Objective To determine the median effective effect-site concentration (EC50 ) of remifentanil inhibiting responses to laryngeal mask airway insertion when combined with propofol in elderly male patients . Methods Thirty ASA physical status Ⅰ or Ⅱ male patients ,aged 65>yr ,with body mass index <30 kg/m2 , scheduled for elective transurethral resection of bladder tumor or prostate under general anesthesia ,were enrolled in this study .Anesthesia was induced with target-controlled infusion of propofol with a target plasma concentration (Cp) of 3 μg/ml .When Observer′s Assessment of Alertness/Sedation (OAA/S ) score ≤1 ,remifentanil target-controlled infusion was started with the initial target Cp set at 4.0 ng/ml . The concentration of propofol was adjusted until BIS value reached 55-65 ,and then the laryngeal mask airway was inserted .Modified Dixon’s up-and-down method was used to determine the Cp of remifentanil . Each time the Cp of remifentanil increased/decreased in the next patient depending on whether or not the response to laryngeal mask airway insertion occurred . The ratio of the two successive Cps was 1.2 .The response to laryngeal mask airway insertion was defined as development of coughing ,laryngospasm and/or body movement during insertion or within 3 min after insertion .The number of patients in whom inhibition of responses to insertion was effective/ineffective was recorded .The EC50 of remifentanil required to inhibit responses to laryngeal mask airway insertion and the 95% confidence interval when combined with propofol were calculated .Results The EC50 (95% confidence interval ) of remifentanil required to inhibit responses to laryngeal mask airway insertion was 1.86 (1.64-2.12) ng/ml when combined with propofol in elderly male patients .Conclusion The EC50 of remifentanil required to inhibit responses to laryngeal mask airway insertion is 1.86 ng/ml when combined with propofol in elderly male patients .

Objective To investigate the effect of sevoflurane preconditioning on CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) expression in the cerebral cortex after focal cerebral ischemiareperfusion (I/R) injury in rats and the mechanism. Methods Thirty-six male SD rats weighing 250-280 g were randomly divided into 3 groups ( n = 12 each) : sham operation group (group S) , focal cerebral I/R group (group I/R) and sevoflurane preconditioning group (group Sevo-pc). The animals were anesthetized with intraperitoneal chloral hydrate 300 mg/kg. In groups I/R and Sevo-pc, focal cerebral ischemia was induced by middle cerebral artery occlusion using a nylon thread with rounded tip inserted into the right internal carotid artery and advanced cranially until resistance was met. The occlusion was maintained for 1 h followed by 24 h reperfusion. Group Sevo-pc inhaled 2.7% sevoflurane for 1 h before ischemia. Neurological deficits were assessed and scored at the end of 24 h reperfusion and then the rats were decapitated. Their brains were immediately removed. The cerebral infarct size was determined by TTC staining. The CHOP expression in the ischemic cerebral cortex was determined by immunohistochemistry. The number of apoptotic neurons was counted using TUNEL. Results The neurological deficit scores were significantly higher, the cerebral infarct size was significantly larger, and the CHOP expression and the number of apoptotic neurons were significantly higher in groups I/R and Sevo-pc than in group S ( P ＜ 0.01) . The neurological deficit scores were significantly lower, the cerebral infarct size was significantly smaller, and the CHOP expression and the number of apoptosis neurons were significantly lower in group Sevo-pc than in group I/R ( P ＜ 0.05 or 0.01) . Conclusion Sevoflurane preconditioning may protect the brain against focal cerebral I/R injury by down-regulating CHOP expression in the cerebral cortex in rats.

