Dexmedetomidine is a highly selective alpha2Adrenergic receptor agonists with central anti-sympathetic and anti-anxiety effects that produce a sedative effect similar to natural sleep; At the same time, it has certain analgesic and diuretic effects, has no obvious inhibition on respiration, and may have certain protective properties on the function of heart, kidney and brain. It can be used for sedation of patients treated with ventilator by endotracheal intubation, perioperative anesthesia combined with medication and sedation during invasive examination or treatment.