergency situation that is the COVID-19 pandemic. In patient monitoring. The described bespoke design was principle open source ventilator alternatives can be pro- used in patient care at University Hospital Galway, Ireland. posed. However, what is proposed here, is a much more There has been significant open source innovation rapid solution, and requires a minimal amount of clinical during the COVID-19 pandemic, in particular to address validation of non-standard components. the global shortage of vital respiratory equipment (e.g. Invasive Mechanical Ventilators – IMV) using 3D printed Computer Aided Design (CAD) and 3D printing components. Most of these initiatives have attempted to The two novel components were designed using the open create an IMV device either de novo or by adapting exist- source Computer Aided Design (CAD) software FreeCAD ing respiratory equipment (e.g. BiPAP) to produce an (version 0.19, revision 20802, https://www.freecadweb. open source IMV. Pearce (2020) has done a comprehen- org/). Both parts are 3D printed from Polylactic Acid sive review of these efforts and highlighted the inherent (PLA) with an Ultimaker S5 (Ultimaker BV, The Nether- humanitarian advantage of an open source collaborative lands) using an extrusion-based layer-by-layer process at approach during a global public health emergency. Our a resolution of 200 micron and 100% infill to prevent air research work is different from contemporary open source leaks (note however that the ventilator employed does Art. 3, page 4 of 8 Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

Figure 2: A system-level schematic of the proposed modified Dual NIV CPAP. automatically compensate to keep the required pressure support regions. These manually defined print support if minor leaks occur i.e. by increasing its output volume). features were used to avoid the Ultimaker 3D printing The Cura Ultimaker Projects and G-Code files have also software from proposing a sub-optimal amount of sup- been made available in the project repository. port material in these regions, and should be removed PLA is a biodegradable thermoplastic material com- after 3D printing is completed. monly used in medical products (e.g. sutures (Madhavan Nampoothiri et al., 2010; Ulery et al., 2011)). While PLA is The 3D Printed non-vented mask-tubing connector one of the most widely-used filament materials for desk- knuckle top 3D printing, it should be noted that the final parts will The knuckle valve component is highlighted in Figure 4 vary across printing platforms depending on the constitu- and was designed to fit the 22mm circuit tubing to the tive PLA formulation, the addition of dyes to filaments, 32mm swivel port on the face mask. This modified design and/or the processing parameters used during the print- replaces the standard version that typically includes an ing process itself (e.g. temperature, feed rate). In this case, anti-asphyxiation valve that has the potential to expire we used the Ultimaker Tough PLA 2.85 mm black filament harmful viral particles to the room. Instead, this modified (see also the filament data-sheet), which was the recom- respiratory knuckle is a closed section that connects to mended filament for the Ultimaker S5 printer. While PLA the 22mm circuit tubing via a virus filter (component E in is biodegradable, this only takes place in the presence of Table 1) prior to expiration, thereby reducing the risk of water, with the process taking well over 2 years. PLA will viral aerosolization being released during operation. remain in-tact for very long periods when stored in a cool, dry place. (2) Quality control Safety The 3D printed T-Piece splitter To facilitate the emergency use of the bespoke design The T-piece splitter (Male-Male-Female) design is high- & 3D printed components to clinical use, the Galway lighted in Figure 3A. The part was designed to be com- University Hospital Medical Device Equipment Manage- patible with the standard 22mm breathing circuit tubing. ment Policy (Ref EF-SD-0052, Nov 2019), which is based This female port of the T-piece attaches directly to the on national Health Service Executive (HSE) policy (HSE, ventilator outflow port and splits the airflow into two 2020), was consulted, particularly the sections on the channels. Standard respirator tubing is used to create the modification of medical devices. A risk assessment was two limbs of the dual circuit, which is connected to the carried out to ensure the safety of the innovative circuit male ports of the T-piece splitter via two separate inspira- proposal, with particular consideration to robustness, dis- tory viral filters (component D in Table 1) to protect the infection, design dimensions, leak appraisal and evalua- patient against potential harmful particles originating tion of legal and ethical considerations during emergency from the ventilator end. use. The 3D printed components were disinfected by The CAD design (Figure 3A) includes two thin features, soaking in chlorine-based disinfectant (F in Table 1) for which are also labelled in the technical drawing, which 2 hours at 1000ppm using 1 × 1.7g tablet in 1 Litre of are not part of the final design but are “enforced” print water. These components underwent manual assessment Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Art. 3, page 5 of 8 Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

