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Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Drugs which can be used for sedation include propofol, etomidate, ketamine, fentanyl, and midazolam.
Sedation is typically used in minor surgical procedures such as endoscopy, vasectomy, or dentistry and for reconstructive surgery, some cosmetic surgeries, removal of wisdom teeth, or for high-anxiety patients. Sedation methods in dentistry include inhalation sedation (using nitrous oxide), oral sedation, and intravenous (IV) sedation. Inhalation sedation is also sometimes referred to as Relative Analgesia.
Levels of sedation
Sedation scales are used in medical situations in conjunction with a medical history in assessing the applicable degree of sedation in patients in order to avoid under-sedation (the patient risks experiencing pain or distress) and over-sedation (the patient risks side effects such as suppression of breathing, which might lead to death). Typically, levels are (i) agitation, (ii) calm, (iii) responsive to voice alone, (iv) responsive to tactile stimulation, (v) responsive to painful stimulation only, and (vi) unresponsive to painful stimulation.
Examples of sedation scales include: MSAT (Minnesota Sedation Assessment Tool), UMSS (University of Michigan Sedation Scale), the Ramsay Scale (Ramsay, et al. 1974) and the RASS (Richmond Agitation Sedation Scale).
- Minimal Sedation - Normal response to verbal stimuli.
- Moderate Sedation - Purposeful response to verbal/tactile stimulation. (This is usually referred to as "conscious sedation")
- Deep Sedation - Purposeful response to repeated or painful stimulation.
- General Anesthesia - Unarousable even with painful stimulus.
In the United Kingdom, deep sedation is considered to be a part of the spectrum of general anesthesia, as opposed to conscious sedation.
Ramsay Sedation Scale
The Ramsay sedation scale is used to assess the level of sedation of a hospitalized patient. It was described by Michael A. E. Ramsay.
- anxious and agitated or restless, or both
- cooperative, oriented, and calm
- responsive to commands only
- exhibiting brisk response to light glabellar tap or loud auditory stimulus
- exhibiting a sluggish response to light glabellar tap or loud auditory stimulus
Prior to any oral sedation methods being used on a patient, screening must be done to identify possible health concerns. Before using sedation, doctors try to identify any of the following that may apply:
- known drug allergies, and sensitivities,
- heart defects
- other allergens, such as latex allergy
- history of stroke or transient ischemic attack (TIA), (certain oral sedation methods may trigger a TIA)
- neuromuscular disorders, (such as muscular dystrophy)
- a current list of medications and herbal supplements taken by the patient
A patient with any of these conditions must be evaluated for special procedures to minimize the risk of patient injury due to the sedation method.
In addition to the above mentioned precautions, patients should be interviewed to determine if they have any other condition that may lead to complications while undergoing treatment. Any head, neck, or spinal cord injuries should be noted as well as any diagnosis of osteoporosis.
- Brown, TB.; Lovato, LM.; Parker, D. (Jan 2005). "Procedural sedation in the acute care setting.". Am Fam Physician 71 (1): 85–90. PMID 15663030.
- "Continuum of Depth of Sedation: Definition of general anesthesia and levels of sedation/analgesia" (pdf). American Society of Anesthesiologists. Approved October 27, 2004, amended October 21, 2009. Retrieved 2010-11-29.
- Ramsay MA, Savege TM, Simpson BR, Goodwin R. Controlled sedation with alphaxalone-alphadolone. Br Med J 1974; 2:656–659. free registration required
- Sedation scales Chinese University of Hong Kong
- Ramsay's description of the scale