Determination of Sevoflurane, Isoflurane and Enflurane in the air of workplace by gas chromatography / 中华劳动卫生职业病杂志

Objective@#To establish a solvent desorption gas chromatographic method for determination of Sevoflurane, Isoflurane and Enflurane in the air of the Workplace.@*Methods@#Sevoflurane, Isoflurane and Enflurane were collected with activated carbon tube and desorbed with dichloromethane, separated with DB-1 capillary columns, and then detected with flame ionization detector.@*Results@#The linearity ranges were 1.9-304.8 μg/ml for Sevoflurane, 2.1-300.4 μg/ml for Isoflurane and 1.7-305.2 μg/ml for Enflurane, The correlation coefficient was both >0.999. Their limits of detection were 0.6 μg/ml, 0.6 μg/ml and 0.5 μg/ml, and Their limits of quatification were 1.9 μg/ml, 2.1 μg/ml and 1.7 μg/ml, and their minimum detectable concentrations were 0.1、0.2 and 0.1 mg/m3 per 4.5 L of air. Their relative standard deviations (RSD) were 2.5%-3.0%, 2.3%-3.1% and 2.2%-3.0%. The average desorption efficiencies were 101.1%-103.3%, 100.7%-102.7% and 101.0%-102.9%. The sampling efficiency was both 100%. The breakthrough volume of 100 mg actived carbon was 3.7 mg, 3.4 mg and 3.4 mg. Sevoflurane, Isoflurane and Enflurane in activated carbon tube could be kept at least 10 days at room temperature without significant losses.@*Conclusion@#The method shows lower detection limit, high accuracy and precision. It is feasible for determination of Sevoflurane, Isoflurane and Enflurane in the air of workplace.

Effects of maternal enflurane exposure on NR2B expression in the hippocampus of their offspring

This work aims to study the pathogenesis of learning and memory impairment in offspring rats resulting from maternal enflurane anesthesia by focusing on the expression of the N-methyl-d-aspartic acid receptor subunit 2B (NR2B) in the hippocampus of the offspring. Thirty female Sprague-Dawley rats were randomly divided into three groups: control (C group), 4 h enflurane exposure (E1 group), and 8 h enflurane exposure (E2 group) groups. Eight to ten days after the initiation of pregnancy, rats from the E1 and E2 groups were allowed to inhale 1.7% enflurane in 2 L/min oxygen for 4 h and 8 h, respectively. Rats from the C group were allowed to inhale 2 L/min of oxygen only. The Morris water maze was used to assay the learning and memory function of the offspring on postnatal days 20 and 30. RT-PCR and immunohistochemistry assays were then used to measure the mRNA levels and protein expression of NR2B, respectively. Relative to offspring rats from the C group, those from the E1 and E2 groups exhibited longer escape latencies, lesser number of crossings over the platform, and less time spent in the target quadrant in the spatial exploration test (P < 0.05). In addition, the mRNA and protein expression levels of NR2B in the hippocampus of offspring rats in the E1 and E2 groups were down-regulated (P < 0.05). No significant differences between the E1 and E2 groups were observed (P > 0.05) in terms of mRNA levels and protein expression of NR2B. The cognitive function of the offspring is impaired when maternal rats are exposed to enflurane during early pregnancy. A possible mechanism of this effect is related to the down-regulation of NR2B expression.

Este trabalho objetiva o estudo da patogênese de deficiência no aprendizado e memória de prole de ratos resultante da anestesia maternal por enflurano, por meio da expressão da subunidade 2B do receptor do ácidoN-metil-D-aspártico (NR2B) no hipocampo dos filhotes. Dividiram-se, aleatoriamente, 30 fêmeas de ratos Sprague-Dawley em três grupos: controle (grupo C), exposição ao enflurano por 4 h (grupo E1) e por 8 h (grupo E2). De oito a 10 dias após o início da gravidez, os ratos dos grupos E1 e E2 inalaram enflurano 1,7% em 2 L/min de oxigênio, por 4 h e 8 h, respectivamente. Ratos do grupo C inalaram apenas 2 L/min de oxigênio. O labirinto de água de Morris foi empregado para analisar as funções de aprendizado e memória da cria em 20 e 30 dias após o nascimento. Utilizaram-se ensaios de RT-PCR e de imuno-histoquímica para medir os níveis de mRNA e expressão da proteína do NR2B, respectivamente. Em comparação com os ratos controle do grupo C, aqueles dos grupos E1 e E2 exibiram latências de escape mais longas, menor número de travessias na plataforma e menos tempo gasto no quadrante alvo no teste de exploração espacial (P < 0,05). Adicionalmente, os níveis de expressão de mRNA e de proteína do NR2B no hipocampo dos filhotes nos grupos E1 e E2 estavam reduzidos (P < 0,05). Não se observaram diferenças significativas entre os grupos E1 e E2 (P < 0,05) quanto aos níveis de mRNA e à expressão de proteína de NR2B. A função cognitiva dos filhotes é prejudicada quando as mães são expostas ao enflurano durante o início da gravidez. O mecanismo possível para esse efeito está relacionado à diminuição na expressão de NR2B.

