Objective: Acute respiratory failure can make long distance transport by air extremely difficult. Despite pressurised cabins, the pressure will fall to about three quarters of one atmosphere, and the oxygen partial pressure will fall proportionally. Interventional lung assist (iLA) is a well documented treatment in the critical care unit, but has not been evaluated scientifically in long range aero-medical evacuation. The present animal study was performed to test the feasibility of treating lung failure with iLA during intercontinental air evacuation in a military setting.
Methods: Eight adult female pigs were cannulated in the right axillary artery and the right jugular vein. An arterio-venous iLA device (Novalung) was connected. The ventilator was adjusted to below half of the needed minute volume before the use of iLA. The animals went through different modalities of transportation in ambulances, helicopters and aircraft. Two of the pigs were tested in a hypobaric chamber, and the remaining two animals underwent a 7.5 h intercontinental transportation from Denmark to Greenland in a Hercules C130J transport airplane.
Results: It was possible to maintain physiological PaCO(2) and PaO(2) in normal flight altitudes with iLA. Compared to pump-driven ECMO systems iLA is safer and more efficient. The current study demonstrates the feasibility of iLA during military aero-medical evacuation.