异氟醚对新斯的明拮抗维库溴铵肌松作用的影响

目的：研究一定浓度的异氟醚对新斯的明拮抗维库溴铵肌松作用的影响。方法：30例病人随机分为三组（各10例）：（1）丙泊酚静脉麻醉组,即对照组（P组）。（2）观察组。以异氟醚维持麻醉,再分为两组;术中呼气未异氟醚浓度均为1MAC,临近手术结束用新斯的明拮抗时,呼气末异氟醚浓度分别为1MAC（1M组（）和0．3MAC（0．3M组）,术中各组均连续输注维库溴铵,术毕以新斯的明0．035mg/kg拮抗并记录以下数据;维库溴铵输注速率,从拮抗开始到T1恢复到90％,TOF恢复到0．7和0．9的时间拮抗后15分钟时的T1,TOF比值,结果：1M组和0．3M组维库溴铵输注速率较P组降低IP＜0．05）,新斯的明拮抗后,0．3M组和1M组T1恢复到90％,TOF恢复到0．7和0．9的时间较P组延长（P＜0．05和P＜0．01）,1M组TOF恢复到0．9的时间较0＝3M组延长（P＜0．05）,在新斯的明拮抗后15分钟,0．3M组和1M组的T1和TOF比值均低于P组（P＜0．05）,1M组的TOF比值低于0．3M组（P＜0．05）,结论：呼气未浓度为1MAC和0．3MAC的异氟醚均能影响新斯的明对维库溴铵肌松作用的拮抗。     

Comparison of recovery after intermediate duration of anaesthesia with sevoflurane and isoflurane

BACKGROUND: The purpose of this study was to compare recovery from anaesthesia after sevoflurane and isoflurane were administered to children for more than 90 min. METHODS: After parental informed consent and ethical committee approval, children aged between 2 months and 6 years, ASA I or II, were randomly allocated to sevoflurane (n=20) or isoflurane (n=20) groups. Halogenated agents were discontinued following skin closure and patients were ventilated mechanically with 100% oxygen until minimum alveolar concentration (MAC) values awake were obtained (endtidal concentrations 0.6 MAC for sevoflurane and 0.4 MAC for isoflurane). Effective perioperative analgesia was provided by a caudal block. RESULTS: The mean (+/- SD) duration of anaesthesia was 132 +/- 38 min and 139 +/- 49 min for sevoflurane and isoflurane, respectively. Early recovery occurred sooner in the isoflurane group (time to extubation was 16 +/- 7 min and 11 +/- 5 min, P<0.01; Aldrete's score at 0 min was 5.5 +/- 1.5 and 7.4 +/- 1.8, P<0.001, respectively). But the time to be fit for discharge from recovery room was similar at 136 +/- 18 min and 140 +/- 20 min, respectively. CONCLUSIONS: After intermediate duration of anaesthesia administered to children for up to 90 min, isoflurane and sevoflurane allow recovery after approximatively the same lapse of time.     

Comparison of the effects of sevoflurane and isoflurane on arterial oxygenation during one lung ventilation

We have compared the effects of sevoflurane and isoflurane on arterial oxygenation, heart rate and mean arterial pressure during one lung anaesthesia in a prospective, crossover study. We studied 28 patients undergoing oesophagogastrectomy, allocated alternatively to one of two groups. Patients in group I/S (n = 14) received 1 MAC (1.1%) of isoflurane in oxygen from induction until the end of 30 min of open chest one lung ventilation (OLV) in the lateral position. This was followed by 1 MAC (2.1%) of sevoflurane in oxygen for the next 30 min of OLV. Patients in group S/I (n = 14) received the two anaesthetic agents in the reverse order. We found no significant difference in arterial oxygenation, heart rate or mean arterial pressure between the two potent inhalation agents. In the subgroup of patients with pulmonary artery catheters (n = 12), we found a significant increase (P < 0.05) in derived shunt during sevoflurane anaesthesia. There was no significant difference in mixed venous saturation and cardiac output. We conclude that during one lung ventilation, the choice between sevoflurane and isoflurane did not significantly influence arterial oxygenation.      

