Dexmedetomidine is a highly selective α2-adrenoreceptor agonist for sedation of adult critically ill patients which exhibits sedative and analgesic effects. Recent studies suggest that dexmedetomidine to restore adrenergic vasoconstrictor responsiveness in septic shock, and prevents alterations of pain rat model intestinal microcirculation Induced by surgical stress，even it can reduce the mortality of endotoxemic rats and patients with severe sepsis. The investigators preliminary study showed that dexmedetomidine might improve microcirculation in septic shock patients. To test this effect, the investigators will conduct double-blinded study.
The investigators preliminary study showed that dexmedetomidine might improve microcirculation in septic shock patients. To test this effect, the investigators will conduct double-blinded study.