Comparação entre o enflurano e o propofol na eletroconvulsoterapia: um estudo preliminar, aleatório, aberto e cruzado sobre a duração de convulsões e a recuperação anestésica / Comparison of enflurane and propofol in electroconvulsive therapy, a randomized crossover open preliminary study on seizure duration and anaesthetic recovery

JUSTIFICATIVA E OBJETIVOS: A eletroconvulsoterapia (ECT) é comumente utilizada para o tratamento de depressão, mania e transtornos do humor. Anestésicos para anestesia geral durante a ECT devem ter início e despertar rápidos, não interferir com a atividade da convulsão e não encurtar a duração das crises. O objetivo deste estudo é comparar os efeitos do enflurano, um agente anestésico pró-convulsivo, e o propofol na duração das ocnvulsões, no índice de supressão pós-ictal e nos tempos de recuperação durante a eletroconvulsoterapia. MÉTODO: Pacientes sem uso de medicação pré-anestésica foram alocados em dois grupos de acordo com a indução da anestesia. Os pacientes foram induzidos para a ECT com 5 por cento de enflurano no grupo E e 1,2 mg.kg-1 de propofol no grupo P, até perda de consciência. A duração das crises motora e no eletroencefalograma (EEG), o índice de supressão pós-ictal, o tempo para respiração espontânea, para duração da abertura dos olhos e obedecer aos comandos foram registrados. RESULTADOS: Não houve diferença estatisticamente significativa entre os grupos quanto aos tempos das crises motora e no EEG e índice de supressão pós-ictal nos registros de EEG. Tempos de recuperação (tempo de início de respiração espontânea, de abertura dos olhos e para obedecer aos comandos) foram significativamente menores no grupo E em relação ao grupo P. Não foram observados náuseas ou vômitos e nenhuma anormalidade no ECG, exceto bradicardia sinusal transitória e taquicardia sinusal. CONCLUSÕES: Embora convulsões suficientes para o tratamento tenham ocorrido durante a anestesia com enflurano, nenhum benefício adicional foi observado sobre os tempos de convulsão ou índice de supressão pós-ictal quando comparado à anestesia com propofol. Por outro lado, o tempo de recuperação após anestesia com enflurano foi mais curto que com propofol. No entanto, ainda há necessidade de mais estudos em diferentes níveis de ETCO2.

BACKGROUND AND OBJECTIVES: Electroconvulsive therapy (ECT) is commonly used for treatment of depression, mania and affective disorders. Anaesthetics for general anaesthesia during ECT should have rapid onset, rapid emerge, not interfere with seizure activity and not shorten seizure duration. The aim of this study is to compare effects of enflurane, a pro-convulsive anaesthetic agent, and propofol on seizure durations, postictal suppression index and recovery times during electroconvulsive therapy. METHODS: Unpremedicated subjects were divided into two groups according to induction of anaesthesia. Patients were induced for ECT with 5 percent enflurane in group E and 1.2 mg.kg-1 propofol in group P until loss of consciousness. The durations of electroencephalogram (EEG) and motor seizures, postictal suppression index, time to spontaneous breathing, duration of eye opening, and obeying commands were recorded. RESULTS: There was no statistically significant difference between the groups regarding motor and EEG seizure times and postictal suppression index on the EEG records. Recovery times (times of starting spontaneous breathing, eye opening, and obeying command) were significantly shorter in group E compared to group P. No nausea or vomiting were observed and no ECG abnormality was noted except transient sinus bradycardia and sinus tachycardia. CONCLUSIONS: Although sufficient seizure for the treatment was provided during enflurane anaesthesia, any additional benefit was not revealed regarding seizure times or postictal suppression index when compared to propofol anaesthesia. On the other hand, recovery times after enflurane anaesthesia were shorter than propofol anaesthesia. However, there is still a need for further study in different ETCO2 levels.

