Avaliação de parâmetros antioxidantes em ratos tratados com sevoflurano / Evaluation of antioxidant parameters in eats treated with sevoflurane / Evaluación de parámetros antioxidantes en ratones tratados con sevoflurano

JUSTIFICATIVA E OBJETIVOS: O sevoflurano é um éter halogenado com flúor que sofre biotransformação hepática através do citocromo P450 2E1. Éteres halogenados que sofrem biotransformação pelo P450 2E1 podem produzir espécies reativas do oxigênio (ERO) e promover enfraquecimento do sistema de defesa antioxidante. O objetivo deste trabalho foi investigar a relação entre a atividade das enzimas antioxidantes eritrocitárias e o sevoflurano. MÉTODO: Os animais foram distribuídos em quatro grupos: Grupo 1 controle: apenas oxigênio a 100 por cento (1 L.min-1 por 60 minutos durante 5 dias consecutivos); Grupo 2 - sevoflurane 4,0 por cento em oxigênio a 100 por cento (1 L.min-1 por 60 minutos durante 5 dias consecutivos); Grupo 3 - isoniazida (i.p.), 50 mg.kg-1 de peso corporal /dia, durante 4 dias e em seguida tratados apenas com oxigênio a 100 por cento (1 L.min-1 por 60 minutos durante 5 dias consecutivos); Grupo 4 - isoniazida por via intraperitoneal na dose de 50 mg.kg-1 de peso corporal, diariamente durante 4 dias, seguido da administração do sevoflurane a 4,0 por cento em oxigênio a 100 por cento (1 L.min-1 por 60 minutos durante 5 dias). Após 12 horas da última exposição ao sevoflurane, os animais foram sacrificados e o sangue foi coletado através da veia porta para análise da atividade das enzimas antioxidantes. RESULTADOS: Aumento da atividade específica da glicose-6-fosfato desidrogenase, diminuição da atividade específica da catalase, principalmente no grupo de animais pré-tratados com isoniazida e, em seguida, tratados com sevoflurano. A glutationa peroxidase não apresentou alteração na sua atividade. CONCLUSÕES: A interação do sevoflurano com indutores enzimáticos do citocromo P450 2E1 pode propiciar a instalação do estresse oxidativo caso a exposição se torne prolongada e repetitiva.

BACKGROUND AND OBJECTIVES: Sevoflurane is a halogenated fluorinated ether that undergoes hepatic biotransformation through cytochrome P4502E1. Halogenated ethers undergoing biotransformation by P4502E1 can produce reactive oxygen species (ROS), weakening the antioxidant defense mechanism. The objective of this study was to investigate the relationship between the activity of erythrocyte antioxidant enzymes and sevoflurane. METHODS: Animals were divided in four groups: Group 1 - control: 100 percent oxygen (1 L.min-1 for 60 min during five consecutive days); Group 2 - 4.0 percent sevoflurane in 100 percent oxygen (1 L.min-1 for 60 minutes during five consecutive days); Group 3 - isoniazid (i.p.), 50 mg.kg-1/ day for four consecutive days, followed by 100 percent oxygen (1 L.min-1 for 60 minutes during four consecutive days); Group 4 - intraperitoneal isoniazid, 50 mg.kg-1 daily for four days, followed by 4.0 percent sevoflurane in 100 percent oxygen (1 L.min-1 for 60 minutes during five days). Twelve hours after the last exposure to sevoflurane, animals were sacrificed and their blood was collected through the portal vein for analysis of antioxidant enzymes. RESULTS: An increase in the activity of glucose-6-phosphate dehydrogenase and a decrease in the activity of catalase were observed, especially in the group of animals pre-treated with isoniazid. Changes in the activity of glutathione peroxidase were not observed. CONCLUSIONS: The interaction between sevoflurane and cytochrome P450 2E1 with enzymatic inducers can lead to oxidative stress with prolonged and repetitive exposure.