Figure 3: The novel T-piece component. A CAD file view (A), part of the technical drawing showing characteristic dimensions (B), the PLA 3D printed T-Piece (C), and the T-Piece connected to a NIV machine and tubing (D).

for robustness and visual checks carried out for unwanted delivered remains at 10 cm H2O in normal circumstances. deformation or material damage post-disinfection. This was a motivating factor in splitting the NIV CPAP circuit as it was hypothesized that the ventilator would auto-

General testing matically regulate the flow, maintaining it at 10 cm H2O, The Dual NIV CPAP Circuit was tested using a standard and facilitating delivery to both test lungs. Following the NIV machine (device A in Table 1) in CPAP configuration above testing, developers manually verified the function to ensure it could deliver 10 cm H2O to two 1L test lungs and ease of breathing with the NIV CPAP circuit (featuring (device G in Table 1) (see Figure 5), for a duration of at both the splitter and the filtered expiratory valve), by sim- least 5 minutes. The 1L test lungs had a compliance of 16 ply wearing the mask and breathing through the system mL/cm H2O and a resistance of 20 cm H2O/L/s. Based on normally. this it was established that the dual NIV CPAP circuit main- Further to the above functional testing, the University tained a pressure of 10 cm H2O with both lungs inflated Hospital Galway Ireland approved the use of our design, for the duration of the testing time-frame. and we can report the system was successfully deployed in It may be important to note that this would be a stand- patient care during the COVID-19 pandemic. ard test used to verify the operation of a single arm NIV CPAP circuit in a hospital setting. Under normal operation, (3) Application NIV CPAP is typically designed to accommodate a certain Use case(s) amount of leakage in the circuit, in particular around the The modified Dual NIV CPAP Circuit is intended for use face mask. In particular, NIV CPAP automatically regulates in emergency situations only, where clinical demand for the air flow in the circuit to ensure that pressure being NIV CPAP machines exceeds hospital capacity. The modi- Art. 3, page 6 of 8 Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

Figure 4: The novel knuckle component. A CAD file view (A), part of the technical drawing showing characteristic dimensions (B), the PLA 3D printed knuckle (C), and the knuckle connected to a face mask and tubing (D). fied respiratory knuckle used at the distal end may also • The CAD vendor-neutral Initial Graphics Exchange be used on single circuit devices to reduce the risk of viral Specification (IGES) format (.IGES) aerosol being released during general operation of NIV • STL (stereolithography) files (.STL) CPAP. • 3D Manufacturing Format files (.3mf)

Reuse potential and adaptability In addition detailed technical drawings have been pro- The project repository (found on GitHub https://github. vided. com/3DNIV/3DNIV), and the archived version (Vaughan The proposed T-piece and knuckle components et al., 2020)), contain the CAD source files, G-CODE, and are here 3D printed in PLA using an Ultimaker S5 documentation needed for this project. Users may reuse (Ultimaker BV, The Netherlands), and with settings and adapt these files, as outlined in the open source (200 micron layers, 100% infill) to ensure an air-tight licenses used. The source CAD files are for the open source material is obtained. Others may wish to manufacture software FreeCAD (available through https://www.freec- these parts using different 3D printers and different adweb.org/). To maximise the potential for others to use materials (such as ABS). Furthermore, the designs can and build upon this work, the project repository contains be altered to suit available materials and manufacturing the following CAD files: methods. The documentation is available at the GitHub project repository and contains easy to follow assembly • The FreeCAD source files (.FCStd) which can be re- instructions. The GitHub repository includes an issue used, altered by others. tracker where issues, comments, questions, and feature Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Art. 3, page 7 of 8 Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

Dual NIV CPAP circuit is compatible with a wide range of similar equipment/hardware models. Furthermore, since the CAD source files have been provided the parts can easily be adjusted to fit the dimensions of other hardware components used.

