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0. 5mv. LAD occlusion was maintained for 50min and then released for reperfusion (120min) . Myocardial infarct size was measured by nitroblue tetrazolam at the end of experiment. Results There was no statistically significant difference in HR, MAP, cardiac output (CO), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure ( LVEDP) and rate-pressure products ( RPP) among all groups during ischemia and early reperfusion period except for LVEDP in control group which was much higher than that in all preconditioning groups during the late reperfusion period. Compared with the control group, desflurane, sevoflurane, isoflurane and G+ desflurane reduced myocardial infarct size by 41%, 47%,31.7% and 17.8% respectively without significant homodynamic effects. Myocardial infarct size in G + desflurane groups was significantly larger than that in desflurane group. Conclusion Preconditioning with desflurane, sevoflurane and isoflurane reduce myocardial infarct size in rabbits to some extent. The protective effects may be partly medialed via activation of KATP channel.
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Objective To investigate the effects of regional myocardial stunning on systemic hemodynamics and myocardial oxygen balance Methods Thirty three open chest anesthetized dogs were subjected to 15min left anterior descending (LAD) coronary artery occlusion under normal temperature, the systemic hemodynamics, coronary blood flow (CBF), myocardial oxygen delivery(MDO 2) and consumption(MVO 2)were determined following reperfusion Results MAP decreased slightly during LAD occlusion, but returned to baseline following reperfusion CO, SV and LVSWI reduced rapidly after LAD occlusion, increased slightly 5min following reperfusion, followed by a more severe reduction , with the progressive increases of SVR and PVR during whole periods At the early stage of reperfusion (5min), CBF, MDO 2 and MVO 2 increased significantly, then decreased rapidly 10min following reperfusion Myocardial oxygen extraction rate remained stable during whole procedures Histological changes of ischemic area 30min following reperfusion showed interstitial and intracellular edema, mitochondrial vacuolization, and capillary stasis under electronic microscopy Conclusions Regional myocardial stunning may resulte in sinificant changes of systemic hemodynamics; at the early stage of reperfusion, oxygen consumption paradox occurres ,but MDO 2 matches MVO 2 10min following myocardial reperfusion
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desflurane. The one of hepatotoxic mechanism of inhatational anesthetics may be to inhibit the proliferation and albumin secretion.
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To assess the concentration-responses relationships of propofol, 16 adult patient,ASA grade Ⅰ-Ⅱ,scheduled for upper abdominal operation, were randomly allocated to undergoing epidural block (group Ⅰ, n = 8)or combined anesthesia (group Ⅱ, n = 8) respectively. After a bolus injection of propofol 2.5mg ?kg, blood pressure (BP), heart rate (HR) and tidal volume (TV) were recorded, and drowsiness,amnesia,cooperation and orientation were evaluated by scorring scales in both groups. The venous samples were taken before and after the administration to measure the propofol plasma concentration by spectrofluorophotometric detector. The results revealed that there were no significant differences in pharmacokinetic parameters between two groups;the plasma concentration of propofol at 2. 5rag. L~(-1) was required for adequate anesthesia,and 1.5 to 1.9rag. L~(-1) for hypnosis,the patients were fully awake at 0.94?0.3mg. L~(-1); BP,HR and TV were significantly depressed at more than 2.0rag. L~(-1), and recovered to baseline at less than 1.5mg. L~(-1). It is suggested that there are good relationships between propofol plasma concentrations and its pharmacodynamic responses.