Objective To determine the effective volume of 1.5％ lidocaine for obturator nerve block (ONB) in 50％ of patients (EV50) undergoing transurethral resection of bladder tumor (TURBT).Methods Thirty-six ASA physical status Ⅰ or Ⅱ patients with bladder tumor,aged 18-64 yr,with body mass index of 19-30 kg/m2,scheduled for elective TURBT and required ONB before TURBT,were enrolled in the study.ONB was performed with 1.5 ％ lidocaine using the pubic approach under the guidance of a nerve stimulator.The volume of 1.5％ lidocaine was determined by up-and-down sequential trial.The initial volume of hdocaine was 10 ml and the ratio between the two successive volumes was 1.1.Successful ONB was considered to be positive response.The EV50 and 95 ％ confidence interval (CI) of 1.5 ％ lidocaine for ONB were calculated.Results The EV50 of 1.5 ％ lidocaine for ONB was 5.53 rnl and the 95 ％ CI was 5.10-6.00 ml.Conclusion The EV50 of 1.5 ％ lidocaine is 5.53 ml when used for ONB in patients undergoing TURBT.

Objective To compare the efficacy of suprainguinal approach and pubic tubercle approach to obturator nerve block (ONB) in patients undergoing transurethral resection of bladder tumor.Methods Sixty ASA physical status Ⅰ or Ⅱ patients of both sexes,aged 41-80 yr,with body mass index of 17.5-31.0 kg/m2,scheduled for elective transurethral resection of bladder tumor,were randomly divided into 2 groups (n =30 each) using a random number table:pubic tubercle approach group (group P) and suprainguinal approach group (group S).Nerve blocks were performed using a 100-mm insulated needle for ONB (21-gauge) under the guidance of a nerve stimulator.In group P,the insertion point of the needle was 1.5 cm lateral and 1.5 cm inferior to the pubic tubercle.In S group,the insertion point of the needle was at the midpoint of the line drawn in the inguinal crease between the femoral artery and the inner border of the adductor longus tendon and the needle was advanced 3 cm cephalad in the major axis of thigh.The number of puncture eliciting contraction of adductor muscle,time taken to elicit contraction of adductor muscle starting from onset of puncture,depth of puncture,and highest visual analog scale (VAS) pain scores during application of the block were recorded.The myodynamia of adductor muscle was evaluated.The development of complications was also recorded.Results Compared with group P,the number of puncture,highest VAS scores,and myodynamia of adductor muscle at 4 and 6 min of blockade were significantly decreased,the time taken to elicit contraction of adductor muscle was shortened,and the success rate of puncture at first attempt was increased in group S (P ＜ 0.05 or 0.01).There was no significant difference in the incidence of puncture point bleedings between the two groups (P ＞ 0.05).Conclusion The suprainguinal approach for ONB offers more accurate location,faster onset,lighter degree of noxious stimulation and better safety than the pubic tubercle approach in patients undergoing transurethral resection of bladder tumor.

Objective Comparing the effects of ultrasound with nerve stimulation guided obtu-rator nerve block(ONB)with simple nerve stimulation guided ONB for transurethral resection of blad-der tumor(TURBT),so as to realize the validity and advantages of ultrasound with nerve stimulation guided ONB.Methods Sixty ASA Ⅰ or Ⅱ,male or female,age 39-77 years old,BMI 1 9-30 kg/m2 patients undergoing elective TURBT were randomly divided into two groups,nerve stimulation group (group S)and ultrasound and nerve stimulation group (group US).Success rate of the first puncture, visual analog scale (VAS)pain score,insertion-adductor contraction interval (ICI),puncture times corresponding to ICI,adductor strength,incidence of complications and validity were observed during and after ONB.Results There was no significant difference of the general validity,adductor strength and complication incidence between the two groups.The success rate of the first puncture was signifi-cantly higher in group US than that in group S (P < 0.01).VAS pain score,ICI and puncture times were significantly lower in group US than those in group S (P < 0.05).Conclusion Compared with simple nerve stimulation guided ONB,ultrasound with nerve stimulation guidance showed less punc-ture time,more accurate positioning and more comfort.

