Clinical events form the basis of patient care practice. Their computerization is an important aid to the work of clinicians. Clinical guidelines or protocols direct clinicians and patients on when and how to handle clinical problems. Thus, clinical guidelines are an encapsulation of clinical events. Hence, an event-driven approach to computerizing the management of clinical guidelines is worthy of investigation. In our framework, called SpEM, the main clinical guideline management dimensions are specification, execution, and manipulation. This paper presents an event-driven approach, within the context of the SpEM framework, to manage clinical guidelines. The event-driven approach is based on the event-condition-action (ECA) rule paradigm in which the ECA rules are specified using an XML-based language over an electronic healthcare record (EHCR) implemented using an XML-enabled DBMS. This approach facilitates the easy querying, operations and execution replay for clinical guidelines. The approach provides a ready solution to the problem of the integration of clinical guideline management systems (CGMS) and the EHCR. This creates an "active EHCR" in which reactivity is defined by the medical logic in the clinical guideline. The paper practices the approach presented here by using a simplified clinical guideline/protocol from the domain of clinical laboratory investigation for microalbuminuria screening.