Clinical comparison of sevoflurane and isoflurane when administered with nitrous oxide for surgical procedures of intermediate duration

The purpose of this study was to compare the haemodynamic effects and emergence times of anaesthesia with sevoflurane with those of isoflurane when the agents were administered with nitrous oxide to adult inpatients (ASA I and II) undergoing surgery of at least an hour in duration. Fifty patients were randomly assigned to receive either 0.65 minimum alveolar concentration (MAC) (1.3%) sevoflurane or 0.65 MAC (0.8%) isoflurane together with 60% nitrous oxide following induction with thiopentone, fentanyl, and succinylcholine. Systemic blood pressure and heart rate trends were similar for both groups for the duration of anaesthesia. However, differences in systolic blood pressure measurements were noted at one minute after incision (99 ± 3 mmHg, mean ± SE, in the sevoflurane group compared with 109 ± 4 mmHg for isoflurane), and at emergence (125 ± 3 mmHg for sevoflurane, 134 ± 3 mmHg for isoflurane), and in diastolic blood pressure measurements at five minutes after intubation (64 ± 2 mmHg for sevoflurane, 73 ± 3 mmHg for isoflurane). Recovery of response to command was more rapid after discontinuation of sevofluranenitrous oxide (9.9 ± 1.1 min) than after isoflurane-nitrous oxide (13.9 ± 1.3 min). Despite earlier emergence, patients who had received sevoflurane did not request postoperative analgesia sooner. We conclude that the purported advantages of sevoflurane, namely haemodynamic stability and rapid emergence, can be expected even when the agent is administered at 0.65 MAC (1.3%) in nitrous oxide to a typical adult surgical population undergoing procedures of intermediate duration (2.3 ± 0.2 hr).     

Hemodynamic and catecholamine response to a rapid increase in isoflurane or sevoflurane concentration during a maintenance phase of anesthesia in humans

Purpose The purpose of this study was to compare hemodynamic and catecholamine changes due to a sudden increase in inhalation anesthetic concentrations (isoflurane and sevoflurane) during surgery.Methods Thirty patients aged 40–70 years scheduled for lower abdominal surgery were anesthetized with either isoflurane or sevoflurane with nitrous oxide and epidural block. During surgery the isoflurane or sevoflurane concentration was kept at 0.5 minimum alveolar concentration (MAC) (end-tidal concentration) for 15 min. Then the isoflurane or sevoflurane concentration (inhalation concentration) was changed to 1.5 MAC and maintained at that level for 10 min. Thereafter, it was decreased to 0.5 MAC for 10 min. Blood pressure, heart rate, and plasma concentrations of epinephrine and norepinephrine were measured.Results The blood pressure decreased significantly in both groups after increasing the anesthetic concentration, and it increased after decreasing the concentration. The decrease in systolic blood pressure was significantly larger in the isoflurane group. The heart rate increased significantly after increasing the anesthetic concentration only in the isoflurane group. Plasma concentrations of epinephrine and norepinephrine increased significantly in the isoflurane group, whereas the epinephrine concentration (but not the norepinephrine concentration) decreased in the sevoflurane group.Conclusion During surgery a sudden increase in isoflurane concentration induced larger changes in hemodynamics and sympathetic nerve activity than sevoflurane.     

