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.

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.

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.

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.

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.

Mild hypothermia significantly increases perioperative complications,such as adverse myocardial outcomes,coagulopathy,infection and delayed recovery.So it is important to maintain the core temperature above 36 ℃.Redistribution is the major cause of hypothermia during the first hour of intravertebral or general anesthesia.There are many methods to protect patients from hypothermia including passive insulation and active warming.Forced-air and electric heating pad are currently the most effective noninvasive choices.The contribution of intravenous fluids heating to patients' temperature is limited but it should be performed when large volume is required.

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 effects of forced-air prewarming combined with fluid warming on body temperature and thermal comfort in patients undergoing lobectomy.Methods Forty six patients scheduled for video-assisted thoracoscopic surgery (VATS) of lobectomy were randomized into two groups (n=23 each):warming group (group T) and the control group (group C).Forced-air prewarming combined with infusion heating was applied in the warming group,while only conventional passive warming was used in control group.The tympanic membrane temperatures were recorded before prewarming,after prewarming, during the anesthesia, the end of operation, the moment in and out of the postanesthesia care unit (PACU).Incidence of postoperative shivering, thermal comfort and the time in the PACU were recorded.Results The warming group had a slower temperature decrease at 1,2, 3 hours after operation and end of operation(P< 0.01), warming group had significantly lower incidence of hypothermia and shivering than control group(8.7% vs 56.5%, 4.3% vs 34.8%,P<0.05),and the thermalcomfort score was higher in warming group than in control group(8.52±0.94 vs 7.65±0.83,P<0.05).Conclusions Forced-air prewarming combined with fluid warming has significant clinical effects to stabilize patients` body temperature during operations,to reduce the incidence of hypothermia and shivering and to improve the thermal comfort, which provides a simple and effective temperature protection strategy for patients undergoing lobectomy.

Perioperative pain management play a critical role in rapid recovery and long term outcome in patient undergoing total knee arthroplasty.With the advancement of peripheral nerve block, technique such as femoral nerve block, sciatic nerve block, abductor canal block have play an important role in perioperative pain management.Local infiltration analgesia have also gained popularity.The ultimate goal of perioperative pain management is to ensure analgesia effect and maintain good motor function of lower extremity.We are still in searching of a safe, effective, analgesia without motor block.Currently multimodal analgesia seems to be the most favorable choice.