Effects of High Thoracic Epidural Anesthesia on Cerebral Blood Flow and Hippocampal Apoptosis during Global Cerebral Ischemia and Reperfusion in Rats / 现代生物医学进展

Objective:To investigate the effects of high thoracic epidural anesthesia (HTEA) on the cerebral blood flow (CBF) and hippocampal apoptosis-related proteins Bcl-2 and Bax during global cerebral ischemia and reperfusion (GCI) in rats.Methods:Fifteen-minute global ischemia was established by 4-vessel occlusion and epidural catheterization was performed through T4-5 intervertebral spaces in adult male Wistar rats.According to the different drugs infused into the epidural space,the rats were randomly divided into four groups:Sham group (0.9 ％ NaC1),Sham-HTEA group (0.25 ％ bupivacaine),GCI group (global cerebral ischemia,0.9 ％ NaC1) and HTEA group (global cerebral ischemia,0.25 ％ bupivacaine).And 0.25 ％bupivacaine or 0.9 ％ saline (20 μL·h-1) was infused continuously to the thoracic epidural space from 15 minutes before ischemia to 24 hours after reperfusion.Mean arterial pressure (MAP),heart rate (HR) and cerebral blood flow (CBF) were determined until 2 hours after reperfusion,and the hippocampal Bcl-2 and Bax proteins at 24 hours after reperfusion were examined by Western-blot.Results:Compared with the GCI group,HTEA group has no significant difference on MAP and HR during ischemia and 2 hours after reperfusion,andcompared with the Sham group,MAP in GCI group increased in ischemia 0 min and decreased in reperfusion 0 min.The CBF in HTEA group was significantly lower than that in GCI group (123.1％± 35.2％ vs 177.5％± 32.4％,P＜0.01) in reperfusion 10 min,and higher than that in GCI group during the hypoperfusion of 60 to 120 minutes after reperfusion (P＜0.05),and the ratio of Bax/Bcl-2 in hippocampus was significantly decreased in HTEA group 24 hours after reperfusion (P＜0.01).Conclusions:Continuous HTEA infusion of 0.25 ％ bupivacaine 20 μL ·h-1 could maintain the hemodynamic stability,and improve the CBF of hypoperfusion period in rats,as well as reduce the ratio of Bax/Bcl-2 at 24 hours after reperfusion.

Non-intubated thoracoscopic surgery for decortication of empyema under thoracic epidural anesthesia: a case report / 대한마취과학회지

General anesthesia is the main strategy for almost all thoracic surgeries. However, a growing body of literature has reported successful cases of non-intubated thoracic surgery with regional anesthesia. This alternative strategy not only prevents complications related to general anesthesia, such as lung injury, incomplete re-expansion and intubation related problems, but also accords with trends of shorter hospital stay and lower overall costs. We experienced a successful case of non-intubated thoracoscopic decortication for a 68-year-old man who was diagnosed as empyema while the patient kept spontaneously breathing with moderate sedation under thoracic epidural anesthesia. The patient showed a fast recovery without concerns of general anesthesia related complications and effective postoperative analgesia through thoracic epidural patient-controlled analgesia device. This is the first report of non-intubated thoracoscopic surgery under thoracic epidural anesthesia in Korea, and we expect that various well designed prospective studies will warrant the improvement of outcomes in non-intubated thoracoscopic surgery.

Is there any benefit in associating neuraxial anesthesia to general anesthesia for coronary artery bypass graft surgery? / Existe algum benefício em associar a anestesia neuroaxial à anestesia geral para revascularização miocárdica?

ABSTRACT BACKGROUND AND OBJECTIVES: The use of neuraxial anesthesia in cardiac surgery is recent, but the hemodynamic effects of local anesthetics and anticoagulation can result in risk to patients. OBJECTIVE: To review the benefits of neuraxial anesthesia in cardiac surgery for CABG through a systematic review of systematic reviews. CONTENT: The search was performed in Pubmed (January 1966 to December 2012), Embase (1974 to December 2012), The Cochrane Library (volume 10, 2012) and Lilacs (1982 to December 2012) databases, in search of articles of systematic reviews. The following variables: mortality, myocardial infarction, stroke, in-hospital length of stay, arrhythmias and epidural hematoma were analyzed. CONCLUSIONS: The use of neuraxial anesthesia in cardiac surgery remains controversial. The greatest benefit found by this review was the possibility of reducing postoperative arrhythmias, but this result was contradictory among the identified findings. The results of findings regarding mortality, myocardial infarction, stroke and in-hospital length of stay did not show greater efficacy of neuraxial anesthesia.