Hardware documentation and files location The project repository is where the active development for this project takes place and where the community may interact with the content and the developers. The content of the repository, for the first version of the hardware proposed, has also been archived on ZENODO (Vaughan et al., 2020).

Project repository: https://github.com/3DNIV/3DNIV Hardware licence: CERN Open Hardware Licence Version 2 – Strongly Reciprocal (see also: https://cern- ohl.web.cern.ch/). Content licence: CC-BY-4.0 Persistent identifier for archived release: 10.5281/ zenodo.3818306 Archived release tag: v1.0 Date published: 09/05/2020

(5) Discussion Figure 5: Testing of the T-piece splitter component with a Due to the COVID-19 pandemic and potential emer- NIV CPAP machine and test lung setup. gency clinical need, we have developed and described a potential methodology for doubling NIV capacity and preventing viral aerosolization using standard and requests may be posted. In addition, basic contribution bespoke 3D printed components. Our innovative dual guidelines are provided for those interested in contrib- circuit design from a single NIV CPAP machine uses a uting to the project. custom made splitter and incorporates a novel bespoke respiratory knuckle using 3D printed components, (4) Build Details which we have made available through open access Availability of materials and methods repositories. We have carried out a comprehensive The modified components can be 3D printed using PLA. local risk assessment which has confirmed that the 3D Full instructions and an equipment list can be found in printed components are safe and suitable for use in an the documentation in the project repository. emergency. Here we present the use of simple 3D printed com- Ease of build ponents to double the capacity of a NIV CPAP circuit in The modified Dual NIV CPAP circuit was designed to emergency situations. The limiting factor is the actual be easily assembled, with minimal post-processing of NIV CPAP machines’ capability to provide the clinician

3D printed components required. Circuit construction selected pressure (e.g. 10 cm/H2O). Here we verified that involves only passive assembly, with components and tub- that our NIV CPAP machine, through the use of the test ing simply press-fit to one another through compatible lungs and user assessment, can compensate sufficiently Male/Female ports. to deliver the set-pressure to an additional face mask by monitoring the NIV CPAP machine pressure display. Dependencies Splitting the NIV CPAP machine output to more than The modified Dual NIV CPAP circuit (and testing) relies on the two facemask circuits that we have done, could be a number of commercially available (and routine) medi- explored by others but would be NIV CPAP machine cal components, which are listed in Table 1. First of all dependent. a pressure-control ventilator is required, here a Philips Respironics Trilogy 202® ventilator (A in Table 1). The Acknowledgements circuit uses an NIV face mask (B in Table 1) connected Construction and testing of the novel NIV circuit was com- through a 32mm swivel port, and standard respirator tub- pleted at Galway University Hospital Ireland in conjunc- ing (C in Table 1) that uses universal 22mm ports/con- tion with input from the Biomedical Engineering depart- nections. The modified circuit uses viral filters connected ment at the National University of Ireland Galway. through 22mm ports at inspiratory (D in Table 1) and expiratory (E in Table 1) ends. Given the routine compo- Competing Interests nents employed it is therefore expected that the modified The authors have no competing interests to declare. Art. 3, page 8 of 8 Vaughan et al: A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

