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Inhalational anesthetics have been used for induction and maintenance of general anesthesia for more than 150 years. All of the currently used inhalational anesthetics are chlorinated and fluorinated derivatives of ether. Dosing is carried out using the minimal alveolar concentration (MAC) concept. The pharmacokinetic properties of the various inhalational anesthetics are governed by the specific distribution coefficients. Mechanisms of action include specific modulations of various receptors of the central nervous system as well as an unspecific interaction with the cell membrane. Organ toxicity of modern inhalational anesthetics is considered to be minimal. The role of inhalational anesthetics in the context of postoperative nausea and vomiting (PONV) has been reassessed in recent years. The superiority of inhalational anesthetics over intravenous hypnotics with respect to intraoperative awareness is undisputed. The organ protective mechanism of preconditioning is an exclusive property of inhalational anesthetics among all the currently available hypnotics.Inhalationsanästhetika werden seit mehr als 150 Jahren zur Durchführung von Allgemeinanästhesien verwendet. Alle heute verwendeten Substanzen sind chlorierte und fluorierte Ätherderivate. Ihre Dosierung erfolgt nach dem Konzept der „minimal alveolar concentration“ (MAC). Die pharmakokinetischen Eigenschaften der einzelnen Inhalationsanästhetika werden durch spezifische Verteilungskoeffizienten beschrieben. Die Wirkmechanismen umfassen spezifische Modulationen verschiedener Rezeptoren des Zentralnervensystems (ZNS) und eine unspezifische Interaktion an der Zellmembran. Die Organtoxizität heutiger Inhalationsanästhetika wird als minimal erachtet. Die Rolle von Inhalationsanästhetika im Zusammenhang mit „postoperative nausea and vomiting“ (PONV) ist in den letzten Jahren neu bewertet worden. Unbestritten ist die Überlegenheit von Inhalationsanästhetika gegenüber i.v.-Hypnotika bezüglich intraoperativer Awareness. Den organprotektiven Mechanismus der Präkonditionierung bieten unter den heute verfügbaren Narkosemitteln einzig die Inhalationsanästhetika.

Removal of the laryngeal mask airway in the post-anesthesia care unit could potentially contribute to a faster turnover from one operation to the next. The aim of this study was, therefore, to obtain an insight into the potential time saving and the safety of planned removal of the ProSeal™-LMA (PLMA) in the post-anesthesia care unit.In this study 120 adult patients with American Society of Anesthesiologists (ASA) classification I-II, age range 18-85 years, undergoing a surgical procedure under general anesthesia in which the PLMA was used were randomly assigned to one of two groups. In group I, the PLMA was removed in the awake patient in the operating room close to the end of the procedure. In group II, the anesthetised but spontaneously breathing patients were moved to the recovery room and the PLMA removed when the patient was awake. The anesthesia technique was standardized [balanced, sevoflurane, fentanyl, bispectral index-guided (BIS) target value=35±5] and identical in both groups until randomization. Patients were breathing room air during transport to the recovery room. Different time intervals as well as the incidence of critical incidents were compared between groups. An oxygen saturation (S(p)O(2)) value95% was considered a clinically relevant and S(p)O(2) values90% as clinically critical O(2)-desaturation.Removal of the PLMA took place after an average of 4.9±5.1 min in group I and after 19.5±9.6 min in group II. There was no difference in the availability of the anesthetist in the operating room for the following procedure between groups (group I: 12±5.6 min vs. group II: 10.7±4.2 min, p0.05) despite the fact that patients of group II left the operating room faster (4.9±3.9 min) than patients of group I (7.1±5.1 min, p0.01). In group II patients were ready for discharge (White score=12) from the recovery room later (13.2±8.2 min) than in group I (3.6±4.8 min, p0.01). There were no significant differences in other process related time intervals between group I and group II: duration of the operation (113.2±45.9 min vs. 105.3±42.6 min), duration of dressing (5.1±3.7 min vs. 4.6±2.8 min), duration of transport to the recovery room (3.9±1.3 min vs. 3.6±1.3 min) and information at end of surgery by the surgeon (22.5±9.3 min vs. 22.4±10.5 min). The incidence of clinically relevant as well as clinically critical O(2) desaturation at the time of recovery room arrival (S(p)O(2)≤90%) was increased in group II with 33.3% vs. 56.6% and 13.3% vs. 6.7%, p0.01, respectively.Planned PLMA removal in the recovery room after BIS-guided balanced anesthesia did not enable the anesthetist to be available earlier for induction of anesthesia in the following patient. Hence the anesthetist could not contribute to a faster turnover of cases. Obviously, with the type of close communication between surgeon and anesthetist dictated by the study protocol (announcement of expected end of surgery by the surgeon 20 min before end of surgery) it is possible for the patient to regain consciousness within a very small time window following the end of surgery. Following this kind of protocol, postponement of removal of the LMA in the recovery room does not seem to be attractive neither from a clinical nor an economic point of view. In contrast, removal of LMA in the recovery room should be restricted to occasional cases with an abrupt end of the operation or prolonged emergence from anesthesia. The obvious risk of hypoxemia necessitates continuous O(2) application and S(p)O(2) monitoring during transport to the recovery room.

According to numerous pharmacoeconomic studies new anaesthesia techniques can improve recovery times and thus can have a positive economic impact on patient turnover. However, artificial study protocols do not always match real world situations and thus the practical impact of such studies remains unclear.At 10 hospitals exclusively using sevoflurane as a volatile anaesthetic, the ad hoc implementation of desflurane was studied with respect to post-anaesthetic recovery times (primary endpoint) and postoperative outcome measured by the Quality of Recovery Score- (QoR-)40, on the first postoperative day was investigated. Randomization of patients undergoing elective surgical procedures under general anaesthesia with sevoflurane (n=186) or desflurane (n=176) was started immediately after a period of a few days after introducing the new drug to all participants. Except for the volatile anaesthetic the anaesthetic procedure was performed according to local standing operating procedures.All parameters indicating the immediate postanaesthetic recovery were superior in the patients receiving desflurane (mean±SD). Time to extubation was accelerated from 8.7±9.7 to 6.2±6.8 min. Times to recalling name and date of birth were accelerated by 2.6 and 3.8 min, respectively. Transferring the patients from the operating theatre to the post-anaesthetic recovery unit was 17.3±11.5 min after sevoflurane and 13.7±7.8 min after anaesthesia with desflurane. Eligibility for discharge according to a modified Aldrete score (White and Song 1999) was reached after 103±98 and 79±76 min, respectively. The postoperative recovery (QoR 40 questionnaire) did not differ 24 h later.The implementation of a new drug (here: desflurane to substitute sevoflurane) can improve speed of recovery immediately after termination of anaesthesia even after a very short period of introducing the new technique but has no positive long term effects. Thus, the results of this trial performed under a real world scenario (health service research) without tight standardization by an artificial study protocol supports the results originating from randomized controlled clinical trials.

