Individualized System for Augmenting Ventilator Efficacy (iSAVE): A Rapidly deployable system to expand ventilator capacity

Shriya Srinivasan; Khalil Ramadi; Franceso Vicario; Declan Gwynne; Alison Hayward; Robert Langer; Joseph Frassica; Rebecca Baron; Giovanni Traverso

Animal experiments were approved by the Committee on Animal Care at the Massachusetts Institute of Technology (MIT). The experiment was performed as part of a terminal procedure on a 70kg female swine (n=1). The iSAVE was connected to a veterinary anesthesia ventilator (Model 200IE, Hallowell EMC) delivering 2% isoflurane in oxygen. One inspiratory circuit was connected to the anesthesia machine delivering gas to the animal while the other inspiratory circuit was connected to an artificial linear test lung (IngMar Medical). Pressure and flow measurements were recorded on the inspiratory limb of the animal. A VetTrends Vital Signs Monitor was utilized to measure SpO2, ETCO2, RR, and other physiological parameters. 600mL of VT were equally distributed between the animal and test lung. A respiratory rate between 18-20/min was set on the ventilator. We carried out the same tests outlined in the benchtop testing protocol, modulating the parameters of the test lung, to validate the capabilities of the iSAVE to restore the system to baseline. Once the animal was euthanized, to acutely change the compliance of the pig's lung, we utilized an endoscope (PENTEX) to deliver 50mL of phosphate buffered saline (PBS, Sigma Aldrich) into the left and right bronchi. We then ventilated the animal, aiming to restore tidal volume to the baseline values prior to euthanasia. Approximately 10 minutes later, we delivered an additional 700mL of saline into the right and left bronchi. Ventilation was performed and the valves were titrated to achieve desired flow parameters.