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Objective To evaluate the roles of K ATP channels in desflurane-induced myocardial protection from anoxia/reoxygenation injury Methods Primary cultured rat myocardial cells were randomly allocated to four groups: control group(A): without any treatment; anoxia/reoxygenation group(B): reoxygenation of 1 h following anoxia of 2 h; desflurane preconditioning group(C): 20 min of 9% desflurane preconditioning followed by 10 min washout before anoxia/reoxygenation and K ATP channel blocker group(D): adding glybenclamide at final concentration of 12?g/ml to culture medium 10 min before the same procedures as group C The activities of lactic dehydrogenase (LDH) and creatine kinase (CK), rates of cell viability and apoptosis, contents of cellular malondiadehyde (MDA) and adenosine triphosphate (ATP), and intracellular free calcium concentration were measured Results Compared with control group, anoxia/reoxygenation caused great increases of levels of LDH, CK, apoptosis and MDA ,and decreases of ATP and cell viability (P
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Ⅳ, SVR and PVR decreased markedly at the same time MERO 2 and MDO 2/MVO 2 dod not change significantly but MVO 2/MDO 2 showed a tendency of decreasing after the inotropics administration compared with the control group Electronic microscopy examinations: 30min after the inotropics were stoped, the myocardial ultrastructure of ischemic area did not improved significantly in group Ⅱ and Ⅲversus the group Ⅰ, but in group Ⅵ, Ⅴ and Ⅳ, the interstitial and intracellular edema reduced markedly, the capillary stasis vanished, and very few vacuole could be seen in mitochondria Conclusions 1 The response of stunned myocardium to ? agonists decreases 2 Inotropic can restore regional work by restoring mechanical synchrony and improving energy efficiency, the effects of combined inotropics are better than the inotropics given alone in myocardial stunning
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The pharmacodynamics and its circulatory effects of alcuronium and atracurium were investigated in cardiac and noncardiac surgical patients.The results demonstrated that:l Compared with atracurium group,the duration of action of alcuronium is longer in cardiac patients than that of non-cardiac patients, but there is no difference in the onset of action between these two groups; 2. Half of the patients which received alcuronium need reversal with neostigminel 3. The effects on the circulation of these two drugs were nor remarkable;Therefore,alcuronium is also suitable for cardiac and non-cardiac surgical patients
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Objective: To compare cumulative dose technique with single dose technique for determining dose-re sponse relationship of rocuronium during balanced anesthesia. Method: Thirty-four ASA grade Ⅰ-Ⅱ patients, aged 23- 65 years, undergoing elective surgery,were randomly allocated to single dose group(n=24) or cumulative dose group (n=10). Single dose group was further divided into 4 subgroups receiving 150,200,250 or 300?g/kg of rocuronium re spectively. In cumulative dose group, the initial dose of 150 or 200 ?g/kg rocuronium was followed by a second dose de termined individually to produce about 90% neuromuscular block. The ulnar nerve was stimulated at the wrist to mea sure the accelography of thumb adduction. The relationship between probit-transformed depression of first twitch height of TOF and the logarithm dose of rocuronium was analysed using linear regression. Result: ED_50 and ED_95 of rocuronium were 193.6?69.1 and 367.2?72. 7?g/kg respectively in single dose group, and 213.0?55.1 and 418.5? 61.7?g/kg respectively in cumulative dose group. No statistically significant differences were found in the slope,inter cept,ED_50 and ED_95 values between two groups. Conclusion: The two-dose cumulative technique can be used as effec tively as traditional single dose technique in determining the dose-response relationship of rocuronium.
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Objective To investigate the effect of desflurane pretreatment on the density of muscarinic (M)-receptors on anoxic/reoxygenated rat cardiac myocytes. Methods Myocytes were obtained from ventricle of 2-3 day SD rats and incubated for 3 days. Then they were randomly allocated to one of 5 groups: group I received no treatment and served as control ( n = 5); group Ⅱ underwent 2 h hypoxia (liquid culture medium was insufflated with a gas mixture of 1 % CO2 , 1 % O2 and 98% N2) followed by 1h reoxygenation ( n = 6) ; group Ⅲ was pre-treated with 1.5 MAC desflurane (9% ) for 20 min, followed by 10 min washout before the same duration of hypoxia/reoxygenation as in group II ( n = 6) ; group IV underwent longer duration of hypoxia (48 h) followed by 24 reoxygenation ( n = 5) ; group V was pre-treated with 1.5 MAC desflurane (9% ) for 20 min followed by 10 min washout, then underwent longer duration of hypoxia/reoxygenation as in group IV ( n = 5) . The density of M-receptors was measured by the radio-ligand binding assay (RLBA) .Results The density of M-receptors was significantly lower in group Ⅱthan that in group I ( P