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

BACKGROUND: The inhalation of high concentrations of desflurane transiently increases the cardiovascular responses. This study examined the effects of age on the cardiovascular response to desflurane. METHODS: Eighty two patients were divided into one of three groups: under 3 years (Group 1), 2050 years (Group 2), and over 65 years (Group 3). In each group, the inspired concentration of desflurane was increased abruptly to 12.0 vol% 2 minutes after a thiopental injection. The heart rate, blood pressure (BP), cardiac index (CI), End-tidal concentration of desflurane (ETdesf), and end-tidal concentration of CO2 were measured at the baseline and every 30 seconds. RESULTS: The heart rate, BP, and CI increased transiently in the three groups compared with the baseline. The ETdesf increased more rapidly in Groups 1 and 3 than in Group 2. The ETdesf to reach the maximal mean arterial pressure (MAP) was highest in Group 3 among three groups. The relative maximal HR to the baseline value was similar in the three groups, but the relative maximal MAP to baseline value was significantly highest in the elderly patient group. The times to reach the maximal HR and BP were shortest in Group 1 among three groups. There were no significant differences in the CI between three groups. CONCLUSIONS: The inhalation of a high concentration of desflurane increases the HR, BP and CI transiently in all age groups. In pediatric patients, HR and BP increases more rapidly than in young adults and elderly patients. The relative maximal MAP to the baseline value is higher in elderly patients.

Intraventricular Hemorrhage during Cesarean Section under General Anesthesia: A case report / 대한마취과학회지

An intracranial hemorrhage is a fatal complication associated with general anesthesia. It can occur in patients with an intracranial aneurysm, hypertension, cerebral vascular malformation, and blood dyscrasia, etc. A sudden hemodynamic change during intubation and extubation in general anesthesia is dangerous, particularly in these patients. We encountered an intraventricular hemorrhage in a 42 year old pregnant woman after a cesarean section. The patient was induced with 300 mg of thiopental and 45 mg of rocuronium. The anesthesia was maintained with N2O/O2 and sevoflurane after endotracheal intubation. Five hours after surgery, the patient had a seizure at the ward. A MRI and CT scan of the brain showed a right intraventricular and basal ganglia hematoma. The CT 3-D brain angiography showed an unruptured small aneurysm on the right posterior communicating artery.

Hydrothorax Detected at Postanesthetic Care Unit after Percutaneous Nephrolithotomy: A case report / 대한마취과학회지

Percutaneous nephrolithotomy (PCNL) is a well-established procedure for treating nearly all types of stones in the kidneys and middle-to-upper ureters. In addition, PCNL is less invasive, and provides safe results comparable to open surgery. However, there is risk of an increased risk of thoracic complications when performing a puncture above the 12 th rib to optimize kidney access. We experienced a 30-years-old female who had oxygen desaturation and complained dyspnea and chest pain at the postanesthetic care unit after percutaneous nephrolithotomy. Therefore, patients undergoing percutaneous renal manipulation need to be monitored for pulmonary complications during and after the procedure.

Comparison of Desflurane-induced Circulatory Responses by the Rate of Increase in Inhaled Desflurane Concentration / 대한마취과학회지

BACKGROUND: A rapid increase in desflurane concentration induces tachycardia and hypertension and increases plasma catecholamine concentration. No clinical study is available as to whether the desflurane-induced circulatory responses is blunted by the rate of increase in inhaled desflurane concentration although there were many studies about methods to blunt the circulatory responses. The current study examined to compare desflurane-induced circulatory responses by the rate of increase in inhaled desflurane concentration. METHODS: Unpremedicated sixty ASA physical status 1 patients, aged 20-60 years, scheduled for elective surgery under general anesthesia were randomly allocated into one of two groups. The inspired concentration of desflurane via mask was increased to 12.0 vol% abruptly (group 1), or during 120 seconds (group 2). The target was to produce an end-tidal concentration of desflurane (ETdesf) of 10.0 vol% which was maintained until the end of the study by adjusting the vaporizer setting, when necessary. Heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), systemic vascular resistance (SVR), ETdesf, end-tidal concentration of carbon dioxide, and peripheral oxygen saturation were measured at baseline and every 30 seconds for 5 minutes after inhalation of desflurane and for 2 minutes after intubation. RESULTS: HR, blood pressure, and CI were significantly increased in two groups compared with baseline, but significant differences in maximum values were not observed between two groups. There were no significant differences between groups of the ETdesf at the maximal HR and MAP. Incidences of hypertension and tachycardia were lesser in slowly increased inhaled desflurane concentration (group 2) than abruptly increased group (group 1). CONCLUSIONS: The present study demonstrates that increasing inhaled desflurane concentration slowly for mask ventilation is partially effective in attenuating desflurane-induced circulatory responses.

