| Objective During the perioperative period,some factors can cause stress response such as the stimulation of operation,blood loss,postoperative pain stimulation,hypoxia,mental tension,anxiety,anesthesia,trauma and other related factors.The stress response is characterized by increased secretion of pituitary hormones,activation of the sympathetic nervous system and inflammatory immune response.The stress reaction causes a series of changes in the body,which plays an important role in maintaining the homeostasis of the body.Further,serious stress will cause physiological dysfunction and postoperative complications,and even increase the perioperative mortality,and seriously affect the long-term outcomes of patients.It is very important to reasonably control the stress to reduce complications and enhance rapid recovery by using anesthetic agents and methods.Epidural anesthesia is one of the most widely used anesthesia methods,which can effectively attenuate sympathetic hyperactivity,blunt the surgical stress response,spare the use of opioids,and promote rapid recovery after surgery.However,the epidural anesthesia is not without complications and risks.Dexmedetomidine is a new and highly selective α2 adrenergic receptor agonist.This class of agents is known to have sedative-,anxiolytic-,anti-shivering-,analgesic-,and anesthetic sparing effects.In addition,α2-adrenoceptor agonists reduce central sympathetic outflow and attenuate the stress response associated with surgery and are easier to be administered in general anesthesia when compared with epidural analgesia.Therefore,the study was to compare the stress response,hemodynamic parameters and recovery profiles of patients of dexmedetomidine with epidural anesthesia combined general anesthesia undergoing radical gastrectomy.Methods Ninety patients undergoing elective open gastrectomy under general anesthesia were recruited and randomly assigned to three groups: a control group receiving general anesthesia only(group C);an epidural group(group E)receiving epidural anesthesia and general anesthesia;and a dexmedetomidine group(group D)receiving IV dexmedetomidine and general anesthesia.In group E,an epidural catheter was placed at the T8-T9 interspace.After successful epidural placement and before induction,4 ml of 1.6% lidocaine was given as a test dose.The blockade was then established before induction with 5 ml ropivacaine of 0.375% followed by a continuous epidural infusion of the same concentration of solution at 5 ml/h during surgery.The dexmedetomidine group(group D,n=30)received intravenous dexmedetomidine of 0.6μg/kg before the induction of general anesthesia,followed by dexmedetomidine at 0.4μg/kg/h until peritoneal closure.The control group(group C,n=30)received volume-matched normal saline infusion as placebo.The hemodynamic parameters and Bispectral index(BIS)were evaluated at the administration of dexmedetomidine or epidural anesthesia(T0),before induction(T1),pre-intubation(T2),intubation(T3),incision(T4),celiac exploration(T5),extubation(T6).Recovery characteristics during postoperative period were obsevered,and the postoperative VAS score of 1h,6h,12 h,24h,48 h were recorded as well respectively.Blood samples for norepinephrine(NE),epinephrine(E),cortisol(Cor)and cytokines(TNF-α,IL-6 and IL-10)were obtained prior to the administration of dexmedetomidine or epidural anesthesia(baseline),immediately after tracheal intubation,upon incision,at the time of celiac exploration,and at tracheal extubation.The first postoperative flatus,first food intake,hospital stay and related complications were recorded.Results There were no baseline differences among groups with respect to age,sex,weight,amount of intraoperative fluid,blood loss,length of surgery,and anesthesia(P>0.05).Compared with the groups C and E,the values of BIS were significantly lower in group D at T1(P<0.01).In group D,the heart rate(HR)was significantly lower after commencing dexmedetomidine and remained significantly lower throughout the operation course(P<0.01 or P <0.05).The incidence of patients who required intervention due to intraoperative hypotension was significantly higher in group E(36.7%),compared with the groups D and C(13.3% and 10.0%)(P <0.05).There were no differences in the consumption of propofol and remifentanil between group D and group E,but both consumed significantly less compared with group C(P<0.01 or P <0.05).The time to eye opening and tracheal extubation were similar among the three groups.The incidence of agitation in group D(6.7 %)were lower than that in group C(26.6 %)(P<0.05).Compared with group E,there were no differences in the plasma concentration levels of NE,E,Cor and cytokines(TNF-α,IL-6 and IL-10)in group D at all time points.The levels of NE and E in groups D and E were significantly lower than that in group C,at all time points following induction(P < 0.01),and the levels of Cor in groups D and E were significantly lower than that in group C at celiac exploration(P< 0.05)and immediately after tracheal extubation(P < 0.01).The levels of TNF-α,IL-6 and IL-10 were increased after the celiac exploration in the three groups.The levels of plasma TNF-α,IL-6 and IL-6/ IL-10 ratio were higher in group C than that in groups D & E at celiac exploration and tracheal extubation(P<0.01 or P<0.05).Compared with the groups C,the postoperative VAS score at rest were significantly lower in group D and group E at 6h,12 h,24h,48h(P<0.01 or P<0.05),and the VAS score at mobilizing were significantly lower in group D at postoperative 1h,6h,12 h,24h and group E at 1h,6h,12 h,24h,48 h of postoperation(P<0.01 or P<0.05).Compared with group C,the first flatus and first food intake in the group D and group E were earlier,with shorter postoperative hospital stay(P <0.05).However,there were no difference in postoperative surgical and pulmonary complications among the three groups(P >0.05).Conclusions When used in conjunction with general anesthesia undergoing radical gastrectomy,intraoperative dexmedetomidine blunts surgical stress responses to an extent comparable with combined epidural and general anesthesia without compromising hemodynamic stability and with improvement of the postoperative analgesic effect,earlier first flatus and first food intake and shortened postoperative hospital stay. |
