General Anesthesia
General anesthesia is a drug-induced loss of consciousness during which an individual is not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. The individual often requires assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired.
Levels of Sedation/Analgesia
Minimal Sedation (Anxiolysis) is a drug-induced state during which an individual responds normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.
Moderate Sedation / Analgesia ("Conscious Sedation") is a drug-induced depression of consciousness during which an individual responds purposefully* to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.
Deep Sedation / Analgesia is a drug-induced depression of consciousness during which an individual cannot be easily aroused but responds purposefully* following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. The individual may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
* Reflex withdrawal from a painful stimulus is NOT considered a purposeful response.
SOURCES
American Society of Anesthesiologists. (2004, October). Continuum of depth of sedation: Definition of general anesthesia and levels of sedation / analgesia. Retrieved January 7, 2005 from http://www.asahq.org/publicationsAndServices/standards/20.pdf.
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