JUSTIFICATIVA Y OBJETIVOS: El sevoflurano es un éter halogenado con flúor que sufre una biotransformación hepática a través del citocromo P450 2E1. Los éteres halogenados que sufren biotransformación por el P450 2E1, pueden generar especies reactivas del oxígeno (ERO) y promover el debilitamiento del sistema de defensa antioxidante. El objetivo de este trabajo fue investigar la relación entre la actividad de las enzimas antioxidantes eritrocitarias y el sevoflurano. MÉTODO: Los animales fueron distribuidos en cuatro grupos: Grupo 1 control: apenas oxígeno a 100 por ciento (1 L.min-1 por 60 minutos durante 5 días consecutivos); Grupo 2 - sevoflurano 4,0 por ciento en oxígeno a 100 por ciento (1 L.min-1 por 60 minutos durante 5 días consecutivos); Grupo 3 - isoniazida (i.p.), 50 mg.kg-1 de peso corporal /día, durante 4 días y enseguida tratados apenas con oxígeno a 100 por ciento (1 L.min-1 por 60 minutos durante 5 días consecutivos); Grupo 4 - isoniazido por vía intraperitoneal en dosis de 50 mg.kg-1 de peso corporal, diariamente durante 4 días, seguido de la administración del sevoflurano a 4,0 por ciento en oxígeno a 100 por ciento (1 L.min-1 por 60 minutos durante 5 días). Después de 12 horas de la última exposición al sevoflurano, los animales se sacrificaron y la sangre se recolectó a través de la vena porta para el análisis de la actividad de las enzimas antioxidantes. RESULTADOS: Aumento de la actividad específica de la glucosa- 6-fosfato deshidrogenasa, reducción de la actividad específica de la catalasis, principalmente en el grupo de animales pretratados con isoniazida y enseguida, tratados con sevoflurano. El glutatión peroxidasa no presentó ninguna alteración en su actividad. CONCLUSIONES: La interacción del sevoflurano con inductores enzimáticos del citocromo P450 2E1 puede propiciar la instalación del estrés oxidativo en el caso que la exposición se prolongue y sea repetitiva.

Vital Capacity Induction with Sevoflurane in Children Results in Less Incidence of Withdrawal after Rocuronium than Tidal Volume Induction / 대한마취과학회지

BACKGROUND: The Vital capacity technique is known to have some advantages over the tidal volume technique during inhalation induction of anesthesia.The aim of this study was to compare the incidence of withdrawal movement associated with the intravenous administration of rocuronium 0.3 mg/kg in children during inhalation induction with sevoflurane using the tidal volume and vital capacity techniques. METHODS: We randomly assigned 130 patients (aged 5-12 years) to either tidal volume (group T) or vital capacity (group V) groups for inhalation induction with sevoflurane.Rocuronium 0.3 mg/kg was administrated after loss of the eyelash reflex.The time to loss of the eyelash reflex was recorded and adverse events during induction were documented.The patient's response to rocuronium injection was graded using a four-point scale. RESULTS: No significant differences were observed between the groups with respect to age, weight, and gender.The time to loss of the eyelash reflex was more rapid in group V than in group T (P < 0.05).Excitatory movement developed more frequently in group T, and no significant differences were found in the incidence of other adverse events between the groups.The incidence of withdrawal movement associated with the injection of rocuronium was significantly lower in group V compared to group T (30 vs. 60%; P < 0.05). CONCLUSIONS: Inhalation induction with sevoflurane using the vital capacity technique decreased the incidence of withdrawal movement during the injection of rocuronium compared to the tidal volume technique.

The Spectral Analysis of EEG according to Change in the Concentration of Isoflurane / 대한마취과학회지

BACKGROUND: Adequate depth of anesthesia requires a sufficient amount of the agent to secure unconsciousness and other components of anesthesia as needed for that particular surgical procedure, without jeopardizing vital organ functions. To evaluate the relationship of depth of anesthesia to EEG, we studied the effects of increasing minimum alveolar concentration (MAC) of isoflurane (arousal, 1, 1.3, 1.5 MAC) on power spectral analysis of the EEG. METHODS: To determine 1 MAC, we studied sixty patients undergoing general anesthesia who were randomly allocated to receive isoflurane at several predetermined end-tidal concentration. A minimum of 15 min was allowed between induction and skin incision to allow steady state condition. Patients were observed for gross purposeful movement for 60 seconds after incision. The MAC was calculated using maximum likelihood solution to a logistic regression model. Another forty patients were randomly allocated to have their EEGs recorded. General anesthesia was induced with oxygen and isoflurane only. After loss of consciousness, succinylcholine 1.5 mg/kg was given and intubation followed. The EEG was recorded awake and after 15 min at steady state conditions of 1, 1.3 and 1.5 MAC isoflurane had been achieved. Spectral edge frequency 95% (SEF95), median spectral frequency (MSF), total power (TP) and relative power in the delta, theta, alpha and beta band were calculated. RESULTS: The MAC of isoflurane was 1.21 vol% (20 - 40 years) and 1.09 vol% (40 - 60 years). The distribution of spectral EEG indices of the EEGs were established and compared. The threshold value of SEF95 14 Hz to differentiate between arousal and 1.3 and 1.5 MAC had a sensitivity of 60.5% (1.3 MAC), 71% (1.5 MAC) and specificity of 74.4% (1.3 and 1.5 MAC) and that of MSF 5 Hz had a sensitivity of 71% (1.3 MAC), 81.5% (1.5 MAC) and specificity of 48% (1.3 MAC), 48.8% (1.5 MAC). CONCLUSIONS: With regard to the dose-related decrease in SEF95 and MSF under increasing end- expiratory concentrations of isoflurane as described in the present study, future studies may have todetermine whether EEG feedback control of volatile anesthetic administration may be used successfully. It seems that if neglected parts by MSF and SEF95, which are really true values are considered in the future studies, those would increase the sensitivity and specificity of EEG could be used as tool for determining depth of anesthesia.

