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.

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.

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.

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 effect of gabapentin on Cav3.2 channels in the dorsal root ganglia ( DRG) of rats with neuropathic pain. Methods Thirty male Sprague?Dawley rats, aged 6-7 weeks, weighing 225-275 g, were divided into 3 groups ( n=10 each) using a random number table:sham operation group ( S group) , neuropathic pain group ( NP group) and gabapentin group ( G group) . In NP and G groups, neuropathic pain was induced by chronic constriction injury to the left sciatic nerve. Starting from 7th day after operation, gabapentin 100 mg∕kg in 1 ml of normal saline was injected intraper?itoneally twice a day for 7 consecutive days in group G, and the equal volume of normal saline was given twice a day for 7 consecutive days in S and NP groups. The mechanical paw withdrawal threshold ( MWT) and thermal paw withdrawal latency ( TWL) were measured on day 3 before operation and on postoperative days 3, 7 and 14. After the last measurement of pain thresholds on the postoperative day 14, 4 rats were sacrificed for determination of Cav3. 2 mRNA expression ( by real?time polymerase chain reaction) and Cav3.2 protein expression (by Western blot) in the DRG. Results Compared with S group, the MWT was significantly decreased, and TWL was significantly shortened on postoperative days 3, 7 and 14, and the expression of Cav3.2 protein and mRNA in the DRG was significantly up?regulated in group NP, and the MWT was significantly decreased, and TWL was significantly shortened on postoperative days 3 and 7 ( P<0.05), and no significant change was found in the expression of Cav3.2 protein and mRNA in the DRG in group G ( P>0.05) . Compared with NP group, the MWT was significantly increased, and TWL was signif?icantly prolonged on the postoperative day 14, and the expression of Cav3.2 protein and mRNA in the DRG was significantly down?regulated in group G ( P<0.05) . Conclusion The mechanism by which gabapentin attenuates neuropathic pain may be related to inhibition of the function of Cav3.2 channels in the DRG of rats.

Objective To identify the risk factors for the development of intraoperative hypothermia in the patients undergoing thoracic surgery.Methods One hundred twenty patients of both sexes,aged 23-83 yr,weighing 43-92 kg,of ASA physical status Ⅰ or Ⅱ,scheduled for elective thoracic surgery,who had an expected surgical duration of more than 2 h,with the core body temperature of 36.0-37.5 ℃,were included.After admission to the operating room,the core body temperature was measured.Intraoperative nasopharyngeal temperature of lower than 36 ℃ was defined as hypothermia.The patients were randomly divided into hypothermia group or non-hypothermia group according to whether or not intraoperative hypothermia occurred.Factors including the patient characteristics,the total amount of fluid infused (including the volume of blood transfused),duration and way of anesthesia and duration and type of surgery were recorded.The risk factors associated with intraoperative hypothermia were identified by logistic regression analysis.Results A total of 94 patients developed hypothermia during surgery,and the incidence of hypothermia was 78.3％.The lowest body temperature was 33.6 ℃.There was significant difference between the two groups in age,duration of surgery,the total amount of fluid infused,and the body temperature when patients were admitted to the operating room.Logistic regression analysis revealed that the total amount of fluid infused＞2 000 ml (OR =3.499) and low body temperature when patients were admitted to the operating room (OR =0.074) were independent risk factors for intraoperative hypothermia in the patients undergoing thoracic surgery.Conclusion The total amount of intravenous fluid infused＞2 000 ml and low body temperature when patients were admitted to the operating room are independent risk factors in the patients undergoing thoracic surgery.

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.

Objective To compare the GlideScope video-laryngoscope and Macintosh laryngoscope for double-lumen tube (DLT) intubation.Methods Seventy ASA Ⅰ-Ⅲ patients,aged 18-75 yr,scheduled for thoracic surgery and requiring one-lung ventilation,were randomly divided into 2 groups (n =35 each):Macintosh laryngoscope group (group M) and GlideScope video-laryngoscope group (group G).Anesthesia was induced with propofol,fentanyl and rocuronium.The exposure of glottis obtained with Macintosh laryngoscope and GlideScope video-laryngoscope was assessed using Cormack-Lehane grade.DLT intubation was assisted with Macintosh laryngoscope or GlideScope video-laryngoscope.The Cormack-Lehane grade,difficulty of DLT placement,and reverse DLT placement were recorded.The success rate of DLT placement at first attempt and intubation time were also recorded.Blood pressure and heart rate were recorded before intubation and at 0 and 3 min after intubation.The postoperative side effects were recorded.Results Compared with M group,the intubation time was significantly prolonged,the difficulty of DLT placement and blood pressure at 0 and 3 min after intubation were increased in G group (P ＜ 0.05).There was no significant difference in the success rate of DLT placement at first attempt,rate of reverse DLT placement,Comark-Lehene grade and heart rate at each time point between the two groups (P ＞0.05).The Comark-Lehene grade obtained with GlideScope video-laryngoscope was superior to that obtained with Macintosh laryngoscope in G group (P ＜ 0.05).Conclusion GlideScope video-laryngoscope can provide a better exposure of glottis and improvement in the intubating conditions,but the method is more complex and the response to intubation is stronger than Macintosh laryngoscope for DLT intubation.

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.