After problem-free induction of narcosis in an 84-year-old female patient an intra-operative drop in sevoflurane and oxygen concentrations occurred during low-flow anesthesia. Although the concentrations of sevoflurane and oxygen in the fresh gas flow were increased no adequate elevation of the inspiratory concentrations could be achieved. Disconnection of the Dräger Primus IE manual bag-valve-mask could be identified as the cause of the drop in concentrations. Interestingly no error alarm function was initiated. This case demonstrates how important knowledge of the function, set-up and alarm conditions of respiratory machines is. This should be an important component of training in anesthesiology as well as securely established algorithms for difficult ventilation to ensure safe anesthesia despite technical failures.

The safe use of cuffed tracheal tubes for children necessitates a cuff pressure limitation at 20-25 cmH2O. The aim of the study was to evaluate the reliability and benefit of a new cuff pressure release valve (opening pressure 20 cmH2O) for children intubated with a cuffed tracheal tube.In a prospective, observational trial cuff pressure was recorded in paediatric and adolescent patients intubated with a cuffed tracheal tube during sevoflurane/nitrous oxide anaesthesia. The cuff pressure release valve was interposed between the cuff manometer and the pilot balloon. In 25 patients measurements were started at the initial opening pressure (group A) and in a further 25 patients measurements were started at the minimal sealing cuff pressure (group B).A total of 50 patients, aged from 0.4 to 17.8 years (median 7.4 years) were enrolled in the study. The opening pressure measured (group A) was 19.7+/-0.8 cmH(2)O and the cuff sealing pressure (group B) was 11.7+/-2.9 cmH2O (range 6-16 cmH2O). Mean cuff pressure values in group A were 20.4+/-1.6 cmH2O and 16.5+/-3.3 cmH2O in group B. In one patient (group A) the cuff pressure exceeded 25 cmH2O and was manually decreased to 20 cmH2O. In total, 24 filling procedures (group A 14; group B 10) were required during 103.1 h of investigation because of cuff pressure drop and audible air leakage, mainly caused by cuff pressure increases and consequent releases during patient positioning.Our data demonstrate that the tested cuff pressure release valve was useful and reliable to limit cuff pressure in tracheal intubated children and adolescents within an acceptable pressure range.

The aim of the present study was to compare the safety and efficacy of sevoflurane and isoflurane during low flow anaesthesia (fresh gas flow (FGF) 14 ml/kg/min) as well as to compare the consumption of both anaesthetics. Data were gathered from 60 dogs assigned for surgery under general anaesthesia with an expected duration of 75 minutes or longer. All dogs were induced with 0.6 mg/kg (maximum 25 mg) l-methadone and 1 mg/kg (maximum 25 mg) diazepam i.v.. Anaesthesia was maintained with isoflurane (group 1) or sevoflurane (group 2) in a mixture with 50% O2 and 50% N2O as carrier gases, under controlled ventilation. Monitoring included electrocardiogram, body temperature, the temperature of in- and exspired gases, arterial oxygen saturation, arterial blood pressure as well as a continuous monitoring of inhaled and exhaled gas concentrations (O2, N2O, CO2, isoflurane, sevoflurane). The consumption of isoflurane and sevoflurane as well as the dogs' recovery times were evaluated for both groups. In all groups the inspired oxygen concentrations ranged above the minimum value of 30 Vol% during low flow anaesthesia, with an arterial oxygen saturation above 97%. End tidal concentration of CO2, heart rate and arterial blood pressure were within the physiological ranges and showed no differences between the two groups. Recovery time was significantly shorter after sevoflurane compared to isoflurane anaesthesia, whilst the consumption of sevoflurane was higher than that of isoflurane. Sevoflurane appears to be as clinically safe as isoflurane in low flow anaesthesia. Even considering that sevoflurane is more expensive than isoflurane, the use of the low flow technique decreases the cost of anaesthesia due to the reduced volatile anaesthetic consumption.

Purpose of the study was to investigate the mitotic index (MI) and sister chromatid exchange (SCE) levels to identify the mutagenic and carcinogenic effects of sevoflurane (sevoflurane).42 non-smoking male and female turkish patients of ASA-risk I and II were included. The patients received an anaesthesia induction with 8 % sevoflurane in 100 % oxygen ("tidal volume methode") and 0.1 mg/kg BW vecuronium for neuromuscular block and endotracheal intubation. Anaesthesia was maintained with 2.0 - 2.5 sevoflurane in 60 % N(2)O and 40 % O(2). Four 5 ml venous blood samples werde taken: before induction (control), 60 minutes, 24 hours and 5 days after sevoflurane anesthesia. Samples were prepared according to the periferic blood culture assay, modified by Morhead and co-workers, and levels of MI and SCE were examined.60 minutes after sevoflurane-anaesthesia a significant decrease of MI was found compared to controls (p0.01). This depression was lower after 24 hours (p0.05) and reversible after 5 days. SCE increased significantly during 60 minutes of anaesthesia (p0.001), was also lower after 24 hours (5.6 +/- 2.4 vs. 4.4 +/- 1.7) and returned to normal levels after 5 days (p0.05).The application of sevoflurane for anaesthesia may influence the cell division in humans and may have a mutagenic effect on DNA at the cell level, which is reversible.

Occupational exposure to volatile anaesthetics cannot be completely avoided even in modern operating theatres. In 1997, the staff exposure during balanced anaesthesia in our hospital was low (sevoflurane 0.49 ppm; N(2)O 11.5 ppm). In 1999, N(2)O was completely omitted at our hospital, therefore, exposure to volatile anaesthetics, namely sevoflurane, might have increased.Environmental exposure was measured by photoacoustic infrared spectrometry. To determine the personal exposure and to compare it with environmental exposure, 14 anaesthetists wore diffusion samplers near their breathing zones for 1 week.The median environmental concentration of sevoflurane was between 0.09 and 0.21 ppm in central operating theatres and between 0 and 24.8 ppm in intervention rooms. The median personal concentration was 0.19 ppm.The occupational exposure to volatile anaesthetics is not higher using sevoflurane alone compared to the combination of sevoflurane and N(2)O. In addition, the data acquired from environmental and personal measurements showed similar results.

