OxVent: Design and evaluation of a rapidly-manufactured Covid-19 ventilator

Richard Beale, Jacqueline Beddoe Rosendo, Christos Bergeles, Anair Beverly, Luigi Camporota, Alfonso A. Castrejón-Pita, Douglas C. Crockett, John N. Cronin, Timothy Denison, Sebastian East, Chantal Edwardes, Andrew D. Farmery, Filiberto Fele, James Fisk, Carla V. Fuenteslópez, Michael Garstka, Paul Goulart, Clare Heaysman, Azad Hussain, Prashant Jha, Idris Kempf, Adhithya Senthil Kumar, Annika Möslein, Andrew C. J. Orr, Sebastien Ourselin, David Salisbury, Carlo Seneci, Robert Staruch, Harrison Steel, Mark Thompson, Minh C. Tran, Valentina Vitiello, Miguel Xochicale, Feibiao Zhou, Federico Formenti and Thomas Kirk

@article{Oxvent:2022,
  author = {Richard Beale and Jacqueline Beddoe Rosendo and Christos Bergeles and Anair Beverly and Luigi Camporota and Alfonso A. Castrejón-Pita and Douglas C. Crockett and John N. Cronin and Timothy Denison and Sebastian East and Chantal Edwardes and Andrew D. Farmery and Filiberto Fele and James Fisk and Carla V. Fuenteslópez and Michael Garstka and Paul Goulart and Clare Heaysman and Azad Hussain and Prashant Jha and Idris Kempf and Adhithya Senthil Kumar and Annika Möslein and Andrew C.J. Orr and Sebastien Ourselin and David Salisbury and Carlo Seneci and Robert Staruch and Harrison Steel and Mark Thompson and Minh C. Tran and Valentina Vitiello and Miguel Xochicale and Feibiao Zhou and Federico Formenti and Thomas Kirk},
  title = {OxVent: Design and evaluation of a rapidly-manufactured Covid-19 ventilator},
  journal = {eBioMedicine},
  year = {2022},
  pages = {103868},
  url = {https://www.sciencedirect.com/science/article/pii/S2352396422000524},
  doi = {10.1016/j.ebiom.2022.103868}
}

Summary Background The manufacturing of any standard mechanical ventilator cannot rapidly be upscaled to several thousand units per week, largely due to supply chain limitations. The aim of this study was to design, verify and perform a pre-clinical evaluation of a mechanical ventilator based on components not required for standard ventilators, and that met the specifications provided by the Medicines and Healthcare Products Regulatory Agency (MHRA) for rapidly-manufactured ventilator systems (RMVS). Methods The design utilises closed-loop negative feedback control, with real-time monitoring and alarms. Using a standard test lung, we determined the difference between delivered and target tidal volume (VT) at respiratory rates between 20 and 29 breaths per minute, and the ventilator's ability to deliver consistent VT during continuous operation for >14 days (RMVS specification). Additionally, four anaesthetised domestic pigs (3 male-1 female) were studied before and after lung injury to provide evidence of the ventilator's functionality, and ability to support spontaneous breathing. Findings Continuous operation lasted 23 days, when the greatest difference between delivered and target VT was 10% at inspiratory flow rates >825 mLs. In the pre-clinical evaluation, the VT difference was -1 (-90 to 88) mL (mean (LoA)), and positive end-expiratory pressure (PEEP) difference was -2 (-8 to 4) cmH2O. VT delivery being triggered by pressures below PEEP demonstrated spontaneous ventilation support. Interpretation The mechanical ventilator presented meets the MHRA therapy standards for RMVS and, being based on largely available components, can be manufactured at scale. Funding Work supported by WellcomeEPSRC Centre for Medical Engineering,King's Together Fund and Oxford University.