Spontaneous breathing with the use of a laryngeal mask airway in children: comparison of sevoflurane and isoflurane

We compared respiratory parameters during anaesthesia with sevoflurane and isoflurane through a laryngeal mask airway (LMA). Children were anaesthetized with O₂ and air with 2.3% (1MAC) sevoflurane ( n =20) or 1.5% (1MAC) isoflurane ( n =20). After insertion of LMA, patients were allowed to breathe spontaneously and respiratory rate (RR) and P ECO2 were measured (presurgery state). After the measurement, anaesthetic concentration was increased to 1.3 MAC (3.0% sevoflurane or 2.0% isoflurane) and surgical stimulation was added. Fifteen min after incision, the measurements were again performed (during surgery). In the sevoflurane group, mean RR and P ECO2 were 32 breaths.min⁻¹, and 6.0 kPa (45 mmHg) respectively, before surgery, and 35 breaths.min⁻¹ and 7.0 kPa (52 mmHg) during surgery. In the isoflurane group, mean RR and P ECO2 were 32 breaths.min⁻¹ and 6.1 kPa (46 mmHg) respectively, before surgery, and 37 breaths.min⁻¹ and 6.7 kPa (52 mmHg) during surgery. There were no statistical differences between the two anaesthetic groups. Clinical respiratory and cardiovascular parameters during spontaneous breathing with LMA in children are similar during sevoflurane and isoflurane anaesthesia.     

Emergence times from xenon anaesthesia are independent of the duration of anaesthesia

Xenon (MAC = 71%) has an extremely low blood:gas partition coefficient (0.14). Therefore, we predicted that the rate of emergence from xenon anaesthesia would not be affected greatly by duration of anaesthesia. We studied 54 ASA I-II patients undergoing lower abdominal surgery who received equal MAC anaesthesia with 60% xenon, 60% nitrous oxide with 0.5% isoflurane or 60% nitrous oxide with 0.7% sevoflurane (n = 18 per group), each supplemented with extradural mepivacaine anaesthesia. Duration of anaesthesia was 58-380 min. At the end of operation, all inhalation anaesthetics were discontinued and patients were allowed to wake up while breathing oxygen spontaneously. A blinded investigator recorded the time until patients opened their eyes on command (T1), were judged ready for tracheal extubation (T2), could correctly state their name, date of birth and name of the hospital (T3), and could count backwards from 10 to 1 in less than 15 s (T4). Emergence times after xenon and nitrous oxide-sevoflurane anaesthesia did not correlate with duration of anaesthesia, whereas those from nitrous oxide- isoflurane had positive correlations. Mean emergence times from xenon anaesthesia were: T1, 3.3 (SD 1.0) min; T2, 3.6 (1.0) min; T3, 5.0 (1.1) min; and T4, 6.2 (1.7) min. These values were approximately 50% of those after nitrous oxide-sevoflurane anaesthesia (T1, 5.6 (1.4) min; T4, 10.5 (2.0) min). We conclude that xenon provided fast emergence from anaesthesia, regardless of the duration of anaesthesia.      

Hepatic Effects of Halothane,Isoflurane or Sevoflurane Anaesthesia in Dogs

The effects of halothane, isoflurane and sevoflurane anaesthesia on hepatic function and hepatocellular damage were investigated in dogs, comparing the activity of hepatic enzymes and bilirubin concentration in serum. An experimental study was designed. Twenty‐one clinically normal mongrel dogs were divided into three groups and accordingly anaesthetized with halothane (n = 7), isoflurane (n = 7) and sevoflurane (n = 7). The dogs were 1–4 years old, and weighed between 13.5 and 27 kg (18.4 ± 3.9). Xylazine HCI (1–2 mg/kg) i.m. was used as pre‐anaesthetic medication. Anaesthesia was induced with propofol 2 mg/kg i.v. The trachea was intubated and anaesthesia maintained with halothane, isoflurane or sevoflurane in oxygen at concentrations of 1.35, 2 and 3%, respectively. Intermittent positive pressure ventilation (tidal volume, 15 ml/kg; respiration rate, 12–14/min) was started immediately after intubation and the anaesthesia lasted for 60 min. Venous blood samples were collected before pre‐medication, 24 and 48 h, and 7 and 14 days after anaesthesia. Serum level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma‐glutamyltransferase (GGT), lactate dehydrogenase (LDH GGT) activities and bilirubin concentration were measured. Serum AST, ALT and GGT activities increased after anaesthesia in all groups. In the halothane group, serum AST and ALT activities significantly increased all the time after anaesthesia compared with baseline activities. But in the isoflurane group AST and ALT activities increased only between 2 and 7 days, and in the sevoflurane group 7 days after anaesthesia. GGT activity was increased in the halothane group between 2 and 7 days, and in the isoflurane and sevoflurane groups 7 days after anaesthesia. All dogs recovered from anaesthesia without complications and none developed clinical signs of hepatic damage within 14 days. The results suggest that the use of halothane anaesthesia induces an elevation of serum activities of liver enzymes more frequently than isoflurane or sevoflurane from 2 to 14 days after anaesthesia in dogs. The effects of isoflurane or sevoflurane anaesthesia on the liver in dogs is safer than halothane anaesthesia in dogs.     

