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Objective To evaluate the effects of different administration routes of lipid emulsion on bupivacaine-induced cardiotoxicity in rats.Methods Forty-eight clean healthy adult male Sprague-Dawley rats,weighing 300-350 g,were divided into 6 groups (n=8 each) using a random number table:Ⅳ infusion of normal saline (NS) group (group VN),Ⅳ infusion of lipid emulsion group (group VL),duodenal infusion of NS group (group DN),duodenal infusion of lipid emulsion group (group DL),intraperitoneal intusion of NS group (group PN) and intraperitoneal infusion of lipid emulsion group (group PL).In VN and VL groups,preheated NS and 20％ lipid emulsion 3 ml · kg-1 · min-1 were infused via the femoral vein for 5 min,respectively,and then 0.75％ bupivacaine was infused at the rate of 2 mg · kg-1 · min-1 until cardiac arrest happened.Preheated NS and 20％ lipid emulsion 15 ml/kg were infused via the duodenum (over 1 min,at a constant rate) in DN and DL groups,respectively,and were intraperitoneally infused in PN and PL groups,respectively,followed by an infusion of 0.2 ml/min for 15 min in DN,DL,PN and PL groups.Then 0.75％ bupivacaine was infused via the left femoral vein at a rate of 2 mg · kg-1 · min-1 until cardiac arrest happened.The time to ventricular arrhythmia,mean arterial pressure (MAP) decreasing to 50％ of the baseline and cardiac arrest was recorded.The amount of bupivacaine consumed was calculated immediately after ventricular arrhythmia occurred (T0),immediately after MAP decreased to 50％ of the baseline (T1) and immediately after occurrence of cardiac arrest (T2).Arterial blood samples were collected at T0-2 for determination of the concentration of bupivacaine in plasma by high-performance liquid chromatography.Results Compared with group VN,the time to ventricular arrhythmia,MAP decreasing to 50％ of the baseline and cardiac arrest was significantly prolonged,and the amount of bupivacaine consumed was increased at T0-2 in group VL (P＜0.01).There was no significant difference in the parameters mentioned above between group DN and group DL,and between group PN and group PL (P＞0.05).Compared with group VL,the time to ventricular arrhythmia,MAP decreasing to 50％ of the baseline and cardiac arrest was significantly shortened,and the amount of bupivacaine consumed was decreased at T0-2 in DL and PL groups (P＜0.01).Compared with group DL,the time to ventricular arrhythmia,MAP decreasing to 50％ of the baseline and cardiac arrest was significantly prolonged,and the amount of bupivaeaine consumed was increased at T0.2 in group PL (P＜0.05).There was no significant difference in the concentration of plasma bupivacaine between six groups (P＞0.05).Conclusion Ⅳ infusion of lipid emulsion can decrease bupivacaine-induced cardiotoxicity when compared with duodenal and intraperitoneal infusion in rats.
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Objective To compare the accuracy of stroke volume variation (SVV),central venous pressure (CVP) and puhnonary arterial wedge pressure (PAWP) in monitoring the changes in blood volume in the patients undergoing renal transplantation.Methods Sixteen patients with chronic renal failure,of American Society of Anesthesiologists physical status Ⅱ or Ⅲ,aged 18-55 yr,scheduled for elective allograft renal transplantation under general anesthesia,were enrolled in the study.SVV was continuously monitored with the FloTrac/Vigileo monitor,and CVP,PAWP and stroke volume index (SVI) were continuously monitored with the volumetric pulmonary artery catheter during surgery.The parameters of hemodynamics were recorded at 30 min after induction of anesthesia,5 min before renal artery opening,5 and 30 min after renal artery opening,and at the end of surgery.Hydroxyethyl starch 130/0.4 electrolyte solution 6 ml/kg was infused over 15 min via the central venous catheter to perform fluid responsiveness starting from 30 min after induction of anesthesia.Positive fluid responsiveness was defined as the change in SVI ≥ 15％.The relationship between SVV and CVP and between SVV and PAWP was analyzed using the Pearson correlation analysis.The receiver operating characteristic curve for CVP,SVV and PAWP in monitoring the changes in blood volume was drawn,and the area under the curve was calculated.Results Compared with the value at 5 min before renal artery opening,SVV was significantly increased after renal artery opening (P＜0.05),and no significant change was found in CVP and PAWP after renal artery opening (P＞0.05).SVV was negatively correlated with CVP,and r=-0.82 (P＜0.01);SVV was negatively correlated with PAWP,and r=-0.77 (P＜0.01).The area under the curve of SVV in monitoring the changes in blood volume was 0.87,and of CVP and PAWP was 0.69 and 0.66,respectively.Conclusion SVV provides better accuracy than CVP and PAWP in monitoring the changes in blood volume in the patients undergoing renal transplantation.