Application of One Lung Ventilation in the Detection of Pulmonary Embolism during Operation / 대한마취과학회지

Intraoperative pulmonary thromboembolism (PTE) is rare, but is nevertheless one of the important causes of morbidity and mortality in patient undergoing surgery. However, The detection of PTE is difficult because it's clinical symptoms and signs are nonspecific during surgery, and specialized diagnostic tools are not readily available in the operating room. We report a case of PTE due to cancer emboli with thrombi encountered during a nephrectomy in patient with renal cell cancer, and demonstrate that one-lung ventilation can aid in the diagnosis of massive PTE when the evaluation is suspected.

The Effects of Measurement Time and Blood Temperature on Thromboelastographic Parameters / 대한마취과학회지

BACKGROUND: Thromboelastography (TEG) measures the viscoelastic properties of clotting blood, displaying a visual trace of all phases of coagulation and fibrinolysis. When performing a TEG, it is commonly recommended to store whole blood at 37oC with only a 3-6 min delay after sampling. However, it is difficult to actually keep this recommend time and temperature. The purpose of this study is to investigate the effects on TEG by inadvertent technical errors due to inappropriate measurement time and temperature. METHODS: Twenty healthy male volunteers were studied. TEG measurements were performed at: stat, 4 min, and 8 min at room temperature, and 4 min and 8 min at 37 degrees C. Parameters used were: reaction time (R), clot formation time (K), maximal amplitude (MA), clot formation velocity (alpha-angle), clot lysis 60 min (LY60) and TEG index. RESULTS: When compared with the routine recommendation, 4 min lag time at 37 degrees C, R and K were shortened and alpha angle and LY60 were increased at 8 min after the sample. However, temperature differences did not significantly affect TEG parameters. CONCLUSIONS: Inappropriate measurement temperature does not result in significant changes of TEG parameters, but, delayed storage resulted in a false hypercoagulation state and increased fibrinolysis.

Comparisons between Etomidate and Thiopental Sodium as an Induction Agent of General Anesthesia in Elderly Patients / 대한마취과학회지

BACKGROUND: This study was designed to determine whether etomidate-based induction can provide better hemodynamics than a standard thiopental sodium-based anesthetic induction in elderly patients. METHODS: Sixty ASA physical status 1 or 2 elderly patients scheduled for elective surgery were randomly allocated into one of three groups (Group 1; thiopental sodium, Group 2; etomidate, Group 3; pre-treatment with 0.02 mg/kg of midazolam and etomidate). We measured and compared hemodynamic changes (mean arterial pressure, heart rate), the doses of thiopental sodium and etomidate for loss of consciousness, the incidence and grade of myoclonus, and the bispectral index during induction of anesthesia. RESULTS: There were no significant differences in mean arterial pressure and heart rate among the three groups. Myoclonus occurred in 45% of patients receiving etomidate, 40% of patients receiving midazolam pre-treatment and etomidate. Pre-treatment of midazolam reduced the dose of etomidate for loss of consciousness by 20% in Group 3. The values of BIS decreased significantly from 1 minute after infusion of thiopental and etomidate, and reached 56.9 +/- 12.3 in group 1, 41.8 +/- 9.1 in group 2, and 45.8 +/- 8.5 in group 3 just before endotracheal intubation. CONCLUSIONS: These results indicate that there is no significant difference between etomidate and thiopental sodium as anesthetic induction agents in elderly patients. Pre-treatment with a small dose of midazolam reduced the dose of etomidate for loss of consciousness, but did not affect the incidence of myoclonus and hemodynamic changes during induction of anesthesia with etomidate.

Traumatic Aortic Regurgitation Caused by Blunt Chest Injury / 대한마취과학회지

Blunt chest trauma can result in significant cardiothoracic injury, which can include a cardiac contusion, aortic injury, and myocardial valvular injury. Traumatic aortic regurgitation is an uncommon consequence of closed chest injury. Isolated aortic valvular injury following blunt chest trauma is difficult to diagnose in a patient with multiple injuries. We report a case of traumatic aortic regurgitation which was detected just before anesthesia induction in the operating room. This report is presented to emphasize the possibility of aortic regurgitation and the need for careful evaluation of the cardiac status in patients with blunt chest trauma.