Interactions of nicardipine to inhalation anesthetics sevoflurane and isoflurane

The hemodynamic effects and pharmacokinetics of nicardipine under general anesthesia were compared between two different volatile anesthetics, sevoflurane and isoflurane. Sixteen adult neurosurgery patients were divided into sevoflurane and isoflurane groups. Anesthesia was maintained with either sevoflurane or isoflurane (0.5–1.5%) and nitrous oxide in oxygen. When the blood pressure was stabilized [0.5 minimum alveolar concentration (MAC) in both anesthetics] during surgery, nicardipine 1 mg, i.v. was administered. Plasma catecholamines and nicardipine concentration were measured, and the pharmacokinetics of nicardipine were calculate. The decrease in blood pressure and the increase in heart rate 30 min after nicardipine administration were significant in the isoflurane group but not in the sevoflurane group. Although plasma catecholamine levels increased after nicardipine administration in the isoflurane group, no significant changes were observed in the sevoflurane group. The sevoflurane group had a significantly longer elimination half-life, a larger area under the plasma concentration curve, and smaller clearance of nicardipine compared to the isoflurane group. In summary, the effects of nicardipine on blood pressure and heart rate were significantly longer under isoflurane anesthesia than under sevoflurane anesthesia. However, the etabolism and excretion of nicardipine were significantly delayed under sevoflurane anesthesia.     

The influence of halothane, isoflurane and sevoflurane on rocuronium infusion in children

BACKGROUND: Rocuronium is a non-depolarizing neuromuscular blocking agent with intermediate duration of action and without significant cumulative properties, suitable for continuous infusion. This study was designed to determine the infusion requirements in children under nitrous oxide and fentanyl, halothane, isoflurane or sevoflurane anaesthesia. METHODS: Forty children, 3-11 years old, ASA physical status group I or II were studied. They were randomly allocated to receive fentanyl-nitrous oxide, 1 MAC halothane-nitrous oxide, 1 MAC isoflurane-nitrous oxide or 1 MAC sevoflurane-nitrous oxide anaesthesia. Rocuronium, 0.6 mg(-1) was used to facilitate endotracheal intubation. Electromyographic response of adductor pollicis to train-of-four (TOF) stimulation, 2 Hz for 2 s, applied to the ulnar nerve at 10-s intervals was recorded using Relaxograph (Datex, Helsinki, Finland). Once the first twitch response (T1) returned to 5%, muscle relaxation was maintained by continuous infusion of rocuronium, adjusted automatically in a closed-loop system to maintain a stable 90-99% T1 depression. The block was considered stable if it changed by no more than 2% over a 10-min observation period. RESULTS: Halothane, isoflurane and sevoflurane groups had ower infusion requirements than the fentanyl-nitrous oxide group (P<0.00075). Rocuronium requirement (mean +/- SD) at one hour from the commencement of anaesthesia was 16.7+/-2.3, 13.6+/-3.7, 13.1+/-5.1 and 8.4+/-1.6 microg x kg(-1) x min(-1) for children receiving fentanyl-nitrous oxide, halothane, isoflurane and sevoflurane anaesthesia, respectively. CONCLUSIONS: The rocuronium infusion rate required to maintain stable 90-99% T1 depression was reduced by approximately 20% with halothane and isoflurane anaesthesia, and by 50% with evoflurane anaesthesia when compared to fentanyl-nitrous oxide anaesthesia. Significant patient-to-patient variability of infusion rate makes monitoring of neuromuscular transmission necessary.     

