Objective To investigate the effect-site concentration for 50% of maximal effect (EC50 )of propofol required for loss of consciousness and onset of burst suppression and to assess the effect of target-control infusion(TCI)of remifentanil on these EC50 of propofol.Methods Sixty patients undergoning general anesthesia for scheduled surgery were randomly divided into 2 groups (n=30):group R received TCI of remifentanil with a target concentraton of 4 ng/ml 10 minutes before TCI of propofol,which started at a target plasma concentration of 1μg/ml and then increased by 1μg/ml step every 1 minute until the burst suppression ratio reach to 15%.Group N received a mock TCI of saline instead of remifentanil and the other procedures were as same as group R.During this,all patients were assessed by modified Observ-er’s Assessment of Alertness/Sedation (OAA/S)scale,the loss of consciousness was definited by modified OAA/S values less than 2,the onset of burst suppression was definited by 15% of burst suppression ratio. Results The EC50 of effect-site concentration of propofol required for loss of consciousness and onset of burst suppression were 2.35 (95%CI 2.29-2.41)and 6.31 (95%CI 6.13-6.47)μg/ml respectively.The EC50 of propofol required for loss of consciousness was decreased to 1.73μg/ml by TCI of remifentanil,but the EC50 of propofol required for onset of burst suppression did not changed by TCI of remifentanil. Conclusion TCI of remifentanil could decrease the EC50 of propofol effect-site concentration required for loss of consciousness but has no effect on the EC50 of propofol required for onset of burst suppression.

Objective To compare the safety and efficacy of the caudal block and Total Intravenous Anesthesia (TIVA) for transrectal ultrasound (TRUS) guided prostate biopsy.Methods 60 elderly patients with transrectal ultrasound guided transperineal prostate biopsy were randomized into Group A and Group B.Patients in Group A received ultrasound guided caudal block (0.33％ ropivacaine 15 ml) and patients in Group B received TIVA.In operation room (T1),immediately before operation (T2) and at the end of operation (T3),mean artery pressure (MAP),heart rate (HR),breathing rate (BR) and pulse oxygen saturation (SpO2) were recorded.The patients in two groups were rated the level of mini-mental state examination (MMES) at 2 h,8 h and 24 h after operation.Complications during the whole study period were also evaluated.Results The values of MAP,HR and BR of T1 in group B were significantly lower than those at T2 (P＜0.05),and were lower than those in the group A (P ＜0.05).The MMSE value in group A [2 h (25.66 ± 1.71) and 8 h (26.13 ± 1.52)] was significantly higher than that in group B [2 h (27.96 ± 1.71) and 8 h (29.01 ± 0.77)] at after operation (P ＜ 0.05).The rate of usage of ephedrine (13％) and assisted ventilation (20％) in group B was higher.No significant differences were detected in side effects between the two groups.Conclusions Caudal block provides better anesthesia than TIVA for TRUS guided prostate biopsy without an increase of side effects,and it may be safely used during ambulatory surgery.

Objective:To explore the value of lumbar plexus-sciatic nerve block combined with low-dose Remimazolam in elderly proximal femoral nail anti-rotation(PFNA)surgery.Methods:60 elderly patients with PFNA surgery were treated from September 2021 to March 2022 in our hospital.They were randomly divided into Propofol group receiving intravenous general anesthesia with laryngeal mask combined with Propofol(control group, n=30)and Remimazolam group with lumbar plexus-sciatic nerve block with laryngeal mask combined with low-dose Remimazolam anesthesia(experimental group, n=30). Mean arterial pressure(MAP)at different time points, heart rate, awakening quality[laryngeal mask removal time], vigilance / sedative observation(OAA / S)score at 15 min after surgery, observation time and various adverse reactions in anesthesia recovery room(in a postanaesthesia care unit, PACU), Montreal cognitive function scale(MoCA)1 day after operation, visual analog score(VAS)at different time points were compared between the two groups.Results:The levels of MAP and HR at the moments of T1, T2, T3, and T4 were lower in the observation group than in the control group(all P<0.05). The time of laryngeal mask removal was shorter in the observation group than in the control group[(8.7±1.3)min and(12.3±1.4)min, t=7.09, P<0.001]. The OAA/S scale value at 15 min after surgery was higher in the observation group than in the control group[(4.6±0.3)and(4.1±0.5), t=4.841, P<0.001]. The incidence of adverse reactions was lower in the observation group than in the control group(3.3% and 20%, χ2=4.043, P=0.044). Visual analogue scale(VAS)value at 3, 6 and 9 hour after surgery were lower in the observation group than in the control group(all P<0.05). The MoCA scores at 6 and 12 hours after operation were higher in the observation group than in the control group( P<0.05). Conclusions:Lumbar plexus-sciatic nerve block combined with low-dose Remimazolam in elderly PFNA surgery is effective and safe, which can reduce the intraoperative hemodynamic fluctuations, optimize the patient's recovery quality, facilitate the postoperative cognitive function recovery, reduce the various adverse reactions, and provide the good analgesic effect within 12 hours after operation.