Objective To investigate the hemodynamic and rheological effects of acute hypovolemic hemodilution with 6% hydroxyethyl starch (HES) at different infusion rates. Methods 20 ASA Ⅰ adult patients undergoing elective surgery were randomized to one of two groups with 10 patients each. The patients were premedicated with intramuscular midazolam 0.06 mg/kg and atropine 0.01 mg/kg 30 min before anesthesia. Before anesthesia an intravenous line was established and lacted ringer solution was infused at a rate of 5 ml. kg-1. h-1 . Anesthesia was induced with midazolam 0.2mg/kg , fentanyl 5μg/kg and vecuronium 0. lmg/kg and maintained with inhalation of 50 % N2O and 1% isoflurane. After tracheal intubation the patients were mechanically ventilated and PET CO2 was maintainted between 4.6-6.0 kPa.Swan-Ganz catheter was inserted via right internal jugular vein. The dorsalis pedis artery was cannulated for direct measurement of arterial pressure. 6% HES infusion rates were 10 ml.kg-1.h-1 in group Ⅰ and 20ml.kg-1 .h-1 in group Ⅱ respectively. ECG, heart rate (HR), arterial blood pressure (SBP, DBP and MAP), CO, CL, CVP, PAP, PCWP, SpO2, PET CO2 and inhalation concentrations of N2O and isoflurane were monitored before and 30, and 60 min after infusion was started. Arterial and venous blood samples were taken for blood gas analysis and rheological studies. Results The two groups were comparable with respect to demographic data. During HES infusion HR decreased and CL increased in both groups and there was no significant difference between the two groups. BP increased slightly at 60 min in group Ⅰ , whereas in group Ⅱ it tended to decrease. CVP, PAP and PCWP increased significantly in both groups especially at 60 min. Hct decreased from 36.2% ±4.5% to 30.4% ±4.1% in group Ⅰ and from 39.6%±8.0 % to 30.8% ± 5.9 % in group Ⅱ at 60 min. Hb and K value of erythrocyte sedimentation rate (ESR) equation decreased significantly in both groups especially at 60 min. Conclusions Intravascular volume expansion ismore efficient with increased infusion rate of HES but the influences on hemodynamics would be more significant. HES infused at 20 ml. kg-1 . h -1 is safe in healthy patient during operation with blood loss.[Key Words] Hemodilution; Hydroxyethyl starch; Hemodynamics; Hemorheology

Objective To determine the appropriate concentration of ropivacaine for differential sensory and motor block of brachial plexus.Methods Ninety ASA Ⅰ - Ⅲ patients aged 16-75 yr weighing 40-85 kg undergoing upper extremity operation under axillary brachial plexus block were randomly divided into 3 groups according to the concentration of ropivacaine used for the block(n = 30 each): group A 0.15% ropivacaine;group B 0.10% ropivacaine and group C 0.05% ropivacaine.Axillary brachial plexus block was performed using ultrasound guidance and electric nerve stimulation.Sensory and motor block were assessed and recorded at 10,30,60and 240 min after local anesthetic injection(T1-4).The rate of adequate sensory block,the rate of differential sensory and motor block(the areas innervated by radial,median and ulnar nerves were numb but the patients could still move their elbow,wrist and fingers)and effectiveness of the block(excellent - completely no pain;good slight pain,iv fentanyl was needed;poor -rescue brachial plexus block was needed or general anesthesia was induced).Operation time and duration of analgesia and success rate of the block were recorded.Results 0.15%ropivacaine produced excellent or good block and no failure in group A.The rate of differential sensory and motor block was significantly higher in group B(0.10% ropivacaine)than in group A.The effect of block with 0.05% ropivacaine was unsatisfactory in group C.Conclusion Axillary brachial plexus block with 0.10% ropivacaine can induce differential sensory and motor block in the majority of patients.

Objective To investigate the use of laryngeal mask airway (LMA) ProSeal for airway management during open heart surgery performed under CPB in children. Methods Seventy-six ASA Ⅱ and NYHA class Ⅰ or Ⅱ patients aged 3 months-8 yr, weighing 3.3-34.5 kg undergoing open heart surgery under CPB were randomly divided into 2 groups ( n = 38 each): tracheal intubation group (group T) and ProSeal LMA group (group P1). Tracheal tube and LMA were inserted after induction of anesthesia with 8% sevoflurane. The rate of successfultracheal intubation and LMA placement, placement time, peak airway pressure and side effects during and after surgery including hypoxemia, tachycardia, bradycardia, hypotension and hypertension, laryngesl edema, dysphagia, bucking, dyspnea and hoarseness were recorded. Results There were no significant differences in the rate of successftl tracheal intubation and LMA placement, peak airway pressure, bucking, dyspnea and hoarse voice between the two groups (P＞ 0.05). The LMA placement time was significantly shorter than tracheal intubation time and the incidence of laryngeal edema and dysphagia lower in group P than in group T ( P ＜ 0.05). Conclusion The LMA ProSeal can provide adequate ventilation during operation with less complications and can be used effectively for cardiac surgery performed under CPB in children.

