Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of 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.
Sedation is also used extensively in the intensive care unit so that patients who are being ventilated tolerate having an endotracheal tube in their trachea. Also can be used during a long term brain EEG to help patient relax.
Airway obstruction, apnea and hypotension are not uncommon during sedation and require the presence of health professionals who are suitably trained to detect and manage these problems.
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).
The American Society of Anesthesiologists defines the continuum of sedation as follows: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.
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 aforementioned 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.