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Objective To discuss the effects on the output concentrations with different lengths and pipe sizes of variable bypass va -porizer.Methods The output concentrations of different lengths and pipe sizes of variable bypass vaporizer were detected .Results Compared with concentrations controlled ,the output concentrations with different lengths and pipe sizes were lower (P<0.05).Conclusion The effect of length and pipe size can affect the accuracy of output concentration of sevoflurane ,the data in our research can also help in the design of variable bypass vaporizer .
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Objective To investigate the changes in pentane (marker of lipid pemxidation) concentuation in the expired air induced by hepatic ischemia-reperfusion(IR)injury in rabbits.Methods Thirty healthy male Japanese white rabbits weighing 2.4-3.0 kg Were randomly divided into 2 groups(n=15 each):group Ⅰ sham operation and group Ⅱ hepatic IR.Anesthesia was induced with 3% pentobarbital 30mg/kg iv and maintained with The animals were tracheostomized and mechanically ventilated.Femoral artery and vein were cannulated for BP monitoring and blood sampling.Hepatic blood flow was occluded for 25 min followed by 180 min reperfusion.The expired air was collected before(baseline,T0)and at 1,10 and 25 min of ischemia and at 1,10,25,60,120 and 180 rain of reperfusion (T1-9) for determination of pentane concentration which was extracted by solid phase micro-extraction (SPME) and detected by gas chromatography-mass spectrography(GC-MS).Blood samples were also taken at the above time points for measurement of serm ALT,AST and SOD activities and MDA concentration.The animals were killed at the end of 180 min reperfusion.Liver specimens were obtained for histology.Results There was no significant difference in age,body weight,MAP and HR between the two groups.There was no significant change in pentane concentration in the expired air and the ALT,AST and SOD activities and MDA concentration at all time points as compared with the baseline in sham operation group.In IR group the pentane concentration in the expired air was significantly increased at T4,5 and the ALT and AST activities and MDA concentration were significantly increased and SOD activity was significantly decreased at T7-9 as compared with the basehne and the sham operation group.Conclusion The pentane concentration in the expired air can reflect the occurrence of lipid peroxidation during hepatic IR injury.
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Objective To investigate the protective effect of penehyclidine hydrochloride pretreatment on focal cerebral ischemia/reperfusion injury and expression of caspase-3 in rats.Methods Sixty male Sprague-Dawley rats weighing 250-300 g were randomly divided into 3 groups(n=20): control (C) group in which sham operation was performed; ischemia-reperfusion (I-R)group, in which saline (2.0 mg?kg-1)was administered for intraperitoneal injection 30 min before anesthesia,then the ischemia model was made by occlusion of the left middle cerebral artery for 120 min; penehyclidine hydrochloride pretreatment (P) group, in which penehyclidine hydrochloride(2.0 mg?kg-1)was administered for intraperitoneal injection 30 min before anesthesia,then the same 120 min focal cerebral ischemia was performed as described in I-R group.At the end of 24 h reperfusion the animals were decapitated and the brains were removed.The volume of cerebral infarction was detected with TTC staining;Coronal sections including hippocampal tissue were obtained for HE staining.The levels of caspase-3 mRNA expression in hippocampus were detected by using semi-quantitative RT-PCR technique.Results Compared with group I-R,the volume of cerebral infarction in group P were reduced significantly(P
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OBJECTIVE： To determine the concentration of fentanyl in human plasma by HPLC with ultraviolet detection METHODS： External standard method was used The eluation of fentanyl was carried out by shim－ Pack CLC－ ODS（ 6 0mm× 150mm， 5μ m） column with 0 015mol/L NaH2PO4 acetonitril－ H2O（ 30∶ 70， v/v） as the mobile phase， and detection wavelength was 195nm RESULTS： Calibration curve for fentanyl was linear in the range of 2 0～ 100ng/ml（ r=0 999） The detection limit was 1 0ng/ml The within－ day RSD was （ 6 50± 2 79） ％ ， the between－ day RSD Was （ 6 70± 3 04） ％ The method recovery was （ 91 70± 4 70） ％ The extraction recovery was （ 97 38± 3 69） ％ CONCLUSION： This method was quick and accurate for the determination of fentanyl in human plasma and useful for pharmakinetic study of fentanyl
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soda lime). It took significant less time to reach the peak CO concentration with baralyme than with the other two CO2 absorbents. The temperature of top canister went up faster than that of the bottom one with soda lime; whereas with baralyme the temperature of the bottom canister went up faster. Conclusion In a simulated closed circuit the risk of CO poisoning was higher with baralyme than with soda lime. But KOH-free soda lime which still contains NaOH, such as sofnolime, may produce more CO than standard soda lime.