Objective To investigate the effects of ischemic pre- and postconditioning on cerebral glycogen synthase kinase-3 beta (GSK-3β) activity in a rat model of global cerebral ischemia-reperfusion (I/R).Methods Forty male Wistar rats weighing 200-230 g were randomly allocated into 4 groups (n =10 each) : Ⅰ group sham operation (group S); Ⅱ group I/R; Ⅲ group ischemic preconditioning (group IPR) and Ⅳ group ischemic postconditioning (group IPO). The animals were anesthetized with intraperitoneal 10% chloral hydrate 0.4 ml/100 g. Global cerebral ischemia was induced by four-vessel-occlusion in group Ⅱ , Ⅲ and Ⅳ. Bilateral vertebral arteries were cauterized and bilateral carotid arteries were occluded for 10 min. In group IPR cerebral ischemia was preceded by 3 cycles of 10 s ischemia followed by 30 s reperfusion. The group IPO received 3 cycles of 30 s reperfusion followed by 10 s ischemia at the end of 10 min cerebral ischemia. The animals were killed 2 days later. The brains were immediately removed for determination of neuronal apoptosis in the cortex (by TUNEL), the infarct size (by TTC), p-GSK-3β activity (by spectrum assay) and the expression of Bcl-2, Bax and Caspase-3 (by SP). Linear correlation of p-GSK-3β activity with the number of apoptotic neurons in the cortex and cerebral infarct size was analyzed. Results Cerebral I/R significantly increased the number of apoptotic neurons in the cortex and infarct size, decreased p-GSK-3β activity, down-regulated Bcl-2 expression and up-regulated Bax and Caspase-3 expression in group I/R as compared with group S. Ischemic pre- and postconditioning significantly attenuated these cerebral I/R-induced changes. The p-GSK-3β activity was negatively correlated with the number of apoptotic neurons in the cortex and cerebral infarct size. Conclusion Ischemic pre- and postconditioning reduces cerebral I/R injury through inhibiting the activity of GSK-3β.

Objective To investigate the efficacy of centrally fixed eyeball for assessment of the depth of anesthesia in premature infants undergoing outpatient fundus examination. Methods Fifty eight premature infants undergoing examination of fundus of eyes were enrolled in this study. Their gestational age (from the first day of last menstruation period to birth) + after birth age (from birth to the day when examination of fundus of eyes was performed) = 44-64 weeks. The patients were randomly divided into 2 groups: Ⅰ group body movement (group M, n = 27) and Ⅱ group centrally fixed eyeball (group E, n = 31). Anesthesia was induced and maintained with isoflurane inhalation. The patients were breathing spontaneously. The eyelids were kept open with speculum after induction of anesthesia. The EC50 of sevoflurane concentration which could inhibit body movement or make eyeballs centrally fixed was determined by up-and-down sequential experiment. The initial isoflurane concentration was 3% in both groups. Each time the isoflurane concentration was increased/decreased by 0.5 %. 95 % confidence interval (CI) was calculated. The lowest SpO2, respiratory rate and coughing during maintenance of anesthesia were recorded. Results The EC50 of sevoflurane (95% CI) was 2.9% (2.2%-3.6%) in group M and 3.4%(2.6%-4.6%) in group E. Examination was successfully completed in all patients. No respiratory depression and coughing occurred during examination and no vomiting and coughing were observed during feeding at 1 h after recovery from anesthesia. No body movement occurred in 15 patients whose eyeballs were centrally fixed in group E. Conclusion Centrally fixed eyeball can be used as sign of appropriate depth of anesthesia for fundus examination in premature infants.

