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Objective:To evaluate the effect of general anesthesia guided by electroencephalography (EEG) monitoring on postoperative delirium (POD) in elderly patients with non-acute fragile brain function.Methods:Sixty patients of both sexes with non-acute fragile brain function, aged 65-85 yr, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, with body mass index of 18-30 kg/m 2, undergoing hip replacement, were divided into 2 groups ( n=30 each) by a random number table method: conventional general anesthesia group (group C) and general anesthesia guided by EEG monitoring group (group E). Anesthesia was maintained by intravenous infusion of propofol 50-150 μg·kg -1·min -1 and remifentanil 0.05-0.30 μg·kg -1·min -1 and intermittent intravenous boluses of rocuronium.In group E, the dose of anesthetic was reduced when the EEG burst-suppression ratio≥10% for more than 1 min or anesthesia index (AI) <40.If the situation mentioned above still existed after 1 min, the dose of anesthetic was continued to be reduced or norepinephrine was injected intravenously.In group C, the amount of intraoperative anesthesia was adjusted according to the changes in hemodynamics.Norepinephrine 4-10 μg or dopamine 1 mg was given intravenously in the light of the patients′ heart rates when intraoperative hypotension occurred.At 10 min after anesthesia induction, immediately after skin incision, immediately at the end of surgery and at 1 h after surgery, blood samples were obtained from the artery and jugular venous bulb for blood gas analysis and for calculation of jugular bulb blood oxygen content (CjvO 2), artery-jugular bulb blood oxygen content difference (Ca-jvO 2), cerebral oxygen uptake rate (CERO 2) and jugular-arterial blood lactate concentration difference (Djv-aLac). The emergence time, amounts of intraoperative anesthetics, use of noradrenaline, cumulative time of EEG burst inhibition and duration of AI<40 were recorded.The development of POD was assessed within 5 days after surgery by the confusion assessment method for the intensive care unit and the duration was recorded. Results:Compared with group C, recovery time, cumulative time of EEG burst inhibition and duration of AI<40 were significantly shortened, the intraoperative consumption of propofol and remifentanil was decreased, the requirement for intraoperative noradrenaline was increased, CjvO 2 was increased, Ca-jvO 2 and CERO 2 were decreased immediately at the end of surgery and at 1 h after surgery, the incidence of POD within 5 days after surgery was decreased, and POD duration was shortened in group E ( P<0.05). Conclusion:General anesthesia guided by EEG monitoring can reduce the development of POD in elderly patients with non-acute fragile brain function.
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Objective To evaluate the relationship between postoperative cognitive dysfunction and inflammatory responses of patients with non-acute fragile brain function. Methods Sixty American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients of both sexes, aged 65-83 yr, weighing 52-85 kg, scheduled for elective lumbar spinal internal fixation under general anesthesia, were divided into 2 groups (n=30 each) using a random number table method: brain function normal control group (group C) and non-acute fragile brain function group ( group F) . The blood samples were obtained from the peripheral vein at 30 min before anesthesia induction, at the end of operation and at 2 days after operation to determine the concentrations of tumor necrosis factor-alpha ( TNF-α) , interleukin-6 ( IL-6) , IL-10 and C-reactive pro-tein by enzyme-linked immunosorbent assay. Confusion assessment method was used to assess the develop-ment of delirium at 2 days after operation. Mini Mental State Examination was used to assess the develop-ment of postoperative cognitive dysfunction at 7 days after operation. Results Compared with the baseline at 30 min before anesthesia induction, the concentrations of TNF-α, IL-6 and C-reactive protein in plasma were significantly increased at 2 days after operation in two groups ( P<0. 05) . Compared with group C, the concentrations of TNF-α and IL-6 in plasma and incidence of postoperative delirium were significantly in-creased at 2 days after operation in group F ( P<0. 05) . Conclusion The mechanism of delirium occurred after surgery may be related to inflammatory responses of patients with non-acute fragile brain function.