This is the set of resources that conform to either of the profiles Preoperative Diagnosis Section (http://hl7.org/cda/us/ccda/StructureDefinition/PreoperativeDiagnosisSection) and Preoperative Diagnosis Section (http://hl7.org/cda/us/ccda/StructureDefinition/PreoperativeDiagnosisSection). E.g. what you have to deal with if you get resources conforming to one of them