Neostigmine antagonism of rocuronium block during anesthesia with sevoflurance, isoflurane or propofol

PURPOSE: To examine the influence of continuing administration of sevoflurane or isoflurane during reversal of rocuronium induced neuromuscular block with neostigmine. METHODS: One hundred and twenty patients, divided into three equal groups, were randomly allocated to maintenance of anesthesia with sevoflurane, isoflurane or propofol. Neuromuscular block was induced with rocuronium and monitored using train-of-four (TOF) stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. Neostigmine was administered when the first response in TOF had recovered to 25%. At this time the volatile agent administration was stopped or propofol dosage reduced in half the patients in each group (n = 20 in each group). The times to attain TOF ratio of 0.8, and the number of patients attaining this end point within 15 min were recorded. RESULTS: The times (mean +/- SD) to recovery of the TOF ratio to 0.8 were 12.0 +/- 5.5 and 6.8 +/- 2.3 min in the sevoflurane continued and sevoflurane stopped groups, 9.0 +/- 8.3 and 5.5 +/- 3.0 min in the isoflurane continued and isoflurane stopped groups, and 5.2 +/- 2.8 and 4.7 +/- 1.5 min in the propofol continued and propofol stopped groups (P < 0.5-01). Only 9 and 15 patients in the sevoflurane and isoflurane continued groups respectively had attained a TOF ratio of 0.8 within 15 min (P < 0.001 for sevoflurane). CONCLUSIONS: The continued administration of sevoflurane, and to a smaller extent isoflurane, results in delay in attaining adequate antagonism of rocuronium induced neuromuscular block.     

地氟醚、七氟醚和异氟醚对犬血液动力学和氧供需平衡的影响

目的　采用连续温度稀释法观察不同浓度地氟醚对血液动力学和氧供需平衡的影响 ,并与七氟醚和异氟醚比较。方法　犬 18只 ,1.5 %硫喷妥钠 2 0 mg/ kg、阿曲库胺 0 .8mg/ kg麻醉诱导 ,气管插管后机械通气。左股静脉穿刺置入 7.5 F的六芯肺动脉漂浮导管 ,接 CCO/ SvO2 监测仪 ,连续测定并计算血液动力学及氧供需平衡各项指标。操作完成后平稳 1小时 ,取基础指标。然后随机依次吸入 0 .7、1.2和 1.7MAC的地氟醚、七氟醚或异氟醚 ,呼气末浓度达预定值后稳定 2 0分钟 ,记录各指标 ,再增加吸入浓度达下一个预定浓度。结果　 MAP、SVR和 CO在三组均呈剂量依赖性下降 ,地氟醚和异氟醚组 HR明显增快 ,七氟醚组 HR则明显减慢 ,异氟醚组 1.7MAC时 VO2 增加 ,DO2 和Sv O2 下降。结论　地氟醚对循环功能和氧供需平衡的影响与异氟醚相似 ,与七氟醚则有所不同     

Mivacurium infusion requirement and spontaneous recovery of neuromuscular transmission in children anaesthetized with nitrous oxide and fentanyl,halothane, isoflurane or sevoflurane