JUSTIFICATIVA Y OBJETIVOS: La electroconvulsoterapia (ECT), se usa a menudo para el tratamiento de la depresión, manía y transtornos del humor. Los anestésicos para la anestesia general durante la ECT deben tener un inicio y un despertar rápidos, no interferir en la actividad de la convulsión y no acortar la duración de las crises. El objetivo de este estudio, es comparar los efectos del enflurano, un agente anestésico pro convulsivo, y el propofol, en la duración de las convulsiones, en el índice de supresión postictal y en los tiempos de recuperación durante la electroconvulsoterapia. MÉTODO: Pacientes sin uso de medicación preanestésica que fueron colocados en dos grupos de acuerdo con la inducción de la anestesia. Los pacientes fueron inducidos para la ECT con 5 por ciento de enflurano en el grupo E y 1,2 mg.kg-1 de propofol en el grupo P, hasta la pérdida de la conciencia. También fueron registrados la duración de las crises motora y en el electroencefalograma (EEG), el índice de supresión postictal, el tiempo para la respiración espontánea, para la duración de la abertura de los ojos y obedecer a los comandos. RESULTADOS: No hubo diferencia estadísticamente significativa entre los grupos en cuanto a los tiempos de las crises motora y en el EEG e índice de supresión postictal en los registros de EEG. Los tiempos de recuperación (tiempo de inicio de la respiración espontánea, de abertura de los ojos, y para obedecer a los comandos), fueron significativamente menores en el grupo E con relación al grupo P. No se observaron náuseas o vómitos, ni ninguna anormalidad en el ECG tampoco fue notada, excepto bradicardia sinusal transitoria y taquicardia sinusal. CONCLUSIONES: Aunque las convulsiones suficientes para el tratamiento hayan sucedido durante la anestesia con enflurano, ningún beneficio adicional fue observado sobre los tiempos de convulsión o sobre el índice de supresión postictal cuando se le comparó con la anestesia con propofol. Por otro lado, el ti...

The effects of propofol and enflurane anesthesia on the proliferative responsiveness of peripheral blood mononuclear cells in culture as determined by the level of bromodeoxyuridine incorporation / 대한마취과학회지

BACKGROUND: Various aspects of immunological homeostasis are affected by anesthesia and surgery, including the function of immunocompetent cells and the modulation of stress responses. To evaluate immunologic changes that occurred following propofol and enflurane anesthesia, we evaluated the proliferative responsiveness of peripheral blood mononuclear cells (PBMC) in patients undergoing laparoscopic gynecologic surgery. METHODS: PBMC were isolated from patients prior to anesthesia and on the first postoperative day (n = 10). The proliferative response was then evaluated based on the level of 5-bromo-2-deoxyunridine (BrdU) incorporation that occurred during DNA synthesisafter the induction of mitogenic stimulation by treatment with 1 microgram/ml lipopolysaccharides (LPS). To accomplish this, cell proliferation was assayed by enzyme-linked immuno-sorbent assay (ELISA), after which a stimulation index was calculated. RESULTS: Although the calculated stimulation index decreased in response to both propofol and enflurane anesthesia, the stimulation index did not differ significantly between groups. However, following stimulation with LPS, the stimulation index was significantly higher in the enflurane group than in the propofol group (P < 0.05). CONCLUSIONS: Propofol and enflurane anesthesia inhibit the PBMC proliferation. However, the decrease in proliferation that occurred in response to enflurane was attenuated by LPS.

