Dexmedetomidine was found might be beneficial to sepsis. Dexmedetomidine were found to improve microcirculation in sepsis animal studies and non-sepsis patients. However, the effect of dexmedetomidine on microcirculation in septic shock patients is unknown.

Septic shock is characterized by significant decline in vascular response and relative hypovolemia. Fluids and exogenous catecholamines are mainstay. However, even after initial resuscitation, microcirculatory dysfunctions still exist, and represent a direct physiologic link to organ failure and death. Therefore, therapeutic strategies aiming at improving microcirculation are performed.

Dexmedetomidine was found might be beneficial to sepsis. Dexmedetomidine were found to improve microcirculation in sepsis animal studies and non-sepsis patients. However, the effect of dexmedetomidine on microcirculation in septic shock patients is unknown.

Based on the hypothesis that dexmedetomidine might improve microcirculation in initial resuscitated septic shock patients, the study was to investigate the effects of dexmedetomidine on microcirculation in early septic shock patients despite initial resuscitation. Meanwhile, to observe the possible mechanism of the effect, the correlation between dexmedetomidine dose and microcirculatory parameters as well as catecholamine level were performed.

Adult patients who met the following inclusion criteria were enrolled in the study: 1) With septic shock defined by the 2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference for less than 24 hours.

2) After initial fluid resuscitation but still requiring norepinephrine to maintain arterial pressure or hyperlactacidemia.

3) Need ongoing analgesia and sedation. 4) Using advanced invasive hemodynamic monitoring techniques.

Exclusion criteria were as follows:

1. age less than 18 years.
2. pregnancy.
3. heart rate less than 55 beats per minute.
4. acute hepatic failure
5. brain injury.