Objective To compare cerebral oximetry(rSO 2 %)and somatosensory evoked potential (N 35 ) in their accuracy in monitoring cerebral perfusion during carotid endarterectomy procedure under general anesthesia. Methods Ten patients (6 males, 4 females), scheduled for selective carotid endarterectomy, were enrolled in the study. Their rSO 2 %and N 35 were also continuously monitored and recorded during perioperative periods. The patients' cognitive function was evaluated at the same time. The MAP, HR, SpO 2 were continuously monitored during operation. Results There was a significant difference in rSO 2 % between that at the period of elamping and that at the period of declamping of the carotid artery. No patients suffered from cognition dysfunction during perioperative period. Conclusion With comparison to the amplitude of N 35 it was rSO 2 % which was earlier to show alteration in cerebral perfusion in case of cerebral oxygen deficit. In monitoring cerebral perfusion, rSO 2 % was better than N 35

Objective To investigate the relationship of intraoperative cerebral oxygen saturation(rSO_2 )monitored with near-infrared cerebral oximeter (INNOS 5100) and postoperative cognitive dysfunction in patientsoperated upon under isoflurane or sevoflurane anesthesia and to determine the critical rSO_2 value below whichpostoperative cognitive dysfunction may occur.Methods Sixty ASA Ⅰ- Ⅱ patients of both sexes aged 62-80 yr,weighing58-77 kg schedules for elective abdominal surgery or surgery on the low limb were divided into threegroups according to their levels of education: group Ⅰthe illierate and uneducated (n = 20); group Ⅱ primaryschool education (6yr education (n = 20). Each group was furtherdivided into isoflurane and sevoflurane subgroups (n = 10 in each subgroup). The patients were unpremedicated.Anesthesia was induced with intravenous atropine 0. 3mg, propofol 1 .0-1. 5 mg?kg~(-1), fentanyl 2-3?g?kg~(-1) andvecuronium o. 1-0.2 mg?kg~(-1) and maintained with isoflurane or sevoflurane inhalation (0.9-1. 1 MAC )supplemented with intermittent i.v. boluses of fentanyl and recorded before anesthesia (baseline), after O_2inhalation(T_1), after induction of anesthesia(T_2), after skin incision (T_3), during operation (T_4)and at the end ofsurgery (T_5). Mini-Mental State Examination (MMSE) was performed before anesthesia and 1,4, 8, 12 and 24 hafter surgery. BP, HR, ECG, SpO_2, P_(ET) CO_2 and end-tidal concentration of inhalational anesthetics werecontinuously monitored during anesthesia. Results In all three groups rSO_2 was significantly lower during operation(T_4) and at the end of surgery (T_5 ) than baseline (T_0 ) (P

0.05) ,but the BIS and SEF95% were significantly different between the isoflurane group and the desoflurane group (P

Objective To evaluate the accuracy of spectral entropy including response entropy(RE)and state entropy(SE)as a new electroencephalographic measure of depth of sedation during general anesthesia.Methods Twenty ASA Ⅰ or Ⅱ patients aged 20-55 yr undergoing elective abdominal surgery were studied.Anesthesia Was induced with intravenous propofol,fentanyl and vecuronium.After tracheal intubation anesthesia was maintained with sevoflurane inhalation and intermittent iv boluses of fentanyl and vecuronium.BP,HR,SpO2,spectral entropy(Datex-Ohmeda)and BIS(Aspect Medical)were monitored during anesthesia.Loss of eyelash reflex and unresponsiveness to verbal stimulus and mild prodding and shaking were considered to be signs of loss of consciousness(LOC).The time of regaining consciousness Was defined as the time when patients started responding to verbal commands.RE,SE and BIS were recorded before anesthesia(baseline),10 min before LOC,immediately after LOC,immediately after tracbeal intubation,1 h after skin incision,10 min before regaining consciousness immediately after consciousness was regained and 10 min after extubation.Results There were sisnificant changes in RE,SE and BIS during the transition from consciousness to LOC.The RE,SE and BIS values for LOC were 76,73 and 68 with sensitivity of 94%,95%and 92%and specificity of 92%,94%and 91%respectively.The accuracy of RE.SE and BIS in predicting LOC was 93%,95%and 94%respectively.The RE,SE and BIS values for regaining consciousness were 82,75 and 70 with sensitivity of 95%,95%and 91%and specificity of 93%,96%and 93%respectively.The accuracy in predicting regaining of consciousness was 98%,96%and 97%respectively.Conclusion Entropy index Can accurately monitor level of sedation during general anesthesia.