RESUMO JUSTIFICATIVA E OBJETIVOS: O uso da anestesia neuroaxial em cirurgia cardíaca é recente, porém os efeitos hemodinâmicos dos anestésicos locais e a anticoagulação podem trazer riscos aos pacientes. OBJETIVO: Revisar os benefícios da anestesia neuroaxial em cirurgia cardíaca para revascularização miocárdica por meio de uma revisão sistemática de revisões sistemáticas. CONTEÚDO: Foi feita pesquisa nas bases de dados Pubmed (de janeiro de 1966 a dezembro de 2012), Embase (1974 a dezembro 2012), The Cochrane Library (volume 10, 2012) e Lilacs (1982 a dezembro de 2012) em busca de artigos de revisões sistemáticas. Foram analisadas as seguintes variáveis: mortalidade, infarto do miocárdio, acidente vascular cerebral, tempo de internação hospitalar, arritmias e hematoma peridural. CONCLUSÕES: O uso da anestesia neuroaxial para revascularização miocárdica permanece controverso. O maior benefício encontrado por meio desta revisão foi a possibilidade de redução das arritmias pós-operatórias, porém esse resultado foi contraditório entre as evidências identificadas. Os resultados das evidências encontradas referentes à mortalidade, ao infarto do miocárdio, ao acidente vascular cerebral e ao tempo de internação hospitalar não mostraram maior efetividade da anestesia neuroaxial.

Analysis of thoracic epidurography and correlating factors affecting the extent of contrast medium spread

BACKGROUND: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. METHODS: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. RESULTS: The mean number of vertebral segments evaluated by contrast medium was 7.9 ± 2.2 using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = −0.311, P < 0.05). CONCLUSIONS: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of 7.9 ± 2.2 spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

Analysis of thoracic epidurography and correlating factors affecting the extent of contrast medium spread

BACKGROUND: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. METHODS: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. RESULTS: The mean number of vertebral segments evaluated by contrast medium was 7.9 ± 2.2 using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = −0.311, P < 0.05). CONCLUSIONS: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of 7.9 ± 2.2 spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

Anesthesia for off-pump coronary artery bypass surgery.

The evolution of techniques and knowledge of beating heart surgery has led anesthesia toward the development of new procedures and innovations to promote patient safety and ensure high standards of care. Off-pump coronary artery bypass (OPCAB) surgery has shown to have some advantages compared to on-pump cardiac surgery, particularly the reduction of postoperative complications including systemic inflammation, myocardial injury, and cerebral injury. Minimally invasive surgery for single vessel OPCAB through a limited thoracotomy incision can offer the advantage of further reduction of complications. The anesthesiologist has to deal with different issues, including hemodynamic instability and myocardial ischemia during aorto-coronary bypass grafting. The anesthesiologist and surgeon should collaborate and plan the best perioperative strategy to provide optimal care and ensure a rapid and complete recovery. The use of high thoracic epidural analgesia and fast-track anesthesia offers particular benefits in beating heart surgery. The excellent analgesia, the ability to reduce myocardial oxygen consumption, and the good hemodynamic stability make high thoracic epidural analgesia an interesting technique. New scenarios are entering in cardiac anesthesia: ultra-fast-track anesthesia with extubation in the operating room and awake surgery tend to be less invasive, but can only be performed on selected patients.

Thoracic epidural anesthesia for modified radical mastectomy in a patient with diffuse systemic sclerosis: A case report

Systemic sclerosis is a systemic autoimmune disease. It is characterized by deposition of collagen in skin, blood vessels and internal organs. Systemic sclerosis can cause skin, cardiovascular, pulmonary, gastrointestinal, renal and other complication. A 42 year old woman with systemic sclerosis and breast cancer was scheduled for modified radical mastectomy under thoracic epidural anesthesia because of exertional dypnea, decreased diffusion lung capacity and Raynaud's phenomenon. There was no dyspnea or significant hemodynamic change during operation under epidural anesthesia. She discharged 12 days after operation without complications.

Effect of thoracic epidural anesthesia on oxygen delivery and utilization in cardiac surgical patients scheduled to undergo off-pump coronary artery bypass surgery: A prospective study.

