Objective To investigate the role of KATP channel in cardioprotective effects of remifentanil preconditioning (RFC) against ischemia-reperfusion (I/R) injury.Methods Forty-eight male SD rats weighing 200-250 g were killed and the hearts were immediately removed and perfused retrogradely at 100 cm H2 O with Krebs- Ringer's solution aerated with 95 % O2 and 5 % CO2 in an Langendorff apparatus. Myocardial ischemia was achieved by tightening the snare which was placed around anterior descending branch of left coronary artery and confirmed by the appearance of a regional cyanosis, decrease in coronary flow (CF) and S-T segment changes on ECG. After 15 min stabilization all hearts were subjected to 30 min ischemia followed by 120 min reperfusion. The 48 isolated hearts were randomly divided into 6 group ( n = 8 each): ( I ) I/R group; ( II ) RPC group received 3 episodes of 5 min remifentanil (100 ?g ? L-1 ) perfusion at 5 min interval before ischemia; ( III ) HMR group; (IV ) 5-HD group; ( V ) HMR + RPC group and ( VI) 5-HD + RPC group. Group III and IV received HMR-1098, a selective sarcolemmal KATP channel blocker (1? 10-4 mol?L-1 ) or 5-HD, a selective mitochondrial KATP channel blocker (1 ? 10 3 mol?L-1 ) perfusion for 45 min before ischemia. In group V and \1 HMR-1098 or 5-HD perfusion was started 10 min before RPC. Infarct size (IS) was determined by 2, 3, 5-triphenyl-tetrazolium staining. Coronary outflow was collected and recorded and lactate dehydrogenase (LDH) activity in coronary outflow was measured. Results The infarct size was significantly smaller and significantly less LDH was released in group II (RPC) than in I/R group. The protective effects of RPC was abolished by pretreatrnent with 5-HD but not HMR-1098. RPC and HMR-1098 caused a slight but significant increase in CF, however there was no significant difference in CF among ail groups during ischemia and reperfusion. Conclusion Mitochondrisl KATP channel activation is involved in the protective effect of RPC on myocardium against I/R injury.

Objective To elucidate the direct effect of remifentanil on intracellular Ca2+ ( [Ca2+ ]) transients using electrically stimulated individual rat ventricular cardiomyocytes. Methods Male SD rats weighing 190-210 g were used. The animals were decapitated and their hearts were immediately removed. Fresh ventricular cardiomyocytes were enzymatically isolated with collagenase. For measurement of the electrically induced [ Ca2 + ] transients, cells were first loaded with fura-2/AM as a Ca2+ indicator and [Ca2+ ] transient was determined by spectrofluorometric method. The fluorescence ratio of 340/380 run was used as an index of [ Ca2+]. Myocytes were placed in a chamber and perfused with a bicarbonate Kreb's solution at room temperature. Myocytes were randomly divided into 10 groups according to the different concentrations of remifentanil contained in Kreb's solution: control group (no remifentanil n = 8) and 9 remifentanil groups (0.1, 0.3, 1.0, 3.0, 10, 30, 100, 300 and 1 000 ng ?ml-1) ( n = 8 each) .Results Remifentanil caused decrease in [Ca2+ ] transients in a dose-dependent manner. Except for group remifentanil 0.1 and remifentanil 0.3, [ Ca2+] transients were significantly lower in remifentanil groups than in control group (P

0.05). Conclusion:Administering propofol or midazolam is helpful in avoiding cerebral oxygenation imbalance during CPB.

