This is the ValueSet that contains all the codes in Vital Signs Units (http://hl7.org/fhir/ValueSet/ucum-vitals-common) and LOINC POLST discuss part List (http://hl7.org/fhir/us/pacio-adi/ValueSet/LOINCPOLSTDiscussPartAnswerList). E.g. what you have to deal with if you get resources containing codes in either of them