Conscious or moderate sedation is a term used in anesthesiology and many related medical fields to describe a level of sedation where most people are relaxed and comfortable, but are capable of responding to verbal commands. Some of the medications used have an amnesic effect or will make it seem to the patient that time goes by quickly. During this type of treatment, most people can breathe on their own, and may have little to no depression of cardiac function, though this is still monitored in most cases. Conscious sedation is used for a variety of procedures where more significant sedation is not necessary, and it may be especially important for use if the patient must move or perform any type of action, such as taking or holding a breath, during a procedure.
Generally, the medical field describes four levels of sedation. The first is referred to as minimal and usually produces slight fatigue or relaxation through the use of anxiolytic drugs like benzodiazepines. Moderate sedation is next and is achieved by using either oral medications or injections/intravenous infusions. As stated, unless a negative reaction to a drug occurs, there is minimal to no cardiac depression and people can breathe without support. Patients under moderate sedation can also be awake and respond to verbal commands.
The next two levels are deep sedation and general anesthesia. When a patient is in deep sedation it can be difficult to rouse them, though it is possible. The amount or type of medications used can depress breathing and cardiac function, so use of these need to be carefully monitored. Typically, with general anesthesia, breathing must be supported and a patient cannot be woken up until drug administration is stopped.
It’s a general rule that the deeper the sedation level, the higher the risk, as breathing and cardiac function are compromised. With moderate sedation, risk is generally much lower, and doctors or sometimes dentists may prefer this level of sedation due to its decreased risk to patient health. This does not mean risk is completely absent. It is certainly possible for some patients to have allergic or adverse reactions to medications, which is why, in most cases, patients are closely monitored for any sign of medical distress.
The number of procedures that employ moderate sedation are too numerous to list. Examples include cardiac catheterization, bronchoscopy, cervical epidural, elective cardioversion, and many dental procedures. These are only examples, and in any given case a medical professional might choose another anesthesia level. Much depends on the patient's reaction to drugs, allergies, and health status. Also, patient desire to have a heavier or lighter form of sedation for a procedure may influence the health care provider’s choice.