Objective To investigate the relationship between intraoperative cerebral oxygen saturation (rSO2) and postoperative cognitive dysfunction with near-infrared cerebral oximeter (INVOS 5100) in patients operated under inhalational combined intravenous anesthesia, and to determine the critical rSO2 value below which postoperative cognitive dysfunction may occur. Methods Sixty ASAⅠ-Ⅱ patients of both sexes were selected, aged 62-80yr, weighed 58-77kg, scheduled for elective abdominal surgery or surgery on the low limb. All the patients were divided into three groups according to their educational background: in group Ⅰ were the illiterate and uneducated patients (n=20);group Ⅱ the primarily educated patients (<6yr education) (n=20), and group Ⅱ the well educated patients (>6yr education) (n=20). Each group was further divided into isoflurane and sevoflurane subgroups (n=10 in each subgroup). All patients received no pre-medication. Anesthesia was induced with intravenous atropine 0.3mg, propofol 1.0-1.5mg kg-1, fentanyl 2-3μg*kg-1 and vecuronium 0.1-0.2mg*kg-1, and maintained with isoflurane or sevoflurane inhalation(0.9-1.1 MAC) supplemented with intermittent i.v. boluses of fentanyl, and recorded after entering room (baseline) (T0), after O2 inhalation (T1), after induction of anesthesia (T2), after skin incision (T3), during operation (T4), the end of surgery (T5), and awaking (T6). Mini-Mental State Examination (MMSE) was performed before anesthesia and 1, 4, 8, 12 and 24h after surgery. BP, HR, ECG, SpO2, PETCO2 and end-tidal concentration of inhalational anesthetics were continuously monitored during anesthesia. Results In all three groups rSO2 was significantly lower during operation (T4) and at the end of surgery (T5) than baseline (T0) (P<0.05). In all patients the MMSE scores at 1h after operation were significantly lower than the baseline value (P<0.05). The MMES scores in all patients significantly declined within 1-4h after surgery, and the cognitive function recovered at 4h after surgery in 85% patients. The critical values of rSO2 below which postoperative cognition dysfunction may occur were: 45 (group Ⅰ), 47 (group Ⅱ) and 49 (group Ⅲ) for isoflurane anesthesia subgroups;47 (group Ⅰ), 48 (group Ⅱ) and 50 (group Ⅲ) for sevoflurane subgroups. Conclusion The perioperative rSO2 should be maintained up to above 50% to reduce the incidence of postoperative cognitive dysfunction under inhalational combined intravenous anesthesia.

Objective To study the relationship of implicit memory and amnesia effect of oral midazolarn premedication and toobserve its anterograde amnesia, the effect on short-term memory and the onset time and out come of retrograde amnesia. Methods60 patients with ASA I - Ⅱ status undergoing abdomen and limb operations were divided into 3 groups with 20 cases each. Group A:oral midazolam 7.5mg;Group B:oral 15mg;Group C:placebo. The patients received combined spinal-epidural anesthesia after oral midazolam. The parameterns of EEG, SEF 95 %, BISwere collected at the same time and the degree and remark of sedation were dome according to OAA/S. The amnesia and implicit memory were investigated with pictures and muddy identified hearing rate 6 hours after operation. Results (1)Twenty min following drug ad dministration the remarks of sedation of group A and B were significantly loWver than that before and that of group C, Which was not significently different between group A and B. ( 2)The amnesia rates tested six hrs after surgery were significantly higher at 30min in group A, 20min in group B than those before treatment and were kept at 70%-80% levels, which in group C was remained zero. (3)The muddy identified hearing rate was not different significantly, among the three groups. (4) The short-term memory was all 100%during the period of drug action. (5)BIS and SEF 95% Were lower 30min after the treatment and all kept at 80 Hz and 20 Hz, which were not different remarkably between group A and B. ConclnsionOral midazolam 7. 5mg has a good effect on anterograde amnesia 30min after treatment, which may not be improved with increament in dosage. It does not lead to retrograde amnesia. The long-term memory, but not short-term memory, was impaired by midazolam. It only affects the explicit memory. Oral premnedication with midazolam can not prevent the awareness during operation totally.