The Effects of Lidocaine, Bupivacaine or Combined with Enflurane on the Contraction of Tracheal Smooth Muscle in Guinea Pig / 대한마취과학회지

BACKGROUND: The effects of local and inhalation anesthesia on the contraction of the tracheal smooth muscle have been reported. However, when inhalation and local anesthesia are administered simultaneously, their effects on the contraction of the airway smooth muscle are not well known. Therefore, this study evaluated the effects of lidocaine, bupivacaine, with or without enflurane, on the histamine induced tracheal smooth muscle contraction in guinea pigs. METHODS: Isolated tracheal rings of guinea pigs were suspended in Krebs solution. The contractions were recorded isometrically using a transducer. A contraction was induced by histamine (10(-5) M). Enflurane (1 MAC) was administered for 15 min after administering the histamine. The cumulative dose responses of the lidocaine and bupivacaine (10(-8) M, 10(-7) M, 10(-6) M, 10(-5) M, 10(-4) M, and 10(-3) M), enflurane-lidocaine and enflurane-bupivacaine groups were checked. RESULTS: The contraction by histamine were inhibited by lidocaine (10(-4) M and 10(-3) M) and bupivacaine (10(-5) M, 10(-4) M and 10(-3) M). In addition, the contractions were inhibited more significantly in the bupivacaine group (10(-7) M, 10(-6) M, 10(-5) M, 10(-4) M and 10(-3) M) after administering enflurane. CONCLUSIONS: Lidocaine and bupivacaine inhibited the contractions induced by histamine. The contractions by bupivacaine were further inhibited after administering enflurane.

The Heart Rate Response to Intravenous Atropine during Propofol or Enflurane Anesthesia / 대한마취과학회지

BACKGROUND: Propofol increases the risk of bradycardia compared with other anesthetics. This paper reports the heart rate response to intravenous atropine during propofol and enflurane anesthesia. METHODS: Sixty patients undergoing a transabdominal hysterectomy under general anesthesia were randomly assigned to two groups: the propofol group and the enflurane group. All the patients received midazolam 2 mg intramuscularly and were then anesthetized with propofol or enflurane. The blood pressure and heart rate were taken at 1 min intervals for 10 min after a bolus injection of atropine 5microgram/kg. RESULTS: In the enflurane group, the systolic blood pressure and heart rate were increased significantly at 1, 2 and 3 min after the atropine injection (P<0.05). When the two groups were compared, the heart rate in the enflurane group was significantly higher at 1, 2 and 3 min after atropine injection than in the propofol group (P<0.05). CONCLUSIONS: The heart rate response to intravenous atropine during propofol anesthesia is attenuated compared with enflurane anesthesia.

Comparisons of Propofol, Enflurane, Sevoflurane, and Desflurane Anesthesia in Laparoscopic Cholecystectomy on Postoperative Liver Enzyme Levels / 대한마취과학회지

BACKGROUND: Many factors cause postoperative hepatic dysfunction, and anesthetic agents and type of surgery are belived to contribute to hepatic dysfunction. The authors planned this study to evaluate the effect of different anesthetic agents (sevoflurane, desflurane, enflurane or propofol) on liver enzymes in the patients who undergone laparoscopic cholecystectomy. METHODS: 80 patients were randomly selected from among those who had undergone cholecystectomy and divided into 4 groups; an enflurane group (n = 20), a sevoflurane group (n = 20), a desflurane group (n = 20) and a propofol group (n = 20). Preoperative values of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were compared with those on postoperative days 1 and 3 in all groups. RESULTS: In all groups, ALT and AST were significantly elevated after operation, and then showed a decrease 3 days after operation, but remainrd of above preoperative levels (P < 0.05). However, no differences were observed between the 4 groups (P < 0.05). CONCLUSIONS: We consider that propofol, sevoflurane, desflurane and enflurane are equally usable and that they have little effect on liver function after laparoscopic cholecystectomy.

The Effects of Heparin and Protamine on Contraction of Tracheal Smooth Muscle Induced by Carbachol in the Guinea Pig / 대한마취과학회지