To evaluate the effect of thoracic epidural anesthesia (TEA) on tissue oxygen delivery and utilization in patients undergoing cardiac surgery. This prospective observational study was conducted in a tertiary referral heart hospital. A total of 25 patients undergoing elective off-pump coronary artery bypass surgery were enrolled in this study. All patients received thoracic epidural catheter in the most prominent inter-vertebral space between C7 and T3 on the day before operation. On the day of surgery, an arterial catheter and Swan Ganz catheter (capable of measuring cardiac index) was inserted. After administering full dose of local anesthetic in the epidural space, serial hemodynamic and oxygen transport parameters were measured for 30 minute prior to administration of general anesthesia, with which the study was culminated. A significant decrease in oxygen delivery index with insignificant changes in oxygen extraction and consumption indices was observed. We conclude that TEA does not affect tissue oxygenation despite a decrease in arterial pressures and cardiac output.

The effects of TIVA combined epidural anesthesia and postoperative epidural analgesia on cellular immune function and erythrocytes glycometabolism in the patients undergoing thoracic surgery / 临床麻醉学杂志

Objective To investigate the effects of thoracic epidural anesthesia and analgesia on cellular immune function and erythrocytes glycometabolism in the patients undergoing thoracic surgery.Methods Forty esophageal carcinoma patients,classified as ASA Ⅰ or Ⅱ,scheduled for elective thoracic surgery were randomly divided into two groups with 20 cases each：group A underwent general anesthesia plus thoracic epidural anesthesia （TEA） during thoracic surgery and received patient-controlled epidural analgesia （PCEA） with fentanyl and ropivacaine postoperatively;group B received general anesthesia during thoracic surgery and patient-controlled intravenous analgesia （PCIA） postoperatively. Venous blood samples were collected for the measurement of Th1,Th2 and the activities of PFK,G-6PD and AR before the induction（T0）,2 h after the initiation of the incision（T1）,and 4 h（T2）,24 h（T3）and 48 h（T4）after surgery. Results The Th1/Th2 ratio in both groups were decreased significantly after completion of surgery compared with baseline levels （P0.05）. At T2,T3 and T4 the Th1/Th2 ratio in group A were higher than group B. Compared with these before operation,the activity of PFK was decreased significantly and the activities of G-6PD and AR in erythrocytes were increased markedly at T3 in group B（P0.05）.But erythrocytes PFK,G-6PD and AR activity slightly changed in group A.Conclusion These findings show that thoracic epidural anesthesia and PCEA may inhibit Th0 cells to differentiate into Th2 cells,protect cellular immune function and moderate erythrocyte glucose metabolism changes.

Thoracic epidural anesthesia attenuates hemorrhagic-induced splanchnic hypo-perfusion in post-resuscitation experimental hemorrhagic shock.

The purpose of present study was to assess the effects of thoracic epidural anesthesia on splanchnic perfusion, bacterial translocation and histopathologic changes in experimental hemorrhagic shock in short-tailed macaques (Macaca nemestrina). Sixteen Macaca nemestrinas were randomly assigned to one of two groups i.e. the lidocaine group (n = 8), receiving general anesthesia plus lidocaine thoracic epidural anesthesia; and the saline group (n = 8), receiving general anesthesia alone as control. Hemorrhagic shock was induced by withdrawing blood gradually to a mean arterial pressure (MAP) of 40 mm Hg, and maintained for 60 minutes. Animals were then resuscitated with their own blood and ringer lactate solution (RL). After resuscitation, epidural lidocaine 2% was given in the lidocaine group and saline in the control group. Resuscitation that was performed after one hour hemorrhagic shock, with hemodynamic variables and urine output returned to normal, revealed there was no improvement of splanchnic perfusion. PgCO2, P(g-a)CO2, and pHi remained in critical value and tended to deteriorate in the saline group. Contrast to saline group, splanchnic perfusion in lidocaine group tended to improve. This condition was supported by the finding of less bacterial translocation and better histopathologic changes in lidocaine thoracic epidural anesthesia group than in saline group. This study concludes that lidocaine thoracic epidural anesthesia attenuates splachnic hypoperfusion in post-resuscitation hemorrhagic shock in Macaca nemestrina.