Aim To determine whether remifentanil preconditioning has cardioprotection against ischemia and reperfusion induced injury via opioid receptor(OR) in rats.Method Male Sprague-Dawley rats of 300～350 g were anaesthetized and the chests were opened and hearts exposed via a left thoracotomy.They were randomly assigned to 12 groups:Control(CON,saline vehicle),naltrindole(NTD,5 mg?kg~(-1) iv.10 min before 30 min ischemia);CTOP(CTOP,1 mg?kg~(-1) iv.10 min before ischemia),nor-binaltorphimine(nor-BNI,5 mg?kg~(-1),iv.15 min before 30 min ischemia);remifentanil preconditioning(RPC,6 ?g?kg~(-1)?min~(-1)),ischemic preconditioning(IPC),NTD+RPC or NTD+IPC(naltrindole 5 mg?kg~(-1) iv.10 min before RPC or IPC),nor-BNI+RPC or nor-BNI+IPC(nor-binaltorphimine 5 mg?kg~(-1),iv.15 min before RPC or IPC),CTOP+RPC or CTOP+IPC(CTOP 1 mg?kg~(-1) iv.before RPC or IPC).Infarct size(IS),a percentage of the area at risk(AAR),was determined by triphenyltetrazolium(TTC) staining.Results IPC and RPC markedly reduced IS/AAR from(52.7?1.8)% to(12.9?2.7)% and(16.2?2.4)%,respectively. CTOP,a selective ?-OR antagonist,or NTD,a selective ?-OR antagonist,administered 10 min before remifentanil PC completely abolished,while nor-BNI,a selective ?-OR antagonist,administered 15 min before RPC attenuated the cardioprotective effect of RPC.In the group preconditioned with ischemia,blockade of ?-OR with NTD abolished,while blockade of ?-OR with nor-BNI attenuated the protection.Blockade of ?-OR with CTOP did not alter the cardioprotective effect of IPC.Conclusion The cardioprotective effect of RPC was abolished by all the three OR antagonist,CTOP,naltrindole and nor-binaltorphimine,suggesting that this effect is mediated via ?-,?-and ?-ORs.Part of the effect of RPC may be produced by ?-OR agonist activity outside the heart.

Objective To evaluate the effect of dexmedetomidine on the intestinal mucosal injury in the patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Forty patients of both sexes with rheumatic heart disease,aged 32-64 yr,weighing 40-75 kg,of ASA physical status Ⅱ or Ⅲ (NYHA class Ⅱ or Ⅲ),scheduled for elective cardiac valve replacement with CPB,were randomly divided into 2 groups (n =20 each) using a random number table:control group (group C) and dexmedetomidine group (group D).After induction of anesthesia,the patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with 0.8％-2.0％ sevoflurane inhalation and intermittent iv boluses of sufentanil 0.5-1.0 μg/kg and vecuronium 0.04-0.06 mg/kg.Before routine induction of anesthesia,a loading dose of dexmedetomidine 1 μg/kg was injected intravenously over 10 min,followed by continuous infusion at 0.3 μg · kg-1 · h-1 until the end of surgery in group D,while the equal volume of normal saline was given in group C.Before CPB,at 30 min after aortic clamping,at the termination of CPB,at the end of surgery and at 6 and 24 h after surgery,central venous blood samples were taken for determination of concentrations of tumor necrosis factor-alpha,interleukin-6 (IL-6) and IL-10 and intestinal fatty acid binding protein in plasma (by ELISA),and the plasma concentration of endotoxin (using turbidimetry).The time of postoperative mechanical ventilation and duration of ICU stay were recorded.Results Compared with group C,the concentrations of tumor necrosis factor-alpha,IL-6,IL-10 and endotoxin and intestinal fatty acid binding protein in plasma were significantly decreased,and the time of postoperative mechanical ventilation and duration of ICU stay were shortened in group D.Conclusion Dexmedetomidine infused continuously at 0.3 μg · kg-1 · h-1 (until the end of surgery) after a loading dose of 1 μg/kg before routine induction of anesthesia can reduce intestinal mucosal injury in the patients undergoing cardiac valve replacement with CPB.

The teaching team of undergraduates of anesthesiology in Anhui Medical University applied the primary trauma care system of encourage, heuristic teaching and practical teaching to further deepen the educational reform and improve teaching quality for undergraduate education.They designed the diversified section such as drills, discussion, teaching, questions, feedback and so on, implemented the simulation training of anesthesia crisis management skills and completed the feedback evaluation of comprehensive ability before and after the teaching, and then achieved the effect of improving the actual operation ability and clinical thinking capacity of students.So it is a good method and worth extending.

