The Effect of Halothane and Enflurane on the Contraction of Bronchial Smooth Muscle Induced by Histamine in Rabbits / 대한마취과학회지

BACKGROUND: Inhalation anesthetics are known to be bronchodilators. However there are several reports that these effects are not consistant, and depend on the way of experiments. Some reports showed that inhalation anesthetics don't affect broncheal smooth mucle contraction. So, we tried to evaluate the effects of inhalation anesthetics on the histamine induced contraction of broncheal smooth muscles in rabbits. METHODS: Isolated broncheal rings of rabbit were suspended in a Tyrode's solution. Contractions were recorded isometrically using a transducer. Cumulative dose responses of histamine (10(-6), 10(-5) & 10(-4) Mol, histamine group) were observed and also cumulative dose responses of histamine with halothane and enflurane administration (0.5 MAC & 1 MAC) were evaluated. RESULTS: A contraction by histamine was weakened with enflurane administration, but with halothane, the contraction was slightly weakened at 0.5 MAC and no changes were observed at 1.0 MAC compared to a contraction induced by histamine. CONCLUSIONS: At 0.5 MAC of halothane, a contraction induced by histamine was slightly weakened, but at 1 MAC, no changes of contraction occurred. However enflurane weakened the contraction at 0.5 MAC and 1 MAC. It showed that in vitro studies of the direct effect of inhalation anesthetics on smooth muscle contraction are different from the results of in vivo study reports.

The Effect of Anesthetic Technique on White Blood Cell Response to Surgery in Patients Who Underwent Laparoscopic Cholecystectomy and Cesarian Section / 대한마취과학회지

BACKGROUND: Surgical stress causes changes in the composition of white blood cells in peripheral blood. In addition, anesthesia itself has been suggested to have an immunosuppressive effect. Therefore, the aim of the present study was to investigate the effect of anesthetic technique on the changes of postoperative peripheral white blood cell (WBC) subsets in laparoscopic cholecystectomy patients and cesarian section patients. METHODS: We reviewed 100 patients who had laparoscopic cholecystectomy under conventional general anesthesia or propofol infusion. Each group contained 50 patients equally. We also reviewed 100 patients who had cesarian section under spinal and epidural anesthesia, 50 patients in each group, respectively. The changes of total WBC, lymphocytes, neutrophils and monocytes at 24 h and 48 h postoperatively were compared to baseline values within the groups and these values were compared between the groups. RESULTS: There were significant increases in total WBC and neutrophils, decreases in lymphocytes, no changes in monocytes at 24 h after surgery compared to baseline values for the groups receiving laparoscopic cholecystectomy. No differences were found between the two laparoscopic cholecystectomy groups. Cesarian section patients showed significant differences in total WBC, neutrophils, lymphocytes and monocytes at 48 h after surgery compared to baseline values for the groups. There were no significant differences between the groups. CONCLUSIONS: Neither laparoscopic cholecystectomy nor cesarian section showed significant differences in WBC subsets after surgery according to anesthetic technique.

VD/VT and Arterial Blood Gas Changes during Gynecologic Laparoscopic Surgery under Enflurane or Propofol Anesthesia / 대한마취과학회지

BACKGROUND: Laparoscopic gynecologic surgery is a standard procedure today for its small skin incision and short hospital admission stay. However pneumoperitoneum (PP) and Trendelenberg position induce adverse effects in hemodynamics and pulmonary gas exchange. The purpose of this study is to evaluate the effects of propofol compared with enflurane for pulmonary gas exchange in the Trendelenberg position and pneumoperitoneum. METHODS: Twenty women were randomly allocated to either the enflurane (n = 10) or propofol (n = 10) with fentanyl-N2O/O2 anesthesia. PaCO2, PaO2, PETCO2 were checked at pre-PP, 10 min after PP, 30 min after PP, and 10 min after CO2 deflation. In addition the Vd/Vt ratio was calculated according to the Bohr equation. Vital sign and peak airway pressure were checked at each stage. RESULTS: PaCO2 and PETCO2 increased and PaO2 decreased significantly during PP in both groups. Vd/Vt increased significantly in the enflurane group at 30 min after PP. Peak airway pressure increased significantly in both groups. Blood preassure and heart rate were not changed significantly. All of the parameters were not significantly different between groups. CONCLSIONS: Propofol compared with enflurane did not show any advantage in gas exchange during gynecologic laparoscopic surgery under Trendelenberg position and PP.

A Comparison of Recovery from Mivacurium during Enflurane or Propofol Anesthesia in Children / 대한마취과학회지

BACKGROUND: Mivacurium is a new, short acting, nondepolarizing muscle relaxant of the benzylisoquinolinium type. Enflurane produces relaxation and augments the neuromuscular blockade from muscle relaxation, but propofol does not produce muscle relaxation. We compared maintenance infusion rates, recovery index and correlations of recovery index to maintenance infusion rates and infusion duration after mivacurium during enflurane or propofol anesthesia in children. METHODS: Maintenance infusion rates, and the recovery index after mivacurium were studied in 30 pediatric patients in enflurane anesthesia (n = 15) and propofol anesthesia (n = 15). The ulnar nerve was stimulated at the wrist by repeated single twitch (1Hz) stimulus using the peripheral nerve stimulator (Model ST5 MaxiStimTM, Life-Tech , Inc, Texas, USA). We recorded the contraction of adductor pollicis longus via mechanomyography (MYOTRACE, Life-Tech, Inc, Texas, USA). RESULTS: The infusion rates of mivacurium for the maintenance of muscle relaxation (below 10% of control) were 9.6 0.80 microgram/kg/min in the enflurane anesthesia, and 11.04 1.22 microgram/kg/min in the propofol anesthesia. There was a significant difference between the groups. The recovery index was shorter in the propofol anesthesia, but regarding this index, there was no significant difference between both groups. The correlation between the recovery index and the infusion duration was significantly different in the enflurane anesthesia. CONCLUSIONS: We conclude that maintenance infusion rates are significantly lower in the enflurane anesthesia, the recovery index is insignificantly shorter in the propofol anesthesia, that there is a significant correlation between the maintenance infusion rates and recovery index in the enflurane anesthesia.

