Objective To evaluate the efficacy of bispectral index (BIS) in guiding sevoflurane anesthesia in children. Methods Forty-eight ASA Ⅰ or Ⅱ pediatric patients aged 1-12 yr undergoing elective urological surgery were randomized into 2 groups ( n = 24 each) : group Ⅰ control and group Ⅱ BITS. Each group was further divided into 3 subgroups according to the age (n = 8 each) : subgroup A ( 1 yr≤age < 3 yr) ,subgroup B (3 yr≤ age<6 yr ) and subgroup C (6 yr≤age ≤ 12 yr). The patients were premedicated with IM atropine 0.015-0.02 mg/kg. Anesthesia was induced with 5% sevoflurane and 60% N2O in O2. Tracheal intubation was facilitated with vecuronium 0.1 mg/kg. Anesthesia was maintained with inhalation of sevoflurane and,50% N2O in O2 and intermittent Ⅳ bolnses of vecuronium and fentanyl. In BIS group, BIS was maintained at 40-60 during operation and at 60-75 during the 15 min before the end of surgery. BIS was monitored and recorded but not available to the anesthesiologist in control group and the depth of anesthesia was maintained based on hemodynamic changes and clinical signs. MAP, HR, end-tidal sevoflurane concentration, BIS, emergence time, extubation time and PACU discharge time were recorded. The amount of sevoflurane consumed was calculated. Results There was no significant difference in the demographic data between the cotresponding age groups of BIS and control group. The BIS were maintained at 40-60 in control group. The BIS was significantly higher in BIS group than in control group except the subgroup A. The end-tidal sevoflurane concentration was significantly lower, and the emergence time, extubation time and PACU discharge time were significantly shorter in BIS group than in control group. There was no significant difference in MAP and HR between the 2 groups. Conclusion BIS monitoring can reduce sevoflurane consumption and allow faster emergence from sevoflurane anesthesia in children over 1 yr of age.

Objective: To examine the effects of midazolam-induced sedation on heart rate variability (HRV). Method:Fifteen ASA Ⅰ- Ⅱ adult patients,undergoing elective surgery under lumbar epidural anesthesia were randomly selected. An intravenous bolus dose of midazolam(1.5mg) was administered every 3-5 minutes until patients' sedation levels assessed by observers assessment of alertness sedation(OAA/S) scale had scores of 1. Spectral analysis of HRV was performed at different OAA/S scores and at 3min,5min and 10min following OAA/S score of 1. Result:All frequency components of HRV were significantly reduced as patients' OAA/S scores decreased,especially low frequency (LF) and total power. Midazolam decreased normalized unit power of LF from 33.5%?8.9% to 16.65?9.6% and increased normalized unit power of high frequency(HF) from 11.7%?4.2% to 20.5%?26.5%. LF/HF ratio also reduced. Conclusion:Midazolam shiftes the balance of autonomic nervous activity toward the parasympathotonic.

Objective To study the effects of propofol on enhancement of persistent sodium currents in isolated rat hippocampal CA1 pyramidal neurons induced by ischemia. Methods Whole-cell patch clamp recordings were made from enzymatically isolated SD rat hippocampal CA1 pyramidal neurons. Ischemia was induced by anoxia and glucose deprivation. Results Both propofol 10 umol.L-1 and 100umol . L-1 significantly inhibited the enhancement of persistent sodium currents induced by ischemia and the effect of propofol 100 umol. L-1 was significantly greater than that of propofol 10umol.L-1 . Propofol 1 umol.L-1 didn't have any significant eflect on the enhanced persistent sodium currents induced by ischemia.Conclusion Propofol can inhibit the enhancement of persistent sodium currents induced by ischemia. It may explain the cerebral protective effect of propofol.

