Anesthesia services have spread far beyond the operating room over the past several decades. The demand for sedation and analgesia has gone up dramatically, reflecting not just population growth but also an increasing variety of nonsurgical procedures requiring that patients be protected against pain or prevented from moving.Meanwhile, the numbers of anesthesiologists, nurse anesthetists and anesthesiologist assistants have not kept pace.  Leaving the OR for other floors or even buildings, where the anesthesia professional may have a single patient to care for, reduces his or her efficiency and costs the practice too much uncompensated time.  Into the breach have stepped clinicians from other specialties and disciplines.  This Alert will focus on the role of registered nurses in procedural sedation, also known as “conscious” or “moderate” sedation.The Continuum of Anesthesia:  Moderate and Deep SedationGranted that anesthesia is a continuum, agreeing on the definitions is nevertheless important.  Disagreement on terminology, or at least on...