Objective To evaluate the pharmacokineties of ropivacaine for single sciatic nerve block in dogs.Methods Twelve healthy adult mongrel dogs weighing 14-17 kg were randomized to receive 0.5% ropivaeaine 10 mg/kg or 20 mg/kg for single sciatic nerve block(n=6 each).ECG,BP and HR were monitored and recorded during anesthesia.Blood samples were obtained from femoral artery before ropivacaine injection (baseline)and at 10,20,30,40,60,90,120,150,180,240,360 and 720 min after ropivacaine injeetion for determination of plasma ropivaeaine concentration(by reversc-phasc high performance liquid chromatography).Arterial blood samples were also taken when adverse reactions occurred.The pharmacokinetic parameters were eMeulated with DAS 1.0 software package.Results The concentration-time curve of ropivacaine for single sciatic nenre block was fitted to two-compartment open model in both groups.The peak plasma concentration of ropivaeaine was significantly lower in 10 mg/kg group than in 20 mg/kg group.Two dogs developed convulsion in 20 mg/kg group.The plasma ropivaeaine concentration was 12.56 and 13.67 mg/L respectively during convulsion.Conclusion Pharmaeokinetic profile of ropivaeaine for single sciatic nerve block is best described by two-compartment model.Bopivaeaine 20 mg/kg for sciatic nerve block can hardly be tolerated by dogs.

After first report of local anesthetics on cardiac toxicity was published in 1979, A lot of researches of local anesthetics on the mechanism of cardiac toxicity and its treatments were reported, and some advances were reviewed in this article during recent years.

Spinal opioids have been widely used in clinical anesthesia and analgesia. In this article, we reviews the characteristics about the clinical applications of spinal opioids, including the opioid selection, drug dosage, administration route, effects of different opioids, drug combination, associated adverse effects and so on.

As a new laboratory test for evaluation of endogenous pain inhibition,conditioned pain modulation (CPM) deficiency means dysfunction of endogenous pain inhibitory systems and higher incidence of chronic pain.Age,psychological factors and physical activity all seem to influence the individual CPM effect.A standard CPM testing way has an important role in comparison between different researches.

NMDA(N-Methyl-D-Aspartate)receptor is a kind of ionotropic receptors, which have been widely localized in peripheral somatic tissues and visceral pain pathways. The activation or expression changes of peripheral NMDA receptor may play an important role in pain occurrence. Peripheral administration of NMDA receptor antagonist can alleviate or prevent pain and enhance the analgesic effect of opiate. This method of administration can reduce the side effect of central action induced by the drug. It will be an important research direction of pain management.

Objective To investigate the effect of ketamine pretreatment on acute tolerance to morphine in rats with chronic inflammatory pain.Methods Twenty-four adult male SD rats weighing 180-200 g were randomly divided into 3 groups (n=8 each): group Ⅰ morphine (M) ,group Ⅱ ketamine (K) and group Ⅲ ketamine + morphine (KM). Chronic inflammatory pain was induced by subcutaneous injection of Freund's adjuvant 0.125 ml into the plantar surface of left hindpaw. Three days after Freund's adjuvant injection, the animals received intraperitoneal (IP) morphine 5 mg/kg in group M, IP ketamine 10 mg/kg in group K or IP ketamine 10 mg/kg 10 min before IP morphine 5 mg/kg in group KM once a day for 3 consecutive days respectively. The paw withdrawal threshold to yon Frey hair stimulation (PWT) and paw withdrawal latency to noxious thermal stimulation(PWLT) using the hot plate test were measured before Freund's adjuvant injection (T0, baseline), and every day before (T1) and at 15 (T2), 30 (T3), 60 (T4) and 120 min (T5) after medication for 3 days (D1,2,3).Results PWT was significantly increased after medication on D1,2,3 in group KM but only on D1,2 in group M. PWLT was significantly prolonged after medication on D1,2,3 in group KM but only on D1 in group M. Conclusion Ketamine 10 mg/kg pretreatment can decrease the acute tolerance to morphine in rats with chronic inflammatory pain.

Objective To investigate the safety and feasibility of anesthesia for patients with myasthenia gravis using target controlled infusion without muscle relaxant.Methods Thirty-one patients with myasthenia gravis were recruited into study.A target controlled infusion was started with targeting effect-site concentration of propofol 3 μg/mL and remifentanil 4 ng/mL.Intubation was performed when patients were unconsciousness and target concentrations of both drugs were reached.No muscle relaxant was used during anesthesia.Blood pressure,heart rate,performance of intubation and respiratory recovery including extubation and wake time were observed.Results All patients were intubated successfully in one attempt.38.7% patients had mild cough when the endotracheal tube past through the vocal cord during intubation.Blood pressure and heart rate at post-intubation increased significantly as compared with pre-intubation (P＜0.01).After cease of drugs,time of spontaneous breathing recovery was (6.5±2.9) min.Extubation and wakeup time were (9.8±3.6) and (7.4±3.1) min respectively.No adverse event was noted.Conclusion Target controlled infusion without muscle relaxant was safe and effective anesthesia for myasthenia gravis patients undergoing thymectomy.

0.05] between group L and other two groups.Conclusion PCEA with 0.125% levobupivacaine containing fentanyl 2 ?g?ml-1 provides adequate pain relief after cesarean section with recovery of motor function similar to that with 0.2% ropivacaine and 0.125% racemic bupivacaine.

The influences of lactic/hydrochloric acidosis on pulmonary vasoconstriction and gas exchanges were investigated in 36 dogs. The tv infusion of lactic or hydrochloric acid reducing arterial pH to 7. 00 could elicit significant changes of pulmonary hemodynamics, including the consistent increase of pulmonary arterial pressure and the decrease of arterial oxygen saturation. It is suggested that pulmonary vasocostriction is related to arterial PH but not to arterial lactic acid levels.

Objective The double-blinded, randomly study was designed to determine the clinical efficacy and safety of ropivacaine for combined spinal-epidural anesthesia (CSE). Methods Sixty patients, ASA class Ⅰ-Ⅱ , 18 to 75 years, undergoing elective lower limb or perineum surgery, were randomly allocated to receiving spinally hyperbaric mixture 1.5-2ml of 1% ropivacaine (group R, n=20), 0.75% bupivacaine(group B,n=20), or 1% tetracaine (group T,n=20), combined with 10% glucose 1ml and 3% ephidrine 1ml respectively,and the anesthesia was maintained with epidural administration with 2% lidocaine if necessary during the operation ,after the B-D DurasafeTM combined spinal epidural anesthesia kit was applied at the L 3-4 interspace.Results The time to maximum spread of anesthesia in group R was longer, but the recovery time was shorter than those in group T(P0.05). Additionally, as compared with ones in group B and T, the onset of motor block and the time to peak motor block were prolonged significantly (P