Although widely utilized in a variety of clinical venues and delivered by nurses and physicians with a broad range of clinical training and experience, core principles guiding safe sedation practice are not well established. Sedation practices (ie, drug choice and dose, patient preparation, procedure room equipment for safe sedation delivery, patient monitoring standards, practitioner training requirements, sedation goals) are often left to the discretion of the individual sedation practitioner and are not well regulated. The chapter will discuss core concepts of anesthetic pharmacology that apply to sedation practice (Table 27–1) that sedation practitioners should consider prior to administering sedatives and analgesics.
Table 27–1Core anesthetic pharmacology concepts in sedation practice. ||Download (.pdf) Table 27–1 Core anesthetic pharmacology concepts in sedation practice.
|The sedation continuum |
|The difference between moderate and deep sedation |
|The importance of recognizing deeper-than-intended sedation |
|The time to peak effect of common analgesics and sedatives used in sedation practice |
|The influence of sedative–analgesic interactions on responsiveness, respiratory depression, and analgesia |
No discussion of safe sedation techniques can begin without first asking “What is sedation?” In general, sedation is a drug-induced, depressed level of consciousness that allows a patient to safely tolerate a procedure or noxious stimuli, while maintaining innate cardiopulmonary functions. Defining sedation more specifically is a difficult task. Terms such as procedural sedation, conscious sedation, deep sedation, sedation and analgesia, monitored anesthetic care, moderate sedation, anxiolysis, and minimal sedation are often used interchangeably in the literature and in daily discussions between caregivers and medical specialists. This lack of standardized language and definitions concerning the practice of sedation has served to confuse communication as well inhibit the development of consistent sedation guidelines, standards, and techniques.1,2
Currently, the majority of position papers, practice guidelines, and medical literature use the definition and taxonomy put forth by the American Society of Anesthesiologist (ASA), called the sedation continuum.3 This sedation continuum presents stages of central nervous system depression that eventually culminate in general anesthesia. Four sedation states are defined: minimal sedation, moderate sedation, deep sedation, and general anesthesia. Each of these states is differentiated by responsiveness to stimulation, ability to maintain a natural airway, adequacy of spontaneous airway, and impairment of cardiovascular functions. For purposes of clarity, the ASA sedation continuum will be used throughout this chapter (Table 27–2).3
Table 27–2The American Society of Anesthesiologist (asa) sedation continuum.a ||Download (.pdf) Table 27–2 The American Society of Anesthesiologist (asa) sedation continuum.a
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|Deep Sedation/Analgesia ||General Anesthesia |
|Responsiveness ||Normal response to verbal stimulation ||Purposeful response to verbal and tactile stimulation ||Purposeful response following repeated painful stimulation ||Unarousable, even with painful stimulus |
|Airway ||Unaffected ||No intervention required ||Intervention may be required ||Intervention often required...|