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ABSTRACT: Purpose: This study aims to investigate the most appropriate effect-site concentration of remifentanil to minimize cardiovascular changes during inhalation of high concentration desflurane. Materials and Methods: Sixty-nine American Society of Anesthesiologists physical status class I patients aged 20-65 years were randomly allocated into one of three groups. Anesthesia was induced with etomidate and rocuronium. Remifentanil was infused at effect-site concentrations of 2, 4 and 6 ng/mL in groups R2, R4 and R6, respectively. After target concentrations of remifentanil were reached, desflurane was inhaled to maintain the end-tidal concentration of 1.7 minimum alveolar concentrations for 5 minutes (over-pressure paradigm). The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) and end-tidal concentration of desflurane were measured for 5 minutes. Results: The end-tidal concentration of desflurane increased similarly in all groups. The SBP, DBP, MAP and HR within group R4 were not significantly different as compared with baseline values. However, measured parameters within group R2 increased significantly 1-3 minutes after desflurane inhalation. The MAP within group R6 decreased significantly at 1, 2, 4, and 5 minutes (p<0.05). There were significant differences in SBP, DBP, MAP and HR among the three groups 1-3 minutes after inhalation (p<0.05). The incidence of side effects such as hyper- or hypo-tension, and tachy- or brady-cardia in group R4 was 4.8% compared with 21.8% in group R2 and 15.0% in group R6. Conclusion: The most appropriate effect-site concentration of remifentanil for blunting hemodynamic responses by inhalation of high concentration desflurane is 4 ng/mL.
Yonsei medical journal 05/2013; 54(3):739-46. · 0.77 Impact Factor
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ABSTRACT: Clonidine has been shown to be a potent neuroprotectant by acting at α(2) receptors on glutamatergic neurons to inhibit the release of glutamate. The aim of this study is to investigate the effects of clonidine on the activity of EAAT3 that can regulate extracellular glutamate.
EAAT3 was expressed in the Xenopus oocytes. Using a two-electrode voltage clamp, membrane currents were recorded after application of 30 µM L-glutamate both in the presence and absence of various concentrations of clonidine. To determine the effects of clonidine on the K(m) and Vmax of EAAT3 and the reversibility of clonidine effects, membrane currents were recorded after the application of various concentrations of L-glutamate both in the presence and absence of 1.50 × 10(-7) M clonidine.
Clonidine reduced the EAAT3 responses to L-glutamate in a concentration-dependent manner. This inhibition was statistically significant at higher concentrations than at the clinically relevant range. Clonidine at 1.50 × 10(-7) M reduced the Vmax, but did not affect the K(m) of EAAT3 for L-glutamate.
These results suggest that the direct inhibition of EAAT3 activity is not related to the sedation effect of clonidine and that the clonidine-induced reduction of EAAT3 activity provides additional data for the possible involvement of glutamatergic hyperactivity in the proconvulsant effect of clonidine.
Korean journal of anesthesiology 03/2012; 62(3):266-71.
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ABSTRACT: The purpose of this study was to evaluate the effect of the addition of 5 mg dexamethasone to 10 ml of 0.5% levobupivacaine on postoperative analgesic effects of ultrasound guided-interscalene brachial plexus block (ISBPB) in arthroscopic shoulder surgery under general anesthesia.
In 60 patients scheduled for arthroscopic shoulder surgery that underwent general anesthesia, ISBPB was preoperatively performed with 10 ml of 0.5% levobupivacaine under the guidance of ultrasound and a nerve stimulator. Patients were randomly allocated to receive the same volume of normal saline (Group I), 5 mg of dexamethasone (Group II), or 1 : 400,000 epinephrine (Group III) as an adjuvant to the mixture. A blind observer recorded total analgesic consumption, sleep quality, complication, and patient satisfaction using a verbal numerical rating scale (VNRS) at 0, 1, 6, 12, 24, 48 h after the operation.
All patients had successful ISBPB and excellent analgesic effects less than VNRS 4 up to discharge time. VNRS in Group II at 12 h and 48 h was statistically much lower than in Group I and III. There were no differences in total analgesic consumption, sleep quality, complications, and patient satisfaction.
We conclude that the addition of 5 mg of dexamethasone to 10 ml of 0.5% levobupivacaine in ISBPB showed improvement of postoperative analgesia for arthroscopic shoulder operation without any specific complications.
Korean journal of anesthesiology 02/2012; 62(2):130-4.
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ABSTRACT: Benzodiazepines have a hypnotic/sedative effect through the inhibitory action of γ-aminobutyric acid type A receptor. Flumazenil antagonizes these effects via competitive inhibition, so it has been used to reverse the effect of benzodiazepines. Recently, flumazenil has been reported to expedite recovery from propofol/remifentanil and sevoflurane/remifentanil anesthesia without benzodiazepines. Endogenous benzodiazepine ligands (endozepines) were isolated in several tissues of individuals who had not received benzodiazepines.
