| Background and purposePostoperative cognitive dysfunction (POCD) is a decline in cognitive performance after surgery and anesthesia especially in elderly patients undergone cardiac and osteopathic procedures. POCD may be related to risk factors such as advanced age, education, stress produced by surgery and anesthesia, inflammation, pain and sleep disturbance. Dexmedetomidine is a new highly selective alpha2adrenergic agogist, the selectivity for the adrenocepter (α2:α1) is1620:1. It can provide effects such as sedation, analgesia as well as hypnosis to spare anesthetics. Recently its anti-inflammatory and neuroprotective function is reported. This study was aimed to probe the effect of intraoperative infusion dexmedetomidine on POCD.Materials and Methods40elderly patients were enrolled, who aged from65to85undergone gastrointestinal cancer resection. They were assigned randomly to the study group (D group, n=20) or control group (C group, n=20). The combined anesthesia was carried out with proper analgesic level lower than T4, which was produced by epidural anesthesia and general anesthesia with induction by i.v fentanyl (3ug/kg), propofol (2mg/kg), rocuronium (0.6mg/kg).2%sevoflurane supplied the maintenance with fentanyl intravenous injection,0.25%bupivacaine epidural bolus and rocuronium if it is necessary. Anesthesia depth was monitored with maintaining BIS value between40-60titrated by sevoflurane. Central venous and left radial arterial catheters were placed to maintain stable hemodynamic status. In Group D dexmedetomidine dosage ranged for a loading infusion of0.5ug/kg infused over10minutes followed by0.3ug/kg continuous infusion till prior to the end of surgery procedures. Record BIS, Ramsay, VAS, HRmax, HRmin, HRdi, MAPdi, MAPmax, MAPmin, MMSE scores at responding timing.Take blood samples to test S100beta proteins at the following time points:T1(Before anesthesia), T2(lhour after surgery), T3(48hours after surgery)T4(7days after surgery).Results1. Preoperative general statuses between two groups showed no statistical significance.2. Intraoperative and postoperative results 1) Intraoperative general statuses between two groups showed no statistical significance.2) Intraoperative average exhaled sevoflurane concentration:Group D (1.40±0.21) and Group C (1.67±0.27) exhibited statistical significance (P<0.01). Fentanyl consumption between Group D (285.50±28.37ug) and Group C (309.50±37.20ug) displayed significantly difference as well (P<0.05).3) Hemodynamic results. At T3(intubation), MAPdi (maximum MAP subtract minimum MAP) and HRmax (maximum HR) manifested statistical significance (P<0.01and P<0.05, respectively).At T4(extubation) HRmax and HRmin showed statistical significance (P<0.01).4) After24hours of surgery, the lymphocyte counts between groups showed statistical significance,GroupD0.96±0.35×109, Group C1.53±1.32×109, P<0.05。5) Because of non-normal distribution of MMSE score (48hours after surgery) and S100beta protein values, these values were expressed as median and range, M (P25-P75), and the Mann-Whitney U-test was used for comparison of MMSE (48hours after surgery) and S100beta. Group D MMSE score28(median range:27-28.75, Group C26(median range:25.25-27), P=0.039. The incidence rate of POCD at every time point varies but failed to exhibit statistical significance inter-groups. In group D at T4, S100beta protein values is lower than that of T1(P<0.05).Conclusion1. Using this dose of dexmedetomidine in our study can spare general anesthetics, and can also attenuate stress response during anesthesia.2. Using this dose of dexmedetomidine in our study can affect lymphocytes counts in a moderate degree.3. We failed to investigate the correlation between S100beta and POCD, the relationship of the two objects still need to be researched further more.4. Using this dose of dexmedetomidine in our study can protect cognitive function of patients in a moderate degree. |
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