The objective of this study was a comparison of the volatile anaesthetics isoflurane and sevoflurane in terms of their clinical effects in gerbils (Meriones unguiculatus) (n=12 each). Induction of anaesthesia was performed in a body chamber with an anaesthetic concentration of 4.0 Vol.% at an oxygen flow of 500 ml/min for isoflurane and 8.0 Vol.% at an oxygen flow of 1000 ml/min for sevoflurane, respectively. Anaesthesia was maintained via nose cone with an anaesthetic concentration of 2.8 to 3.2 Vol.% at an oxygen flow of 200 ml/min for isoflurane and 5.0 to 5.2 Vol.% at an oxygen flow of 400 ml/min for sevoflurane. Those anaesthetic concentrations ensured reflex status conform with surgical tolerance. In spite of its higher blood-gas coefficient induction time was slightly faster for isoflurane. Recovery time was significantly longer in the isoflurane group than it was in the sevoflurane group. Both inhalants caused respiratory depression. Respiratory rate was lower in sevoflurane animals compared to isoflurane. The animals were positioned on a heating pad immediately after induction, thus a decrease of the body temperature could be prevented. Both inhalants can be recommended for usage in gerbils. Sevoflurane showed no clinical benefit compared to isoflurane.

Total intravenous anaesthesia (TIVA) is increasingly used in diagnostic surgery such as stereotactic biopsy of the brain. TIVA could lead to a faster recovery of cerebral function, which may lead to a better behavior and advantages in the postoperative management. The aim of this prospective, single-blind study was to compare the hemodynamics, the postoperative recovery period, the side-effects and the need for additional cardiovascular medication during and after the operation between the three study groups.After giving informed consent and approval by the ethical committee of our hospital, 51 patients (ASA I and II) undergoing stereotactic biopsy of a brain tumor were randomized to receive either propofol via the TCI-system (group 1: TCI-TIVA), propofol by a manual technique (group 2: MAN-TIVA) or methohexitone-sevoflurane (group 3: BAL-SEVO). Remifentanil was used as the analgetic component in all groups. Systolic and diastolic blood pressure, heart rate und transcutaneous oxygen saturation were noted before and after induction and before and after the end of anaesthesia. The time until return of complete orientation relative to person, location and time were measured. The patients' ranking of their satisfaction with the anaesthesia was questioned 60 min and 24 hours after the end of the procedure (VAS). Undesirable side-effects (i. e. PONV, shivering, pain, dysphoria, tiredness) were noted, whenever they occurred. The number of hemodynamic interventions by the anaesthesiologist was counted, and the total doses of remifentanil and propofol were quoted. Depth of anaesthesia was monitored by using a BIS-system, a range between 40 and 50 was thought to be adequate. Besides this, the total doses of remifentanil, propofol and sevoflurane were ruled out and the costs of the three regimens were ranked.Heart rate dropped markedly in all groups with a maximum in the TIVA-collective. Systolic and diastolic pressure also fell in the groups. In the SEVO-group, the difference was statistically significant only at the end of anaesthesia. After extubation, the three groups reached their hemodynamic starting-point with a slight overshoot in the SEVO-group. The number of required hemodynamic interventions was two (TCI-TIVA) vs. 7 (MAN-TIVA) vs. 8 (BAL-SEVO) in each group, respectively. The difference scarcely failed to get significance. The remifentanil requirements were similar between the collectives, group 1 needed more propofol per time than group 2. The number of side-effects was very little after the different regimens. There were no differences with regard to the other measured parameters between the groups. The use of TCI-TIVA was more expensive than manual TIVA (18,85 euro vs. 12,50 euro). Surprisingly, balanced anaesthesia using Sevoflurane was the most expensive method during the first hour, mainly due to the use of methohexitone as the induction agent (23,90 euro).Each of the three techniques compared in our study is suitable for anaesthesia in diagnostic neurosurgery. Since fast recovery of vigilance is important to justify the neurological outcome, none of the methods seems to be superior to the others. The hemodynamics were largely stable with a strong trend towards minor necessity for hemodynamic intervention in the TCI-TIVA group. This is also the best method from the subjective point of view of the anaesthesiologist due to the easy handling and the low number of interventions. The use of newer TCI-systems (e. g. fm-controller, Braun, Melsungen) not operating with special application syringes will cheapen TCI-TIVA.

We report on a 25-year old ASA physical status I patient, who developed within 20 minutes a full-blown malignant hyperthermia (MH) in the context of a living donor liver transplantation after 180 minutes of uneventful anaesthesia. The only trigger substance applied was Sevoflurane. The patient had already received a short, uneventful anaesthesia with Isoflurane a couple of years ago. In the context of the special constellation an initial dose of Dantrolene of 10 mg/kg body weight was administered. The patient was stabilised within 30 minutes, and the enzyme levels remained low compared with other case reports. The post-operative in vitro caffeine halothane contracture testing confirmed that son and mother were susceptible to MH, contracture testing in the father was negative. All known triggers may cause life-threatening MH crisis - even after hours and after inconspicuous multiple exposures to known trigger substances. Therefore all trigger substances must be avoided in all patients susceptible to MH.

BACKGROUND AND STUDY GOALS: Strabismus surgery in children is frequently associated with a very high incidence of postoperative nausea and vomiting (PONV). In this study we investigated, whether TIVA is superior to inhalation anaesthesia concerning PONV when a prophylaxis using dimenhydrinate (diphenhydramine chlorotheophyllate) is administered in both groups.110 patients (3-10 years) were prospectively and randomly allocated to one of the following groups: Group TD (TIVA/dimenhydrinate; n= 55): anaesthesia was induced and maintained using remifentanil and propofol in common clinical dosages. Patients were ventilated with 30% O(2) in air. Group VD (Volatile/ dimenhydrinate; n= 55): anaesthesia was induced and maintained with sevoflurane in common clinical concentrations together with N(2)O in 30% O(2). All patients received dimenhydrinate 1 mg.kg(-1) i.v. after induction. PONV was recorded within the first 24 h postoperatively. The chi-square test and a multivariate analysis were used for statistical analysis.52 patients of group TD and 54 of group VD were analysed. There was a trend in the incidence of postoperative nausea (PN): group TD 17%, 95% CI: 8-30%) compared to group VD 31%, 95% CI: 20-46%), p = 0.09. No difference was seen for PV and PONV: 21% (95% CI: 11-35%) in group TD vs. 35% (95% CI: 23-49%) in group VD, p = 0.109. These non-significant results can be easily attributed to the lack of power about 30%) of this study. According to the results of the multivariate analysis volatile anaesthesia was identified as an independent risk factor for PONV (OR: 2.92, 95% CI: 1.02-8.36). Other variables that were found to be an independent risk factor included history of PONV (OR: 8.19, 95% CI: 1.84-36.43), surgery lasting longer than 30 min (OR: 5.89, 95% CI: 1.82-19.82) and "Faden-operations" (retroequatorial myopexy) (OR: 5.48, 95% CI: 1.74-17.21).TD only showed a trend to lower PN incidences and no differences as for PV and PONV incidences, most likely due to a lack of power of this study. However, according to the results of the multivariate analysis, inhalation anaesthesia was shown to be an independent risk factor for PONV, as were history of PONV, surgery30 min and "Faden-operations".

