Pneumonia Severity Index (PSI) - The PSI was developed from an administrative data set of 14,199 adults and validated by the original investigators in a second group of 2,287 community-based and nursing home patients.3 It was subsequently validated in a number of populations #Management #EM #IM #Pneumonia #Risk #Stratification #PSI #PneumoniaSeverityIndex #Criteria #AAFP