Essential reading for intensivists: things you didn't even dream were going on in your ventilated patients' lungs. With credit to @robertpdickson who does some very clever translational work on lungs

Firstly, we are aware of the inherent badness of oxygen. Here is protein content in alevoli after 48 hours of FiO2 95% (i.e. oedema), delightful.

Secondly, all those VAP's we get cross with (can someone silver impregnante the ET tube or something) that we think is just orally communicating flora/immunosuppression? Mais non. High FiO2 all but destroys weakling bacteria, leaving the redox-armoured king, staph aureus, to rule

Unmitigated staph surges and produces a truckload of PAMPs (pathogen associated molecular patterns). Being redoxically armoured, it is fairly happy to thwart oxidative burst from neutrophils attempting to kill them too.

Indeed the lung flora changes prior to the alveolar protein content - like both a canary in the coalmine moment, and then contributing to pathology.