BACKGROUND: Forty children, aged 3-11 years, ASA I or II, were allocated at random to receive N2O/O2-fentanyl or 1 MAC halothane, isoflurane or sevoflurane-N2O/O2 anaesthesia. Mivacurium was used for muscle relaxation. METHODS: Electromyographic response of the adductor pollicis to train-of-four (TOF) stimulation, 2 Hz for 2 s, applied to the ulnar nerve at 10-s intervals was recorded using the Relaxograph (Datex, Helsinki, Finland). An intubating dose of mivacurium, 0.2 mg.kg-1 was given, and when T1 returned to 5%, muscle relaxation was maintained by continuous infusion of mivacurium, adjusted manually to maintain a stable 90-99% block. RESULTS: Halothane, isoflurane and sevoflurane groups had lower infusion requirements for mivacurium than the N2O-fentanyl group (P=0.000083). Mivacurium requirement was 18.8 +/- 6.8, 10.8 +/- 4.2, 6.9 +/- 3.9 and 9.6 +/- 5.6 microg.kg-1.min-1 for children receiving N2O/O2-fentanyl, halothane, isoflurane and sevoflurane anaesthesia, respectively. CONCLUSIONS: Spontaneous recovery from T1=10% to TOF ratio=0.7 was insignificantly prolonged from 6.3 to 12.5 min in the fentanyl group to 7-16.5 min in children anaesthetized with inhalational anaesthetics.     

Sevoflurane--nitrous oxide anaesthesia supplemented with remifentanil: effect on recovery and cognitive function

The aim of this study was to compare recovery and psychomotor performance after maintenance of anaesthesia with sevoflurane or sevoflurane supplemented with remifentanil. Sixty-six per cent nitrous oxide was used in all patients. Twenty patients each were randomly allocated to maintenance of anaesthesia with sevoflurane only in concentrations necessary to maintain adequate anaesthesia or with 1.5, 1.0 or 0.5 MAC (end-tidal) of sevoflurane supplemented with remifentanil. The median dosage of remifentanil required in the last three groups was 0.21, 0.25 and 0.34 microg x kg(-1) x min(-1), respectively (p < 0.05). The median times to eye opening were 10.3, 12.7, 11.0 and 6.5 min in the four groups (p < 0.05 between the 0.5 MAC and the other groups) and for orientation 12.1, 14.9, 12.3 and 8.3 min, respectively (p < 0.05 between 0.5 and 1.5 MAC groups). There was no significant difference in the mini-mental state assessment scores or the actual discharge times from the recovery ward among the groups. Significantly greater numbers of patients could perform the critical flicker fusion test at 15 min in the group receiving the lowest concentration of sevoflurane and the highest dosage of remifentanil (p < 0.05). Patients in this group also showed the highest incidence of chest wall rigidity (p < 0.003). We conclude that, while the use of remifentanil with lower concentrations of sevoflurane facilitates early recovery, it does not influence discharge time from recovery ward and may be associated with side-effects such as chest wall rigidity.     

BLOOD CONCENTRATIONS OF SEVOFLURANE AND ISOFLURANE ON RECOVERY FROM ANAESTHESIA

We studied 16 healthy ASA physical status I patients (aged 13–71yr for sevoflurane and 22–74 yr for isoflurane) to determinemaximum blood concentrations on awakening (MBC_awake) from sevofluraneand isoflurane anaesthesia, and determined if age and durationof anaesthesia significantly influenced MBC_awake After operation,the end–tidal concentration of anaesthetics was decreasedgradually. During recovery from anaesthesia, patients were askedrepeatedly to open their eyes. We obtained blood samples tomeasure the anaesthetic concentration when patients first openedtheir eyes. MBC_awake of sevoflurane and isoflurane (ml of anaestheticgas per ml of blood) were 0.40 (SE 0.04) % and 0.53 (0.04) %,respectively. MBC_awake values of sevoflurane and isofluranecorrelated significantly with age (P < 0.05) but not withduration of anaesthesia. Blood: gas partition coefficients ofsevoflurane and isoflurane were 0.65 (SD 0.05) and 1.36 (0.09),respectively. There was no significant correlation between ageand blood:gas partition coefficient for sevoflurane and isoflurane.Awakening alveolar concentrations (MAC_awake calculated fromMBC_awake were 0.61 (SE 0.05) % for sevoflurane and 0.39 (0.02)% for isoflurane, and correlated significantly with age. Theratios of awakening alveolar concentration to MAC were reasonablyconstant–0.33 for sevoflurane and 0.33 for isoflurane.     

