AACN levels of evidence: what's new?

tice related to disease management or skills. As a leader in this area, the American Association of CriticalCare Nurses (AACN) has published numerous resources to help practitioners appraise evidence for integration into clinical practice. Publications such as Practice Alerts, Protocols for Practice, and Procedure Manual contain recommendations for clinical practice based on a comprehensive and scientific review of the evidence. To support these recommendations, AACN developed a hierarchy system to grade the level of evidence. AACN’s grading system was originally referred to as a rating scale and was used to rank individual recommendations according to the level of supporting evidence available (Table 1).