Objective To compare the therapeutic effect of inhaled aerosolized and intravenous milrinone (a phosphodiesteraee-3 inhibitor) on postoperative pulmonary artery hypertension (PAH) in children with congenital heart disease (CHD).Methods Forty CHD complicated with PAH children aged 5-14 yr weighing 15-38 kg with pulmonary artery pressure (PAP) 30-90 mm Hg were randomly divided into 2 groups (n = 20 each): Ⅰ milrinone inhalation group and Ⅱ intravenous milrinone group. At the end of CPB, aerosolized milrinone 1 ml/kg was inhaled for 12 h at 30 min intervals, and each time milrinone was inhaled for 10 min in group Ⅰ . In group Ⅱ , a bolus of 10 g/kg milrinone was given iv followed by 12 h milrinone infusion at 0.5 μg·kg-1 ·min-1 . Blood samples were taken from aorta and pulmonary artery for blood gas analysis at the end of administration and venous oxygen saturation (S(-v)O2) was recorded. MAP, PAP, pulmonary vascular resistance index (PVRI) and systemic vascular resistance index (SVRI) were recorded every 2 h during milrinone administration. The duration of endotracheal tube, PAH, lung infection and postoperative hyoxemia were recorded during milrinone administration. Results PAP, PVRI and the incidence of lung infection and PAH were significantly lower, while MAP, SVRI and S(-v)O2higher in group Ⅰ than in group Ⅱ (P ＜ 0.05), but there was no significant difference in the duration of endotracheal tube and incidence of hyoxemia between the two groups(P ＞ 0.05). Conclusion Inhaled aerosolized milrinone has better therapeutic effect than intravenous milrinone on PAH in children with CHD.

Objective To investigate the pharmacokinetics of different concentrations of levobupivacaine for lumbar epidural anesthesia.Methods Twenty ASA Ⅰ or Ⅱ patients of both sexes, aged 35-59 years and scheduled for elective radical resection of rectal or colon carcinoma under general anesthesia combined with epidural block, were randomly divided into 2 groups (n=10 each):group Ⅰ (receiving 0.75% levobupivacaine) and group Ⅱ (receiving 0.5% levobupivacaine). Epidural block was performed at L1-2 interspace. Group Ⅰ and Ⅱ received epidural 0.75% and 0.5% levobupivacaine 2 mg/kg (containing adrenaline 5 μg/kg)injected slowly over 2 min, respectively. And 30 min later, general anesthesia was induced with y-hydroxybutyrate 60-80 mg/kg and remifentanil 1-2μg/kg. Tracheal intubation was facilitated with succinylcholine 1-1.5 mg/kg and the patients were mechanically ventilated. Anesthesia was maintained with inhalation of nitrous oxide (N2 O) and O2 (1:1) and continuous infusion of remifentanil 0.01-0.1μg·kg-1·min-1 and intermittent intravenous boluses of atracurium. Sensory and motor blocks were assessed after epidural levobupivacaine. Blood samples were taken from the central vein at 0, 10, 20, 30, 45, 60, 90, 120, 210, 300, 420,540, 660 and 840 min, respectively, after epidural administration for determination of plasma concentrations of levobupivacaine by high performance liquid chromatography.Results The plasma concentration-time curves of levobupivacaine were fitted to a two-compartment open model in the two groups and there were no significant differences in the pharmacokinetic profiles between the two groups. The onset time of sensory and motor blocks was shorter and the duration of the two blocks was longer with 0.75% levobupivacaine as compared with 0.5%levobupivacaine. The incidences of nausea and vomiting and hypotension were low and no severe cardiovascular and neurological side-effects developed.Conclusion The pharmacokinetic parameters do not differ significantly between epidural 0.75% and 0.5% levobupivacaine when the total doses are the same. And epidural anesthesia with either 0.75% or 0.5% levobupivacaine is safe.

Objective To investigate the changes in blood coagulation during cardiopulmonary bypass (CPB) in children of different ages undergoing open heart surgery for cyanotic congenital heart disease.Methods Sixty children with cyanotic congenital heart disease undergoing open heart surgery under CPB were divided into 3 age groups: Group A(age≤12 mort, n=25), Group B (12mon＜age≤24 mon, n= 17) and Group C (24 mon＜ age＜4 yr, n=18). Venous blood samples were taken immediately after induction of anesthesia(T1) and at 10 min after protamine administration (T2)for determination of activated coagulation time (SonACT), clot rate and platelet function (PF) using Sonoclot coagulation and platelet function analyzer-type DP2951 (Sieuco Co., USA).Results There was significant difference in SonACT, clot rate and PF at T1 among the 3 groups: the SonACT was significantly shorter in Groups B and C than in Group A, the clot rate was significantly higher in Group B than in Group C, and the PF was significantly lower in Group C than in Group A. At T2 , the SonACT was significantly prolonged in all 3 groups, the clot rate was significantly decreased in Groups A and B, and the PF was significantly decreased in Group A.Conclusion There are significant differences in blood coagulation and PF among the 3 different age groups of children with cyanotic congenital heart disease after induction of anesthesia and CPB has different effects on their blood coagulation and PF.

