Rationale, aims and objectives: Current day realities of diminishing resources, reductions in spending and organizational change within health care systems have resulted in an increased emphasis on a multidisciplinary team approach to quality patient care. The movement of nursing towards more autonomous practice combined with the current trend towards 'evidence-based practice' in health care demands increased accountability in clinical decision making. This paper focuses on one aspect of nurses' clinical decision making within the demands of evidence-based practice and cardiac surgery. In this field recent advances, combined with increasing demands on health care institutions, have promoted early extubation of post-operative cardiac patients. While this remains a medical role in many institutions, an increasing number of intensive care units now consider it as a nursing role. Method: This paper explores the realities of nurses' clinical decision making through a discussion of current practice in the extubation of patients following cardiac surgery. In addition, it considers the implications of current practice for both nurse education and the continued development of clinical nursing practice. Conclusion: The findings indicate that evidence-based practice appears to be an incomplete model of the relationship between theory and professional work.