132 Development of a porcine model for the testing of the RapidVent emergency ventilator for the treatment of COVID-19 infection

The COVID-19 pandemic brought forward the need for rapidly producible and affordable ventilators due to widespread incidence of respiratory distress, which led to a desperate need for mechanical ventilators. To meet this need, a team was assembled to design a gas-powered emergency ventilator, named RapidVent. The interdisciplinary team designing RapidVent based the design off commercially available ventilators and used additive manufacturing to rapidly produce a prototype that was tested for over 2 million cycles (https://rapidvent.dev.engr.illinois.edu). Once the prototype was designed and its functions were confirmed, it was ready to be tested in animals. The pig (Sus scrofa) is well studied for biomedical instrument testing, but ventilator testing using a live, healthy animal has not been explored. A pilot study was performed to determine if RapidVent would ventilate a live subject and to see if adding weight to the ribs of a laterally recumbent animal could simulate labored breathing while connected to a patient that is breathing on their own. Yorkshire cross-bred pigs weighing ~131 kg were used in this study. The animals were sedated using a cocktail of 1.4 mg mL⁻¹ telazol, 0.441 mg mL⁻¹ atropine, 2.94 mg mL⁻¹ xylazine, and 5.88 mg mL⁻¹ ketamine (TARK) was administered intramuscularly at 0.1 mL kg⁻¹ of bodyweight. The ventilators were connected directly to the endotracheal tube. During the trial, the respiration and heart rate of the pig were constantly monitored. Rectal body temperature, heart rate, and respiration rate were recorded every 15 minutes for the duration of the trial. End tidal CO₂ was monitored with a portable electronic capnograph. For the duration of the trial, the pig was placed in lateral recumbency. The pig was turned over on its other side after 2 hours. Rectal temperature, appetite, and behaviour were monitored for 2 weeks following the ventilator trial. The mean heart rate was 108 beats per minute, the blood oxygen saturation (SpO₂), had a mean of 89.9%, and the mean body temperature was 101.3°F. Body temperature negatively correlated with time (r value = −0.92). There was no correlation between the SpO₂ of the pig and any of the other variables. There were no effects of the animal’s spontaneous breathing on any of the measured parameters. The RapidVent Emergency Ventilator withstands continuous use over an extended period and allows for the control of physiological parameters of the pig. Weight added to the ribs of the animal may be a viable model for labored breathing with more evidence.