Forty-five healthy unpremedicated patients were randomly allocated to either flumazenil or a control groups. Each patient received either a single dose of 0.3 mg of flumazenil (n = 24) or placebo (n = 21). After drug administration, various recovery parameters and bispectral index (BIS) values in the flumazenil and control groups were compared.
Mean time to spontaneous respiration, eye opening on verbal command, hand squeezing on verbal command, extubation and time to date of birth recollection were significantly shorter in the flumazenil group than in the control group (P = 0.004, 0.007, 0.005, 0.042, and 0.016, respectively). The BIS value was significantly higher in flumazenil group than in the control group beginning 6 min after flumazenil administration.
Administration of a single dose of 0.3 mg of flumazenil to healthy, unpremedicated patients at the end of sevoflurane/fentanyl anesthesia without benzodiazepines resulted in earlier emergence from anesthesia and an increase in the BIS value. This may indicate that flumazenil could have an antagonistic effect on sevoflurane or an analeptic effect through endozepine-dependent mechanisms.
Korean journal of anesthesiology 01/2012; 62(1):19-23.
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ABSTRACT: There have been some conflicting reports showing that muscle relaxants and anticholinesterases affect the level of the bispectral index (BIS). The purpose of this study was to investigate whether pyridostigmine affects the level of the BIS during recovery from sevoflurane anesthesia.
Fifty-two adult patients scheduled for laparoscopic cholecystectomy and laparoscopic appendectomy. Anesthesia was induced with thiopental 4 mg/kg and rocuronium 0.6 mg/kg. The lung was mechanically ventilated with 1-3 vol% sevoflurane, 50% oxygen and 50% nitrous oxide. After a specimen was removed, the sevoflurane concentration was maintained at 1.5 vol%. When skin closure began, sevoflurane was stopped; however, 50% oxygen and 50% nitrous oxide were maintained. The patients then received either (1) a group that received an injection of glycopyrrolate 0.04 mg/kg and pyridostigmine 0.2 mg/kg (reverse (R) group, n = 26) or (2) a group that received normal saline (control (C) group, n = 26). Group assignment was random. Pyridostigmine, a reversible cholinesterase inhibitor, is a parasympathomimetic. End-tidal sevoflurane concentration, train of four (TOF) ratio, bispectral index (BIS), blood pressure and heart rate were measured from the end of the operation to 15 min after inject of pyridostigmine or placebo.
There were no significant between group differences in the time dependent decrease in end-tidal sevoflurane concentration (P = 0.0642). There were significant differences between the two groups for the time course for increases in the TOF value (P < 0.0001). There were significant differences between the two groups for the time course for increases in the BIS value (P = 0.0107). There were no significant differences in the mean BIS value up to 10 minutes after administering drug, but 15 minutes after administrating the reverse drug or the control drug, the BIS value showed significantly different BIS values: 68.2 ± 6.2 (Group R) and 63.2 ± 6.2 (Group C) (P = 0.0058).
The finding that pyridostigmine increases TOF and BIS suggests that pyridostigmine may enhance recovery during recovery from sevoflurane anesthesia.
Korean journal of anesthesiology 12/2011; 61(6):460-4.
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ABSTRACT: Bladder perforation during laparoscopy is a recognized, uncommon complication. We present two cases of bladder perforation during laparoscopic gynecologic operations that were detected by gaseous distention of the urinary bag. Bladder perforation occurred through laparoscopic division of adhesion. One bladder perforation was repaired laparoscopically, and the other case was repaired by laparotomy during the same general anesthesia. In this report, we present evidence that monitoring a gas-distended urinary bag during a laparoscopic procedure can help detect intraoperative bladder perforation.
Korean journal of anesthesiology 04/2011; 60(4):282-4.
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ABSTRACT: The sniffing position is recommended for conventional laryngeal mask airway (LMA) insertion. However, there has been a high success rate of LMA insertion with the head in the neutral position. The effect of a difficult airway on the ease of LMA insertion is not clear. In this study, we compared the ease of LMA ProSeal™ (PLMA) insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway.
After obtaining informed consent from the subjects, we enrolled 144 adult patients (age range: 18-65) with an ASA physical status 1 or 2. After evaluation of the airway, all the patients were grouped into the EA (easy airway) group (n = 68) and the DA (difficult airway) group (n = 76). According to the head position, each group was divided into the EA-SE (extension) group (n = 35), the EA-SN (sniffing) group (n = 33), the DA-SE group (n = 39) and the DA-SN group (n = 37). The success rate and insertion time at the first attempt were evaluated. The position of the PLMA was fiberoptically scored from the mask aperture of the airway tube in the original head position. After the head position was changed to the sniffing and neutral positions in the SE and SN group, respectively, the position of PLMA was re-evaluated fiberoptically.
The success rate and insertion time at the first attempt and the fiberoptic score showed no significant difference among the groups. After head position was changed, there were no significant changes in the fiberopitc scores.
