Pulsed dosed delivery of oxygen in mechanically ventilated pigs with acute lung injury.

BACKGROUND: Acute lung injury (ALI) is a condition that leads to impaired oxygen delivery. We demonstrated previously that using a portable oxygen concentrator (POC) with pulsed dose delivery of oxygen is an alternative option to conserve oxygen while still maintaining adequate oxygen delivery in a mechanical model. We hypothesized that using a modified POC, pulsed dose oxygen delivery can provide adequate oxygenation in an animal model.

METHODS: In a crossover study, we induced ALI in 15 pigs using an oleic acid model. We ventilated the pigs using equipment that is used by Critical Care Air Transport Teams of the US Air Force. We compared oxygen delivery using a POC in both continuous flow and pulsed dose modes, while in both volume-control and pressure-control mechanical ventilation.

RESULTS: The PaO2/FIO2 ratios were increased in both the continuous flow and pulsed dose delivery for volume control and pressure control. In volume control, the pulsed dose demonstrated a significant increase in the PaO2/FIO2 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).

CONCLUSION: We were able to demonstrate that oxygen delivery using a POC in mechanically ventilated pigs with ALI is feasible. We were also able to demonstrate that pulsed dose delivery from a POC is superior to continuous flow oxygen delivery for oxygenation in ALI, when using volume control. We propose that this is a safe alternative to conserve oxygen in the transport of critically ill patients.