Pulsed Dosed Delivery of Oxygen in Mechanically Ventilated Pigs With Acute Lung Injury

Abstract

Abstract : Acute lung injury (ALI) is a common condition that leads to respiratory impairment with patients, specifically regarding oxygenation. We have previously demonstrated in a mechanical model that using a portable oxygen concentrator (POC) with pulsed dose delivery of oxygen is an alternative to continuous flow to conserve oxygen and prolong battery life, while still maintaining adequate oxygen delivery. We hypothesize that using a modified POC and pulsed dose oxygen delivery can provide similar oxygenation in an animal model compared to continuous flow oxygen delivered to a reservoir bag. In a crossover study, we induced ALI in 15 locally bred pigs using an oleic acid model. We ventilated the pigs with equipment that is used by Critical Care Air Transport Teams of the United States Air Force. Each animal served as its own control as we compared oxygen delivery using a POC in both continuous flow with a reservoir bag and pulsed dose. We performed this in both volume control and pressure control mechanical ventilation. There was no statistical difference regarding any of the ventilator variables including respiratory rate and tidal volume in the ventilator modes or in oxygen delivery methods, with the exception of mean airway pressures (4.1 +/- 0.9 cm H2O vs. 6.5 +/- 2.7 cm H2O, p=0.03). There was no between groups for the pulsed dose delivery and continuous flow. In volume control, pulsed dose oxygen delivery demonstrated a significant increase in the P:F ratio (168.8 +/- 96.1 vs. 91.7 +/- 65.4, p=0.002) compared with continuous flow. However, this was not seen in pressure control ventilation (89.0 +/- 74.5 vs. 79.1 +/- 65.4, p=0.67). We were able to demonstrate that oxygen delivery using a POC in mechanically ventilated pigs with ALI is feasible.