ObjectiveTo investigate the effects of intravenous (iv) remifentanil infusion on myocardial oxidative stress in rats.MethodsOne hundred and eighty male SD rats weighing 250-300 g were randomly divided into 15 groups (n =12 each):group control (group C); group ischemic preconditioning (group IPC); group remifentanil preconditioning ( group RPC ) ; while ia iv remifentanil infusion groups,iv remifentanil was infused at 4 different rates ( 1,5,10,20μg· kg- 1 · min- 1 ) and each rate was maintained for 15,60 and 120 min respectively.Myocardial ischemia was induced by occlusion of left coronary artery anterior descending branch for 30 min followed by 120 min reperfusion in 6 rats in each group.In group IPC myocardial ischemia was preceded by 3 cycles of 5min ischemia-5min reperfusion;whilein group RPC3cycles of 5min remifentanil infusion at 5 μg· kg-1 · min-1 were applied at 5 min interval before ischemia.Six rats in which I/R was produced were sacrificed in each group,myocardial infarct size (IS) and the area at risk (AAR) were measured and IS/AAR was calculated.The left 6 rats in each group were sacrificed at the corresponding time point (the end of each treatment)and superoxide radical expression and MDA and nitrotyrosine contents in myocardium were determined.Results IS/AAR was significantly decreased in groups IPC,RPC,1 μg·kg-1 ·min-1 × 120 min,5 μg·kg-1 ·min-1 × 60or 120 min and 10 μg· kg- 1 · min- 1 × 60 min as compared with group C.Compared with group C,the myocardial superoxide radical expression was significantly up-regulated in groups 1 μg· kg-1· min-1 × 120 min, 5 μg·kg-1 ·min-1 ×60 or 120 min,10μg·kg-1 ·min-1 ×60 or 120 min and 20 μg·kg-1 ·min-1 × 15,60 or 120min,and myocardial MDA and nitrotyrosine contents were significantly increased in group 20 μg· kg-1 · min-1 ×15,60 or 120 min.ConclusionLonger duration of high rate remifentanil infusion can induce myocardial oxidative stress in rats.

Objective To investigate the relationship between maintaining concentration and loss of consciousness (LOC) concentration of propofol target controlled infusion (TCI) in patients undergoing heart valve replacement.Methods Thirty patients undergoing elective heart valve replacement were enrolled to receive propofol by ladder plasma TCI for anesthesia induction,8 males and 22 females.The initial plasma concentration (Cp) of propofol was set to 1.0 μg/ml,0.3 μg/ml Cp was increased every 1 min until LOC when the prediction effect-cite concentration (Ce) reached 0.5 μg/ml,then sufentanil 0.8-1.0 μg/kg and rocuronium 0.6-0.9 mg/kg were given for intubation.When BIS reached 50,Cp was decreased to the level of Ce.All the surgeries were performed under hypothermia CPB.MAP,HR,CVP,CO,SV,SVR,BIS,propofol Cp and Ce values were recorded at baseline (T0),LOC (T1),BIS reached 50 (T2),and other time points during operation (T3-T9).The correlation analysis between propofol Ce at LOC and perioperative variables were completed.Results In correlation analysis,there was a significant positive correlation between propofol Ce at LOC and baseline CO,SV (P<0.01),there was a significant negative correlation between propofol Ce at LOC and age (P<0.05),there was a significant positive correlation between propofol Ce at LOC and propofol Ce at T2-T9(P<0.01).Conclusion In patients undergoing valvular replacement,the Ce of propofol at maintenance are related to the concentration of propofol at LOC,which is helpful for adjusting the Ce of propofol at maintenance according to the Ce of propofol at LOC.