The study was undertaken to compare different anaesthetic techniques for scheduled or urgent caesarean section with respect to maternal circulatory parameters, maternal and fetal endocrine stress response, fetal vitality parameters and further clinical parameters such as recovery and analgesic demand.After ethical approval,patients scheduled for general anaesthesia were randomly allocated to the esketamine group ( n=21; induction with 0.5 mg/kg BW esketamine and 1.5 mg/kg BW methohexitone, ventilation until cord cutting with FiO(2) 1.0) and the sevoflurane-group ( n=21; induction with 1.5-2.0 mg/kg BW methohexitone, ventilation until uterotomia with N(2)O/O(2) [FiO(2) 0,5] and endtidal sevoflurane concentrations about 1.0 vol%). After fetal development, all patients received 2.5 microg/kg BW fentanyl and sevoflurane (about 1.0 vol% endtidal) during ventilation with N(2)O/O(2) (FiO(2) 0.33). As a further control, a group with spinal anaesthesia ( n=22; 2.6-3.0 ml isobaric bupivacaine 0.5 %) was investigated. Maternal circulatory and endocrine plasmatic stress parameters were investigated at five time points and fetal parameters once after development.alphaor =0.05 was considered significant.Biometric data were comparable in all groups. Systolic arterial pressure was higher in the esketamine group ( p=0.008), whereas the heart rate was lower during spinal anaesthesia ( p0.001). Plasma noradrenaline decreased in all collectives ( p0.001) and mean group levels of noradrenaline ( p=0.04) and adrenaline ( p0.001) were lower during spinal anaesthesia. In all groups, antidiuretic hormone (ADH) remained within the normal range or was slightly increased. Adrenocorticotropic hormone (ACTH) initially increased in all groups and decreased in later time course ( p0.001). Cortisol increased in all groups ( p0.001) but group levels were lower during spinal anaesthesia ( p0.001). In the groups with general anaesthesia, no significant differences in recovery times were obvious, and neither recall nor dream reactions were observed. Postoperative hypoxic incidents (psaO(2)90%) were comparable between the groups. After spinal anaesthesia, first analgesic demand was later than in the controls ( p=0.001), and the total amount of piritramide was lower ( p=0.02). Nausea and vomiting were more frequent during spinal anaesthesia ( p=0.03). All patients were content with their regimen. Apgar scores, pH-values and adrenaline, noradrenaline and cortisol in plasma were comparable in all groups of children (69 children, 5 gemini). The fetal concentration of esketamine (251 ng/ml) was lower than the corresponding maternal values (493 ng/ml).When compared with methohexitone, sevoflurane and N(2)O for caesarean section, initial total intravenous anaesthesia with esketamine and methohexitone mediated specific antinociception without negative maternal or fetal effects and not taking invasion kinetics or elimination between uterotomia and cord cutting into consideration. Avoidance of N(2)O allows optimal oxygenation of the fetomaternal unit. Stress protection and hemodynamic responses were well balanced, and intraoperative recall or negative dream reactions were lacking. Superior postoperative pain protection was advantageous after spinal anaesthesia, but in contrast, nausea and vomiting were more frequent in this group.

Approximate entropy, a measure of regularity, can be used to analyze the electroencephalogram of patients in general anesthesia to discriminate between different states of consciousness. EEG burst suppression patterns reflect a state of deep anesthesia. Due to the instationary character of this EEG pattern approximate entropy values do not correctly classify the patient state. Possible solutions to this problem may be limited by the demand of computing power for entropy calculation and the reaction time following changes in patient state. Different approaches for an online monitoring application are examined.

To compare the onset, duration and maximum effect of 0.1 mg/kg cisatracurium during balanced anesthesia with sevoflurane and remifentanil between infants and children.We measured the time course of the neuromuscular blockade in 15 infants and 15 children by electromyography. Anesthesia was induced with propofol/remifentanil and maintained with sevoflurane (constant 2% endtidal) and remifentanil according to the patients individual requirements. After injection of 0.1 mg/kg cisatracurium we measured the following parameters: onset time: time between the beginning of injection of cisatracurium and maximum T1 depression, clinical duration: time between injection of the drug and recovery of T1 to 25%, recovery index: time between recovery of T1 from 25% to 75%. TOFR 0.9: time between injection of cisatracurium and recovery of the train-of-four ratio to 90%. In addition, we determined the maximum neuromuscular blockade Tmax after 0.1 mg/kg cistracurium.Both groups differed significantly with regard to onset time and clinical duration. In the infants, the onset time was shorter (74 s vs. 198 s) and the clinical duration longer (55 min vs. 41 min) compared to the older children. The TOFR 0.9 was 73 min (range 56-86 min) in the group of the infants and 59 min (range 43-72 min) in the group of the older children (p0.001). Tmax was 100% (range 97-100%) in the infants and 98% (range 92-100%) in the children (p0.01). However, the recovery index was comparable in both groups (21 vs. 16 min).Infants are substantially more sensitive to cisatracurium than children, which can be demonstrated in a significantly shorter onset time, a prolonged clinical duration and a delayed neuromuscular recovery. As there exist large interindividual differences, we recommend the use of neuromuscular monitoring in the routine practice of pediatric anesthesia.

In adults, sevoflurane augments the intensity of rocuronium evoked neuromuscular blockade. However, in children effective doses and onset of action of rocuronium have not been reported during sevoflurane anaesthesia. To test in children the hypothesis that sevoflurane speeds the onset and potentiates the degree of rocuronium induced neuromuscular blockade we studied 50 children aged 2 - 7 years following approval by the local ethics committee.After induction and maintenance of anaesthesia with either 2 % endtidal sevoflurane in 60 % N(2)O/O(2) (n = 30) or with propofol (3 mg small middle dot kg(-1) and 10 mg small middle dot kg(-1)h(-1), n = 20) and 60 % N(2)O/O(2) for 17 +/- 1 min, we injected either 0.15, 0.22, or 0.3 mg small middle dot kg(-1) rocuronium and quantified by mechanomyography the evoked (0.1 Hz ulnar nerve stimulation) response of the adductor pollicis muscle. Dose-response relationships of rocuronium under both anaesthetic regimes were assessed using a generalised linear model based on the maximum-likelihood-technique. Data were compared by analysis of covariance, F-test, and Mann-Whitney-U-test as indicated, p0.05, mean +/- SD, (95% confidence interval).The degree of neuromuscular blockade was greater (p0.05) during sevoflurane (estimated ED 50: 0.15 (0.076 - 0.177) mg small middle dot kg(-1)) than propofol (ED 50: 0.25 (0.15 - 0.35) mg small middle dot kg(-1)) anaesthesia. Furthermore, onset time was significantly faster under sevoflurane/N(2)O compared to propofol/N(2)O anaesthesia (110 +/- 31 versus 230 +/- 52 s, p0.01, after rocuronium 0.3mg small middle dot kg(-1)).In young children during steady state anaesthesia onset of action of rocuronium is halved and the degree of neuromuscular blockade is markedly augmented during sevoflurane/N(2)O anaesthesia compared to propofol.

