Conscious sedation: Pharmacology.
Levels of sedation

There is a continuous spectrum of consciousness that extends from fully conscious and alert to deeply unconscious.

For convenience, we refer to four levels of sedation when using drugs for this:

Minimal sedation (anxiolysis)

The patient is conscious and alert, but less anxious. This is be achieved with small doses, e.g. as an oral premedication.

Moderate sedation (conscious sedation)

Verbal contact with the patient is maintained throughout the period of sedation. Most reflexes (e.g. coughing on accidental inhalation) are preserved. Serious side effects are unlikely (unless the patient is accidentally caused to become deeply sedated, e.g. by accidental overdose of the sedative).

The term Relative Analgesia (RA) is sometimes used when referring to conscious sedation with nitrous oxide.

Deep sedation

The patient retains a degree of responsiveness, e.g. to pain, but verbal contact is reduced or absent. Some reflexes may be lost. This level of sedation requires close monitoring by a highly trained expert in sedation, as it can cause respiratory depression and other serious side effects.

General anaesthesia

General anaesthetic induces a state of complete unconsciousness in a patient.