Sedation
Encyclopedia
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
.
, vasectomy
, RSI (Rapid Sequence Intubation), or minor surgery and in dentistry
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
.
, 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.
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 only, (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:
In the United Kingdom, deep sedation is considered to be a part of the spectrum of general anesthesia, as opposed to conscious sedation.
The scale, from 1 to 6, describes a patient as follows::
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
.
Irritability
Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
or agitation by administration of sedative
Sedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
drugs, generally to facilitate a medical procedure
Medical procedure
A medical procedure is a course of action intended to achieve a result in the care of persons with health problems.A medical procedure with the intention of determining, measuring or diagnosing a patient condition or parameter is also called a medical test...
or diagnostic procedure. Drugs which can be used for sedation include propofol
Propofol
Propofol is a short-acting, intravenously administered hypnotic agent. Its uses include the induction and maintenance of general anesthesia, sedation for mechanically ventilated adults, and procedural sedation. Propofol is also commonly used in veterinary medicine...
, etomidate
Etomidate
Etomidate is a short acting intravenous anaesthetic agent used for the induction of general anaesthesia and for sedation for short procedures such as reduction of dislocated joints, tracheal intubation and cardioversion...
, ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...
, fentanyl, and midazolam
Midazolam
Midazolam is a short-acting drug in the benzodiazepine class developed by Hoffmann-La Roche in the 1970s. The drug is used for treatment of acute seizures, moderate to severe insomnia, and for inducing sedation and amnesia before medical procedures. It possesses profoundly potent anxiolytic,...
.
Uses
Sedation is now typically used in procedures such as endoscopyEndoscopy
Endoscopy means looking inside and typically refers to looking inside the body for medical reasons using an endoscope , an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ...
, vasectomy
Vasectomy
Vasectomy is a surgical procedure for male sterilization and/or permanent birth control. During the procedure, the vasa deferentia of a man are severed, and then tied/sealed in a manner such to prevent sperm from entering into the seminal stream...
, RSI (Rapid Sequence Intubation), or minor surgery and in dentistry
Dentistry
Dentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...
for reconstructive surgery, some cosmetic surgeries, removal of wisdom teeth, or for high-anxiety patients. Sedation methods in dentistry
Dentistry
Dentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...
include inhalation sedation (using nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
), oral sedation, and intravenous (IV) sedation. Inhalation
Inhalation
Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....
sedation is also sometimes referred to as Relative Analgesia.
Sedation is also used extensively in the intensive care unit
Intensive Care Unit
thumb|220px|ICU roomAn intensive-care unit , critical-care unit , intensive-therapy unit/intensive-treatment unit is a specialized department in a hospital that provides intensive-care medicine...
so that patients who are being ventilated
Mechanical ventilation
In medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. This may involve a machine called a ventilator or the breathing may be assisted by a physician, respiratory therapist or other suitable person compressing a bag or set of bellows...
tolerate having an endotracheal tube in their trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
.
Risks
Airway obstructionAirway obstruction
Airway obstruction is a respiratory problem caused by increased resistance in the bronchioles that reduces the amount of air inhaled in each breath and the oxygen that reaches the pulmonary arteries...
, apnea
Apnea
Apnea, apnoea, or apnœa is a term for suspension of external breathing. During apnea there is no movement of the muscles of respiration and the volume of the lungs initially remains unchanged...
and hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
are not uncommon during sedation and require the presence of health professionals who are suitably trained to detect and manage these problems.
Levels of sedation
Sedation scales are used in medicalMedicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
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 only, (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
American Society of Anesthesiologists
The American Society of Anesthesiologists is an association of physicians, primarily anesthesiologists, that share a common goal of raising the standard of the medical specialty of anesthesiology and the improvement of patient care by fostering and encouraging education through research and...
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.
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.The scale, from 1 to 6, describes a patient as follows::
- anxious and agitated or restless, or both
- co-operative, 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
- unresponsive
Patient screening
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,
- hypertensionHypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
- heart defects
- kidney
- other allergens, such as latex allergy
- history of strokeStrokeA stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
or transient ischemic attackTransient ischemic attackA transient ischemic attack is a transient episode of neurologic dysfunction caused by ischemia – either focal brain, spinal cord or retinal – without acute infarction...
(TIA), (certain oral sedation methods may trigger a TIA) - neuromuscular disorders, (such as muscular dystrophyMuscular dystrophyMuscular dystrophy is a group of muscle diseases that weaken the musculoskeletal system and hamper locomotion. Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.In the 1860s, descriptions of boys who...
) - 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
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
.