The aim of this study was to compare total intravenous anaesthesia (TIVA) using propofol and remifentanil (P/R-group) and balanced anaesthesia (BA) using sevoflurane and remifentanil (S/R-group) for paediatric surgery.A total of 120 patients aged 6 months to 16 years scheduled for elective minor lower abdominal surgery were randomly assigned to receive either propofol (5-10 mg/kg/h) and remifentanil (0.125-1.0 microgram/kg/min) or sevoflurane (1.0-1.5 MAC) and remifentanil (0.125-1.0 microgram/kg/min). Perioperative haemodynamics as well as recovery and discharge times, PONV and side-effects were studied. The patients vigilance, comfort and pain intensity were assessed postoperatively using the objective pain discomfort scale, the Steward post-anaesthetic recovery score and a visual analogue scale.Postoperative recovery (9.0 vs 11.6 min) and extubation times (11.8 vs. 15.0 min) as well as the time taken until a Steward post-anaesthetic recovery score3/4 (15.2 vs. 21.4 min) was reached were significantly shorter in the P/R-group. However, the length of time until discharge to the ward, postoperative comfort, pain intensity and analgesic requirements as well as PONV were comparable in both groups.With regards to the investigated parameters, TIVA with propofol and remifentanil is equally effective as BA with sevoflurane and remifentanil in paediatric patients. However, considering the selected dosing regimen, recovery times were significantly shorter for children after TIVA.

In a randomized double-blind placebo-controlled trial in children 2-7 years of age, we investigated the effect of a single prophylactic midazolam bolus (0.1 mg/kg b.w.) prior to the termination of anaesthesia, on the incidence and severity of agitation occurring after sevoflurane administration. Compared to the placebo group, midazolam prophylaxis significantly decreased the incidence of postanaesthetic delirium. However, the incidence of severe agitation requiring treatment was not different between the groups (placebo: n = 6; midazolam: n = 4). The mean severity of agitation was significantly lower in patients with midazolam prophylaxis. When midazolam was administered for the treatment of severe agitation it reduced the severity but did not abolish agitation. All patients were discharged from the recovery room after the 2 h observation period. From our study we conclude that a small prophylactic midazolam bolus is able to reduce the incidence and severity of agitation after sevoflurane anesthesia in some patients but is insufficiently effective in patients with severe agitation. Thus, the prophylactic administration of midazolam extenuates but does not solve the problem of post-sevoflurane agitation.

The alkali hydroxide content in soda lime induces Compound A formation from Sevoflurane (Sevo). This study was designed to answer the question if the use of potassium hydroxide-free Soda Lime (SL) would lead to lower Compound A levels as compared to Sodasorb (SO). A total of 30 patients scheduled for elective laparoscopic cholecystectomy received Sevo anaesthesia under low-flow conditions (0.8 l/min fresh gas flow). Each absorbent was used in 15 patients, but 3 patients of the SO group were excluded due to technical problems with Compound A analysis. Hemodynamic parameters, parameters of ventilation and gas concentrations were documented. Compound A concentrations were measured by gas chromatography from gas samples before Sevo application and 20, 40, 60, 90 and 120 min after low-flow start. Mean endtidal Sevo concentrations were 1.94 +/- 0.17 (SO) and 1.97 +/- 0.15 (SL) vol %, the total anaesthetic exposition was 1.52 +/- 0.36 (SO) and 1.64 +/- 0.47 (SL) MAC-h (n.s). The maximum Compound A concentration was significantly higher in SL group (19.6 +/- 2.8 vs. 11.7 +/- 4.1 ppm, p0.001). Therefore, elimination of potassium hydroxide from carbon dioxide absorbents alone did not lead to a reduction of Compound A formation during low-flow anaesthesia.

Before laparoscopic cholecystectomy and endoscopic therapy became gold standard the nonsurgical treatment of symptomatic cholelithiasis, i.e. contact dissolution using methyl-tert-butyl ether (MTBE), was a valuable alternative. Even nowadays, stone dissolution may be helpful in critically ill patients.A 85-year-old man admitted in poor general condition due to cholangitis with septicemia following endoscopic retrograde cholangiopancreatography (ERCP) with papillotomy and partial stone removement because of impending perforation of the gallbladder empyema was treated by a percutaneous cholecystostomy with a pigtail catheter. After clinical improvement a successful contact dissolution was initiated by irrigation of the common bile duct and gallbladder with MTBE. The patient is asymptomatic three months after treatment.Symptomatic cholelithiasis is usually treated by endoscopic techniques. Percutaneous cholecystostomy in association with contact litholysis using MTBE is an effective treatment in patients who can not be operated due to critical conditions. The success rate in case of cholesterol stones averages 70 to 95% depending on number and size of stones. It is a non-invasive treatment with few side effects.In high-risk patients with severe cholecystitis, percutaneous catheter cholecystostomy combined with contact litholysis using MTBE is a successful, safe, and cheap treatment.

In a 62-year-old female patient without a history of epileptic seizures EEG monitoring (EEG monitor: Narcotrend) was routinely performed during propofol/remifentanil and during sevoflurane/remifentanil/nitrous oxide anaesthesia. In the first course of anaesthesia after a bolus of propofol 1% a continuous EEG slowing was followed by a burst suppression pattern without occurrence of epileptiform activity throughout this sequence. During the second course of anaesthesia the sevoflurane concentration was increased from 2 to 8 % by volume. After 5 min epileptiform activity appeared in the EEG at an endtidal concentration of 5.9% by volume.

