| Background Tumorigenesis is closely related to the body’s immune function,so how tobetter control the perioperative stress response and protect the immune function is animportant issue.Objective To investigate the effects of dexmedetomidine on perioperative stressresponse and immune function.Methods Forty patients undergoing redical resection of rectal carcinoma were includedin this prospective,randomized,double-blind,controlled study after we received theapproval of our institutional human investigation committee and written informedconsent from the patients.Entry criteria include rectal cancer patients older than30-year-old but yonger than70-year-old,the distance between tumor center and anusare greater than5cm.All patients are absence of significant preexisting pulmonarydiseases and coronary heart diseases.Exclusion criteria were any history of impairmentof the immune system,immunosuppressive therapy,and signs of preexistinginfection(white cell blood count＞10,000/μL,body temperature＞38.0℃，as well asliver insufficiency. Patients with increased catecholamine therapy (NE、dopamine)before, during, and after surgery, as well as transfusion were also excludedfrom the study.All eligible patients were equally randomized into two groups.Thepatients in group D（n=20） were injected dexmedetomidine1μg/kg at10min beforeanesthesia induction,which were followed by infusion of dexmeditomidine0.2μg·kg-1·h-1during operation.And those in group C (n=20) were given the same volume of normal saline infusion as the controls. Induction of anesthesia was achievedby administration of oxygen by facemask (100%O2) for3min followed by0.04mg/kgmidazolam,1-2.5mg/kg propofol,4μg/kg fentanyl, and0.60mg/kg Rocuronium tofacilitate tracheal intubation. Anesthesia was maintained with40～90μg·kg-1·min-1propofol,0.2～0.7μg/kg/min remifentanil and5～10μg·kg-1·min-1Rocuronium in bothgroups. Vasoactive drugs were used according to the dynamics of blood flow. Wedefined adequate anaesthetic depth as the maintenance of Mean arterial pressure(MAP)within15%of the baseline. Nondepolarizing motor blockade was reversed by1mgneostigmine and0.5mg atropine after spontaneous respiratory recovery. At the end ofsurgery, the patients of both groups received patient-controlled intravenous analgesia(PCIA) with morphine1.5mg/h(PCA dose0.5mg/10min). After surgery, the amount ofpropofol and remifentanil were calculated, The VAS pain scores were assessed at2，6，12and24h after extubation. The morphine consumption within24hours werecalculated. Plasma concentration of cortisol were measured before the induction ofanesthesia(T0)、2h after the beginning of the operation(T1)、6h after the end of theopration(T2)、24h after the end of the opration(T3).The levels of peripheral bloodT-lymphocyte subsets(CD3+、CD4+、CD8+)and serum IFN-γ、IL-10were also detectedin T0、T1、T2、T3.Results1、The consumption remifentanil was less in group D than that in group C(P＜0.05);The VAS pain scores at2h and6h during morphine analgesia were lower ingroup D than those in group C(P＜0.05);The24-h morphine consumption was less ingroup D than that in group C(P＜0.05).Plasma concentrations of cortisol at6h and24hafter extubation were lower in group D than those in group C(P＜0.05).2、Compared with T0,T-lymphocyte subsets CD3+%and CD4+%at T1～T2decreasedin both groups，but compared with C group at T1～T3,the level of CD4+/CD8+、IFN-γ/IL-10were significantly reduced in the group D(P＜0.05).Conclusion A continuous intravenous infusion of dexmedetomidine may have protective effect on stress response, but could break immune balance and up regulateTh2cytokine who will damage the cellular immune. So there need further explorationon dexmedetomidine application in cancer surgery. |
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