Objective Orthotopic liver transplantation (OLT) without bypass is technically simpler butimposes additional stress and strain on already compromised ciroulatory function and milieu interieur. The purposeof this study was to investigate the changes in arterial blood concentrations of glucose and lactate during OLTwithout bypass. Methods Eighty patients (66 male, 14 female) aged 12-67 yr weighing 40-130 kg undergoingOLT without veno-venous bypass for terminal liver cirrhosis (40 patients), liver cancer (28 patients), hepato-lenticular degeneration (5 patients), polycystic liver (3 patients) and severe hepatitis (4 patients). Nine patientswere classified as ASA physical status Ⅱ, thirty-nine patients as ASA Ⅲ, thirty patients ASA Ⅳ and two patientsASAV. Anesthesia was induced with midazolam 2 mg, fentanyl 10-15?g?kg~(-1), propofol 1 .0 - 1 .5 mg?kg~(-1) andpancuronium 0. 15 mg?kg~(-1) and maintained with isoflurane inhalation and intermittent i. v. boluses of fentanyl,midazolam and pipecuronium. The patients were mechanically ventilated after intubation, P_(ET) CO_2 was maintained at32-35 mm Hg. No fluid containing glucose was infused during operation. Radial artery and internal jugular veinwere cannulated for BP and CVP monitoring. ECG, MAP, CVP, SpO_2, P_(ET)CO_2, temperature and urine outputwere continuously monitored during operation. Blood samples were taken from artery before anesthesia (T_0 ), beforecross-clamping of portal vein (T_1), 30 and 60 min during anhepatic phase (T_2, T_3), 5 and 30 min afterunclamping of vena cava before the unclamping of portal vein (T_4, T_5 ) and at the end of surgery (T_6 ) fordetermination of blood glucose and lactate concentrations. Blood lactate was determined only in 50 patients whoreceived no lactated but acetated Ringer's solution during operation. In 70 patients blood samples were obtainedfrom hepatic vein after unclamping of portal vein and before the end of exsanguination from the hepatic vein fordetermination of blood glucose and lactate. Results No patient developed hypoglycemia during operation. Bloodglucose increased slightly before cross-clamping of portal vein (T_1) and during anhepatic phase (T_2, T_3) comparedwith the baseline value before anesthesia (T_0 ) (P

Objective To evaluate the effects of propofol and thiopontal on calcium and potassium channels in rat ventricular myocytes and to elucidate the underlying mechanisms of their inhibitory effect on myocardium. Methods Freshly isolated ventricular myocytes were prepared from hearts of rats by trypsin. The effects of propofol and thiopental on L-type calcium current(Ica) and delayed rectifier potassium current(IK)were compared using whole-cell patch clump technique. Results Propofol and thiopontal produced a concentration-dependent inhibition of Ica. Peak concentration of propofol(50 ?mol?L~(-1)) and thiopental(100 ?mol?L~(-1)) during induction of anesthesia decreased Ica by 28% and 46% and shifted the steady-state inactivation curve to more negative voltage, but had no effect on the steady-state activation curve. Propofol and thiopental also decreased IK in a concentration-dependent manner, but the effects of both anesthetics on IK were smaller compared with their effects on Ica. Conclusion The findings of this study suggest that the negative inotropic of propofol and thiopental are, at least in part, related to decrease in Ca~(2+) trans-sarcolemmal current by accelerating L-type calcium channel inactivation. Both anesthetics decrease delayed rectifier potassium current, thus partially antagonizing the effect of decreased calcium current.

Objective To investigate the effects of propofol on the release of noradrenaline ( NE) from the locus coeruleus in the brain of rabbits trying to elucidate the central mechanism of the cardiovascular inhibition induced by propofol.Methods Nine healthy male New Zealand rabbits weighing 2.0-2.5 kg were used in this study. A trocar (0.8 mm in diameter) was inserted into locus coeruleus using the stereotactic technique and fixed. Four days later push-pull perfusion of the brain was performed. 37℃ artificial cerebrospinal fluid (aCSF) was infused through the trocar at 0.1 ml?min-1 . A loading dose of propofol 2 mg?kg-1 was given i.v. followed by continuous infusion at 150 ?g?kg-1?min-1 for 30 min. The experiment was concluded at 20 min after propofol infusion. The perfusate having passed through the locus coeruleus was collected before and every 10 min during and after infusion. The NE concentration of the perfusate was measured by high performance liquid chromatography. Results The NE concentration of the perfusate from locus coeruleus significantly decreased after the loading dose and during the infusion of propofol and reached its bottom level at 10 min after loading dose. The maximal decrease was 75.5% [from (15.9 ? 3.2) pg??l-1 to (3.9?0.5) pg ? ?l-1]. Conclusion Intravenous propofol decreases the NE concentration in locus coeruleus. The cardiovascular inhibition induced by propofol may partly be explained by this central mechanism.