The anticonvulsant effects of volatile anesthetics on lidocaine-induced seizures in cats

Large concentrations of sevoflurane and isoflurane, but not halothane, induce spikes in the electroencephalogram. To elucidate whether these proconvulsant effects affect lidocaine-induced seizures, we compared the effects of sevoflurane, isoflurane, and halothane in cats. Fifty animals were allocated to 1 of 10 groups: 70% nitrous oxide (N2O), 0.6 minimum alveolar anesthetic concentration (MAC) + 70% N2O, 1.5 MAC + 70% N2O, and 1.5 MAC of each volatile agent in oxygen. Lidocaine 4 mg x kg(-1) x min(-1) was infused IV under mechanical ventilation with muscle relaxation. Electroencephalogram in the cortex, amygdala, and hippocampus and multiunit activities in the midbrain reticular formation (R-MUA) were recorded. Lidocaine induced spikes first from the amygdala or hippocampus in the 70% N2O and halothane groups and from the cortex in the sevoflurane and isoflurane groups. Lidocaine induced seizures in all cats in the 70% N2O and 0.6 MAC + N2O groups. Seizure occurrence was reduced in the 1.5 MAC + N2O group (P < 0.05 versus 70% N2O). The onset of seizure was delayed in the 0.6 MAC + N2O and 1.5 MAC groups for sevoflurane and isoflurane, but not for halothane, compared with the 70% N2O group (P < 0.05). Lidocaine increased R-MUA with seizure by 130%+/-56% in the 70% N2O group. The increase of R-MUA with seizure was more suppressed in the volatile anesthetic groups than in the 70% N2O group (P < 0.05). In the present study, sevoflurane and isoflurane attenuated seizure when the blood lidocaine concentration was accidentally increased. IMPLICATIONS: Increasingly, epidural blockade is combined with general anesthesia to achieve stress-free anesthesia and continuous pain relief in the postoperative period. In the present study, sevoflurane and isoflurane attenuated seizure when the blood lidocaine concentration was accidentally increased.     

Transkranielle Dopplersonographie Effekte von Sevofluran im Vergleich zu Isofluran

Methods: Using transcranial Doppler sonography (TCD), we studied the effects of sevoflurane compared to equipotent doses of isoflurane on blood-flow velocity in the middle cerebral artery (MCA) before, during, and after general anaesthesia. In random order, 30 patients received sevoflurane (n=15) or isoflurane (n=15) given in stepwise-increasing doses of 0.5, 1.0, and 1.5 MAC in oxygen/air (FiO₂=0.5). Oxygen/air was then replaced by oxygen/nitrous oxide 33%/65% with decreasing doses (1.5, 1.0, 0.5 MAC) of sevoflurane or isoflurane. During each step, ventilation was controlled to provide first normocapnia (end-tidal pCO₂=38 mmHg) and then hypocapnia (end-tidal pCO₂=27 mmHg). MCA blood-flow velocity and pulsatility, arterial blood pressure, heart rate, and body temperature were recorded simultaneously at the end of each period. For statistical analysis, within-group comparison was made by one-way ANOVA. Differences between groups were determined by two-way analysis of variance. Age, weight, and height of the patients were compared using Student’s t-test; P<0.05 was considered significant. Results: Groups were comparable regarding age, weight, and height. TCD parameters were not significantly changed by increasing doses of sevoflurane or isoflurane given in oxygen/air when compared to the awake data. However, increasing MCA blood-flow velocity was found with decreasing doses of sevoflurane or isoflurane given in oxygen/nitrous oxide (P<0.05 for 0.5 MAC, normoventilation) without intergroup differences. In both groups, hyperventilation always decreased MCA blood-flow velocity. Conclusions: We conclude from our TCD data that equipotent doses of sevoflurane and isoflurane comparably affect cerebral perfusion, especially when nitrous oxide is given simultaneously.     