BACKGROUND: Several reports have indicated that heparin has a bronchodilative effect in asthma patients, and that it enhances airway smooth muscle contraction in vitro, protamine is known to inhibit or enhance contraction of tracheal smooth muscle. Thus the effects of protamine and heparin on airway smooth muscle contraction are not consistent. However, no report is available on the effects of enflurane on heparin and protamine tracheal smooth muscle contraction. We performed this study to evaluate the effects of heparin or protamine on the carbachol induced contraction of tracheal smooth muscle in the guinea pig. And we also evaluated the effects of enflurane on heparin or protamine induced tracheal smooth muscle contraction. METHODS: Isolated tracheal rings of the guinea pig were suspended in Krebs solution. Contractions were recorded isometrically using a transducer. Contraction was induced by carbachol (10-6 M) and then cumulative dose responses of heparin or protamine (0.006 mg/ml, 0.02 mg/ml, 0.06 mg/ml, 0.2 mg/ml, 0.4 mg/ml) and in heparin (E) group and protmine (E) group, enflurane (4.34%) was administered for 15 minute after carbachol adminstration. RESULTS: Contraction by carbachol was inhibited by level of heparin or protamine at concentrations of 0.2 mg/ml and 0.4 mg/ml. At an enflurane (4.34%) contraction was inhibited, and no further inhibition of contraction by heparin or protamine was observed. CONCLUSIONS: Heparin or protamine inhibited the tracheal smooth muscle contraction induced by carbachol at 0.2 mg/ml and 0.4 mg/ml, and no further significant inhibition of contraction by heparin or protamine was observed after enflurane administration (4.34%).

The Study of EEG Spectrum Analysis as a Method of Monitoring the Depth of Anesthesia / 대한마취과학회지

BACKGROUND: Monitoring the "depth of anesthesia" is an ongoing problem. To identify a useful parameter for determining the depth of anesthesia with enflurane, EEG data was obtained using a Physiolab 800. METHODS: Variations in EEG signals were measured and analyzed by the stage of anesthesia. EEG data was obtained from 15 patients during general anesthesia with enflurane. The EEG signal was acquired and analyzed in 5 steps (one day before anesthesia, during induction, during skin incision, at end of anesthesia, and one day after anesthesia). Fp1 electrode and the EEG data mainly from the forehead were used to determine the depth of anesthesia using EEG characteristics during enflurane anesthesia. All data were preprocessed by filtering, baseline correction and using the linear detrend method to reliable analyze of sample data in the surgical environment. Data obtained were transformed to frequency and power spectrum analysis was performed. RESULTS: alpha, beta, delta and theta waves were detected by frequency area separation and the trend of each wave was observed during each anesthesia stage. EEG data was slowed down and the theta wave ratio increased as the depth of anesthesia increased. Accordingly, spectral edge frequency (SEF) and median frequency (MF) were used as parameters to determine the depth of anesthesia. The frequencies of SEF and MF decreased during anesthesia and returned to the preanesthetic level after the cessation of anesthesia. CONCLUSIONS: Our results suggest that SEF and MF can contribute as useful parameters to determine the depth of anesthesia. Anesthetics not only affect the central nervous system, but also affect the autonomic nervous system. If the autonomic nervous system signals such as heart rate variability are taken into account, more reliable evaluations would be possible.

Monitoring System during Enflurane Anesthesia Using Heart Rate Variability / 대한마취과학회지

BACKGROUND:We performed spectral analysis and determined the 1/f noise of heart rate variability during enflurane anaesthesia in order to assess the effect of the activity of the autonomic nervous system. METHODS: Data were acquired from 15 patients (ASA I-II) who received gynecological surgery under general anesthesia using enflurane, nitrous oxide and oxygen. We analyzed the spectral components of heart rate variability (HRV) according to the following five periods: 1) before premedication, 2) after induction, 3) during skin incision, 4) during recovery, and 5) after surgery. For each power spectrum the density and frequency components were identified as follows: (1) low frequency (LF) component (0.04-0.15 Hz) was associated with parasympathetic and sympathetic tone, and was affected by body temperature, the renin-angiotensin system, baroreceptor and vasomotor sympathetic modulation, (2) high frequency (HF) component (0.15-0.5 Hz) was mediated parasympathetic tone and reflected the mechanical influence of the ventilation. In addition the LF/HF ratio, which reflected cardiac sympathovagal balance was monitored. RESULTS: The LF/HF ratio, which reflects the balance of the autonomic nervous system increased remarkably during skin incision and recovery. Also, the beta index, which is related to body activity decreased during skin incision and recovery. CONCLUSIONS: Increased LF/HF was found to be caused by mechanical stimulation, which reflects autonomic nervous system balance, and the beta index was useful for the assessment of body activity.