Effects of Propofol on the Cytosolic Calcium Concentration of the Astrocytoma Cells / 대한마취과학회지

BACKGROUND: Propofol is a widely-used intravenous anesthetic with a rapid onset, short duration of action and rapid elimination but the molecular mechanisms of action are not completely understood. Not only neurons but astrocytes are potential substrates for anesthetics, specifically for propofol. Intracellular calcium ion ([Ca2 ]i) is known to play a key role in the transduction and propagation of various chemical signals in astrocytes. METHODS: In the present study, the effects of propofol on the intracellular calcium concentration of astrocytoma cells by using a fura-2 fluorescence spectroscopy was investigated. RESULTS: In an isotonic standard solution, propofol (50 and 500microM) produced a transient increase in [Ca2 ]i while the intralipid did not change [Ca2 ]i. In several cells (20%), a transient increase in [Ca2 ]i was followed by sustained elevation which was sensitive to depletion of external calcium. A propofol-induced increase in [Ca2 ]i was not altered by an L-type calcium channel blocker (nifedipine 2microM). In cells bathed in a Ca2 -free external solution, a transient increase in [Ca2 ]i was observed. After the pretreatment of cyclopiazonic acid (CPA), an endoplasmic reticulum Ca2 -ATPase blocker, propofol 500microM did not produce any significant increase in [Ca2 ]i. Carbachol, which is known to release calcium from the inositol 1,4,5-triphosphate (IP3)-induced calcium release (IICR) stores, prevented the [Ca2 ]i increase by propofol and vice versa. High concentrations of caffeine (10 mM), which release calcium from the calcium-induced calcium release (CICR) stores, had no effect on [Ca2 ]i. CONCLUSIONS: From the above results, it is suggested that an increase in [Ca2 ]i by propofol in astrocytoma cells is mainly due to calcium release from the IICR stores.

Massive Thrombosis after Central Venous Catheterization in a Patient with Previously Undiagnosed Behcet's Disease

Thrombosis is an important complication of central venous catheterization. Among the many intrinsic and extrinsic factors, the patient's medical disease can play a role in thrombogenesis. Behcet's disease (BD), classified as a vasculitis, is a multisystem disease involving the small blood vessels. It is often difficult to recognize and diagnose the disease. A 24-yr-old female patient showed massive central venous thrombosis which caused superior vena cava syndrome after subclavian vein catheterization. Twenty days after catheterization, the patient exhibited swelling of the face, neck, and both upper extremities. Despite thrombectomy and continuous anticoagulation therapy, her facial and upper extremity swelling reappeared and follow-up chest computed tomography (CT) showed the recurrent thrombosis in the same central veins previously affected. A diagnosis of BD was then made. Following steroid therapy, neither clinical symptoms nor CT findings suggestive of central venous thrombosis were observed during the subsequent 6-months of follow-up period. This case emphasizes that central venous catheterization in a patient with BD should be performed with great caution.

A Comparison of Carbon Dioxide Tensions between Arterial Blood and Oxygenator Exhaust Gas during Cardiopulmonary Bypass / 대한마취과학회지

BACKGROUND: Maintenance of adequate concentration of carbon dioxide during hypothermic cardiopulmonary bypass is important in order to improve tissue perfusion by maintaining vasodilatation. This study evaluated the usefulness of the analysis of gas sampled from the exhaust port of a membrane oxygenator in the estimation of carbon dioxide tension in arterial blood (PaCO2). METHODS: One hundred sixty four arterial blood gases were drawn from 45 adult and 30 pediatric cardiac surgical patients undergoing hypothermic cardiopulmonary bypass. Carbon dioxide tensions were measured in the membrane oxygenator exhaust gas (swept gas; PswCO2) using a capnography and in arterial blood using intermittent gas analysis. We compared the PswCO2 with temperature-uncorrected (alpha-stat) and -corrected (pH-stat) PaCO2 during cardiopulmoary bypass. RESULTS: The mean PaCO2 measured with alpha-stat and pH-stat, and PswCO2 obtained in adult patients during hypothermic cardiopulmonary bypass were 29.8 +/- 4.9, 19.5 +/- 4.1 and 22.3 +/- 4.2 mmHg, respectively. In pediatric patients, alpha-stat PaCO2, pH-stat PaCO2 and PswCO2 were 39.7 +/- 7.7, 24.7 +/- 6.2 and 20.3 +/- 6.0 mmHg, respectively. There was a significant positive correlation between PswCO2 and alpha-stat PaCO2 (adult patients: slope = 0.49, r = 0.64, P < 0.001; pediatric patients: slope = 0.53, r = 0.68, P < 0.001) and pH-stat PaCO2 (adult patients: slope = 0.85, r = 0.81, P < 0.001; pediatric patients: slope = 0.73, r = 0.73, P < 0.001). On comparison of subsequent measurements, 3.8% (adult patients) and 11.4% (pediatric patients) of changes in PaCO2 and PswCO2 were in opposite direction. CONCLUSIONS: Our results indicate that in adult and pediatric patients undergoing hypothermic cardiopulmonary bypass PswCO2 can be an indicator of changes in trend of PaCO2.

