To determine the effect of propofol on myocardial contractility. Method: Twenty hamsters were allocated to receiving intravenous propofol 2.5mg?kg~(-1)(group Ⅰ) or thiopentone 4mg?kg~(-1)as control (group Ⅱ) dp/dt_(max), was determined using a catheter inserted into the left ventricle from right carotid artery. LVP (LVSP, LVDP, LVMP), CVP, HR were recorded simutaneously. Resutt: dp/dt_(max), decreased insignitieantly in group Ⅰ but signitieantly in group Ⅱ. LVP(LVSP, LVDP, LVMP) decreased, while CVP increased significantly in both groups (P0.05). Conclusion.. The influence of propofol on myocardial contractility is weaker than that of thiopenone.

0.05) . Conclusion It is safe to use soda lime containing more than 6.08% of water during enflurane or desflurane anesthesia with low flow (FGF = 500 ml?min-1 ) in children.

Objective The purpose of this study was to determine and compare the hemodynamic effects of desflurane and enflurane in children.Methods Twenty-eight ASA Ⅰ-Ⅱ patients, aged 1-5 years were randomly assigned to receive either desflurane (group D) or enflurane (group E) for maintenance of anesthesia.Cardiac output was continuously monitored by transesophageal Doppler (TECO1).The stroke volume index (SVI), cardiac index (CI),heart rate (HR) and blood pressure(SBP,DBP,MAP) were determined before and during inhalation of desflurane and enflurane at 0.5,1.0 and 1.5 MAC.Results At 0.5 MAC of both agents SVI, CI and HR remained unchanged, but SBP, DBP and MAP were slightly reduced as compared to the baseline values.At 1.0 MAC of desflurane CI was increased and was higher than that in the group E. SVI and HR were significantly higher in group D than those in group E at 1.0 MAC.SBP, MAP and DBP were further reduced and the magnitude of reduction was similar between both groups.At 1.5 MAC CI and SVI were unchanged in group D but greatly reduced in group E.HR increased significantly in group D but remained unchanged in group E.There was further decrease in BP in both groups but SBP and MAP decreased more markedly in group E than in group D .Conclusions Desflurane causes less hemodynamic changes in children of 1-5 years than enflurane.

Objective To assess the effects of hyperventilation on the balance of cerebral oxygen supply and consumption during craniotomy Methods Twenty ASA Ⅰ Ⅱ patients with supratentorial tumor undergoing elective craniotomy were studied Anesthesia was induced with fentanyl 2 4 ?g/kg and propofol 1 2mg/kg I V and tracheal intubation was facilitated with succinylcholine 1 5 2 0mg/kg I V After tracheal intubation the patients were mechanically ventilated Anesthesia was maintained with isoflurane with or without nitrous oxide and intermittent intravenous bolus of vecuroinum The patients were randomly divided into two groups : in group Ⅰ anesthesia was maintained with 1 5% isoflurane alone (ISO group, n=10); in group Ⅱ with 0 8% isoflurane and 60% 65% N 2O(ISO N 2O group, n=10) Demographic data including age, sex and weight were not significantly different between the two groups In group Ⅰ there were 6 male and 4 female, the mean age was (40 1?9 7) years and weight (64 5?7 3)kg whereas in group Ⅱ there were 5 male and 5 female, mean age was(43 6?8 4)years and mean body weight (62 7?6 5)kg After the opening of dura mechanical ventilation was regulated to maintain PaCO 2 at 4 7 6 0kPa(normal ventilation), 0 9) Arterial and venous blood lactate was within normal range but had a tendency to increase Conclusions Severe hyperventilation influences the balance of cerebral oxygen supply and consumption significantly during either isoflurane or isoflurane N 2O anesthesia at equal MAC, particularly in ISO N 2O group Severe hyperventilation should not be used during anesthesia for brain surgery

Objective To determine the effects of propofol on c fos gene expression in the different brain regions following stress in rats Methods Twenty one male Wistar rats (12 18 weeks) weighing 260 300g were randomly divided into three groups of seven animals each: control group(C); electrical stimulation group(S) and propofol group(P) The animals were anesthetized with pentobarbital sodium 40mg?kg -1 Normal saline 2ml (group C and S) or propofol 10mg?kg -1 (group P) was injected intraperitoneally (ip) 5 min after ip injection hindpaw of the animals in group S and P was electrically stimulated with 2 mA direct current (1 s every 30 s) for 15 min 30 min after electrical stimulation the animals were decapitated and brain was immediately removed on -20℃ ice plate and kept in -70℃ liquid nitrogen for determination of c fos mRNA expression in cerebral cortex, hypothalamus and hippocampus At the same time 4 ml of blood was collected from trunk for determination of ACTH and cortisol concentrations by immunoradiometric assay Results Plasma ACTH and cortisol levels and c fos mRNA expression in cerebral cortex, hypothalamus and hippocampus increased significantly in group S as compared with those in group C (P0 05).Conclusions The c fos gene is involved in molecular modulation of stress responses Propofol produces different effects on c fos gene expression in different brain regions