Objective To observe the effect of low tidal volume lung protective ventilation management strategy on postoperative outcome of elderly patients with poor pulmonary function after abdominal surgery.Methods Eighty patients of poor pulmonary function undergoing open gastrointestinal surgery,male 64 cases,female 16 cases,aged over 65 years old,ASA physical status Ⅱ or Ⅲ,NYHA cardiac function Ⅱ or Ⅲ grade,expected operation time 2-4 h were screened.The patients were randomly divided into 2 groups: protective ventilation management group (group P) and conventional mechanical ventilation group (group C),40 cases in each group.Multi-mode anesthetic management was performed in both groups.The respiratory parameters were adjusted according to the group after tracheal intubation,and the respiratory rate was adjusted to maintain PETCO2 35-45 mm Hg.The blood gas evaluated postoperative oxygen and postoperative spontaneous breathing recovery time,recovery time,extubation time,PACU time,gastrointestinal function recovery time,ambulation time,hospital stay and cost of hospitalization were recorded.The occurrence of major complications were observed at 30 days after surgery.Results PaO2 of group C was significantly decreased at 1 and 3 days after surgery than that before operation (P<0.05),PaCO2 of group C was significantly higher at 1 and 3 days after surgery than that of group P (P<0.05);PACU residence time of group P was (76.63±29.72) min,significantly shorter than that of group C [(93.80±42.90) min] (P<0.05);The difference spontaneous breathing recovery time,awake time,extubation time,exhaust time,ambulation time,postoperative hospitalization time and hospitalization expenses of two group was not statistically significant.Within 30 d after operation,2 cases (5%) of respiratory failure patients,3 cases (7.5%) of pneumonia in group P;5 cases (12.5%)of respiratory failure patients,3 cases (7.5%) of pneumonia,postoperative hemorrhage in 1 cases (2.5%) and 1 cases (2.5%) delirium in group C,there was no significant difference of the main complications in 30 d after operation between two groups.Conclusion Under the condition of this research,low tidal volume lung protective ventilation management strategy can improve elderly patients with poor pulmonary function after abdominal surgery postoperative oxygen and help to reduce the occurrence of postoperative adverse reactions.

Objective To evaluate the effect of multimodal warming regimen on the development of intraoperative hypothermia in the patients undergoing precise hepatectomy.Methods Sixty patients of both sexes,aged 28-64 yr,weighing 44-89 kg,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ (Child-Pugh A),undergoing precise hepatectomy,were equally and randomly assigned into control group (group C) and muhi-model warming group (group M) using a random number table.A bed sheet was covered on the body exposed,and the abdominal cavity was washed using the room-temperature peritoneal layage fluid in group C.In group M,after admission to the operating room,the room temperature was raised to 25-26 ℃,the mattress was prewarmed using the medical heating blanket,the temperature was maintained at 40 ℃ during operation,the lower body was simultaneously covered using the forced-air warming system,and the temperature was maintained at 37-39 ℃;the solution used for infusion was warmed to 37 ℃ before anesthesia;the incisional area was washed with 0.9％ sodium chloride injection which was prewarmed to 37 ℃ during operation.The development of hypothermia,hypotension and respiratory depression was recorded during operation.Before induction of anesthesia,at 1 h after anesthesia,at the end of operation,and at 5 min before discharge from postanesthesia care unit (PACU),blood gas analysis was performed,and the pH value,base excess and lactate level were recorded.The intraoperative blood loss,emergence time,duration of PACU stay,and occurrence of shivering,agitation,nausea and vomiting were also recorded.Results Compared with group C,the incidence of intraoperative hypothermia,and shivering,agitation,nausea and vomiting in PACU were significantly decreased,the emergence time and duration of PACU stay were significantly shortened,the pH value was significantly increased at 5 min before discharge from PACU,and the base excess and lactate level were significantly decreased at the end of operation and 5 min before discharge from PACU in group M (P＜0.05 or 0.01).Conclusion Multimodal warming regimen can raise the quality of recovery from anesthesia and decrease the development of intraoperative hypothermia in the patients undergoing precise hepatectomy.