Bench Evaluation of Oxygen Delivery Using Portable Ventilators Paired With Portable Oxygen Concentrators

Background: Military transport of critically ill/injured patients requires judicious use of resources. Maintaining oxygen (O2) supplies for mechanically ventilated is crucial. O2 cylinders are difficult to transport and add the risk of fire in an aircraft. The proposed solution is the use of a portable oxygen concentrator (POC) to supply O2 for mechanical ventilation. As long as power is available, a POC can provide a continuous supply of O2. Evidence suggests that 3 L/min of O2 could manage 2/3 of the mechanically ventilated aeromedical transport patients. Methods: We evaluated two each of the AutoMedx SAVe II, Hamilton T1, Zoll 731,and one Ventec VOCSN portable ventilator over a range of settings paired with two Caire SAROS POCs. The VOCSN operates from an internal O2 concentrator using pulsed dose delivery equivalent to 6 L/min continuous flow O2. Each ventilator was attached to one chamber of a Michigan Instruments Training Test Lung (TTL). Output from the POC was bled-in to each ventilator via the mechanism provided. A Fleisch pneumotach was placed between the ventilator circuit and the TTL to measure delivered tidal volume (VT) and a fast response O2 analyzer (Oxigraf) sampled gas from the TTL to measure FIO2. Deadspace was added between the ventilator circuit and TTL for pulsed dose delivery. Ventilator parameters and FIO2 were continuously measured and recorded for later analysis. One-way ANOVA was used to determine statistically significant differences (P