This is the ValueSet that contains all the codes in Vital Signs Units (http://hl7.org/fhir/ValueSet/ucum-vitals-common) and ValueSet - Personal Data Quality Review example (http://hl7.org/fhir/us/mdi/ValueSet/vs-per-dq-review-example). E.g. what you have to deal with if you get resources containing codes in either of them