In contrast to existing patient-record systems, which merely offer static applications for storage and presentation, a helpful patient-record system is a problem-oriented, knowledge-based system, which provides clinicians with situation-dependent information. We propose a practical approach to extend the current data model with (1) means to recognize and interpret situations, (2) knowledge of how clinicians work and what information they need, and (3) means to rank information according to its relevance in a given care situation. Following the methodology of second-generation knowledge-based systems, that use ontologies to define fundamental concepts, their properties, and interrelationships within a particular domain, we present an ontology that supports three prerequisite features for a future helpful patient-record system: a family-care workflow process, a problem-oriented patient record, and means to identify relevant information to the care process and medical problems.