Effect of Preoperative Fasting Time on Blood Glucose Concentrations in Children / 대한마취과학회지

BACKGROUND: The influence of preoperative starvation on blood glucose concentrations in children remains controversal. This period varies from 6 to 12 hr or even more, in different institutions. A surgical operation causes a rise in the blood glucose concentration, and this increased concentration returns to normal within 8 to 12 hr. The purpose of the present study was to investigate blood glucose concentra tions in children undergoing elective surgery who fasted before anesthesia. METHODS: One hundred sixty-five healthy children, aged less than 7 yr, and scheduled for elective minor surgery were included in the study. Blood samples were collected before induction of anesthesia, after induction of anesthesia and at the recovery room. The correlation between the period of starvation and the blood glucose concentration was estimated and hypoglycaemia was defined as a blood glucose concentration less than 40 mg%. RESULTS: The duration of starvation ranged from 10 to 14 hr in the majority of the patients (66.7%). The duration of starvation beyond 14 hr was 7.8%. No significant correlations were obtained between preoperative blood glucose concentrations and duration of starvation. None of the patients were hypoglycaemia before surgery. The intraoperative and postoperative blood glucose concentrations were significantly higher than the preoperative blood glucose concentration. CONCLUSIONS: In children less than 7 yr, blood glucose concentrations were not influenced by duration of starvation within a 14 time period.

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.

How Long Should a Patient Stay in Lateral Position for Unilateral Spinal Anesthesia with Hyperbaric Bupivacaine? / 대한마취과학회지

BACKGROUND: In searching for a differential spinal block between dependent and nondependent sides, we evaluated the influence of the duration of lateral decubitus on the spread of hyperbaric bupivacaine during spinal anesthesia. METHODS: Spinal anesthesia with 1.2 ml of hyperbaric 0.5% bupivacaine (6 mg) was administered with a 25-gauge Whitacre unidirectional needle to 50 ASA 1 patients undergoing unilateral knee arthroscopy. The patients were allocated randomly to three groups according to the duration of lateral decubitus after spinal injection in the lateral position operation side dependent: Group 1, 10 min in lateral decubitus then supine; Group 2, 20 min in lateral decubitus then supine; Group 3, 30 min in lateral decubitus then supine. Sensory and motor block (pinprick/modified Bromage scale) as well as skin temperature were compared between the dependent and nondependent sides. Circulatory variables were recorded for 10 min after being turned supine. RESULTS: The sensory block between dependent and nondependent sides were significantly different in Group 3. In Group 1, the level of maximum sensory block was higher than Group 3 on nondependent side. There was no difference in the number of patients having achieved Grade 3 and 0 motor block among three groups on dependent and nondependent sides. The skin temperature in lateral decubitus was significantly higher on the dependent side than nondependent side in three groups. In Groups 1 and 2, the skin temperatures of nondependent side were increased after turned supine, but that was maintained during supine position in Group 3. The circulatory variables were stable in all 50 patients. CONCLUSIONS: We conclude that when a small dose of 0.5% hyperbaric bupivacaine is injected into patients in the lateral position, complete unilateral spinal anesthesia is achieved when the patients arekeep in a lateral position for more than 30 min after spinal injection.

