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 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 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 effects of propofol sedation on different areas of cerebral cortex and memory during operation performed under epidural anesthesia using EEG non-linear monitor and determine the critical value of approximate entropy, the EEG non-linear parameter, without implicit memory.Methods Ten ASA I or II patients of both sexes aged 42-56 yr weighing 59-73 kg undergoing elective abdominal or lower limb operation under epidural anesthesia were enrolled in the study. The patients were unpremedicated. After correct placement of epidural catheter was confirmed, a mixture of 2% lidocaine and 0.3% tetracaine 13-15 ml was injected via the catheter. Propofol was then infused i.v. at 6 mg?kg-1?h-1 for sedation. BP, HR and SpO2 were continuously monitored. The EEG non-linear monitor (ZN16E) was used. The sensors were placed on frontal (FP1 , FP2 ) , temporal (T3 , T4 ), parietal (C3 , C4 ) and occipital ( O1 , O2 ) regions. Approximate entropy and topographic map of approximate entropy were recorded before and during propofol infusion. Sedation scores (OAA/S, 1 = deep sleep, 5 = alert) were assessed during operation The patients' explicit and implicit memory scores were estimated by Process Dissociation Procedure during anesthesia sedateon Results The approximate entropy was significantly decreased during propofol sedation compared to the baseline value before sedation. OAA/S score were maintained at 1 during operation. The explicit and implicit memory scores were significantly decreased during propofol sedation compared to the baseline scores before anesthesia sedation( P

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

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