A difficult airway and the head position had no influence on the ease of PLMA insertion and the fiberopic score. Therefore, the head position can be selected according to the individual patient's situation.
Korean journal of anesthesiology 04/2011; 60(4):244-9.
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ABSTRACT: Fat embolism syndrome is a rare and potentially lethal complication most commonly seen in long bone fractures and intramedullary manipulation. The clinical triad of fat embolism syndrome consists of mental confusion, respiratory distress, and petechiae. This study reports a case of cerebral fat embolism syndrome following elective bilateral total knee replacement. After an uneventful anesthesia and initial recovery, the patient developed neurologic symptoms nine hours postoperatively.
Korean journal of anesthesiology 12/2010; 59 Suppl:S207-10.
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ABSTRACT: Evidence suggests that glutamatergic systems may be involved in the pathophysiology of major depression and the mechanism of action of antidepressants. We have investigated the effects of amitriptyline, a tricyclic antidepressant, on the activity of the excitatory amino acid transporter type 3 (EAAT3), a protein that can regulate extracellular glutamate concentrations in the brain.
EAAT3 was expressed in Xenopus oocytes. Using a two-electrode voltage clamp, membrane currents were recorded after application of 30 microM L-glutamate in the presence or absence of various concentrations of amitriptyline or after application of various concentrations of L-glutamate in the presence or absence of 0.64 microM amitriptyline.
Amitriptyline concentration-dependently reduced EAAT3 activity. This inhibition reached statistical significance at 0.38-1.27 microM amitriptyline. Amitriptyline 0.64 microM reduced the pharmacokinetic parameter Vmax, but did not affect the pharmacokinetic parameter Km, of EAAT3 for L-glutamate. The amitriptyline inhibition disappeared after a 4-min washout. Phorbol-12-myristate-13-acetate, a protein kinase C activator, increased EAAT3 activity. However, 0.64 microM amitriptyline induced a similar degree of decrease in EAAT3 activity in the presence or absence of phorbol-12-myristate-13-acetate.
Our results suggested that amitriptyline at clinically relevant concentrations reversibly reduced EAAT3 activity via decreasing its maximal velocity of glutamate transporting function. The effects of amitriptyline on EAAT3 activity may have represented a novel site of action for amitriptyline to increase glutamatergic neurotransmission. Protein kinase C may not have been involved in the effects of amitriptyline on EAAT3.
Journal of Pharmacy and Pharmacology 06/2009; 61(5):577-81. · 2.17 Impact Factor
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ABSTRACT: Patient response to laryngeal mask airway insertion during propofol induction depends on many factors. Lidocaine has been used to reduce cardiovascular responses, coughing, and bucking induced by tracheal intubation. The aim of this study was to determine the effects of intravenous lidocaine on laryngeal mask airway insertion conditions during the induction of anaesthesia with propofol target-controlled infusion.
Eighty patients, 16-54 years of age, weighing between 45 and 100 kg, who underwent minor surgery, were randomly divided into two groups (the lidocaine and control groups). Anaesthesia was induced with propofol target-controlled infusion at a target plasma concentration of 6 microg ml. The lidocaine group received 1.5 mg kg of lidocaine 50 s after starting target-controlled infusion and the control group received an equivalent volume of saline. Laryngeal mask airways were inserted when propofol effect-site concentrations reached 2.5 microg ml. Laryngeal mask airway insertion conditions (mouth opening, gagging, coughing, movements, laryngospasm, overall ease of insertion, and hiccups) were assessed, and haemodynamic responses were monitored for 3 min after laryngeal mask airway insertion.
No significant differences were observed between the two groups in terms of haemodynamic responses. However, the lidocaine group showed lower incidences of coughing (5 vs. 22.5%), gagging (25 vs. 55%), and laryngospasm (2.5 vs. 17.5%) (P < 0.05).
Pretreatment with intravenous lidocaine 1.5 mg kg during induction with propofol target-controlled infusion improves laryngeal mask airway insertion conditions.
European Journal of Anaesthesiology 05/2009; 26(5):377-81. · 2.23 Impact Factor
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ABSTRACT: Glutamate transporters, also called excitatory amino acid transporters (EAATs), uptake extracellular glutamate and regulate neurotransmission. Activation of protein kinase C (PKC) increases the activity of EAAT type 3 (EAAT3), the major neuronal EAAT. We designed this study to determine which amino acid residue(s) in EAAT3 may be involved in this PKC effect. Selective potential PKC phosphorylation sites were mutated. These EAAT3 mutants were expressed in the Xenopus oocytes. Phorbol 12-myristate 13-acetate, a PKC activator, significantly increased wild-type EAAT3 activity. Mutation of serine 465 to alanine or aspartic acid, but not the mutation of threonine 5 to alanine, abolished PKC-increased EAAT3 activity. Our results suggest a critical role of serine 465 in the increased EAAT3 activity by PKC activation.
The International journal of neuroscience 01/2009; 119(9):1419-28. · 0.86 Impact Factor