Comparison of Enflurane Consumptions and Costs in Low Flow and High Flow Anesthesia / 대한마취과학회지

BACKGROUND: The amount and composition of fresh gas flow affect the consumption of inhalational anesthetics. The purpose of this study was to compare the enflurane consumption and economic aspects of low flow and high flow anesthesia. METHODS: Thirty patients, ASA physical status I or II, aged 20 65 yr., scheduled for gastrectomy under inhalational anesthesia, were studied. The patients were randomly assigned to one of three groups according to the fresh gas flow: O2 500 ml/min (group I); N2O 2 L/min - O2 1 L/min (group II); O2 3 L/min (group III). Anesthesia was maintained in group I by a continuous infusion of liquid enflurane into the inspiratory limb of the breathing circuit, using a syringe pump. In groups II and III, enflurane was administered by a conventional vaporizer. The cumulative dose of liquid enflurane was measured every 10 min during anesthesia. Hemodynamic parameters, inspired and expired enflurane concentrations, and enflurane consumptions were measured. RESULTS: There were no significant differences among the three groups in hemodynamic changes. The enflurane consumption was significantly less in group I than in groups II and III over time (P < 0.05). CONCLUSIONS: Low flow anesthesia offers economic advantages over high flow anesthesia.

Comparison of Enflurane Consumptions and Costs in Low Flow and High Flow Anesthesia / 대한마취과학회지

BACKGROUND: The amount and composition of fresh gas flow affect the consumption of inhalational anesthetics. The purpose of this study was to compare the enflurane consumption and economic aspects of low flow and high flow anesthesia. METHODS: Thirty patients, ASA physical status I or II, aged 20 65 yr., scheduled for gastrectomy under inhalational anesthesia, were studied. The patients were randomly assigned to one of three groups according to the fresh gas flow: O2 500 ml/min (group I); N2O 2 L/min - O2 1 L/min (group II); O2 3 L/min (group III). Anesthesia was maintained in group I by a continuous infusion of liquid enflurane into the inspiratory limb of the breathing circuit, using a syringe pump. In groups II and III, enflurane was administered by a conventional vaporizer. The cumulative dose of liquid enflurane was measured every 10 min during anesthesia. Hemodynamic parameters, inspired and expired enflurane concentrations, and enflurane consumptions were measured. RESULTS: There were no significant differences among the three groups in hemodynamic changes. The enflurane consumption was significantly less in group I than in groups II and III over time (P < 0.05). CONCLUSIONS: Low flow anesthesia offers economic advantages over high flow anesthesia.

Low Flow Anesthesia with Continuous Infusion of Liquid Enflurane into Breathing Circuit / 대한마취과학회지

BACKGROUND: Lowe and Ernst's square root of time model employs direct injection of liquid agent into breathing circuit for low flow anesthesia. Intermittent injections of the agent by Lowe's method change rapidly arterial partial pressure of the agent and fail to maintain hemodynamic stability to surgical stimuli. We designed to investigate the possibility and safety of low flow anesthesia with continuous infusion of liquid enflurane into breathing circuit. METHODS: Twenty patients, ASA physical status I or II, undergoing gastrectomy under inhalational general anesthesia were randomly divided into two groups. Anesthesia was maintained with a fresh gas flow of O2 500 ml/min and continuous infusion of liquid enflurane. An identical semiclosed Dr ger circle anesthesia system was used to all patients. Liquid enflurane calculated by the Lowe's method (group I) or simplified by patient's weight (group II) was continuously infused directly into inspiratory limb of breathing circuit using syringe pump. Inspiratory and expiratory concentrations of enflurane, enflurane consumptions, hemodynamic parameters, carboxyheomoglobin were checked intraoperatively. Hepatic and renal functions were evaluted postoperatively. RESULTS: Liquid enfurane was initially infused at a rate in ml/hr of 16.1 0.8 weight in kg in group I and 1.0 weight in kg in group II. After 5 minutes the infusion rate was reduced to 20% of this value and then well adjusted to maintain blood pressure within 20% of the reference preoperative value. Enflurane consumptions and recovery time were similar between the two groups. There were no clinical significant changes in arterial blood gas, carboxyheomoglobin, and hepatic and renal functions. CONCLUSIONS: These data show that low flow anesthesia with continuous infusion of liquid enflurane into breathing circuit is safe and effective, and that the infusion method simplified by patient's weight may easily be applied to clinical practice for low flow anesthesia.

The Effect of Enflurane Anesthesia on HBs Ag Positive Patients / 대한마취과학회지

To evaluate the importance of enflurane metabolism, we selected eleven hepatitis B surface antigen positive, special antigen, antibody negative patients who were schedule for elective surgery. Their physical status were ASA class I or II, liver function tests shoused normal state, and they had no previous history of operation or liver disease. The result were concluded that the influence of enflurane anesthesia on liver function was not significant for anesthesia & surgery.