Is It Mandatory to Incise Immediately after Intubation in Cesarean Section? / 대한마취과학회지

BACKGROUND: If general anesthesia is used for cesarean section, important considerations include minimizing the duration of general anesthesia. One may think that skin incision should be started immediately after endotracheal intubation. If so, intra-operative awareness and perception of pain may occur due to light anesthesia. Allowing skin incision to be started 5 min after intubaton while administering 50% nitrous oxide and isoflurane 0.75%, we investigated the changes of BIS (bispectral index), and Apgar scores. METHODS: The investigation was carried out on 33 full-term ASA 1 or 2 patients underwent elective cesarean section under general anesthesia. If any fetal abnormalities were found, we excluded those cases. Premedication was omitted. After rapid sequence induction with sodium thiopental 4 mg/kg, succinylcholine 1 mg/kg, we made skin incision immediately after intubation in control group (n = 18) and 5 min after intubation in experimental group while administering 50% nitrous oxide and isoflurane 0.75%. Muscle relaxation was maintained with intravenous administration of atracurium 0.5 mg/kg. We measured BIS, mean arterial pressure (MAP), heart rate in 1 min interval from preinduction period to delivery and recorded Apgar scores 1 and 5 min after delivery, skin incision to delivery time and uterine incision to delivery time. And we counted the number of patients whose BIS values had been below 60 and 70 from skin incision to delivery in each group. RESULT: Apgar scores recorded 1 and 5 min after delivery did not show significant differences between control and experimental group. During the periods of abdominal wall traction, uterine incision and delivery, BIS values of experimental group were significantly lower than control group and moreover, tended to remain below 60 while those of control group during the same periods tended to be above 60 (P < 0.05). The number of patients of experimental group, whose BIS values had been below 60 from skin incision to delivery, was twice as much as that of control group (P < 0.05), but in case of BIS value below 70, there was no significant difference between control and experimental group. During the periods of skin incision and abdominal wall traction, the MAP's of experimental group were significantly lower than control group (P < 0.05). In cases of heart rate, skin incision to delivery time and uterine incision to delivery time, there were no significant differences between control and experimental group. CONCLUSION: Allowing the skin incision to be started 5 min after intubation while administering 50% nitrous oxide and isoflurane 0.75%, BIS values remained below 60 from abdominal wall traction to delivery, and anesthetics-induced fetal depression did not occur.

The Effect of Increased Minute Ventilation on the Changes of End-Tidal Isoflurane Concentration and Bispectral Index / 대한마취과학회지

BACKGROUND: An increase in ventilation is known to accelerate the rate of the rise of alveolar concentration of inhalation anesthetics and increase the rate of anesthetic induction. However, it is still debatable whether or not a rise of alveolar isoflurane concentrations by increased minute ventilation (MV) actually increases the depth of anesthesia. METHODS: After anesthetic induction by intravenous thiopental and succinylcholine, and after the bispectral index (BIS) had recovered to 75 after intubation, isoflurane anesthesia was begun (inspired concentration:2 vol.%, respiratory rate:12/min, tidal volume: group I; 8 ml/kg, group II; 12 ml/kg). BIS, spectral edge frequency (SEF), blood pressure, pulse rate were recorded 1 minute before induction, and 1, 2, 3, 4, 5, 7 and 10 minutes after isoflurane anesthesia. End-tidal concentrations of isoflurane and CO2 (ET-iso and -CO2) were recorded at 1, 2, 3, 4, 5, 7 and 10 minutes after isoflurane anesthesia. RESULTS: The increase of ET-iso and the decrease of ET-CO2 were significantly fast in group II. There was no difference in BIS and SEF between the two groups. CONCLUSIONS: Increasing MV induced a rapid rise of alveolar isoflurane concentrations, but changes of BIS and SEF were not affected by increased MV.