Objective: To establish human embryonic kidney(HEK) 293 cell lines that that can stably express the muscle nicotinic acetylcholine receptor(AChR).Methods: The pcDNA3.1 plasmid was constructed and transfected into HEK293 cells with lipofectin,the stable transfectants screened by G418 and the protein expression identified and analyzed by immunohistochemistry.Results: After G418 screening,14 of the transfected cell lines highly expreesed ?-nAchR and 4 showed an obvious expression of ?-nAChR,as demonstrated by the immunohistochemical analysis.Conclusion: HEK293 cell lines stably expressing m-nAChR were constructed successfully.

Objective: To explore the effects of desflurane on systemic and hepatic hemodynamics and oxygen delivery to the liver. Method: 11 healthy mongrel dogs were anesthetized with 0.5 and 1.0 MAC desflurane respectively. The changes of systemic, pulmonary and hepatic hemodynamics,systemic oxgen delivery and consumption,oxygen delivery to the liver were measured continuously. Blood flow of hepatic artery and portal vein was monitored with electromagnetic flowmeter. Result: During inhalation of 0.5 MAC desflurane,HR.MAP.SVR,portal vein and total hepatic oxygen delivery decreased significantly(P

Objective To investigate the effects of midazolam on the delayed rectifier outward potassium channel current (Ik) using the whole-cell patch clamp technique. Methods Pyramidal neurons were isolated acutely from 5-15 d SD rat hippocampus. We measured amplitudes of the delayed outward rectifier potassium currents by activating depolarizing pulse from - 50mV to 30mV. Different concentrations of midazolam were added and potassium channel currents were measured. Results Delayed outward rectifier potassium channel currents were inhibited by midazolam in a dose-dependent manner. EC50 was (8.31 ?2.78) ? 10-8 mol/L and Hill constant was 0.90? 0.16.Conclusions Our results suggest that block of the outward rectifier potassium channel current by midazolam may contribute to the mechanism of midazolam anesthesia action.

Objective To compare the effects of three different crystalloid solutions on arterial blood lactate concentration and acid-base balance during orthotopic liver transplantation (OLT) without veno-venous bypass. Methods Ninety ASA Ⅱ-Ⅳ patients with end-stage liver disease of both sexes (78 males, 12 females) aged 16-67 yrs weighing 45-87 kg undergoing OLT were randomly allocated to one of 3 groups ( n = 30 each): group Ⅰ received normal saline (NS); group Ⅱ received lactated Ringer's solution (LR) and group Ⅲ acetated Ringer's solution (Plasma A, Baxter) (PA). The crystalloid was infused at a rate of 6-8 ml?kg-1?h-1. Colloid, albumin, RBC and whole blood were infused based on BP, CVP and Hb concentration. The arterial pH, BE and lactate concentration were measured before anesthesia (T0 baseline) , before cross-clamping of the portal vein (T1) at 30 min and the end of anhepatic phase (T2,T3) , 5 and 30 min after unclamping of the portal vein (T4,T5) and at the end of surgery (T6). Results There was no significant difference in the amount of crystalloid, colloid and blood products infused during operation among the 3 groups. Arterial pH decreased significantly at T1 (immediately before anhepatic phase) as compared to the baseline value at T0 and the low pH was maintained until the end of operation. BE was significantly decreased during anhepatic phase (at T2 and T3 ) . The blood lactate was increasing during operation and was 3 times that of baseline value at the end of operation. However there was no significant difference in arterial pH, BE and lactate concentration among the 3 groups.Conclusion In OLT without venovenous bypass, blood lactate increases progressively but the lactated Ringer's solution does not have any effect on the blood lactate concentration.