Effects of Enflurane on Pulse Transit Time / 대한마취과학회지

BACKGROUND: In Anesthetic state, many hemodynamic parameters including blood pressure, heart rate and arterial compliance are changed. Moreover pulse transit time (PTT) is influenced by heart rate, blood pressure changes, and the compliance of the arteries. METHODS: In this study, we investigated PTT changes in patients under enflurane anesthesia. PTT of the finger was measured by photoplethysmography (PPG) and electrocardiography (ECG). PTT values were calculated as the time interval between the peak of the ECG R wave and the peak of the second derivatived of the PPG in the finger tip. RESULTS: ECG amplitude and heart rate increased reflecting hemodynamic chnages after enflurane anesthesia, and the PTT increased after enflurane anesthesia treatment by 16.68 ms (n = 24). Moreover, PTT was found to be inversely proportion to aging. CONCLUSIONS: The increase of PTT in the finger due to relaxation of the arterial wall muscle after enflurane anesthesia was used as an indicator of sympathetic block on muscle tone. This result suggests that PTT is strongly related with anesthetic state. And PTT may be one of useful surrogative methods for anesthetic monitoring, but PTT is unfortunately only qualitative.

TThe Evaluation of Anesthesia Depth Using Detrended Fluctuation Analysis Parameters / 대한마취과학회지

BACKGROUND: We examined the use of DFA-Detrended fluctuation analysis-of heart rate variability during general anesthesia in order to assess the depth of anesthesia. METHODS: In this study, we observed changes in alpha1, the short range scaling exponent, in alpha2, the long range scaling exponent, and in the alpha2/alpha 1 ratio during enflurane anesthesia. We monitored 7 stages during general anesthesia, i.e., 1) preoperation (awake state), 2) during induction, 3) after induction, 4) during maintenance, 5) before extubation, 6) after extubation, and 7) postoperation (Next day). RESULTS: The alpha 2/alpha 1 ratio increased during the induction and extubation state compared to preoperation (awake state). This may be related to increased sympathetic activity due to stimulation of the autonomic nervous system. In the postoperation (awakened state), the ratio returned to the preoperation value (awake state). These results are similar to low frequency (LF), high frequency (HF) and LF/HF ratio values which reflect activity of autonomic nervous system. CONCLUSIONS: Detrended fluctuation analysis parameters, especially the alpha 2/alpha 1 ratio, would be used for monitoring the depth of anesthesia. Also these parameters are useful indexes with the LF/HF ratio for the evaluation of sympathetic activity during general anesthesia.

Effect of Enflurane on the Baroreflex Control of Heart Rate in Decerebrate Rats

Volatile anesthetics alter the arterial baroreflex (BRX) but its mechanisms are poorly understood. This study was designed to determine the effect of 1 and 2 minimal alveolar concentrations (MAC) of enflurane on the BRX parameters in unanesthetized brain stem-intact and decerebrate rats. Under enflurane anesthesia, the femoral artery and both femoral vein were catheterized for pressor (phenylephrine) and depressor (nitroprusside) drug delivery and continuous blood pressure measurements. Decerebration was performed at midcollicular level. BRX tests were performed in 3 time periods; before enflurane (conscious brain-intact), during 1 or 2 MAC enflurane exposure 1 hour after a sham operation or a decerebration operation, and 2 hours after the termination of enflurane (zero enflurane). Mean arterial pressure (MAP) and heart rate (HR) were fitted to a sigmoid logistic equation, the Boltzman equation. The curve of best fit was obtained with a computer program. 1 MAC and 2 MAC of enflurane shifted MAP-HR baroreflex curves to the left in the all groups and significantly attenuated the baroreflex range. The slope of conscious intact period and zero enflurane period of each group did not change significantly, but during the enflurane period the slope was significantly lowered. Enflurane depressed the baroreflex sensitivity (slope) and the HR range in a similar dose-dependant manner in both brain stem-intact and decerebrate rats. Such results draw into question whether the suprapontine sites contribute to enflurane's actions on cardiovascular autonomic regulation.

