There is evidence that onset time and potency of the non-depolarizing neuromuscular blocking agents are related. The relationship between onset time and the rate of recovery has been less well studied. In this experiment, the myodynamie response of adductor pollicis to single electric stimulation of wrist ulnar nerve, served as the parameter of neuromuscular blockade, and with the isolated forearm technique being used, the onset and offset times of vecuronium, pancuronium, mivacuronium or doxacurium were recorded in four adult healthy volunteers respectively. The results indicated that there was a positive correlation between onset and offset times (r=0.958, P

Objective To investigate the changes in cerebral cAMP and PKA levels during development of acute opioid tolerance induced by remifentanil and to determine whether post-receptor cAMP/PKA signaling pathway is involved in the process. Methods Fifty-six male Kunming mice weighing 25-35 g were randomly divided into 5 groups: group Ⅰ control (C) (n=8); group Ⅱ received morphine infused intraperitoneally (IP) at 0.6 μg'kg-1·min-1 for 120min(M) (n=8); group Ⅲ,Ⅳ,Ⅴ received remifentnil infused IP at 0.4, 0.8 and 1.6 μg·kg-1·min-1 for 120 min(R1=8, R2n=8; R3 n=24).Control group received IP infusion of normal saline. Tail-flick test was performed td measure the response of animals to a thermal nociceptive stimulus before IP infusion, at 30, 60, 90 and 120 min after beginning of IP infusion and at 15, 30, 45 and 60 min after termination of IP infusion. Eight animals were decapitated at 60 min after termination of IP infusion in all 5 groups and the other 16 animals in group R3 were decapitated at 30 and 45 min after termination of IP infusion (n=8 each) for determination of intracellular contents of cAMP and activities of PKA in cerebral cortex and inferior colliculus-striatum by ELISA or radioactive isotope [32p,] ATP-catalyzing assay. Results The tail-flick latency was significantly prolonged during IP infusion as compared with the baseline before infusion in group M, R1 , R2 and R3 but became significantly shorter at 30 and 45 min after infusion than the baseline values in group R1, R2 and R3indicating hyperalgesia after remifentauil infusion. The cerebral contents of cAMP and PKA activities at 60 min after termination of infusion were comparable or decreased in group M, R1, R2 and R3 as compared with group C. There was no significant difference in cerebral cAMP contents and PKA activities at 30, 60 and 45 min after IP remifentanil infusion in group R3. Conclusion Remifentanil can induce acute hyperalgesic effect on mice, and there is no up-regulation of post-receptor cAMP/PKA signaling pathway in the acute opioid tolerance, which is not similar to that chronic opioid tolerance.

Objective: To investigate the changes of gastric intramucosal pH(pHi)and the association with hemody namics and oxygen utilization during cardiopulmonary bypass (CPB). Method: Adults (n=15)free of hepatic, pulmonary,and renal diseases undergoing nonemergent heart surgery,were selected. After induction of general anesthesia and endotracheal intubation,a tonometer nasogastric tube was positioned in the stomach to determine the intramucosal pH. Hemodynamics and oxygen utilization data and phi were measured at four times:30 minutes after induction of anesthesia; 15 minutes after termination of cardiopulmonary bypass; at the terminal of the surgery;and 1 day after the surgery. Result: Cardiac index significantly increased(P

Objective: To study the effects of the different doses of midazolam in fibreoptic gastroscopy on sedation, respiratory and circulatory function. Method: One hundred and four outpatients undergoing fibreoptic gastroscopy were randomly divided into four groups. The control group(N)was not given drugs, the other groups were intravenously given midazolam 0.07mg/kg(MS),0.05mg/kg(M),diazepam 10mg(D)respectively. The sedative scores, symptom, amnesia,HR,MAP and blood gases were observed. Result: The sedative scores of MS,M and D groups were much better than that of control group. There were significant differences in sedative scores,amnesia and sedative period between MS group and D group or M group. MAP decreased one minute after administering the drugs in MS,D and M groups significantly. The results of blood gases analysis of all groups were in normal ranges. Conclusion: Midazolam 0.07mg/kg can produce safe and effective sedation for fibreoptic gastroscopy.

Objective To evaluate the effect of lidocaine on delayed neuroal death after global cerebral ischemia. Methods Global cerebral ischemia was induced by the occlusions of bilateral commom carotid and vertebral arteries . Twenty-five rabbits were randomly divided into three groups:sham operative group (SH group,n=5) without the four-vessel occlusion; ischemia group(IS group,n=10) with intravenous normal saline of 15 ml followed by the four-vessel occlusion for 5 min; lidocaine group (LI group,n=10) with intravenous lidocaine of 10mg/kg followed by the four-vessel occlusion for 5 min. Three days later, every cerebrum was resected and stained using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) and hematoxylin-eosin (HE) methods,to count the amount of the positive stained cells of hippocampus. Results The positive cell amount of HE staining (ischemic change cells) was correlated with that of TUNEL staining (apoptosis cells) (r=0.915).Compared with that in SH group, the amount of apoptosis cells increased significantly in IS and LI groups (P