Objective To determine the median effective concentration (EC50) of lidocaine for obturator nerve block (ONB) guided by a nerve stimulator in patients undergoing transurethral resection of bladder tumor (TURBT).Methods American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients with bladder tumor,scheduled for elective TURBT,required ONB according to the results of cystoscopy or CT examination performed before operation,with body mass index of 19-30 kg/m2,aged 18-64 yr,were enrolled in the study.ONB was performed with lidocaine using the suprainguinal approach under the guidance of a nerve stimulator.The concentration of lidocaine was determined by up-and-down sequential trial.The initial concentration of lidocaine was 1.5％,and the ratio between the two successive concentrations was 1.2.Successful ONB was considered to be positive response.The EC50 and 95％ confidence interval of lidocaine for ONB guided by a nerve stimulator was calculated.Results The EC50 of lidocaine was 0.57％,and the 95％ confidence interval was 0.55％-0.59％ when used for ONB guided by a nerve stimulator.Conclusion The EC50 of lidocaine is 0.57％ when used for ONB guided by a nerve stimulator in the patients undergoing TURBT.

Objective To evaluate development of gastro-esophageal reflux (GER) during laparoscopic surgery in lateral jack-knife position under general anesthesia through comparing with reverse Trendelenburg/ Trendelenburg position in the patients lying supine.Methods Ninety patients of both sexes,aged 18-64 yr,of ASA physical status Ⅰ or Ⅱ,with body mass index of 18-30 kg/m2,scheduled for elective laparoscopic surgery under general anesthesia,were randomly divided into 3 groups (n =30 each):lateral jack-knife position group (group L),Trendelenburg position group (group T) and reverse Trendelenburg position group (group Tre).Anesthesia was induced with midazolam,sufentanil,propofol and cisatracurium besylate and maintained with propofol and remifentanil given by target-controlled infusion.A pH-sensitive probe was inserted through nose into the lower esophagus and pH value was continuously recorded until 1 min after extubation.GER was defined as pH value ≤ 4 lasting for ≥ 1 min in the lower esophagus during surgery.The development of GER during surgery and the lowest pH value in the lower esophagus when GER developed were recorded.Results Compared with group Tre,the incidence of GER (27％) and total number of times GER had occurred were significantly increased in group L,and no significant changes were found in the indices mentioned above in L and T groups.When GER developed,the lowest pH value in the lower esophagus was 2.1 ± 1.3,2.6 ± 1.2 and 3.5 in L,T and Tre groups,respectively.Conclusion The incidence of GER is 27 ％ during laparoscopic surgery when the patients are in lateral jack-knife position and it is higher than that obtained with reverse Trendelenburg position in the patients lying supine.

Objective To determine the median effective target effect-site concentration (EC50) of sufentanil inhibiting responses to insertion of laryngeal mask airway (LMA) when combined with propofol in the elderly patients.Methods ASA physical status Ⅰ or Ⅱ patients,aged 66-75 yr,with body mass index of 19-30 kg/m2,scheduled for elective transurethral resection of prostate under general anesthesia,were included in this study.Anesthesia was induced with propofol given by target-controlled infusion.The initial target effect-site concentration (Ce) of propofol was 1 μg/ml,and the Ce was increased by 0.5 μg/ml every 1 min until it was increased to 2 μg/ml and maintained at this level for 5 min.Sufentanil was simultaneously administered by target-controlled infusion.The target Ce of sufentanil was 0.3 ng/ml in the first patient.The concentration of sufentanil was determined using the modified Dixon's up-and-down method.After the patients lost consciousness,LMA was inserted after the target effect-site and plasma concentrations were balanced.The insertion response was defined as positive when MAP and HR increased by 20％ of the baseline value within 5 min after insertion of LMA.The Ce of sufentanil was increased/decreased in the next patient if the insertion response was positive or negative.The ratio between the two successive concentrations was 1.2.The EC50 and 95 ％ confidence interval of sufentanil blunting responses to insertion of LMA was calculated using Probit analysis.Results When combined with propofol,the EC50 (95％ confidence interval) of sufentanil blunting responses to insertion of LMA was 0.160 (0.130-0.188) ng/ml.Conclusion The EC50 of sufentanil inhibiting responses to insertion of LMA is 0.160 ng/ml when combined with propofol in the elderly patients.