Effects of thoracic epidural anesthesia on hemodynamic changes during tracheal intubation / 대한마취과학회지

BACKGROUND: We sought to assess whether increasing a single dose of 1.5% lidocaine during thoracic epidural anesthesia (TEA) could suppress hemodynamic responses after laryngoscopy and tracheal intubation. METHODS: A total of 81 patients (ASA physical status I and II, aged 45-75) who scheduled for major abdominal surgery were enrolled. Patients were randomly assigned to three groups, for epidural injection of different amounts of 1.5% lidocaine: 0.1 ml/kg (L0.1, n = 27), 0.2 ml/kg (L0.2, n = 27), and 0.3 ml/kg (L0.3, n = 27). After 15 min, general anesthesia was induced with intravenous thiopental sodium (5 mg/kg) and rocuronium (0.9 mg/kg), followed by tracheal intubation. Changes in blood pressure and heart rate were recorded for 3 min after intubation. Maximum percentage increases in systolic blood pressure (SBP) during the 3 min after tracheal intubation from baseline and the induction value were compared. RESULTS: The maximum increases in SBP from baseline values were significantly higher in L0.1 than in L0.2 and L0.3 (22.6%; 95% CI, 12.2-33.0%; -0.5%; 95% CI, -11.1-10.0%; and -6.9%; 95% CI, -13.9-0.0%, respectively), whereas the maximum increases from induction values did not differ significantly. CONCLUSIONS: Preoperative TEA using a single dose of 1.5% lidocaine at 0.2 ml/kg attenuated hemodynamic responses during tracheal intubation but did not completely suppress blood pressure reactions to laryngoscopy and tracheal intubation.

The Effect of Thoracic Epidural Lidocaine on Blood Flow of Grafted Coronary Vessels in Coranary Artery Bypass Graft Surgery / 대한마취과학회지

BACKGROUND: Thoracic epidural anesthesia (TEA) is increasingly used to reduce stress response, pain and pulmonary complication of patients under coronary artery bypass graft (CABG). However, effects of TEA on blood flow of grafted coronary artery are scarcely noticed. Imbalance between blood flow of grafted coronary artery and myocardial oxygen demand can bring about perioperative myocardial ischemia. Thus we evaluated the effect of TEA on blood flow of coronary grafts. METHODS: Twenty seven patients with triple-vessel coronary artery disease under CABG were recruited. Left internal mammary artery, radial artery, and great saphenous vein were anastomosed to left anterior descending artery, obtuse marginalis, and posterior descending artery, respectively. Before surgery, an epidural catheter was inserted. Total intravenous anesthesia was undertaken using fentanyl, midazolam and vecuronium. After grafts anastomosis, blood flow of grafted coronary artery was measured using transit-time flowmeter (TTFM) before weaning from CPB. And then, mixture of 2% lidocaine 10 ml, fentanyl 50microgram and bicarbonate 1 mEq was injected via epidural catheter. Under the constant pump flow, the blood flow of grafted coronary artery before, 10 and 20 minutes after drug administration were measured using TTFM. RESULTS: The blood flow of coronary artery grafts was similar in three time interval, irrespective of grafted artery. There are no significant differences in changes in coronary blood flow associated with epidural lidocaine injection among 3 types of grafted artery. CONCLUSIONS: The present study shows that there are no significant effects of TEA on blood flow of newly grafted coronary artery after CABG.

Effects of Continuous Epidural Infusion after Thoracic Epidural Anesthesia for Mastectomy on Postoperative Pain, Nausea and Vomiting / 대한마취과학회지

BACKGROUND: Breast cancer is the most common cause of tumors in Korean women. Until recently, oncologic breast surgery was performed by using general inhalation anesthesia. However, this anesthetic method is associated with incomplete postoperative pain control and significantly more postoperative nausea and vomiting (PONV). Therefore, this study examinated the value of thoracic epidural anesthesia (TEA) for a mastectomy, and evaluated the effects of a continuous epidural infusion on postoperative pain control and the PONV, which is known to be a better method than general anesthesia with intravenous patient controlled analgesia (IV PCA). METHODS: Sixty five patients scheduled for a mastectomy were randomly assigned and divided into two groups. The GA group underwent general anesthesia using O2-N2O-sevoflurane with IV PCA. The TEA group was injected with 20 ml of 0.375% ropivacaine with fentanyl 50microgram at T4-5. After surgery the visual analogue scale (VAS) score of postoperative pain and nausea was checked. RESULTS: The postoperative pain intensity was significantly (P < 0.05) lower in the TEA group at the postoperative period and during 6 hours compared with the GA group. Postoperative nausea intensity was significantly (P < 0.05) lower in the TEA group during 6 hours. CONCLUSIONS: These results suggest that TEA is a method suitable of regional anesthesia for a mastectomy and a continuous epidural catheter infusion is more effective on postoperative pain control than general anesthesia with IV PCA. In addition, it is a good method for decreasing the PONV to a similar level as IV PCA with antiemetics.