BIS and Postoperative Recall for Sevoflurane and Enflurane during Cesarean Section / 대한마취과학회지

BACKGROUND: Generally, 0.6-0.7 MAC of anesthetics are used to minimize the effect of anesthetics on the fetus during cesarean section. Therefore the possibility of awareness is a considerable problem in cesarean section. This study was designed to compare enflurane with sevoflurane in terms of intraoperative bispectral index (BIS) and posoperative recall during a cesarean section. METHODS: Eighty patients of ASA physical status 1 who underwent an elective cesarean section under general anesthesia were investigated in this study. Anesthesia was induced with 4 mg/kg thiopental and 1 mg/kg succinylcholine, and then maintained with O2 (2 L), N2O (2 L) and enflurane 1.0 vol% (n = 40) or sevoflurane 1.2 vol% (n = 40). We monitored BIS throughout the operation and recorded recall by asking the patients 1 day after the operation. RESULTS: BIS values of the sevoflurane group were significantly lower than those of the enflurane group after delivery (P < 0.05). However, no patient could recall intraoperative events postoperatively. CONCLUSIONS: Even though no patient could recall intraoperative events, high BIS values, which can produce awareness, were detected by 17.5% of patients after delivery in enflurane group. Therefore, sevoflurane is probably a better choice than enflurane in terms of preventing postoperative recall during cesarean section under general anesthesia.

Does Ketamine Have Effects on Hemodynamic and Stress Hormone Responses to Surgery under Enflurane Anesthesia? / 대한마취과학회지

BACKGROUND: The aims of the study were to evaluate hemodynamic and stress hormone responses during abdominal hysterectomy under enflurane anesthesia supplemented by continuous ketamine infusion. METHODS: Eighteen patients scheduled for elective abdominal hysterectomy under enflurane anesthesia were randomly assigned to two groups, which received intravenous ketamine (0.3 mg/kg initially, followed by a continuous infusion at a rate of 0.15 mg/kg/h) (ketamine group, n = 9) or normal saline (control group, n = 9) 2 min after intubation. Hemodynamic responses, serum cortisol, prolactin, growth hormone, insulin and glucose concentrations were measured before induction, 2 min after intubation, 2 min after incision, at peritoneum closure, and 5 min after extubation. RESULTS: No significant differences were observed between the two groups in terms of hemodynamic responses, serum cortisol, prolactin, growth hormone, insulin and glucose concentrations. Compared with values before induction, significant increases in serum cortisol, prolactin, and glucose concentrations were observed at peritoneum closure and 5 min after extubation in both groups. However, growth hormone levels in the control group, and insulin concentration in both groups were significantly reduced 2 min after skin incision (P < 0.05). CONCLUSIONS: Bolus ketamine 0.3 mg/kg IV followed by a 0.15 mg/kg/h infusion fails to suppress stress responses, such as increases in serum cortisol, prolactin, growth hormone, and glucose concentrations, or insulin reduction at surgery under enflurane anesthesia.

Genotoxicity of Enflurane in Human Peripheral Blood Lymphocytes Studied in vivo by Single Cell Gel Electrophoresis / 대한마취과학회지

BACKGROUND: The alkaline single cell gel electrophoresis comet assay was applied to study the genotoxic properties of enflurane on the human peripheral blood lymphocytes (PBL) of cancer patients before and during anesthesia as compared to an non-cancer control group. Method: The cancer group consisted of 24 patients (aged 15-77 years), while the control group consisted of 14 trauma individuals (aged 20-81 years). After anesthesia induction (thiopental 4 mg/kg and vecuronium 0.1 mg/kg), it was maintained by enflurane inhalation; 1-2 minimal alveolar concentration in oxygen - nitrous oxide mixture. Venous blood samples were obtained before the induction of anesthesia, and after 60 and 120 min of anesthesia. The comet assay detects DNA damage, such as strand breaks and alkaline labile sites induced directly by genotoxic agents, and DNA degradation due to cell death. Fifty cells from each sample were examined and Olive tail moments (OTM) were calculated using Komet 4TM software. RESULTS: OTM values were no different between controls and patients before anesthesia. However, the OTMs of blood sampled from cancer patients at 60 (7.97 +/- 1.83) and 120 min (7.86 +/- 2.05), and from trauma patients at 120 min (8.04 +/- 1.32) of anesthesia were significantly increased. CONCLUSIONS: In immunocompromised cancer patients, we suggest the existence of a higher risk of an association DNA damage and enflurane exposure.

Relationship between amnestic effect of enflurane or isoflurane and NMDA receptor / 中国药理学通报

Aim To investigate the relationship between amnestic effect of enflurane or isoflurane and NMDA receptor.Methods Amnestic model was established by intraperitoneal injection of enflurane(0.4 ml?kg-1)or isoflurane(0.3 ml?kg-1)respectively in mice before intracerebroventricular injection of different doses of NMDA(25,50,75 ng),then the error times,step down latency and step through latency were observed in the step down test and step through test.Results NMDA(50,75 ng)by intracerebroventricular injection could decrease the error times,and increase the step down latency and step through latency of amnestic mice induced by enflurane or isoflurane in the step down test and step through test.Conclusions NMDA by intracerebroventricular injection can improve amnestic effect of enflurane or isoflurane partially.NMDA receptor may be an important target for amnestic effect of enflurane or isoflurane.