Recovery characteristics, haemodynamic profile, analgesic requirement and costs were evaluated and compared in patients undergoing elective lumbar discectomy with remifentanil-based anaesthesia using either desflurane or sevoflurane as the volatile anaesthetic agent. Sixty-two patients (ASA I/II status) were randomly assigned to receive either desflurane and remifentanil or sevoflurane and remifentanil (in oxygen/air) for anaesthesia. After induction with 0.5 microgram/kg/min remifentanil, 4 to 5 mg/kg thiopentone and 0.5 mg/kg atracurium, the patients received 0.25 microgram/kg/min remifentanil and 0.5 +/- 0.05 MAC of one of the volatile anaesthetic agents for further maintenance of anaesthesia. At the end of surgery, early emergence from anaesthesia was recorded by assessing the time to sufficient spontaneous respiration, eye opening and tracheal extubation. The total demand of piritramide in the postoperative period was determined using patient-controlled analgesia (PCA device). Quality of pain therapy was assessed via a verbal ranking scale (VRS). Side-effects such as postoperative nausea, vomiting or shivering were recorded in the postanaesthetic care unit. In both groups, the haemodynamic profile was nearly identical. Mean arterial pressure (-18%) and heart rate (-23%) were significantly reduced throughout anaesthesia in both groups. All recovery parameters were significantly shorter in the desflurane group in comparison with the sevoflurane group (e.g. time to tracheal extubation: 8.5 +/- 3.0 min vs. 11.9 +/- 4.6 min). No significant differences between the groups were observed concerning the amount of piritramide required, side-effects such as nausea and vomiting or the total cost of anaesthesia. In conclusion, both anaesthetic techniques provide adequate haemodynamic stability and postoperative pain control in a surgical procedure with minimal trauma. Incidence and severity of side-effects such as nausea, vomiting or shivering did not differ between the groups and were acceptable under clinical conditions. Costs for desflurane were significantly higher than those for sevoflurane, but total costs were not different between the groups. Concerning recovery profile, desflurane/remifentanil seems to have small advantages over sevoflurane/remifentanil in patients undergoing lumbar vertebral disc resection.

In ambulatory anaesthesia the time required to recover from cognitive impairment should be as short as possible. The aim of this study was to compare the early cognitive recovery after remifentanil/propofol (R/P) and sevoflurane/fentanyl (S/F) anaesthesia.Sixty patients scheduled for elective gynaecological laparoscopy and 24 female volunteers tested for the assessment of learning effects were investigated. After praemedication with midazolam anaesthesia was induced with propofol, atracurium and either 1 microgram/kg fentanyl or 1 microgram/kg remifentanil. For maintenance 0.25 microgram/kg/min remifentanil and 0.6 mg/kg/min propofol (R/P) or 1.7 vol% sevoflurane (S/F) were given. Both groups were ventilated with 30% oxygen in air and received metamizol for postoperative analgesia. Verbal Learning Test, Stroop Colour and Word Interference Test, Digit Symbol Substitution Test and Four Boxes Test were performed the day before surgery and 30 min, 1 h, 2 h and 4 h after termination of anaesthesia.For remifentanil/propofol cognitive function was still impaired 2 h (Verbal Learning) and 4 h (Stroop, Digit Symbol Substitution and Four Boxes Test) after termination of anaesthesia. After sevoflurane/fentanyl anaesthesia cognitive impairment lasted the same duration in Four Boxes Test, but shorter in Stroop and Digit Symbol Substitution and could not be found in Verbal Learning Test.The duration of cognitive impairment in the early postoperative period differed by the test procedures and the anaesthetic procedures used in this investigation. Recovery appeared to be faster after sevoflurane/fentanyl than after remifentanil/propofol at least in aspects of cognitive function.

Aim of the study was the clinical investigation of sevoflurane degradation when using water-free lithiumhydroxide versus moist Drägersorb 800 for carbon dioxide absorption.Concentrations of Compound A in the inspiratory gas mix and serum fluoride levels were measured in two groups of 8 patients each.When water-free lithiumhydroxide was used for carbon dioxide absorption, concentration of Compound A in the inspiratory gas mix was ca. 1 ppm (near minimal level of detection) as compared to ca. 20 ppm for moist Drägersorb 800. The concentration of fluoride increased during sevoflurane anesthesia (15.0 +/- 4.8 mumol/l with lithiumhydroxide versus 21.9 +/- 4.0 mumol/l with Drägersorb 800 after 60 mins).When lithiumhydroxide is used, there is only minimal formation of compound A from sevoflurane degradation. Since serum fluoride levels increased in both patient groups, we conclude that this is caused mainly by metabolism of sevoflurane. Capacity of lithiumhydroxide for carbon dioxide absorption is similar to that of Drägersorb 800. Therefore, the use of lithiumhydroxide increases patient safety.

Oculocardial reflex (OCR) occurs particularly through manipulation of the medial rectus muscle and results in a bradycardic arrhythmia. In children the incidence is between 60 and 80%. After using sevoflurane in clinical practice, the absence or non-occurrence of this reflex was observed. The data of 180 healthy children aged between four and 14 years who had to undergo strabismus surgery under general anaesthesia were analysed: group I (n = 92), group II (n = 88). All children received standard premedication with midazolam, no anticholinergic drugs were administered. During narcosis, analgesia was maintained routinely with alfentanil. In group I sevoflurane was inhaled for hypnosis and in group II propofol was injected as intravenous hypnotic drug. The depth of anaesthesia was adjusted according to clinical criteria. To compare both groups, heart rate (HR) was determined before, during and after surgical intervention. OCR was defined as a heart rate declining by more than 20% from the initial HR.OCR is described in all methods of general anaesthesia. Under sevoflurane the occurrence of the reflex was significantly (p0.05) reduced to 14% of all patients as compared to 75% in patients who received a propofol infusion. Sufficient reflex reduction according to the depth of narcosis under sevoflurane in combination with the sympathomimetic effects of this drug could therefore be discussed as a reason for its positive effects. In our opinion, the use of sevoflurane should be considered as an option for general anaesthesia in strabismus surgery.

Inhalational mask induction with nitrous oxide and sevoflurane in young children is an appropriate alternative to intravenous induction and is considered safe and of rapid onset. Disadvantages of this technique are environmental pollution and occupational exposure to the inhalation agents used. Moreover, the potential health hazards are not yet completely clear. The purpose of the present study was to examine the anaesthesiologist's occupational exposure to nitrous oxide and sevoflurane in paediatric anaesthesia and mask induction. Twenty children underwent inhalational induction with nitrous oxide and sevoflurane in the operating theatre (air exchange rate 20.2/h, anaesthetic waste gas scavenger 40 l/min). Anaesthesia was maintained with the same agents. Air samples were taken from the edge of the anaesthesiologist's mouth continuously every 90 seconds, and trace concentrations of nitrous oxide and sevoflurane were analyzed with a direct reading infrared spectrometer (BrüelKjaer 1302, Denmark). Measurements taken during anaesthesia showed an increase in the concentrations of the anaesthetics used, but these were low. The highest mean concentrations occurred during induction (3.35 +/- 4.23 ppm for sevoflurane and 37.09 +/- 11.65 ppm for nitrous oxide). The overall peak levels measured were 6.31 +/- 4.23 ppm for sevoflurane and 68.78 +/- 40.79 ppm for nitrous oxide. Though the induction period was short compared to the whole length of anaesthesia, its impact on the overall waste gas exposure was 46.3% for sevoflurane (nitrous oxide 40.6%). Nonetheless, applicable German health law regulations were never infringed. The trace concentrations measured during inhalational mask induction and maintenance of anaesthesia were very low. With regard to modern workplace laws and health care regulations, gaseous induction in paediatric anaesthesia does not threaten the personnel's health.