Perioperative Changes of Blood Coagulation by a Thromboelastograph in Patients Undergoing Clipping of Cerebral Aneurysms / 대한마취과학회지

BACKGROUND: Patients undergoing brain surgery have a high risk of developing a number of perioperative coagulation disorders. Anesthesia and surgical stress may affect blood coagulation and fibrinolysis. The aim of this study was to evaluate perioperative changes in hemostatic parameters of patients undergoing clipping of cerebral aneurysms with a thromboelastograph (TEG) in combination with simple laboratory tests. METHODS: Twenty adult patients who had cerebral aneurysms and no history of coagulation disorders were studied. Isoflurane and N2O were used for all anesthetic proceedings. Preanesthetic, intraoperative (after skin incision and after clipping of cerebral aneurysms) and postanesthetic measurements included a TEG and simple laboratory tests. The TEG variables included r time (reaction time for clot formation), k time (clot formation time), alpha angle (rate of clot growth), MA (maximal amplitude of clot strength) and LY30 (fibrinolytic index). RESULTS: In simple laboratory tests, prothrombin time (PT) and partial thromboplastin time (PTT) at intraoperation and postanesthesia were longer than those at preanesthesia (p < 0.05). In the TEG, r and k time at intraoperation and postanesthesia were shorter than those at preanesthesia (p < 0.05). However the alpha angle at intraoperation and postanesthesia was longer than that at preanesthesia (p < 0.05). There was no significant difference in MA and LY30 except an increase in MA after the skin incision (p < 0.05) compared to the MA at preanesthesia. CONCLUSIONS: These results indicate a general hypercoagulability during and after a cerebral aneurysms operation in terms of TEG, although, the level of the PT and PTT can be at the upper limits within normal. Therefore perioperative use of coagulants in cerebral aneurysms may increase the risk of a thromboembolism because of accelerating blood coagulability. By early intraoperative and postoperativeevaluation of the hemostatic abnormality with a TEG, appropriate measures might be initiated to prevent postoperative complications due to hypercoagulability.

The Effects of Desflurane on Ca2+ Release from the Myocardial Sarcoplasmic Reticulum in Vitro / 대한마취과학회지

BACKGROUND: The purpose of this study is to examine the effect of Desflurane on myocardial contractility and cellular electrophysiologic behabior in isolated guinea pig and rat right ventricular papillary muscle. METHODS: The isometric force of a guinea pig ventricular papillary muscle was studied in normal and 26 mM Tyrode's solution at various stimulation rates. Experiments using rat papillary muscles under normal Tyrode's solution at resting-state (RS) and using guinea pig papillary muscles under low Na Tyrode's solution (25 mM) were performed to evaluate the effect on Ca2+ release from the sarcoplasmic reticulum (SR). Normal and slow action potentials (APs) were evaluated by using a conventional microelectrode technique. Effects of desflurane on SR function in situ were examined by its effect on rapid colling contractures (RCCs). 1 MAC (end-tidal concentration: 6%) and 2 MAC desflurane were applied. RESULTS: Desflurane equivalent to 6% and 12% depressed guinea pig myocardial contractions in the control to -70% and -40% from RS to 3 Hz stimulation rates. Contractile force after rest in rat and guinea pig myocardium under low Na Tyrode's solution showed modest depression. In the partially depolarized, beta-adrenergically stimulated myocardium, 6% and 12% desflurane caused marked depression of late force (6%: -60%, 12%: -80%) with moderate changes of early peak force (6%: -20%, 12%: -40%). RCCs were abolished at 6% concentration. CONCLUSIONS: The direct myocardial depressant effects of desflurane is slightly greater to those seen with isoflurane. The rapid initial release of Ca2+ from the SR by depolarization seems to be modestly depressed, although certain release pathways induced by rapid colling appear to be markedly depressed.

The Effects of Diltiazem with Desflurane on Coronary Blood Flow and Contractility in Isolated Rat Heart / 대한마취과학회지

BACKGROUND: Calcium channel blockers and volatile anesthetics have depressant effects on cardiac function. Both groups of drugs appear to exert both qualitatively and quantitatively different effects on electrophys-iologic and mechanical function. The authors examined the direct in-vitro effects of diltiazem in the presence of a desflurane using an isolated rat heart. METHODS: Isolated Sprague-Dawley rat hearts (N = 40) were perfused at a constant pressure with an oxygenated modified Krebs' solution. After the stabilization period, they were subdivided into two groups. The groups were subjected to different concentrations of desflurane (6, 12, 18 vol%) alone or 100 ng/ml diltiazem with the same concentrations of desflurane, respectively. Isovolumetric left ventric ular pressure (LVP), heart rate and rate of change of ventricular pressure (dp/dt) were measured via a thin, saline-filled latex balloon and transducer. Coronary flow and oxygen tension were measured at the coronary inflow and outflow sites. Oxygen delivery, myocardial oxygen consumption and percent oxygen extraction were calculated with each measurement. RESULTS: The combination of diltiazem and desflurane (6, 12 and 18 vol%) dose-dependently depressed LVP and dp/dt more than desflurane alone. Coronary flow and oxygen delivery increased in a dose- dependent fashion, but there was no statistical difference between the groups. The decreases of heart rate, myocardial oxygen consumption and percentage of oxygen extraction were dependent on the concentration of desflurane. Arrhythmias occurred only with a high desflurane (18 vol%) concentration and the high desflurane concentration plus diltiazem. CONCLUSIONS: These results demonstrate that the myocardial depressant effect of diltiazem plus desflurane is greater than desflurane alone. The authors suggest that administration of diltiazem during high concentrations of desflurane anesthesia could result in deleterious cardiac depression and arrhythmias.