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Objective To compare the renal function after neurosurgery performed under closed-circuit anesthesia with sevoflurane and desflurane and determine the safety of the closed-circuit sevoflurane anesthesia. Methods 36 ASA Ⅰ or Ⅱ patients aged 18-60 years were randomly divided into 2 groups to receive either sevoflurane (group S, n = 18) or desflurane (group D, n = 18) . The duration of surgery was expected to be ≥90 min. The patients were premedicated with intramuscular midazolam 0.07 mg?kg-1 . Anesthesia was induced with midazolam 0.1 mg?kg-1, fentanyl 1.5-2.0 ?g?kg-1 , propofol 1-2 mg?kg-1 and vecuronium 0.1-0.15 mg? kg-1. The patients were mechanically ventilated (VT = 8-12 ml?kg-1) after tracheal intubation. PET CO2 was maintained a 35-45 mm Hg. Fresh gas flow (FGF) was first set at 1-5 L?min-1 for 2-3 min, then reduced to 0.18-0.3 L?min-1. In group D end-tidal desflurane concentration was maintained at 6%-10% ; whereas in group S the end-tidal sevoflurane concentration was maintained at 2.7%-4.0% . BP, HR, ECG, SpO2 PET CO2, inspiratory and expiratory O2 , desflurane and sevoflurane concentrations and the temperature in the center of soda-lime canister were continuously monitored during the operation. Gases were collected from breathing circuit for determination of compound A concentration (by gas chromatography) before anesthesia, at the end of 2-3 min wash-in, every 30 min during maintenance of anesthesia and at the end of anesthesia. Venous blood samples were taken before anesthesia (baseline) , at the end of surgery (T1) and at 2, 24 and 72 h after operation (T2-4) for determination of serum F-, creatinine (Cr) and blood urea nitrogen (BUN) concentrations. Urine specimens were taken for determination of total protein (TP), ?2-microglobulin (?2-MG) and ?-N-acetyl-glucuronidase (NAG) levels, before operation (baseline) at the end of operation and at 24, 48 and 72 h after operation. TP/Cr, ?2-MG/ Grand NAG/Cr were calculated to eliminate the influence of the volume of urine.Results There were no significant differences between the two groups with respect to age, sex, body weight, height, duration of anesthesia and temperature in the center of soda-lime canister. The inspiratory O2 concentration was ≥ 75% during anesthesia. There was no significant difference in serum Cr and BUN concentrations and NAG/Cr in urine before and after operation as well as between the two groups. TP/Cr and ?2-MG/Cr in urine were significantly increased after operation compared to the baseline values but there was no significant difference between the two groups. There was no significant correlation between postoperative TP/Cr, ?-MG/Cr and compound A. Conclusion Closed-circuit sevoflurane ansthesia does not affect postoperative renal function.
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Objective To evaluate the efficacy of servo controlled sevoflurane closed-circuit anesthesia and the feasibility of the predictive and intelligent control.Methods One hundred and forty-three ASA Ⅰ-Ⅲ patients (90 males, 53 females) aged between 3-77 yrs undergoing elective surgery were studied. Anesthesia was induced with intravenous fentanyl 2-3 ?g ?kg-1 , midazolam 0.12 mg?kg-1 and vecuronium 0.1 mg?kg-1 . After tracheal intubation the tracheal tube was connected to the servo-controlled closed-circuit system composed of IBM computer, O2 mass flow controller and electrically controlled sevoflurane injection pump and multifunctional monitor. The fresh gas flow of O2 = [body weight (kg)3/4 ? 10 + 20] ml?min-1 . The end-expired sevoflurane concentration was maintained at 1.3 MAC by predictive and intelligent control.Results The average wash-in time to reach the target concentration was (5.2 ?2.4) min. The O2 flow rate was(0.22?0.04) L?min-1 . The cumulative uptake of sevoflurane was 5.16 ml, 7.74ml, 9.17ml, 11.08ml, 12.57ml, 13.00ml, 14.18ml, 15.60ml, 18.56ml and 24.6 ml at 30, 60, 90, 120, 150, 180, 210, 240, 300 and 420 min respectively. The uptake rate of fluid sevoflurane was equivalent to (0.2673e-0.0598t + 0.2269e-0.0597t + 0.1150e-0.002t) ml?min-1 . Conclusion The servo controlled sevoflurane closed-circuit system can effectively control the pre-set end-tidal sevoflurane concentration in spite of the influence of multiple factors and is safe and effective.