Effects Of Dexmedetomidine On Brain Function In Patients Undergoing Off-pump Coronary-Artery Bypass Grafting

ObjectiveThe aim of this study was to explore the effects of Dexmedetomidine on plasma cortisol, epinephrine, noradrenalin, TNF-α、IL-6, S100β protein, and postoperative cognitive in patients undergoing Off-pump Coronary-Artery Bypass Grafting.MethodForty patients of selective operation undergoing Off-pump Coronary-Artery Bypass Grafting were randomly assigned to2groups with one of20patients:normal saline control group (C group), Dexmedetomidine group (D group). The patients in D group were infused with0.6μg/kg Dexmedetomidine for15min with the maintenance dose of0.5μg/kg/h to the end of the operation, while in control group the patients were infused with physiological saline. Midazolam-propofol-cisatracurium-fentanyl was used for anesthesia induction, and remifentanil-propofol-cisatracurium was used for maintenance. MAP, heart rate, BIS, plasma cortisol, epinephrine, noradrenalin, TNF-α、IL-6and S100β protein were recorded at the time of30minutes before anesthesia (T0), instant after the intubation (T1), instant beginning of the operation (T2), instant after the closure of the pleural (T3), instant the end of the operation (T4),6hours after the operation (T5),24hours after the operation (T6). The incidence rate of POCD was observed by MMSE at the time of1day before operation and1day,3days,7days after operation. Results1. Compared with To, MBP at T1and HR at T1, T2, T3, T4, T5was increased in group C (P<0.05). There was significant difference of MBP at T1and HR at T1, T2, T3, T4between two groups (P<0.05).2. Compared with T0, the plasma cortisol were increased at each time in both two groups (P<0.05), and the plasma epinephrine, noradrenalin were increased at each time in group C (P<0.05), while decreased at T3, T4in group D (P<0.05). Compared with C group, the plasma cortisol was lower at each time, and the plasma epinephrine, noradrenalin were lower at T1, T2, T3, T4, T5in group D (P<0.05).3. The concentration of TNF-α、IL-6was increased obviously at T3, T4, T5, T6in both two groups compared with TO (P<0.05or P<0.01) and was significantly lower in group D than in group C at T3, T4, T5, T6(P<0.05).4. The concentration of S100β protein was increased obviously at T2, T3, T4, T5, T6in both two groups compared with TO (P<0.05or P<0.01) and was significantly lower in group D than in group C at T2, T3, T4, T5, T6(P<0.05).5. The incidence rate of POCD in group D (5%) was significantly lower than in group C(15%)(P<0.05).Conclusion1. This study demonstrated that Dexmedetomidine attenuates plasma S100β protein, decreases the incidence rate of POCD, shows some degree of cerebral protective effect in patients undergoing Off-pump Coronary-Artery Bypass Grafting.2. The mechanisms of this effect may be related with maintain the stable hemodynamics, decrease the levels of plasma cortisol, epinephrine, noradrenalin and attenuate plasma proinflammatory cytokines release.