<p>Mice were IT injected with SEB and LPS to model polymicrobial infection and were exposed to 21% or 100% oxygen for 48β60 h. Determination of time-dependent survival curves was prohibited by considerations of unrelieved severe respiratory distress in NIH-approved animal care protocol, which required termination of experiments immediately after differences between groups became apparent. Major differences between groups occurred within 48β60 hours after IT injection of toxins, when the majority of oxygenated animals with inflamed lungs had died, while the nonoxygenated, obviously sick control mice with inflamed lungs were still alive.</p