How Many Attempts are Needed for Learning Fiberoptic Orotracheal Intubation? / 대한마취과학회지

BACKGROUND: The value of the fiberoptic laryngoscope in difficult tracheal intubation is well established. In recent years there has been a significant interest in and increase in learning this valuable skill by anesthesiologists. This study assesses the minimum number of attempts needed for proficiency in fiberoptic orotracheal intubation. METHODS: Eight anesthesia residents with experience in rigid larygoscopic intubation, but who were beginners in fiberoptic intubation, participated in this study. In a randomized fashion, each resident performed 50 fiberoptic orotracheal intubations. All intubations were performed under general anesthesia and muscle paralysis. Success rate and intubation time of fiberoptic orotracheal intubation and SpO2 were recorded. We have compared success rate with intubation time of fiberoptic orotracheal intubation and grade of laryngoscopic view. RESULTS: The mean success rate of fiberoptic orotracheal intubation was 75% in the first 10 intubations. Thereafter the success rates were higher than 90%. The mean time to achieve successful orotracheal fiberoptic intubation were significantly decreased to 30 attempts. There was no correlation of laryngoscopic grade with intubation time and success rate. No hypoxia occurred in any patient. CONCLUSIONS: We concluded that an acceptable level of technical expertise in fiberoptic orotracheal intubation is achieved after 30 intubation attempts.

In Vitro Evaluation of the Effect of Progressive Hemodilution with Several Solutions on Coagulation Profiles Measured by Thromboelastography / 대한마취과학회지

BACKGROUND: Hemodilution reduces the concentration of clotting factors in blood and it may induce some degree of coagulation impairment. The goal of this study is to investigate the changes of coagulation status during progressive hemodilution with several solutions. METHODS: Sixty healthy patients were randomly allocated to six groups according to experimental solution, and each group contained 10 patients. Whole blood was diluted by 0%, 10%, 25%, 50% with 0.9% normal saline, 4% modified fluid gelatin, 10% pentastarch, 10% dextran 40 and two brands of 6% hydroxyethyl starchs (Salinehes(R) , HAES-steril(R) ). At each dilution, thromboelastographic parameters {(r, k, alpha angle, maximum amplitude (MA)} were measured using thromboelastography (TEG) and were compared with those of an undiluted specimen obtained concurrently from the same patients. RESULTS: Hemodilutions of 25% and 50% with 0.9% normal saline decreased r and k times, and increased alpha angle but there was no difference in MA. Hemodilutions of 10% and 25% with modified gelatin solution did not change the parameters. However, 50% hemodilution of the gelatin solution decreased the k time and increased alpha angle. Hemodilutions of more than 10% with 10% pentastarch increased the k time, decreased alpha angle and MA. Hemodilutions of more than 10% with 10% dextran 40 increased r and k times, and decreased alpha angles and MA according to the quantities of this dilutional solution. Hemodilutions of more than 25% with 10% dextran 40 increased k times above 400%. Hemodilutions of more than 10% of 6% HES (Salinehes(R) , M.W: 70,000 dalton) decreased MA. Hemodilutions of more than 10% of 6% HES (HAES-steril(R) , M.W: 200,000 dalton) decreased the alpha angle. CONCLUSIONS: 25% and 50% hemodilutions of 0.9% normal saline induce a hypercoagulable state, but hemodilutions of more than 10% with each colloid solution decreased coagulability of whole blood according to the degree of dilution, except in the case of modified fluid gelatin solution. Hemodilutions of more than 25% with 10% dextran 40 induce a severe coagulation impairment.

Evaluation of the Technique of Central Venous Catheterization via the External Jugular Vein / 대한구급학회지

BACKGOUND: This study was designed to evaluate the effectiveness and feasibility of central venous catheterization via the external jugular vein (EJV). We compared the success rate of left and right EJV catheterization. The influence of the course of left and right external jugular vein on success rate was investigated also. METHODS: Eighty anesthetized adult surgical patients were studied consecutively. Patients were allocated to left or right EJV catheterization and measured the angles between EJV and clavicle and transverse shoulder line. Catheterization was performed under sterile conditions by Seldinger technique after angiography of EJV and subclavian vein. We analyzed the relationship between the angles and success rate and time for catheterization. We compared the success rate of left and right EJV catheterization. RESULTS: The overall rate of intrathoracic placement was 74 from 80 catheterization (92.5%). Analysis of success in left and right EJV catheterization did not reveal statistically significant differences. The success rates did not show any correlation with course of EJV. Complications were few and not serious. CONCLUSIONS: This study indicated that left and right EJVs were good routes for central venous catheterizationan with acceptably high success rate. However, we could not find the predictor of success for central venous catheterization via EJV.