Objective To evaluate the effect of hydrogen-rich saline on Toll-like receptor 4 (TLR4) /nuclear factor kappa B (NF-κB) signaling pathway in the sciatic nerve of rats with diabetic neuropathic pain (DNP).Methods Pathogen-free male Sprague-Dawley rats, aged 8 weeks, weighing 180-210 g, were used in the study.DPN model was established by intraperitoneal injection of 1％ streptozocin (STZ) 65 mg/kg.Twenty-four diabetic rats were randomly divided into 2 groups (n =12 each) using a random number table: DPN group and hydrogen-rich saline group (HRS group).Another 12 normal rats were randomly selected and served as control group (group C).At 14 days after STZ injection, hydrogenrich saline 5 ml/kg was injected intraperitoneally once a day for 14 consecutive days in group HRS, while the equal volume of normal saline was given in C and DNP groups.Mechanical paw withdrawal threshold to yon Frey stimuli (MWT) and thermal paw withdrawal latency (TWL) were measured at 2 days before STZ injection (T0) , and 7, 14, 21 and 28 days after STZ injection (T1-4).The motor nerve conduction velocity (MNCV) of the right hindlimb was measured after pain threshold was measured at T4.After measurement of neurological function was completed, the expression of TLR4 and NF-κB was detected in the sciatic nerve (by Western blot) , the tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) contents in sciatic nerves were measured by enzyme-linked immunosorbent assay, and the neuronal apoptosis was detected by TUNEL.The apoptosis index was calculated.Results Compared with group C, the MWT was significantly decreased at T1-4, TWL was shortened at T2-4, and MNCV was decreased at T4, the expression of TLR4 and NF-κB, contents of TNF-α and IL-6, and apoptosis index were increased in HRS and DNP groups (P＜0.05).Compared with group DNP, the MWT was significantly increased, and TWL was prolonged at T3,4 MNCV was increased T4, and the expression of TLR4 and NF-κB, contents of TNF-α and IL-6, and apoptosis index were decreased in group HRS (P＜ 0.05).Conclusion Hydrogen-rich saline can mitigate DNP through blocking TLR4/NF-κB signaling pathway in the sciatic nerve of rats.

Objective To evaluate the effect of hydrogen?rich saline on nuclear factor erythroid 2?related factor 2 ( Nrf2)∕antioxidant response element ( ARE) pathway in the peripheral nerve in a rat model of diabetic neuropathic pain ( DNP ) . Methods Thirty?six healthy male Sprague?Dawley rats, aged 8 weeks, weighing 180-200 g, were randomly divided into 3 groups ( n=12 each) using a random number table: control group ( C group) , DNP group and hydrogen?rich saline group ( HRS group) . Diabetes melli?tus was produced by intraperitoneal 1% streptozocin ( STZ) 65 mg∕kg and confirmed by fasting blood glucose concentration>16?67 mmol∕L. Hydrogen?rich saline 5 ml∕kg was injected intraperitoneally once a day for 14 consecutive days starting from 14 days after STZ injection in group HRS, and the equal volume of normal saline was given in C and DNP groups. The mechanical paw withdrawal threshold ( MWT) and thermal paw withdrawal latency ( TWL) were measured at 2 days before STZ injection ( T0 ) , and 7, 14, 21 and 28 days after STZ injection ( T1?4 ) . After measurement of the pain threshold at T4 , the motor nerve conduction velocity ( MNCV) of the right hindlimb and distal motor latency were measured. The expression of Nrf2 in nucleoprotein and HO?1 and NQO1 in total protein was detected in the sciatic nerve by Western blot. Re?sults Compared with group C, the MWT was significantly decreased, and the TWL was shortened at T1?4 , and the expression of Nrf2 in nucleoprotein and HO?1 and NQO1 in total protein was up?regulated in DNP and HRS groups (P<0?05). Compared with group DNP, the MWT was significantly increased, and the TWL was prolonged at T3 and T4 , and the expression of Nrf2 in nucleoprotein and HO?1 and NQO1 in total protein was up?regulated in group HRS ( P<0?05) . Conclusion The mechanism by which hydrogen?rich saline mitigates DNP is related to activated Nrf2∕ARE pathway in the peripheral nerve of rats.