References england.nhs.uk/coronavirus/wp-content/uploads/ ASA. American Society of Anaesthesiologists (ASA) COVID- sites/52/2020/03/specialty-guide-NIV-respiratory- 19 resources for anesthesiologists, 2020. URL support-and-coronavirus-v3.pdf. https://www.asahq.org/about-asa/governance- Pearce, J. M. A review of open source ventilators for and-committees/asa-committees/committee-on- COVID-19 and future pandemics. F1000Research, occupational-health/coronavirus. Library Catalog: 9: 218, Apr. 2020. ISSN 2046-1402. URL https:// www.asahq.org. f1000research.com/articles/9-218/v2. DOI: https:// FDA. Ventilator Supply Mitigation Strategies: Letter doi.org/10.12688/f1000research.22942.2 to Health Care Providers. Letters to Health Care Truog, R. D., Mitchell, C., and Daley, G. Q. The Tough- Providers, Mar. 2020. URL https://www.fda.gov/ est Triage Allocating Ventilators in a Pandemic. New medical-devices/letters-health-care-providers/ven- England Journal of Medicine, 0(0): null, Mar. 2020. tilator-supply-mitigation-strategies-letter-health- ISSN 0028-4793. Publisher: Massachusetts Medi- care-providers. Publisher: FDA. cal Society_eprint. DOI: https://doi.org/10.1056/ HSE. HSE Medical Devices Equipment Management Policy NEJMp2005689 and Standard, 2020. URL https://www.hse.ie/eng/ Ulery, B. D., Nair, L. S., and Laurencin, C. T. Biomedi- services/publications/corporate/medicaldevicese- cal Applications of Biodegradable Polymers. Jour- quiptment.html. Library Catalog: www.hse.ie. nal of polymer science. Part B, Polymer physics, Madhavan Nampoothiri, K., Nair, N. R., and John, 49(12): 832–864, June 2011. ISSN 0887-6266. R. P. An overview of the recent developments in URL https://www.ncbi.nlm.nih.gov/pmc/articles/ polylactide (PLA) research. Bioresource Technology, PMC3136871/. DOI: https://doi.org/10.1002/ 101(22): 8493–8501, Nov. 2010. ISSN 0960-8524. polb.22259 URL http://www.sciencedirect.com/science/arti- Vaughan, T., Kirrane, F., Moerman, K. M., Cahill, T., cle/pii/S0960852410009508. DOI: https://doi. O’Regan, A., and O’Keeffe, D. 3DNIV/3DNIV: org/10.1016/j.biortech.2010.05.092 Development of a Dual Non-Invasive Ventilator McEnery, T., Gough, C., and Costello, R. W. COVID-19: Continuous Positive Airway Pressure (CPAP) Circuit Respiratory support outside the intensive care unit. for Emergency Use in the COVID-19 Pandemic using The Lancet Respiratory Medicine, 0(0), Apr. 2020. 3D Printed Components, May 2020. Project reposi- ISSN 2213-2600, 2213-2619. URL https://www. tory: https://github.com/3DNIV/3DNIV License: thelancet.com/journals/lanres/article/PIIS2213- CERN Open Hardware Licence Version 2 – Strongly 2600(20)30176-4/abstract. Publisher: Elsevier. DOI: Reciprocal. DOI: https://doi.org/10.5281/zenodo. https://doi.org/10.1016/S2213-2600(20)30176-4. 3818306 NIH. Guidance for the role and use of non-invasive res- WHO. Coronavirus, 2020. URL https://www.who.int/ piratory support in adult patients with coronavirus emergencies/diseases/novel-coronavirus-2019. (confirmed or suspected), 2020. URL https://www. Library Catalog: www.who.int.

How to cite this article: Vaughan, TJ, Kirrane, F, Moerman, KM, Cahill, T, O’Regan, A and O’Keeffe, DT. 2020. A Novel Dual Non- Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic. Journal of Open Hardware, 4(1): 3, pp. 1–8. DOI: https://doi.org/10.5334/joh.23

Published: 04 September 2020

Copyright: © 2020 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.

Journal of Open Hardware is a peer-reviewed open access journal published by Ubiquity OPEN ACCESS Press.