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Objective To investigate the effect of interleukin-1 (IL-1) on contractile function of rat thoracic aorta.Methods Forty male Sprague-Dawley rats,weighing 250-300 g,were sacrificed to obtain the thoracic aortic rings.The experiment was performed in 2 parts.Part Ⅰ The thoracic aortic rings were divided into 2 segments and randomly divided into 2 groups (n =20 each):control group and IL-1 group.In IL-1 group,the thoracic aortic rings were incubated with Kreb solution containing 20 ng/ml IL-1 for 2 h,and contracted with cumulative concentrations of phenylephrine,ranging from 10-9 to 10-5mol/L.In control group,the thoracic aortic rings were incubated with Kreb solution for 2 h,and contracted with cumulative concentrations of phenylephrine,ranging from 10 9 to 10-5mol/L.Part Ⅱ The thoracic aortic rings were divided into 3 segments and randomly divided into 3 groups (n=20 each):IL-1 group,IL-1+ L-NAME (the NOS inhibitor) group and IL-1 +cyclooxygenase inhibitor indomethacin group (IL-1 +Ⅰgroup).The thoracic aortic rings were incubated with Kreb solution containing 20 ng/ml IL-1 for 1.5 h in the three groups.In addition,in IL-1 +L-NAME and IL-1 +Ⅰ groups,the thoracic aortic rings were incubated for 30 min with Kreb solution containing 100 μmol/L L-NAME and 2.5 mmol/L indomethacin,respectively.Contraction of the thoracic aorta was then induced with cumulative concentrations of phenylephrine,ranging from 10 9 to 10-5 mol/L.In group IL-1,the thoracic aortic rings were incubated with Kreb solution.The maximum contractile tension of the thoracic aortic rings was recorded at each concentration of phenylephrine,and the percentage of the maximum contractile tension at the concentration of 10-6 mol/L in group C was obtained.Results Part Ⅰ The percentage of contractile tension at phenylephrine 10-s,10-7,l0 6 and 10-5mol/L was significantly decreased in IL-1 group as compared with C group.Part Ⅱ The percentage of contractile tension at phenylephrine 10-7,10-6 and 10-5mol/L was significantly increased in IL-1+L-NAME and IL-1+I groups as compared with IL-1 group.Conclusion IL-1 can inhibit the contraction of rat thoracic aorta,and promoted production of NO and prostacyclin may be involved in the mechanism.
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Heart rate is the most common index to directly monitor the level of physical stress by comparing the subject's heart rate with an appropriate "target heart rate" during exercise. However, heart rate only reveals the cardiac rhythm of the complex cardiovascular changes that take place during exercise. It is essential to get the dynamic response of the heart to exercise with various indices instead of only one single measurement. Based on the rest-workload alternating pattern, this paper screens the sensitive indices of exercise load from electrocardiogram (ECG) rhythm and waveform, including 4 time domain indices and 4 frequency domain indices of heart rate variability (HRV), 3 indices of waveform similarity and 2 indices of high frequency noise. In conclusion, RR interval (heart rate) is a reliable index for the realtime monitoring of exercise intensity, which has strong linear correlation with load intensity. The ECG waveform similarity and HRV indices are useful for the evaluation of exercise load.
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Humans , Electrocardiography , Exercise , Heart Rate , Monitoring, Physiologic , WorkloadABSTRACT
Objective To extract envelope of heart sounds exactly,for the purpose of the further analysis of its characteristics.Methods The way that envelope extraction of heart sounds based on key-points was given.The points of local peak and valley were calculated firstly,and then heart sound envelope was gotten by the interpolation of these points.Results Compared with the envelope extracted by Hilbert-transform and mathematical morphology,respectively,the outline of heart sounds was extracted more accurately,and its time-domain characters were acquired by this method.Conclusion The envelope of heart sound is extracted correctly by this method,which is useful for the further analysis.
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Objective:To explore the reliability and validity of Social Skills Inventory(SSI)applied in Chinese college students.Methods:A sample of 542 college students was administered SSI.Results:The Cronbach's ? coefficient of the SSI was 0.81;The test-retest reliability coefficient was 0.75;The Spearman-Brown's split-reliability of SSI was 0.84;The correlation coefficients of the six factors with the total score were 0.305～0.802;The indexes of confirmatory factor analysis were as follows:?2/df(2.2),GFI(0.888),CFI(0.903),IFI(0.916),RMSEA(0.076).Conclusion:SSI showed pretty good validity and reliability applied to Chinese college students.
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Objective:To revise the Psychological Security-insecurity Questionnaire(S-I) developed by Maslow and examine its reliability and validity.Methods:Data were collected from 1893 junior middle school students with the original S-I.Results:The revised S-I consisted of 44 items,including 10 first-order factors and 3 second-order factors.It had good test-retest reliability,homogeneity reliability and criterion validity.Conclusion:The revised S-I has satisfying reliabilities and validities,and is suitable to asses the psychological security and insecurity for Chinese junior school students.