Effect of Elimination of CO2 Absorption Canisters on the Rate of Recovery from General Anesthesia / 대한마취과학회지

BACKGROUND: The most important route for elimination of inhalation anesthetics is exhalation. The lower anesthetic circuit volume and absorption by the anesthetic circuit maKes recovery more fast. The purpose of this study is to evaluate the effect of the elimination of CO2 absorption canisters on the rate of recovery from anesthesia. METHODS: Forty patients were randomly assigned into two groups. Group 1 patients recovered from enflurane anesthesia with CO2 absorption canisters (baralyme), but group 2 patients emerged from anesthesia without CO2 absorption canisters. The changes of expiratory enflurane and inspiratory nitrous oxide concentration at 30, 60, 90, 120, 150, 180 sec after the end of anesthetic administration, and time from the end of anesthetic administration to extubation were measured and compared between the groups. RESULTS: Enflurane and nitrous oxide concentrations after the end of anesthetic administration in group 2 were significantly lower than in group 1 at each time interval (P < 0.05). Time from the end of anesthetic administration to extubation in group 2, 7.7 +/- 1.4 min, was significantly shorter than in group 1, 10.5 +/- 2.6 min (P < 0.05). CONCLUSIONS: The results show that the patients emerging from anesthesia without CO2 absorption canisters can recover from anesthesia more rapidly than those with CO2 absorption canisters.

Monitoring of Anesthetic Depth by BIS & Anemon Monitor / 대한마취과학회지

BACKGROUND: Monitoring of "Depth of anesthesia" is an ongoing problem in anaesthesia. In this study, the author has compared the bispectral index (BIS) and Anemon monitor for monitoring depth of anesthesia in propofol or isoflurane anesthesia. METHODS: Anemon-1 and BIS index were obtained from 24 patients (ASA I, II) during general anesthesia with propofol or isoflurane. For patients in the propofol group, anesthesia was induced with fentanyl 100ng followed by propofol 2 mg/Kg. For patients in the isoflurane group, anesthesia was induced with thiopental 5 mg/Kg. The author observed changes of these values at 5 major times: before induction, during induction, after induction, at sKin incision, before extubation, after extubation. RESULTS: The anemon index showed a significant increase during induction (propofol group: 86.9 +/- 26.4, isoflurane group: 106.0 +/- 18.6) and at sKin incision (propofol group: 89.9 +/- 22.7, isoflurane group: 92.0 +/- 23.1), but this did not correlate with the level of consciousness. The BIS index showed a significant decrease in the score after induction (propofol group: 55.0 +/- 9.6, isoflurane group: 61.0 +/- 17.2), but no response to surgical stimuli. CONCLUSIONS: BIS had a good correlation with level of consciousness. The Anemon-1 index was recognized to reflect invasive stimulus. As the BIS and Anemon-1 had no correlation, it was not possible to assume changes of each index from the other. Both the anemon-1 index and BIS are useful to monitor the anesthesia level during surgery.

Effects of Diltiazem with Sevoflurane on Coronary Flow and Myocardial Contractility in the Isolated Rat Heart / 대한마취과학회지

BACKGROUND: Calcium channel blockers and volatile anesthetics have depressant effects on myocardial contractility by limiting Ca2+ entry and altering intracellular Ca2+ release. The aim of this study was to compare the direct cardiac effects of isoflurane, desflurane and new volatile anesthetics, sevoflurane, in combination with diltiazem on the isolated rat heart. METHODS: Sprague-Dawley rat hearts (N = 60) were isolated and perfused with oxygenated modified Krebs solution at 55 mmHg with 0.5, 1, 2 MAC of isoflurane, desflurane or sevoflurane in combination with diltiazem 42 ng/ml (group 1) and 84 ng/ml (group 2). Isovolumetric left ventricular pressure (LVP), rate of change ventricular pressure (dP/dt), heart rate and coronary flow were measured. To examine the indirect metabolic effect due to autoregulation of coronary flow, O2 delivery (DO2), myocardial O2 consumption (MVO2) and percent O2 extraction (POE) were also monitored. RESULTS: Diltiazem plus volatile anesthetics depressed LVP and dP/dt and increased coronary flow dose-dependently. They also decreased heart rate. In the group 2, at 2 MAC of inhaled anesthetics heart rate was significantly decreased than group 1. There were no statistical significance between isoflurane, desflurane and sevoflurane on myocardial contractility and myocardial oxygenation. CONCLUSIONS: These in vitro RESULTS demonstrate that clinical dose of diltiazem plus isoflurane, desflurane or sevoflurane has similar effects on myocardial contractility and coronary flow.

