Procedural sedation and analgesia (PSA) for unscheduled, time-sensitive procedures is a standard practice in the ED.1,2 The accepted definition and goals of PSA are “the use of anxiolytic, sedative, hypnotic, analgesic, and/or dissociative medications(s) to attenuate anxiety, pain and/or motion. These agents are administered in order to facilitate amnesia or decreased awareness and/or patient comfort and safety during a diagnostic or therapeutic procedure.”1-5 Levels of sedation are defined by the patient’s level of responsiveness and cardiopulmonary function, not by the agents used (Table 37-1).6 Although these are the currently accepted definitions of levels of sedation, sedation is a continuum, and responsiveness alone is not a perfect tool to judge the level of sedation.4,7,8 By definition, patients receiving PSA do not require routine airway protection with endotracheal intubation or other airway adjuncts. This is in contrast to provision of general anesthesia, which typically requires airway protection. This chapter focuses on PSA in adults. For children, see Chapter 115, “Pain Management and Procedural Sedation in Infants and Children.”
TABLE 37-1Levels of Sedation and Analgesia |Favorite Table|Download (.pdf) TABLE 37-1 Levels of Sedation and Analgesia
| ||Responsiveness ||Airway ||Breathing ||Circulation |
|Minimal sedation (“anxiolysis”) ||Normal but slowed response to verbal stimulation ||Unaffected ||Unaffected ||Unaffected |
|Moderate sedation ||Purposeful response to verbal or physical stimulation ||Usually maintained ||Usually adequate ||Usually maintained |
|Dissociative sedation ||Trance-like state with variable responsiveness ||Usually maintained ||Usually maintained ||Usually maintained |
|Deep sedation ||Purposeful response after repeated or painful physical stimulation ||May be impaired ||May be suppressed ||Usually maintained |
|General anesthesia ||Not arousable, even by painful stimulation ||Usually requires assistance ||Often impaired ||May be impaired |
Minimal sedation is characterized by anxiolysis but with normal or slowed responses to verbal stimuli. Minimal sedation is typically used for minor procedures that require patient cooperation and for those in which pain is controlled by local or regional anesthesia. During minimal sedation, ventilatory function is usually maintained with a low risk of hypoxia or hypoventilation.
Moderate sedation is characterized by a depressed level of consciousness and a slower but purposeful motor response to simple verbal or tactile stimuli. Patients at this level generally have their eyes closed or demonstrate ptosis and respond slowly to verbal commands. Moderate sedation can be used for procedures in which patient cooperation is not necessary and muscular relaxation is desired. During moderate sedation, the patient is usually able to maintain a patent airway with adequate respirations,9 and cardiovascular function is usually maintained.2
Dissociative sedation does not easily fit into the PSA continuum outlined in Table 37-1. Dissociation is a state of detachment from immediate surroundings, in which the cortical centers are prevented from receiving sensory stimuli. It is a trance-like cataleptic state characterized by profound analgesia and amnesia, with retention of protective airway reflexes, spontaneous respirations, ...