IL6 and susceptibility to pneumonia measurement: CPAP failure was shown to be independently predicted by pneumonia severity and interleukin-6 level at admission [1], by the presence of hypertension [5], or, more recently, by a combination of age, gender, lactic dehydrogenase, and change in PaO2/FiO2 after CPAP positioning (relative risk 95%CI: 0.998, 0.996–0.999) [6].