Comparison of Cost-Effectiveness of Propofol Using Target-Controlled Infusion (TCI) with Standard Anesthesia Regimens in Major Operations / 대한마취과학회지

BACKGROUND: The purpose of this study was to compare the cost-effectiveness of propofol using a target-controlled infusion (TCI) with two currently used anesthetic regimens during major operations. METHODS: Forty-two patients undergoing major gynecological surgery were divided into three groups according to the period during which the surgeries were performed. Group propofol/TCI (n = 16) received 1% propofol using TCI-50% N2O, Group isoflurane (n = 14) received thiopental 5 mg/kg-isoflurane-50% N2O, and Group enflurane (n = 12) received thiopental 5 mg/kg-enflurane-50% N2O. All patients also received 2 microgram/kg of fentanyl before induction. Concentrations of propofol and volatile anesthetics were varied according to the patient's hemodynamic responses. Consumption of volatile anesthetics was measured by weighing the vaporizers by a precision weighing machine. RESULTS: Biometric data, duration of surgery and of anesthesia were similar in the three groups. Recovery from anesthesia was significantly shorter in the propofol/TCI group. Episodes of postoperative nausea and vomiting in the recovery room were less common in propofol/TCI group. Patient satisfaction was similar in all three groups. Total (intra- and postoperative) costs were significantly higher in the propofol/TCI group. CONCLUSIONS: When compared with the standard anesthetic regimens, the use of propofol using TCI anesthesia during major operations was associated with higher costs, but did not offer any clinically significant advantages in cost-effectiveness over the standard anesthesia regimens.

Influence of History of Alcohol Ingestion on AST and ALT Following Enflurane Anesthesia in Gastrectomy Patients / 대한마취과학회지

BACKGROUND: There are many factors including the operation site, duration of anesthesia, preoperative liver function and hepatitis, which cause postoperative hepatic dysfunction. The purpose of this study is to evaluate postoperative liver function with respect to a history of alcohol intake. METHODS: Seventy-five patients were divided into 2 groups:44 patients without alcohol intake (non-alcohol group), 31 patients with alcohol intake (alcohol group). All patients were anesthetized with about 1.5 vol% of enflurane combined with 50% nitrous oxide and 50% oxygen. AST (aspartate aminotransferase) and ALT (alanine aminotransferase) were measured before anesthesia, 1, 3 and 7 days after surgery in both groups, respectively. Postoperative AST and ALT values were compared to preoperative values within each group, and were also compared between groups. RESULTS: In the alcohol group, postoperative AST and ALT values were significantly higher than preoperative values (P < 0.05). In addition, postoperative ALT values significantly increased in the 1st and 7th day over the upper normal limit of ALT (P < 0.05). In the non-alcohol group, postoperative AST and ALT values increased over preoperative values, but those levels were within the normal limits of AST and ALT. CONCLUSIONS: The data suggest that when surgery can reduce hepatic blood flow, patients with a history of alcohol ingestion may have a risk of raised liver-derived enzyme in the first seven postoperative days.

Comparison of the Effects of Propofol and Isoflurane Anesthesia on Respiratory Gas Exchange during Laparoscopic Cholecystectomy / 대한마취과학회지

BACKGROUND: Introduction of a pneumoperitoneum using CO2 is accompanied by significant alterations in respiratory function and pulmonary gas exchange during laparoscopic cholecystectomy. Previous studies have shown differing results concerning pulmonary gas exchange: a significant decrease of PaO2 was induced with isoflurane. In contrast, no significant changes were observed with propofol. The purpose of the present study was to compare the effects of propofol vs isoflurane on pulmonary gas exchange during general anesthesia for laparoscopic cholecystectomy. METHODS: Forty patients were divided randomly between isoflurane and propofol groups. After induction of anesthesia, ventilation was controlled and intra-abdominal pressure was maintained automatically at 12 mmHg by a CO2 insufflator. After the measuring of baseline values of blood pressure, heart rate, PaO2, PaCO2 and PetCO2 before CO2 insufflation, measurements were also made immediately, 30min after CO2 insufflation and 5 min after CO2 exsufflation. RESULTS: In the isoflurane group, PaCO2, PetCO2, PaO2, and P(a-et)CO2 changed significantly 30 min after CO2 insufflation and 5 min after CO2 exsufflation (P < 0.05). In the propofol group, PaCO2 and PetCO2 increased significantly 30 min after CO2 insufflation and 5 min after CO2 exsufflation (P < 0.05), but PaO2 and P(a-et)CO2 remained constant. When the two groups were compared, there were significant differences in PaO2, PaCO2, PetCO2 and P(a-et)CO2 at 30min after CO2 insufflation and 5 min after CO2 exsufflation (P < 0.05). CONCLUSIONS: These results indicate that during laparoscopic cholecystectomy the PaO2 was significantly lower and PaCO2 and P(a-et)CO2 were significantly higher in the isoflurane group compared with the propofol group.

