1. Minimal sedation (anxiolysis) A drug‐induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.
2. Moderate (conscious) sedation/analgesia A drug‐induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. The difference between analgesia and moderate sedation is the intent. With moderate sedation there is the intent to produce an altered mental state, for the performance of a procedure, as opposed to analgesia (for relief of pain without intentional production of altered mental state such as sedation).
3. Deep sedation/analgesia A drug‐induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function maybe impaired. Patients may require assistance in maintaining a patent airway and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
4. Anesthesia Consists of general anesthesia and spinal or major regional anesthesia. It does not include local anesthesia. General anesthesia is a drug‐induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug‐induced depression of neuromuscular function. Cardiovascular function may be impaired.