The American Society of Anaesthesiologists uses the following definitions for levels of sedation:
# Minimal sedation (formerly known as anxiolysis) is a drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, respiratory and cardiovascular stability is unimpaired.
# Moderate sedation (formerly known as conscious sedation) is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. It is important to remember that reflex response to a painful stimulus is not a purposeful response. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular stability is usually maintained.
# Deep sedation/analgesia is a drug-induced depression of consciousness during which patients cannot be easily roused but respond purposefully following repeated or painful stimulus. Patients may require assistance in maintaining a patent airway and spontaneous ventilation may be inadequate. Cardiovascular stability is usually maintained. In the UK deep sedation is considered to be a part of the spectrum of general anaesthesia.