Objective To investigate the effects of different depths of sedation during combined intravenous-inhalational anesthesia on postoperative cognitive function in patients undergoing gynecological laparoscopic surgery.Methods Ninety ASA Ⅰ or Ⅱ patients,aged 20-64 yr,with a body mass index of 19-30 kg/m2,scheduled for elective gynecological laparoscopic operation,were randomly divided into 3 groups (n =30 each).Anesthesia was induced with midazolam,fentanyl,propofol and rocuronium.The patients were tracheal intubated and mechanically ventilated.Anesthesia was maintained with inhalation of sevoflurane (end-tidal concentration 1.0％-1.5 ％),iv infusion of remifentanil and intermittent iv boluses of rocuronium.The infusion rate of remifentanil was adjusted to maintain BIS value:30 ＜ BIS value ≤ 40 in group Ⅰ,40 BIS value ≤ 50 in group Ⅱ and 50 ＜ BIS value≤60 in group Ⅲ.Cognitive function was assessed using Mini-Mental State Examination (MMSE) and TrailMaking Test (TMT) at 1 d before anesthesia and 1 d after surgery.Results MMSE scores were ＞ 24 at 1 d before anesthesia and 1 d after surgery in all the three groups,and there was no significant difference within each group and among the three groups (P ＞ 0.05).Compared with the baseline value,TMT completion time was significantly prolonged at 1 d after surgery in groups Ⅰ and Ⅲ,while shortened in group Ⅱ (P ＜ 0.05).Compared with groups Ⅰ and Ⅲ,TMT completion time was significantly shortened at 1 d after surgery in group Ⅱ (P ＜0.05).Conclusion The depth of sedation,40 ＜ BIS value ≤ 50,during combined intravenous-inhalational anesthesia with sevoflurane and remifentanil has less influence on postoperative cognitive function in patients undergoing gynecological laparoscopic surgery.

Objective To investigate the changes in non-linear dynamics properties of EEG and the application of real-time monitoring of non-linear indexes during the course of general anesthesia. Methods EEG was recorded in 65 patients undergoing operations. They were randomly divided into five groups: isoflurane, sevoflurane, desflurane (n=15, respectively), propofol 8mg/(kg?h) and propofol 10mg/(kg?h) (n=10, respectively). The EEG derived parameters correlation dimension (D 2 ) and approximate entropy (ApEn) non-linear indexes were calculated simultaneously during the whole operation, including the time of entering the operation room, anesthetic induction, intraoperation, recovery, and regaining consciousness. Results At the time of entering the operation room, their D 2 and ApEn nonlinear indexes appeared to be highest. Both the indexes decreased swiftly during anesthetic induction, and they dropped to lower values and leveled off during the intra-operation period. During recovery period, both of them rose gradually and returned to a high level in the post-operation awaking period. Conclusions Changes in the depth of anesthesia could be real-timely monitored and precisely measured with non-linear indexes of EEG. Non-linear dynamic analysis might provide us with more information on consciousness during general anesthesia

Objective To study the brain distribution of propofol and its effect on memory under intravenous combined anesthesia. Methods 20 patients undergoing elective abdominal abdomen and limb operations were randomly divided into propofol 8mg?kg -1 ?h -1 group (n=10) and 10mg?kg -1 ?h -1 group (n=10). The perioperative EEG non-linear topographic map of approximate entropy was recorded. The perioperative patients' memory was estimated by process dissociation procedure (PDP) after operation. Results Comparing with pre-operative examination results, the intra-operation explicit and implicit memory markedly declined in both propofol 8mg?kg -1 ?h -1 group and 10mg?kg -1 ?h -1 group. There was statistically significant difference between the pre-operative and intra-operative explicit and implicit memory (P

Objective To study the cerebral distribution of inhalational anesthetics and their effect on memory under inhalational combined with intravenous anesthesia. Methods 45 patients, undergoing elective abdominal and limb operations, were randomly divided into: isoflurane group (n=15), sevoflurane group (n=15), and desoflurane group (n=15). The narcosis was maintained by inhalational anesthetics combined with intravenous anesthetics. EEG non-linear topographic map of approximate entropy was recorded. The perioperative memory of the patients was estimated by process dissociation procedure (PDP) after patients awoke. Results Comparing with pre-operative examination results, there was distinct declination of intra-operation explicit and implicit memory in all three groups, and the difference was statistically siqnificant (P