This study was designed to investigate the differences between TIVA with propofol/remifentanil (P/R) and balanced anaesthesia with sevoflurane/fentanyl (S/F) in gynaecological laparoscopic surgery. Emphasis was put on haemodynamic reaction, recovery profile, postoperative side effects and patient satisfaction.Sixty patients were randomly assigned to receive either total intravenous anaesthesia with propofol/remifentanil or anaesthesia with sevoflurane/fentanyl. After premedication (midazolam) and induction of anesthesia (propofol, atracurium) in both groups, either 1 microgram/kg fentanyl (S/F) or 1 microgram/kg remifentanil (P/R) was injected. Anaesthesia was maintained with 0.5 microgram/kg/min remifentanil (reduced to 50% after 5 min) and 0.06 microgram/kg/min propofol (P/R) or 1.7 vol % sevoflurane (S/F). Both groups were mechanically ventilated with 30% oxygen in air. The administration of sevoflurane and the infusion of the anaesthetics were adjusted to maintain a surgical depth of anaesthesia. For postoperative analgesia 1 g paracetamol was administered rectally prior to surgery. After recovery 20 mg/kg metamizol was given intravenously. At the end of surgery the anaesthetics were discontinued and haemodynamics, early emergence from anaesthesia, pain level, frequency of analgesic demand, incidence of PONV, shivering and patient satisfaction were assessed. Parameters were recorded for 24 h postoperatively.Recovery time after propofol-remifentanil anaesthesia was significantly shorter than after administration of sevoflurane and fentanyl (spontaneous ventilation 4.1 vs. 6.3 min, extubation 4.3 vs. 9.3 min, eye opening 4.4 vs 8.2 min, stating name 5.3 vs. 13.2 min, stating date of birth 5.4 vs. 13.3 min). There were no significant differences between the groups in shivering, pain score, analgesic demand and PONV. The S/F group responded to tracheal intubation with significantly higher blood pressure than the P/R group. During maintenance of anaesthesia heart rate in patients with S/F was significantly higher (P/R:HR max +16/-10; S/F:HR max +24/-0.). Measured on a scale (S/F 62%).Compared with patients given balanced anaesthesia with sevoflurane and fentanyl, TIVA with propofol and remifentanil proved to be particularly suited for gynaecological laparoscopic surgery. Its major advantages are haemodynamic stability, significantly shorter times of emergence, and the exceptional acceptance by the patients.

Both clonidine and sevoflurane are interesting drugs for anaesthesia in maxillo-facial surgery. The present study was performed to discover how far it is possible to combine the benefits of sevoflurane (fast modulation of depth of anaesthesia, rapid emergence and recovery) and clonidine (reduction of perioperative stress response, prophylaxis of postoperative shivering, analgetic, antiemetic and anaesthetic-saving effect) without compromising the pharmacokinetic of sevoflurane. Twenty-eight patients were included in the present double-blinded prospective study. These patients were randomly treated with an infusion of 4 micrograms kg-1 clonidine (group 1) or a placebo (group 2) preoperatively. For anaesthesia a standardized procedure with fentanyl, propofol, rocuronium, N2O/O2/sevoflurane and an antiemetic prophylaxis with DHB was performed. The depth of anaesthesia was controlled by using spectral edge frequency (target--SEF90 = 10 Hz). Perioperative stress response was assessed by noting the effects on haemodynamic parameters (MAP, heart rate), and emergence and recovery were assessed by using established standardized tests. We confirmed the anaesthetic-saving property of clonidine only for fentanyl (-20%). On the other hand, there was no difference in MAC-sevoflurane values between the groups in keeping a steady target--SEF90 (1.62 +/- 0.26 versus 1.65 +/- 0.24 vol.%). The time until emergence and recovery was not significantly different. Even the occurrence of PONV, the VAS level or the postoperative analgesic requirement did not differ in the two groups. However, the incidence of postoperative shivering was significantly higher in the placebo group. The stress response to intubation or extubation was lower in the clonidine group. The haemodynamic parameters in the clonidine group were intraoperatively always below the baseline, in some cases by more than 20%, making therapy for hypotension or bradycardia frequently necessary. Postoperatively, the majority of the patients showed similar changes in these parameters, but did not reach the 20% mark. Preoperative clonidine comedication seems to complicate the management of anaesthesia. On the other hand, it is beneficial during the early postoperative period (e.g. stability in haemodynamics, prophylaxis of shivering) without compromising emergence and recovery. Our results show that therapy with clonidine should be better placed at the end of anaesthesia.

Postoperative nausea and vomiting (PONV) is still one of the major problems in strabismus surgery, especially in children. In recent years many studies have been published, suggesting that choosing propofol as the anaesthetic agent may help to reduce the high incidence of PONV in children undergoing strabismus surgery. Experience with remifentanil in children is still very limited and little is known, whether propofol in combination with this new short acting opioid is also superior regarding PONV in squint surgery compared to sevoflurane/N2O. Additionally, little is known, whether the type of operation or the muscle which is operated on has any influence with respect to PONV.Following sample size estimation, ethics committee approval and parents informed consent in a prospective, randomised, observer-blind study 105 ASA I and II children aged 3-8 years scheduled for elective strabismus surgery were assigned into one of the following groups: Group TIVA (propofol/remifentanil, n = 53): anaesthesia was induced by remifentanil 0.5 microgram kg-1 min-1 over 2 min (loading phase), followed by 3 mg kg-1 propofol along with 30% O2 in air. After endotracheal intubation anaesthesia was maintained initially with remifentanil 0.25 microgram kg-1 min-1 and propofol 10 mg kg-1 h-1 by constant infusion. In the course of the operation the infusions of the anaesthetics were adjusted to the decreasing need for anaesthesia. Group VOLATIL (sevoflurane/N2O, n = 52): anaesthesia was induced by inhalation of sevoflurane along with 50% O2 in N2O. After endotracheal intubation anaesthesia was maintained with sevoflurane 1.0-1.5 MAC along with 30% O2 in N2O and in the course of the operation the administration of the inhaled anaesthetics was adjusted correspondingly. Preoperatively collected data included gender, age, weight and history of PONV. Intraoperatively collected data consisted of data belonging to routine monitoring (heart rate, blood pressure, peripheral oxygen saturation and temperature) as well as the duration of the operation and anaesthesia and specific data regarding the operation (including the number and type of muscles as well as the kind of operation). Data collected within the first 24 hours postoperatively in the recovery room and on the ward by blinded observers included any PONV events as well as the antiemetics and analgesics applied.Vomiting was observed less frequently in the TIVA-group than in the VOLATIL-group (21 of 53 vs. 32 of 52, p = 0.03) within the first 24 hours postoperatively. Posterior fixation suture ("faden-operation") compared to other operations was followed rather frequently by nausea and vomiting (30 of 44 and 33 of 44, respectively), whereas recessions were rarely associated with nausea and vomiting (12 of 35 and 9 of 35, respectively).TIVA with propofol/remifentanil proved to be a suitable form of anaesthesia for children in this setting. Propofol showed advantages over sevoflurane/N2O with respect to PONV after squint surgery in children also when applied in the combination with remifentanil. TIVA with propofol/remifentanil may therefore be one way to reduce the high incidence of PONV in this setting, bearing in mind, that PONV is not only influenced by the regimen of the general anaesthesia but rather by the combination of many other factors, in particular the type of operation.

