We code for the physician side and are up against our hospital compliance department (HCD) and we need a little guidance. One of my MD's was approached by the HCD regarding his use of "acute respiratory failure" or lack there of. I know the pO2 less than or equal to 55; sPO2 less than or equal to 88% requiring greather than 28% of FiO2 because of my handy dandy notebook, but where can I find it on the CMS website? Does anybody have the link handy?