Uptake of Enflurane and Isoflurane as Supplement during General Anesthesia for Cesarean Section and Maternal Awareness / 대한마취과학회지

BACKGROUND: Using a semiclosed circle system, general anesthesia for cesarean section was maintained with either 2/3 MAC enflurane or isoflurane in combination with O2: N2O (2 L/min: 2 L/min). METHODS: We studied the rate of uptake of inhalation agents of pregnant women by measuring inspired concentration and end-tidal concentration of enflurane and isoflurane and we measured the differences in maternal awareness in two groups. The 40 patients presented for elective cesarean section under general anesthesia were randomly assigned to receive either 1.0% enflurane or 0.8% isoflurane with O2: N2O (2 L/min: 2 L/min) for maintenance before delivery using a semiclosed circle system. All patients received thiopental 4 mg/Kg (maximum 250 mg) and succinylcholine 100 mg for induction and were intubated and ventilated with a tidal volume of 10 ml/kg at a rate of 10 breaths/min. After intubation, FI (fractonal inspired concentration) and FE (fractional end tidal concentration) were analyzed by gas monitor (Sirecust 734G, Siemens, Germany) every minute. Intraoperative hemodynamic variables were recorded. Maternal awareness was monitored by the isolated forearm technique. RESULTS: FI/FINF (fractional inflow concentration) and FE/FINF for the inhalation agents were significantly higher for isoflurane than for enflurane throughout the study after 2 minutes (P < 0.05). The incidence of maternal awareness signaled by both 'spontaneous movement' and 'followed commands' was high and there were no significant differences in the two groups. No patient in our study showed any recollection. CONCLUSION: We concluded that the rate of uptake of isoflurane was more rapid than that of enflurane but the incidence of maternal awareness was high and there were no significant differences in the two groups.

The Comparison of Propofol, Isoflurane and Enflurane Anesthesia on Recovery in Day Surgery / 대한마취과학회지

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) is expected to provide fast and comfortable recovery, plus an early return to normal daily activities. This study was carried out to compare the characteristics of recovery after VATS in patients anesthetized with isoflurane, enflurane or propofol. METHODS: Sixty patients undergoing VATS were allocated randomly to receive propofol-N2O, isoflurane-N2O or enflurane-N2O anesthesia. The time between the end of anesthesia and extubation were compared. The orientation, cooperation and degree of sedation in Numeric Rating Scale (NRS) were recorded 5, 10, 30 and 60 min after anesthesia. Recovery was also evaluated by the P-deletion test (PDT) and Digit Symbol Substitution test (DSST) 30, 60 and 120 min after anesthesia for the comparison of the recovery of cognitive and psychomotor function. RESULTS: Early recovery was significantly (P < 0.05) faster in the propofol group (orientation, cooperation and degree of sedation in 10 min) when compared to the isoflurane and enflurane groups, but there was no significant difference in the other parameters of recovery. CONCLUSIONS: The authors concluded that although propofol was associated with faster emergence from anesthesia than enflurane and isoflurane after VATS, recovery of cognitive and psychomotor function were similar in the three anesthetic groups.

The Effect of Age on the Cardiovascular Responses Induced by High Concentration of Isoflurane / 대한마취과학회지

BACKGROUND: The inhalation of a high concentration of isoflurane transiently increases heart rate (HR) and blood pressure. The current study examined the effects of age on isoflurane-induced circulatory responses. METHODS: One hundred-ten patients were randomly allocated into one of four groups according to age: under 10 years (Group 1), 20 - 40 years (Group 2), 41 - 60 years (Group 3), and over 65 years (Group 4). In each group, the inspired concentration of isoflurane via mask was increased to 5.0 vol% abruptly. The target was to produce an end-tidal concentration of isoflurane (ETisof) of 2.6 vol% which was maintained until the end of the study by adjusting the vaporizer setting when necessary. HR, mean arterial pressure (MAP), ETisof, and end-tidal concentration of carbon dioxide were measured at baseline and every 30 seconds for 5 minutes after inhalation of isoflurane and for 2 minutes after intubation. RESULTS: HR and MAP significantly increased after inhalation of isoflurane in all four groups compared with the baseline. The time from administration of isoflurane to the maximal HR was less than that for MAP. However, there were no significant differences among the groups for ETisof at the maximal HR and MAP. In Groups 1 and 4, the times for maximal HR were shorter than in Groups 2 and 3. In aged patients (Group 4), the isoflurane-induced HR increase was less than in the other three groups. There were no significant differences among the groups in increases of MAP. CONCLUSIONS: The high concentration of isoflurane transiently increases HR and MAP during inhaled anesthesia induction. In aged patients, the increase in HR is less than in younger-aged patients.