吸入麻醉下内隐记忆与脑电双频谱指数的关系

目的 研究相同ＭＡＣ水平的吸入麻醉药对内隐记忆的影响,分析内隐记忆消失的界值。方法 ５４例行择期腹部手术患者,随机分为异氟醚、七氟醚、地氟醚３组（每组１８例）,麻醉采用吸入麻醉复合硬膜外麻醉,每组又依吸入麻醉浓度不同分成３个亚组（每组６例）,吸入麻醉药呼末ＭＡＣ值分别为０．４、０．５、０．６,监测患者入室后、麻醉后、切皮后、术中的双频谱指数（ＢＩＳ）,９５％的谱边缘频率（ＳＥＦ）,调查患者术后８ｈ     

异氟醚、七氟醚吸入麻醉对鼠骨骼肌微循环白细胞活动的影响

目的 探讨异氟醚、七氟醚吸入麻醉对鼠骨骼肌微循环白细胞活动的影响。方法 选择SD雄性大鼠20只,随机分为两组,制备提睾肌微循环模型。吸入异氟醚、七氟醚麻醉后,分别记录吸入异氟醚、七氟醚1．5MAC3h内微循环、小动脉A1的直径和血流速度,微循环毛细血管后微静脉的白细胞滚动和粘附数量。结果 吸入异氟醚、七氟醚1．5MAC3h内HR,MAP,CVP和A1的直径和血流速度无明显改变（P＞0．05）。微循环毛细血管后微静脉的白细胞流动和粘附数量显著增加（P＜0．01）。结论 长时间吸入异氟醚、七氟醚后,可引起大鼠骨骼肌微循环毛细血管后微静脉的白细胞滚动和粘附数量显著增加。     

Influence of aortic blood flow velocity on changes of middle cerebral artery blood flow velocity during isoflurane and sevoflurane anaesthesia

BACKGROUND AND OBJECTIVE: We studied the influence of systemic (aortic) blood flow velocity on changes of cerebral blood flow velocity under isoflurane or sevoflurane anaesthesia. METHODS: Forty patients (age: isoflurane 24-62 years; sevoflurane 24-61 years; ASA I-III) requiring general anaesthesia undergoing routine spinal surgery were randomly assigned to either group. Cerebral blood flow velocity was measured in the middle cerebral artery by transcranial Doppler sonography (depth: 50-60 mm). Systemic blood flow velocity was determined by transthoracic Doppler sonography at the aortic valve. Heart rate, arterial pressure, arterial oxygen saturation and body temperature were monitored. After standardized anaesthesia induction (propofol, remifentanil, vecuronium) sevoflurane or isoflurane were used as single agent anaesthetics. Cerebral blood flow velocity and systemic blood flow velocity were measured in the awake patient (baseline) and repeated 5 min after reaching a steady state of inspiratory and end-expiratory concentrations of 0.75, 1.00, and 1.25 mean alveolar concentrations of either anaesthetic. To calculate the influence of systemic blood flow velocity on cerebral blood flow velocity, we defined the cerebral-systemic blood flow velocity index (CSvI). CSvI of 100% indicates a 1:1 relationship of changes of cerebral blood flow velocity and systemic blood flow velocity. RESULTS: Isoflurane and sevoflurane reduced both cerebral blood flow velocity and systemic blood flow velocity. The CSvI decreased significantly at all three concentrations vs. 100% (isoflurane/sevoflurane: 0.75 MAC: 85 +/- 25%/81 +/- 23%, 1.0 MAC: 79 +/- 19%/74 +/- 16%, 1.25 MAC: 71 +/- 16%/79 +/- 21%; [mean +/- SD] P = 0.0001). CONCLUSIONS: The reduction of the CSvI vs. 100% indicates a direct reduction of cerebral blood flow velocity caused by isoflurane/sevoflurane, independently of systemic blood flow velocity.