The Cardiovascular Effects of Thoracic Epidural Injection of Ropivacaine during Sevoflurane General Anesthesia / 대한마취과학회지

BACKGROUND: Thoracic epidural anesthesia (TEA) combined with general anesthesia is commonly used in major upper abdominal surgery. The advantages of this method is the suppression of the perioperative stress response, the improvement in endocardial perfusion, and the reduction of myocardial oxygen consumption, postoperative morbidity and mortality. In particular, this method reduces the level of postoperative ileus and intestinal anastomosis leakage during gastrointestinal surgery. However, there is the possibility of severe cardiovascular depression using this combination method. This study evaluates the cardiovascular effects of extensive TEA combined with sevoflurane general anesthesia. METHODS: Fifty patients scheduled subtotal gastrectomy were enrolled in this study. After administering a bolus injection of 20 ml of 0.375% ropivacaine through an epidural catheter during sevoflurane general anesthesia, mean arterial pressure, heart rate, stroke volume, cardiac output, and systemic vascular resistance measured by Hemosonic (HemoSonic(TM) 100, Arrow, USA) every 5 minutes over a 30-minute period after the injection. RESULTS: All the data showed a significant decrease from 5 minutes after the epidural bolus injection except for the stroke volume, but that was not important clinically. CONCLUSIONS: A thoracic epidural injection of 20 ml of 0.375% ropivacaine can be used safely during sevoflurane anesthesia without severe cardiovascular complications during upper abdominal surgery.

A Clinical Measurement of the Distance from the Skin to the High Thoracic Epidural Space in Women / 대한마취과학회지

BACKGROUND: Segmental high thoracic epidural anesthesia and analgesia is now accepted as a popular technique for thoracic and breast surgeries, as well as post operative pain relief. However, a high thoracic epidural puncture is technically difficult, which can cause neurological complications. Having prior knowledge of the distance from the skin to the thoracic epidural space may be helpful for the prevention of complications during this procedure. This study was undertaken to evaluate the distance from the skin to the thoracic epidural space and the insertion angle of the Tuohy needle, as measured using a protractor, and to determine any potential relationship between a patient's height, weight and BMI (body mass index) with the calculated distance on the preoperative chest CT and the distance from the skin to the epidural space in 50 women undergoing a mastectomy. METHODS: In the sitting position, using a mid-line approach, the T4-5 epidural depth was measured in 50 mastectomy patients after the block had been successfully confirmed. The patient's age, height, weight and BMI, as well as the calculated distance on the preoperative chest CT were then checked. RESULTS: The distance from the skin to the thoracic epidural space at the T4-5 intervertebral level and insertion angle were 5.59 +/- 1.26 cm and 54.40 +/- 12.12 degrees, respectively. A significant correlation was found between the epidural depth and, the weight, BMI and calculated distance on the preoperative chest CT. CONCLUSIONS: The distance from the skin to the thoracic epidural space showed significant relationships with the weight, BMI and calculated distance on the preoperative chest CT.

Thoracic Epidural Anesthesia for Mastectomy / 대한마취과학회지

BACKGROUND: Segmental thoracic epidural anesthesia (sTEA) is commonly used for postoperative pain control in chest or upper abdominal surgery. But it is not commonly used for the purpose of pure regional anesthesia. Therefore we investigated the usefulness of sTEA for mastectomy and evaluated the effects of sTEA on respiration and hemodynamics. METHODS: Twenty patients scheduled for mastectomy were randomly assigned. Under sitting position, epidural catheter was inserted at T3-4 or T4-5. 20 ml of 0.375% ropivacaine with fentanyl 50 microg was injected to maintain anesthesia. The targeted sensory anesthetic dermatomal levels were determined by pinprick and measured at 5 min intervals for the first 15 min after injection of the drugs. If sensory block was not adequate, subsequent 5 ml doses of ropivacaine was injected. Supplemental oxygen (3-6 L/min) was administered through a face mask. After dermatomal level was checked, propofol infusion for sedation was started. Arterial blood sampling was taken for ABGA. RESULTS: Average sensory anesthetic dermatomal levels is C5.5 +/- 1.9 - T8.9 +/- 2.7. During surgery, hypotension was noted in 25% of patients. It was treated with ephedrine 6 mg i.v. Average PaCO2 is 47.9 +/- 7.7 mmHg. CONCLUSIONS: Above results suggest that sTEA is suitable for mastectomy as a method of regional anesthesia.