The Effects of the Rate of Increase in Inhaled Isoflurane Concentration on the Circulatory Responses / 대한마취과학회지

BACKGROUND: A rapid increase in isoflurane concentration induces tachycardia and hypertension and increases plasma catecholamine concentration. The current study examined the effects of the rate of increase in inhaled isoflurane concentration on the circulatory responses. METHODS: Unpremedicated sixty three ASA physical status 1 patients, aged 20-40 years, scheduled for elective surgery under general anesthesia were randomly allocated into one of three groups. In each group, the inspired concentration of isoflurane via mask was increased up to 5 vol% at the rate different from other groups. The inspired concentration of isoflurane via mask was increased to 5.0 vol% abruptly (group 1), for 100 seconds (group 2), or 200 seconds (group 3). 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. Heart rate (HR), mean arterial pressure (MAP), ETisof, end-tidal concentration of carbon dioxide, and peripheral oxygen saturation 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 were significantly increased in all three groups compared with baseline, but significant differences in maximum values were not observed in three groups. There were significant differences among the groups in time from the onset of isoflurane inhalation to the maximal effect on HR and MAP. However, there were no significant differences among the groups of the ETisof at the maximal HR and MAP were seen. CONCLUSIONS: The high concentration of isoflurane transiently increase HR and MAP during inhaled anesthesia induction. However, the rate of increase in inhaled isoflurane concentration does not affect the circulatory responses.

The Effects of Forebrain Ischemia on Lidocaine-Induced Seizure Threshold in the Rat / 대한마취과학회지

BACKGROUND: Seizures are common following many cerebral insults, include global and focal ischemia. However, while the mechanism must relate to some change in the relative activities of excitatory and inhibitory pathway, the specific alterations in neurotransmitter concentrations and/or receptor sensitivities which underlie these events, remain unknown. The principal aim of this study was therefore to evaluate the effects of moderately severe forebrain ischemia on lidocaine-induced seizure thresholds, in hopes of gaining some insights into these processes. METHODS: Halothane-anesthetized, normothermic Sprague-Dawley rats were chronically instrumented with screw electrodes and vascular catheters, and were then subjected to 10 min of forebrain ischemia, produced by bilateral carotid occlusion combined with hypotension (MAP = 30 mmHg). After reperfusion, animals were awakened. 6, 24 and 46 hours later, separate groups of awake animals were subjected to intravenous infusion of lidocaine at the rate of 2.6 mg/kg/min. The total dose of lidocaine infused prior to generalized tonic-clonic seizures were noted. Another group of Sham animals (no ischemia) served as control. RESULTS: The lidocaine-induced seizure threshold was significantly increased at 24 h after forebrain ischemia (65.39 12.9 mg/kg vs 36.47 4.24 mg/kg, P < 0.05). Interestingly, at 6 h post-ischemia, rats treated with lidocaine consistently died before seizures. There were no significant differences in seizure threshold between the control and 48 h post-ischemia groups. CONCLUSIONS: Ten minutes of forebrain ischemia is followed by a transient increase in the seizure threshold to infused lidocaine. By 48 h following reperfusion, lidocaine induced seizure threshold had returned to normal.

Effects of Nasopharyngeal Airway on Incidence of Epistaxis and Ease of Tube Advancement duirng Nasotracheal Intubation / 대한마취과학회지

BACKGROUND: When the insertion of endotracheal tube (ETTs) though the nostril, the tube may be encountered some resistance. Forcing ETTs into the nasal cavity develope mucosal and soft tissue injuries and subsequent epistaxis during passage of the tube even when vasoconstictor and/or lubricant tube are employed. Therefore, We determined whether nasopharyngeal airway (NPA) insertion reduces the incidence of epistaxis and increase the ease of the tube advancement in the nasal cavity during nasotracheal intubation. METHODS: Two hundred adult patients who schesuled for elective surgery were divided into two groups, control (n=100), and NPA (n=100). The NPA insertion group received an armored tube after nasoparyngeal airway inserts, while control group received a plain armored tube. All patients in both groups was inserts ETTs by conventional nasotracheal insertion techniques. RESULT: The NPA insertion group had a significantly low incidence of epistaxis (11%) than control group (34%) (p<0.05). But, provided not easier passage during nasotracheal intubation than control group. CONCLUSION: We conclude that nasophryngeal airway reduces the incidence of epistaxis during nasotracheal intubation, but not to increase easy passage of the tube advancement.