Effect Of Dexmedetomidine On Serum IL-6and TNF-a Level And It’s Clinical Observation In Patients Undergoing Neurosurgery

OBJECTIVES:To evaluate the effect of intravenous different doses of dexmedetomidineinfusion in patients undergoing neurosurgery on inflammatory response markers asserum interleukin-6and tumor necrosis factor-a level. It also assessed its clinicaleffect.METHODS:Thirty adult ASA I–Ⅲpatients admitted to the surgery department of ourhospital scheduled for elective neurosurgery surgery under general anaesthesia wereincluded. They were randomly classified into three equal groups of10patients each.Group D1received loading dose of intravenous dexmedetomidine infusion of0.4ug/kg IV15minutes. Group D2received loading dose of intravenousdexmedetomidine infusion of0.8ug/kg IV15minutes. Group C received intravenousinfusion of normal saline0.9%15minutes.After a loading dose, Group D1andGroup D2received maintenance dose of0.4ug/kg/hr till the beginning of duralclosure,and Group C received continuous infusion of normal saline till the beginningof dural closure. Anesthesia was induced with propofol target-controlled infusion,plasma concentrations3-4ug/ml, induction time of2minutes,and rocuronium0.9mg/kg and maintained with propofol target-controlled infusion and remifentanil.Rocuronium was injected Intermittently to maintain muscle relaxation.The infusionrate of propofol was adjusted to maintain the depth of anesthesia at a bispectral indexlevel of45to50. When the surgery finished,stop all the anesthetics,and send thepatients to the PACU(Postanesthesia Care Unit). Heart rate (HR) and direct meanarterial pressure (MAP) were recorded at the following times: before administration(T1), after placed head frame (T2),after Incision(T3),1hours after the start of surgery(T4),2hours after the start of surgery (T5),3hours after the start of surgery (T6),theend of surgery(T7),15min after extubation (T8),30min after extubation (T9),45minafter extubation (T10),60min after extubation (T11). Serum levels of IL-6(interleukin-6) and TNF-α (tumor necrosis factor-a) had been measured at t1(beforeplaced head frame),t2(T5),t3(T7) and t4(24hour after surgery) time points. The racheal extubation time (from stop all anesthetics to extubation) was recorded. TheRamsay score and the VAS(visual analogue scale) score were recorded. levelsincreased successively in the three groupsRESULTS:(1) TNF-α and IL-6: The concentration of IL-6increased successively at all thetime points in all three groups(P<0.05).The concentration of TNF-α were notsignificantly different at all the time points in all three groups(P>0.05).Theconcentration of TNF-α and IL-6among the three groups were not significantlydifferent at any time point during the experimental period (P>0.05).(2) Hemodynamics: The HR and MAP values in group D1and D2at T2and T3time point were lower than that at T1time point(P>0.05),but the HR and MAP valuesin group C at T2and T3time point were significantly higher than that at T1timepoint(P<0.05). The MAP values were significantly lower in group D1and D2thangroup C during most of the intra-and postoperative periods(P<0.05), and it,s valuesbetween group D1and D2were not significantly different(P>0.05). The HR valueswere significantly lower in group D1and D2than group C during all of the intra-andpostoperative periods(P<0.05),and it,s values in group D2were significantly lowerthan that in group D1at T3，T9and T10time points(P<0.05).(3) The racheal extubation time: Tracheal extubation time was longer in groupD2than that in group D1and group C(P<0.05), but it had no significant differencebetween group D1and group C(P>0.05).(4) Ramsay score: Ramsay score was significantly higher in group D2relative togroup D1and C at T8and T9time points after tracheal extubation(P<0.05)，But ithad no significant difference between group D1and C at T8and T9time points(P>0.05). The values had no significant difference in the three groups at T10and T11time points (P>0.05).(5) VAS score: VAS score was significantly less in group D2and D1relative togroup C at all of the time points after tracheal extubation(P<0.05)， but it had nosignificant difference between group D1and D2(P>0.05).Conclusion:The study showed that serum IL-6concentration increased after the neurosurgical injury,but clinically relevant doses of dexmedetomidine had no effecton serum TNF-α and IL-6levels. Dexmedetomidine administration during surgerykept hemodynamic stability.The loading dose of intravenous dexmedetomidineinfusion of0.4ug/kg before surgery followed by maintenance dose of0.4ug/kg/hr canprovid satisfactory sedative and analgesic effect without delaying recovery fromanaesthesia.