The Effect Of Different Doses Of Dexmedetomidine On The Inflammatory Mediators In Infants After Cardiopulmonary Bypass

Object: To explore the application of different doses of dexmedetomidine in infants with congenital heart disease undergoing cardiac surgery. To discuss the anti-inflammatory effect and dose relation of dexmedetomidine, and to provide clinical evidence for the application of dexmedetomidine in infants, by measuring the concentrations of the perioperative inflammatory cytokines TNF-α and IL-6 at different time points.Methods: Sixty NYHA physical status Ⅰ or Ⅱ patients with ventricular septal defect(28 males, 32 females), aged 2-6 month, weighing 3-6 kg undergoing open heart surgery with CPB were selected. Patients with pneumonia, liver and kidney dysfunction, consciousness disorder, or severe heart block were excluded. All patients were randomly divided into three groups(n=20 each) using a random number table: nomal saline control group(group C), low dose dexmedetomidine group(group L) and high dose dexmedetomidine group(group H).Dexmedetomidine was intravenously continuous infused at 0.3 μg·kg-1·h-1 until the end of operation in group L, dexmedetomidine was intravenously continuous infused at 0.6 μg·kg-1·h-1 until the end of operation in group H, while the equal volume of normal saline was given instead in group C. Anesthesia was introduced with intravenous midazolam 0.1mg·kg-1, sufentanil 1.0μg·kg-1 and cisatracurium 0.2mg·kg-1, the patients were endotracheally intubated and mechanically ventilated after assisted respiration for 3 min. Anesthesia was maintained with 2~3% sevoflurane, sufentanil and cisatracurium. ECG, HR, MAP, CVP, SpO2, PETCO2, esophageal temperature and rectal temperature were monitored continuously. Operation time, CPB time, aortic cross-clamping time, open- full resuscitation after time and auto-resuscitation situation were recorded. Venous blood samples were taken at the time of the jugular vein catheter placed in after induction( baseline, T0), 10 min after CPB(T1), 4h after CPB(T2), 24 h after CPB(T3). ELISA was applied to detect the levels of TNF-α and IL-6.Results:1 There were no significant difference in age, weight, height, gender, the cardiac function classification, operation time, CPB time, aortic clamping time, aortic open- full resuscitation time and the rate of auto-resuscitation among the three groups(P>0.05).2 Inflammatory medium: There were no significant difference in the concentrations of TNF-α and IL-6 at T0(P>0.05). Compared with T0, the concentrations of TNF-α and IL-6 were significantly increased at T1 ~ T3(P<0.05). Compared with group C, the concentrations of TNF-α and IL-6 were significantly decreased in group H(P<0.05) at T1 ~ T3, and no significant difference were found in group L.Conclusion:1 Heart surgery under cardiopulmonary bypass may promote the release of inflammatory mediators in patients and induce systemic inflammatory response, thus affecting the prognosis of patients2 Intraoperative infusion of dexmedetomidine can inhibit the release of inflammatory mediators from cardiopulmonary bypass.3 The inhibition to the release of inflammatory mediators of Dexmedetomidine was dose-related, high dose of dexmedetomidine can inhibit the release of inflammatory mediators more effectively.