The Effects of Isoflurane on the Expression of iNOS mRNA in Endotoxemic Rats / 대한마취과학회지

BACKGROUND: It has been known that alveolar macrophage exposed to bacterial lipopolysaccharide (LPS) induces a lots of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) mRNA expression. The Authors elucidated the effects of iNOS mRNA expression by inhalational anesthetics (isoflurane) on endotoxemic rats and positive pressure ventilation with and without LPS. METHODS: Fifty Sprague-Dawley rats (250 - 270 g) were anesthesized with urethane injected in the peritoneal cavity. Then the expression of iNOS mRNA in the alveolar macrophages of the rats were measured after injection of LPS, 2 hours of isoflurane (0.5 - 2.5%) anesthesia, and 2 hours of positive pressure ventilation. The activities of iNOS in macrophages were measured by analysing iNOS mRNA expression by Northern blot analysis with autoradiography using the polymerase chain reaction (PCR) method. RESULTS: The size and patterns of the iNOS mRNA band in the 0.5 - 2% isoflurane group were almost same as with the control group. The size of the iNOS mRNA band in the 2.5% isoflurane group increased more than in the control group. In the continous positive-pressure ventilation with LPS group, the iNOS mRNA band was slightly increased compared to the normal lung and the continous positive-pressure ventilation without LPS group. CONCLUSIONS: Higher concentrations of isoflurane anesthesia may evoke the expression of iNOS mRNA in a septic model. Positive pressure ventilation in sepsis may induce iNOS mRNA production.

Effects of Halothane, Enflurane or Isoflurane on the m1 or m3 Muscarinic Receptor Expressed in Xenopus Oocytes / 대한마취과학회지

BACKGROUND: Muscarinic receptors are distributed abundantly in the central nervous system and peripheral visceral organs, and have a close relationship with anesthesia. We investigated the effects of halothane, enflurane or isoflurane on m1 or m3 muscarinic signaling. METHODS: Using two electrode voltage clamps, Ca2+ -activated Cl- currents (ICl(Ca)) were measured in Xenopus oocytes injected with an m1 or m3 receptor mRNA. ICl(Ca) was induced with the application of acetyl beta-methylcholine with or without exposure to volatile anesthetics. RESULTS: Halothane depressed the m1 and m3 receptor function significantly (m1; 0.49 +/- 0.17 microampere -> 0.1 +/- 0.05 microampere, m3; 0.74 +/- 0.2 -> 0.23 +/- 0.06 microampere, P 0.15 +/- 0.04 microampere, m3; 0.95 +/- 0.34 -> 0.19 +/- 0.05 microampere, P 0.3 +/- 0.09 microampere, P 0.5). From a concentration-response curve, enflurane decreased m1 and m3 signaling dose-dependently. CONCLUSIONS: Our data suggests that m1 and m3 muscarinic receptors were depressed by halothane, enflurane or isoglurane except for the fact that the m1 receptor was not affected by isoflurane.

Comparison of Propofol and Propofol-Isoflurane Anesthesia for Outpatient Surgery / 대한마취과학회지

BACKGROUND: Outpatient surgery has recently grown at a substantial rate. The development and use of short acting anesthetic and analgesic agents have played a major role in the growth of outpatient surgery. This study was designed to evaluate the intraoperative hemodynamic responses and recovery characteristics, using propofol or isoflurane to maintain the anesthesia. METHODS: A total number of 30, ASA physical status I-II patients scheduled for outpatient surgery, all of whom were to undergo excision of breast mass. The patients were randomly allocated to receive either total intravenous anesthesia with propofol, or inhalation anesthesia with isoflurane after induction of anesthesia with propofol. All patients were ventilated via a laryngeal mask airway (LMA) using a mixture of oxygen and air so that the FiO2 would be 0.4. RESULTS: There were no significant differences in hemodynamic changes during anesthesia in recovery time, or in complications between the two groups. CONCLUSIONS: We conclude that both methods provide reasonably rapid and reliable recovery from anesthesia and are equally acceptable to the patients.