Intracerebroventricular injection of nicotine antagonize the amnestic and hypnotic effect of enflurane in mice / 中国药理学通报

Aim To investigate the relationship between neuronal nicotinic acetylcholine receptor and the amnesia and hypnosis induced by enflurane in mice.Methods Animal models were established by Intraperitoneal injecting of enflurane(2.2 ml?kg-1 and 0.4 ml?kg-1).Artificial cerebrospinal fluid or different dose of nicotine were intracerebroventricular injected,then sleeping time in the analeptic test was recorded;and the step down latency and error times in the step down test;step through latency and error times in the step through test.For the independent activity test,recorded the independent activity times of mice treated with enflurane(0.4 ml?kg-1) in 5 min.Results Compared with control group,intracerebroventricular nicotine decreased sleeping time in the analeptic test,increased step down latency and step through latency in both step down test and step through test.Furthermore,the error times were decreased in both tests.All the outcomes were significant and the influence was dose-dependent.There was no significant difference for the independent activity times of mice treated with 0.4 ml?kg-1 enflurane by ip injection.Conclusion All the evidence suggested that neuronal nicotinic receptor is one of important targets for the hypnotic and amnestic effect of enflurane in mice.

Comparison of Sevoflurane with Enflurane Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Sevoflurane has a low blood-gas partition coefficient, resulting in rapid induction and recovery. We compared the effects of sevoflurane with those of enflurane anesthesia on parturients and neonates during and after elective cesarean section. METHODS: Ninety-six parturients were divided into two groups: E (enflurane, n = 47) and S (sevoflurane, n = 49). After endotracheal intubation with intravenous administration of thiopental 4 mg/kg and succinylcholine 1.5 mg/kg, anesthesia was maintained with 50% nitrous oxide in oxygen and enflurane 1 vol% or sevoflurane 1 vol%. Maternal hemodynamic parameters, blood loss, and recovery were monitored. Neonatal outcome was evaluated by Apgar scores, umblical artery blood gas analysis and acid-base status. RESULTS: Recovery times were faster with sevoflurane anesthesia (P < 0.05). All patients in two groups developed transient hypertension and tachycardia after intubation, which returned to baseline in approximately 5 minutes. Maternal blood loss did not differ significantly between the two groups, and one patient in S group developed postoperative recall. Neonatal outcome was equally good in the two groups. CONCLUSIONS: Parturients anesthetized with sevoflurane for cesarean section recovered more rapidly compared with enflurane without any differences in hemodynamic parameters and neonatal outcome.

Spinal Antinociceptive Mechanism of Isoflurane and Enflurane via the GABAA Receptor in Rats / 대한마취과학회지

Background: Several studies have suggested that the spinal cord may be an important site of anesthetic action and have established that general anesthetics potentiate the effects of GABA at the GABAA receptor. It was, therefore, hypothesized that the suppression of nocifensive movements during anesthesia is due to an enhancement of GABAA receptor-mediated transmission. Therefore, the aim of this study was to determine behaviorally whether intrathecal GABA, glycine, or opioid receptor antagonists may change the anesthetic effect of isoflurane and enflurane. Methods: The minimal alveolar concentration (MAC) of isoflurane and enflurane was determined in Sprague-Dawley rats, by the tail-clamp technique. First, MAC was determined and then concentration of each inhalation agent was increased by 0.2% from the sub-MAC level. Moving latencies were observed after the intrathecal administration of each receptor antagonist. Rectal temperature was measured and maintained at a steady level during the experiment. Results: The spinal antinociceptive effects of isoflurane and enflurane were significantly reversed by the GABAA receptor antagonist bicuculline and picrotoxin (P < 0.05). The rectal temperature was well maintained within the range of 37-39 degrees C. Conclusions: Our results suggest that the general anesthesia induced by isoflurane and enflurane, which are similar in terms of their action mechanism, is likely to be related to the spinal GABAA receptor system.