Objective To evaluate the effects of teriipressin on perioperative renal function in patients undergoing liver transplantation. Methods Forty ASA Ⅲ or Ⅳ patients (31 males and 9 females) aged 35-55 yr and weighing 46-81 kg were randomly divided into2 groups (n=20 each): terlipressin group and control group. The patients were premedicated with intramuscular midazolam 2- 3 mg and atropine 0.5 mg. Swan-ganz catheter was placed via the right internal jugular vein and the radial artery was cannulated. Electrocardiography (ECG), blood pressure (BP), heart rate (HR), central venous pressure (CVP) and pulmonary arterypressure (PAP) were monitored during general anesthesia. General anesthesia was induced with midazolam (0.1-0.2 mg/kg), fentanyl (5-10 μg/kg), propofol(1-2 mg/kg) and vecuronium (0.1 mg/kg) and maintained with 0.5%-1.5% isoflurane, propofol infusion at 2-5 mg·kg-1·h-1 and intermittent i.v. boluses of fentanyl and vecuronium. The patients were mechanically ventilated after tracheal intubation. In the terlipressin group, 2 mg of terlipressin was added to 50 ml of normal saline (NS) and was continuously infused at 10 ml/L from beginning of operation until the end of anhepatic phase, while in the control group, NS was infused only. Blood and urine samples were taken before operation(T0), at the end of anhepatic phase (T1), at the end of operation (T2), and on the 1st and 2nd day after operation (T3, T4)for determination of plasma angiotensin Ⅱ (AT- Ⅱ ), serumβ2-microglobulin (MG), blood urea nitrogen (BUN) and creatinine (Cr) concentrations and N-acetyl-βd-glucosaminidase (NAG) concentrations in the urine. Urine output was measured during pre-anhepatic, anhepatic and neo-hepatic phase and on the 1 st and2nd day after operation. Results The urinary NAG and serum β2-MG concentrations were significantly increased at T1 as compared with the baseline at T0in both groups. The urinary NAG, plasma AT-Ⅱ, serum β2-MG, BUN and Cr concentrations were significantly lower and theurinary output was significantly higher during T2-4 in the terlipressin group than in the control group. Conclusion Terlipressin has protective effects on renal function in patients undergoing orthotopic liver transplantation.

Objective To investigate the influence of different carbon dioxide (CO2) absorbents (Dr(a)gersorb 800 plus , Sodasorb,Sodasorb LF) on the production of compound A during low-flow sevoflurane anesthesia.Methods Twenty-seven ASA Ⅰ or Ⅱ patients aged 20-64 years were randomly assigned to three groups according to different CO2 absorbents: Dr(a)gersorb 800 plus' group (group D, n = 10), Sodasorb group (group S, n = 10) and Sodasorb LF group (group LF, n = 7). Anesthesia was maintained with low-flow (500 ml/min) sevoflurane inhalation (with the end-tidal sevoflurane concentration of approximately 2% ). At 2 h after low-flow sevoflurane anesthesia, gas samples were taken from the expiratory limb of the circuit. Compound A was detected by gas chromatography. Serum alanine transaminase (ALT), aspartate aminotransferase (AST), bilirubin (BR), urea nitrogen (BUN) and creatinine (Cr) levels were measured before (T0 ) and 24 h after operation (T1).Results The three groups were comparable with respect to age, body weight and height. After 2 h of low-flow sevoflurane anesthesia, compound A concentrations in the expiratory limb of the circuit were 11.6 ± 5.8 (group D), 2.1 ± 1.9 (group S)and ＜ 0.1 ppm (group LF), respectively. There were no significant changes in the serum ALT, AST, BR, BUN and Cr levels at 24 h after operation as compared with the preoperative baseline values in the three groups.Conclusion After 2 h of low-flow (500 ml/min) sevoflurane anesthesia, compound A concentrations within the circuit with different CO2 absorbents ( Dr(a)gersorb 800 plus' , Sodasorb, Sodasorb LF) are less than 50 ppm, with the lowest in Sodasorb LF.However, they have no significant effects on hepatic or renal function.