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 This study was designed to determine the clinical pharmacokinetics ofcisatracurium in Chinese patients. The purpose of this study was twofold: the determination of ED50 and ED95 of cisatracurium and the intubating conditions and changes in BP and HR produced by 2×ED95 and 3 ×ED95 . Methods 100 patients scheduled for elective surgery, aged 30-65 years, served as the experimental subjects. Anesthesia was induced with propofol 2mg/kg and fentanyl 4μg/kg. 5 min after BP and HR were stabilized the study was started. The study consisted of two parts according to the purpose of the study. In part Ⅰ 70 patients were included and randomized to 7 groups based on the doses of cisatracurium the patients received. The doses were 25, 30, 35, 40, 45, 50 and 55 μg/kg from group Ⅰ to Ⅶ. Neuromuscular transmission was assessed by measuring the responses of adductor pollicis muscle to stimulation of ulnar nerve with TOF pulses.The maximal depression of Tt was measured after administration of cisrtracurium, and ED50 and ED95 were calculated. In part Ⅱ 30 patients were included and divided into two groups to receive 2×ED95 (group Ⅷ ) or 3×ED95 (group Ⅸ ) of cisatracurium. The intubating conditions were evaluated. The onset time and time of recovery from paralysis as well as the changes in BP and HR after administration of cisatracurium were recorded. ResultsED50 and ED95 for cisatracurium were 30.7μg/kg and 53.4μg/kg respectively. The onset times for 2×ED95 and 3×ED95 were (254±84)s and (190±59)s. The durations of action was (38.8±6.1)min and (53.28.8)min respectively. Recovery indexes were (16.4±4.9) min and (15.6±5.2) min. There were little changes in BP and HR after administration of cisatracurium in both group Ⅷ and Ⅸ. The intubating conditions were not significantly different. ConclusionsED50 and ED95 for cisatracurium are 30.7μg/kg and 53.4μg/kg in Chinese patients. The onset time is shorter and duration of action longer with 3×ED95 which does not significantly affect BP and HR.

This study was concerned about comparing the degree and process of cardiopulmonary effect of propofol and midazolam. Forty-five adult patients,ASA grade Ⅱ, scheduled for elective operation, were randomly allocated to intravenously receiving midazolam 0.28mg?kg~(-1)(group Ⅰ,n=16), 0.40mg?kg~(-1) (group Ⅱ,n=16) ,or propofol 2.5mg?kg~(-1) (group Ⅲ,n=13) ,respectively. MAP ,HR, SpO_2 ,TV ,MV ,RR and P_(ET)CO_2 were monitored continuously before and in 30 minutes following the administration ,and the arterial blood gas analysises were performed before and 1,2,3,4,5,10,15,20 and 30 minutes after the administration. The results showed that in group Ⅰ, Ⅱ and Ⅲ after the administration separately,the maximal decrease of MAP were 20.0% ,22.8% and 22.20%, and occured in 10.8, 9.3 and 3.5 minutes;HR decreased maximally by 6.3% ,8.7% and 15.5%,TV by 76.6% ,81.3% and 91.3%/00 ,MV by 87.2%,91.6% and 93.6%,RR by 60.3%,67.5% and 83.6%; the incidences and durations of apnea were 37.5%vs 57.5 seconds,31.3%vs 68. O seconds and 76.9%vs 73.0 seconds. The MV recovered to the baseline 5 minutes in group Ⅲ and more than 10 minutes in group Ⅰ and Ⅱ following the administration. The arterial blood pH reduced and PaCO_2 increased significantly in three groups (P

Objective: To study clinical pharmacodynamics and efficacy for endotracheal intubation of rocuronium and succinylcholine at different dosage. Method: Sixty adult patients under general anesthesia according to the different drugs and dosage, were randomly divided into four groups. In groupⅠorⅡ,2 or 3?ED_(95) rocuronium were administrated,and in group Ⅲ and Ⅳ, 2 or 3?ED_(95) succinylcholine were given respectively. The course of depression and recovery of twitch response of the adductor pollicis muscle were recorded, and intubating condition were assessed. Result:The intubation condition was excellent in all patients of group Ⅱ,but only in 20％ of group Ⅲ.The degree of twitch at maximal depression was similar between all groups. The lag time and the time of twitch reaching maximal depression were not significantly different between group Ⅱ,Ⅲ and Ⅳ, which were shorter than those of groupⅠ.The times of twitch recovery to 25％ and 95％ of baseline in groupⅠor Ⅳ were significantly longer than in groupⅠor Ⅲ, respectively. Conclusion: 3?ED_(95) rocuronium has similar onset time to 2 or 3?ED_(95) succinylcholine with the excellent intubation condition,but the clinical effective duration is more longer than that of 2?ED_(95) rocuronium.