Objective To study the effect of variant concentrations of lidocaine on voltage-dependent sodium current in dissociated hippocampal neurons of the ratMethods Voltage-dependent sodium currents in dissociated hippocampal neurons of the rat were recorded by whole-cell configuration of the patch clamp when a series of doses of lidocaine (10 -5mol/L-10 -2mol/L) were appliedResults Lidocaine reduced the amplitude of sodium current in a dose-dependent manner, with EC50 of (039?005)mmol/LConclusions Voltage-dependent sodium channel is related to cerebral protective effect of lidocaine, but has nothing to do with its nervous toxicity

Objective To observe the time profile of the changes of mRNA of ? and ? subunit of acetylcholine receptor (AChR) in skeletal muscle and the level of calcitonin gene related peptide (CGRP) in spinal motoneuron after upper motoneuron injury. Method The spinal cord of adult male Wistar rats was transected on the lower thoracic segment. The spinal cords below the transection level and soleus muscles were sampled 0,1,2,4,7 and 14 days after surgery, respectively, to detect the levels of mRNA of ? and ? subunit of acetylcholine receptor in soleus muscle using Northern blot method,and CGRP level in spinal motoneuron using radioimmunoassay.Results The levels of mRNA of ? and ? subunit of acetylcholine receptor siginificantly increased after surgery, but the level of mRNA of ? subunit increased earlier and higher than ? subunit. The level of CGRP in spinal motoneuron markedly reduced after surgery, was maintained at 50 80% of normal level since the 2nd day after surgery. Conclusions The levels of AChR ? and ? subunit in skeletal muscle significantly increase after upper motoneuron injury, the expression of which CGRP may regulate.

Objective To assess the changes in coagulation induced by acute normovolemic hemodilution Methods Twenty ASA Ⅰ Ⅱ patients scheduled for elective surgery were divided into two groups: HES group and GEL group in which hydroxyethyl starch(HES) or succinylated gelatin (GEL) was used as the hemodilution fluid Patients with coagulation abnormalities or kidney dysfunction were excluded from the study Anesthesia was induced with propofol,fentanyl and vecuronium and maintained with inhalation of isoflurane and nitrous oxide and intermittent intravenous boluses of fentanyl and vecuronium The patients were mechanically ventilated and PaO 2 and PaCO 2 were maintained within normal range After induction blood was withdrawn from internal jugular vein and collected in standard blood bags containing anticoagulant and at the same time replaced with HES (equal volume) or GEL (1 5 times the volume of blood withdrawn) The amount of blood withdrawn was estimated from the following equation:blood volume withdrawn=body weight(kg)?60?(Hct 0 Hct 1)/Hct M,where Hct 0=patient′s initial Hct, Hct 1=desired end point Hct and Hct M=the average of Hct 0 and Hct 1 Blood routine,prothrombin time(PT),activated partial thromboplastin time(APTT) and fibrinogen level were checked and thromboelastography(TEG) was performed 15 min before and after hemodilution Results The amount of blood withdrawn ranged between 1000 1100ml Hb was still above 80g/L after hemodilution The decreases in Hb and Hct were significant in both groups (P

Objective To determine the influence of general anesthesia on postoperative cognitive function in patients undergoing noncardiac surgery. Methods Forty ASA Ⅰ -Ⅱ patients aged 50-70 years undergoing elective noncardiac surgery under general anesthesia ( n = 20) or general anesthesia combined with epidural block (n =20) were studied.Patients with psychiatrical or neurological disorders or taking hyponotics regularly were excluded.General anesthesia was induced with propofol 1.5-2.5mg/kg and fentanyl 2?g/kg.Tracheal or bronchial intubation was facilitated with vecuronium 0.6mg/kg.The patients were then mechanically ventilated and PETCO2 was maintained at 30-40mm Hg. Anesthesia was maintained with 1.0%-2.0% isoflurane and intermittent iv boluses of vecuronium. Epidural catheter was inserted at T8.9 and a mixture of 0.33% poutocaine and 2%lidocaine was infused through catheter at a rate of 4-6ml/h by using Graseby 3500 infusion pump.Radial artery was cannulated for intra-arterial pressure monitoring. ECG, PETCO2 and end-tidal-isoflurane concentration were monitored during operation. Whenever BP was

Objective To study the use of fiberoptic bronchoscope in the positioning of double-lumen endobronchial tube in Chinese patients. Methods Ninety ASA Ⅰ - Ⅱ patients (60 male and 30 female) undergoing thoracic surgery requiring one-lung ventilation were enrolled in the study. Age ranged from 14-79 years (mean age 56 ?16) and the average height was 169? 6 cm (male) and 158?6 cm (female) respectively. Anesthesia was induced with fentanyl, propofol and vecuronium. Double-lumen endobronchial tube (Broncho-Cath, Mallincrodt Medical) was inserted following conventional procedure. Proper position of double-lumen tube(DLT) was determined by auscultation. Fiberoptic bronchoscope was made if needed. The fiberoptic bronchoscopy was repeated after lateral decubitus positioning of the patient. The depth of the tube inserted was recorded. Results The fiberoptic bronchoscopy revealed that the incidence of malpositioning of the left-sided DLT was 68% and of right-sided DLT was 62% . The most common malposition was that the tube was placed too deep. The dislodgement of DLT in lateral decubitus positioning of the patient occurred in 24% patients and in most cases the DLT was moved upward. The depth of insertion did not correlate with the patient' s height. Conclusion Fiberoptic bronchoscopy is a reliable technique for correct positioning of DLT and should be used routinely.