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

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 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 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 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

Objective To study the effect of inhalational anesthetics on brain cortices under inhalational and intravenous combined anesthesia. Methods 45 patients were randomly divided into isoflurane group (n=15), sevoflurane group (n=15) and desoflurane group (n=15). The narcosis was maintained with inhalational and intravenous combined anesthesia. The EEG non-linear parameters including approximate entropy (ApEn) and correlation dimension (D 2 ) were recorded during operation periods. BP, HR, and SpO 2 were monitored routinely. Results Comparing with that at entrance to the operating room, the EEG activities of frontal and temporal cortices after anesthesia were more suppressed than other cortices. Comparing with that at entrance to the operating room, ApEn and D 2 were significantly declined in the three experimental groups (P

Objective To study effect of propofol on different areas of brain cortex under total intravenous propofol and fentanyl anesthesia. Methods 20 patients were randomly divided into propofol 8mg/(kg?h) group (n=10) and 10mg/(kg?h) group (n=10). The anesthesia was maintained by total intravenous propofol and fentanyl anesthesia. The EEG non-linear parameters, i.e. approximate entropy (ApEn)and correlation dimension (D 2), were recorded during perioperative periods. BP, HR, SpO 2 were monitored routinely. Results Compared with that at entry of OR, the EEG activities of frontal, parietal, and temporal cortices after anesthesia were more inhibited than that of other areas in both groups. Also EEG non-linear parameters were lower significantly after anesthesia in both groups compared with those at entry of OR (P

0.05).Furthermore,logistic regressive equations of prediction probability and RE,SE,BIS were calculated as ln [Pk/(1-Pk)]=-19.825+0.243x,ln [Pk/(1-Pk)]=-18.012+0.236x and ln [Pk/(1-Pk)]=-21.780+0.316x,respectively.From the perspective of sensitivity/specificity,RE,SE and BIS had threshold values for regaining consciousness of 83,76 and 71 with sensitivity/specificity of 0.90/0.85,0.89/0.80 and 0.88/0.78,respectively.RE was 30s earlier than BIS in predicting regaining consciousness.Conclusion Compared with BIS,entropy index seems to be a more accurate and sensitive electroencephalographic measure,and is promising in clinical application.

0.05),while the entropy index showed significant differences between the two groups(P