Effect of Dexmedetomidine vs Esmolol or Placebo on Cerebral Hemodynamics in Septic Shock

It is a single-blinded, single-center, randomized trial. Patients with septic shock established within 24 hours in the ICU of Tibet Autonomous Region People's Hospital will be screened for recruitment. After adequate fluid resuscitation, continuous infusion of norepinephrine is given to the patients to maintain a mean arterial pressure (MAP) of 65-75 millimeter of mercury (mmHg). Midazolam and fentanyl are given to achieve the goal sedation of bispectral index (BIS) 40-60, patients who are still with tachycardia (heart rate over 100 b.p.m.) will be recruited. After recruitment, patients in accordance with the random number table are divided into dexmedetomidine group, esmolol group and control group (T0). Patients in the two experimental groups are required to achieve the heart rate goal of 75-95 b.p.m. in one hour by adjusting the dose of dexmedetomidine or esmolol every twenty minutes. All patients acquired the hemodynamic evaluation at T1, T2, T3, T4 (6, 12, 18, 24hours after enrollment). The hemodynamic evaluation including transcranial Doppler of middle cerebral artery(MCA), deep middle cerebral vein (DMCV), basal vein Rosenthal (BVR) and transverse sinus (TS), hemodynamic parameters acquired by the pressure-recording analytical method through peripheral arterial with Mostcare. Demographic characteristics, diagnosis, laboratory reports and drug dose are collected during the study.