There have been few studies of the occupational exposure of the new volatile anaesthetic agents desflurane and sevoflurane. Because a health risk through long-term exposure to these inhalants cannot as yet be definitely excluded, we undertook to measure the concentrations of these three anaesthetics in different parts of the Frankfurt University Medical Centre. Considering the results the relevance of exposure for surgical and anaesthesia personnel, possible consequences due to laws and possibilities of improvement were shown.The concentration of the three anaesthetics was measured during and after 345 procedures under general anaesthesia, using photoacoustic infra-red-spectrometry every 90 sec in the breathing zone of the same operating room personnel or in the recovery room and the intensive care unit.Exposure of personnel in the air-conditioned operating rooms was very low, but in those rooms that were not or inadequately air conditioned was a times very high. The level of the concentrations was also significantly related to the anaesthesia system and the distance of the exposed person to the patient. The concentration of nitrous oxide was below the maximal working-place concentration (MWC) of 100 ppm, but it exceeded the threshold concentration of 0.1 MAC, as laid down in the "Maternal Protection Law" in the surgical intensive care unit and the recovery room. There are no limiting concentrations for desflurane and sevoflurane yet but their concentrations were clearly below the MWC laid down for isoflurane and enflurane.In principle the use of inhalation anaesthetics can be considered to be without occupational health risk under the present legally defined standards of air-conditioning and the requirements of a modern occupational protection law. Because of the increased concentrations in the recovery room and intensive care unit pregnant and breast-feeding women should not work in these areas.

Both desflurane and sevoflurane have a favourable blood/gas distribution coefficient. There is concern, however, that environmental contamination is higher when these agents are employed since they must be used in relatively high concentrations. Our study seeks to determine the degree of exposure of recovery room staff to trace amounts of these two agents. Two hundred and seven surgical patients were included in the study. The recovery room studied had a volume of 243 cubic metres. The hourly fresh air supply for this room was 1,845 cubic metres, which results in 7.6 air exchanges per hour without air return. Measurements of trace concentrations of the inhalational agents were taken for 12 days. Concentrations of these anaesthetics were assessed in the recovery room with a real-time infrared spectrometer every 90 seconds. Mean exposure to nitrous oxide in the recovery room was 11.5 +/- 3.97 ppm and to isoflurane 1.4 +/- 0.31 ppm. All measured values were below the standard German threshold values. Trace concentrations of desflurane were 2.8 +/- 0.84 ppm and of sevoflurane 3.2 +/- 0.62 ppm. We conclude that the exposure to the inhalational anaesthetics in the climatised recovery room was low. The threshold values of 100 ppm for nitrous oxide and 10 ppm for isoflurane recommended by German law were not exceeded. When the new volatile anaesthetics are used, exposure of recovery room staff to trace concentrations of these agents is higher, but the concentrations do not exceed the levels allowed applicable German health regulations.

In obstetrics, general anaesthesia is increasingly being replaced by peridural anaesthesia. The cases where general anaesthesia is still used are those involving increased risk. It is therefore not surprising that, for example, maternal mortality in cases of caesarian section under general anaesthesia has not decreased. Indeed, large-scale statistical analyses in the USA and the UK show an increase in relative risk. For this reason, continuing efforts have to be made to improve obstetric general anaesthesia. Inhalational anaesthetics have an important role to play, as they represent the only acceptable compromise between the dangers of maternal awareness and neonatal depression. We used literature data and our own experience of urgent caesarian sections to investigate whether the new inhalational anaesthetic sevoflurane is suitable for this purpose. In a comparison of sevoflurane and peridural anaesthesia, there was no difference in outcome for the child and the maternal results showed only the expected procedure-specific differences in circulatory parameters and early postoperative analgesia requirement. A second study involving continuous pEEG monitoring (SEF90) showed advantages of sevoflurane over isoflurane in the initial phase of surgery and in the recovery phase. However, the value of sevoflurane in obstetric anaesthesia will have to be confirmed in more extensive studies.

The cardiovascular effects of sevoflurane are similar to those of isoflurane with some minor exceptions. In contrast to isoflurane and particularly to desflurane, sevoflurane has not been associated with increases in heart rate in healthy volunteers and in patients. The coronary vasodilatory potency of sevoflurane appears to be lower than that of isoflurane and it has not been associated with a reduction of blood flow to collateral myocardium in dogs with steal-prone anatomy. In several multi-center studies of patients with coronary artery disease or at high risk for coronary artery disease receiving either sevoflurane or isoflurane for either cardiac or non-cardiac surgery, the incidence of myocardial ischemia and infarction did not differ between treatment groups. In both human and animal models, sevoflurane preserves cerebral blood flow and reduces cerebral metabolic rate, much like isoflurane.

Sevoflurane, like all currently used volatile anaesthetics, is degraded by carbon dioxide absorbents. The most significant degradant is a haloalkene known trivially as "compound A". Compound A is nephrotoxic in rats and, at higher doses, in nonhuman primates, causing proximal tubular necrosis. There has been much interest in the potential for compound A toxicity in humans. Inhaled compound A concentrations are greatest at low flow rates, high sevoflurance concentrations, warmer absorbent, barium hydroxide vs soda lime, and drier absorbent. Typical inspired compound A concentrations during low-flow and closed-circuit sevoflurane anaesthesia in humans are 8-24 and 20-32 ppm with soda lime and barium hydroxide lime, respectively. Renal effects of compound A production during sevoflurane anesthesia have been examined in surgical patients and volunteers, using standard (creatinine clearance, serum BUN and creatinine) and experimental (urine excretion of protein, glucose, NAG, GST, AAP) markers of renal function. Investigations to date in surgical patients show similar renal effects of low-flow sevoflurane, low-flow isoflurane or high-flow sevoflurane. There have been no case reports of compound A-associated renal injuryin humans. In volunteers, one study found changes in experimental but not conventional renal markers, while other investigations show no significant changes in either standard or experimental markers. The mechanism of compound A nephrotoxicity in rats appears to involve metabolism to glutathione and cysteine conjugates, and their subsequent renal uptake and metabolism by pathways that are different in rats and humans.