The Cardiovascular Effects of Thoracic Bolus Epidural Injection of Lidocaine, Morphine and Fentanyl during Sevoflurane General Anesthesia / 대한마취과학회지

BACKGROUND: Sevoflurane is an inhalational anesthetic that produces rapid induction, emergence and little cardiovascular depression. Elevated sympathetic activity during surgery produces undesirable effects on the cardiovascular system, such as hypertension, tachycardia or arrhythmias. So combined general and epidural anesthesia have been used recently for the operation, especially the abdominal surgery. This study was performed to evaluate the cardiovascular effects of thoracic epidural anesthesia during sevoflurane general anesthesia. METHODS: Forty patients of ASA class 1-2 undergoing elective subtotal gastrectomy were divided into 5 groups. Thoracic epidural bolus injection was administered via an epidural catheter during sevoflurane general anesthesia in a double-blind random manner: Group 1; normal saline (N/S) 10 ml (placebo), Group 2; morphine 0.1 mg/kg mixed with N/S in 10 ml, Group 3; fentanyl 1 mcg/kg mixed with N/S in 10 ml, Group 4; 1% lidocaine 10 ml, and Group 5; 1% lidocaine 10 ml mixed with morphine 0.1 mg/kg and fentanyl 1 mcg/kg. Systolic and diastolic blood pressures, pulse rates, peripheral oxygen saturation levels (SpO2) and end-tidal carbon dioxide partial pressures (ETCO2) were measured every 5 minutes. RESULTS: Systolic and diastolic blood pressures were significantly reduced from 10 minutes after epidural bolus injection in groups 4 and 5, but these decreases in blood pressure were not severe enough to require treatment in either group. Pulse rates were significantly decreased from 10 minutes after injection in groups 3, 4, and 5, but these decreases in pulse rate were not so severe enough to require treatment in 3 groups. SpO2 and ETCO2 were stable, and arrhythmia was not observed. CONCLUSIONS: The thoracic epidural injection of 1% lidocaine mixed with morphine 0.1 mg/kg and fentanyl 1 mcg/kg can be safely used during sevoflurane anesthesia without severe cardiovascular complications during upper abdominal surgery in ASA 1-2 patients.

The Effect of Isoflurane and Thoracic Epidural Anesthesia on Arterial Oxygenation in One Lung Anesthesia / 대한마취과학회지

BACKGROUND: During one lung ventilation (OLV) for thoracic surgery, hypoxic pulmonary vasoconstriction (HPV) may reduce venous admixture and ameliorate the decrease in arterial oxygenation by diverting blood from the non-ventilated to the ventilated lung. Volatile anesthethics are the drugs of choice in thoracic surgery despite numerous experimental data showing their inhibiting effect on the HPV. The effect of thoracic epidural anesthesia (TEA) on HPV during OLV has not been determined. The object of the present study was to compare the effects of TEA with those of isoflurane on oxygenation and shunting during two lung ventilation (TLV) and OLV in human volunteers. METHODS: Thirty patients who needed OLV for elective thoracic surgery were randomly assigned to receive either group isoflurane (1 MAC isoflurane + saline 6 ml TEA + 0.5 - 1ng/dl propofol + fentanyl + vecuronium, n = 15) and group TEA (0.5% bupivacaine 6 ml TEA + 0.5 - 1ng/dl propofol + fentanyl + vecuronium, n = 15) with 100% oxygen in separate groups. Systemic hemodynamic parameters were recorded, and blood gas values were obtained 30 min after the start of TLV and 30, 45 and 60 min after the start of OLV in the lateral position. RESULTS: Reductions in PaO2 and increases in shunt fraction at all study times after the start of OLV were observed. However, there were no differences in percentage changes between the groups. The other blood gas data (SaO2, SO2, PaCO2, PCO2, pH, Hb, CaO2, CO2) and systemic hemodynamics (mean arterial blood pressure, central venous pressure) did not change at all the study times after the start of OLV in the two groups. CONCLUSIONS: In clinical practice, isoflurane and TEA for OLV was no different in terms of arterial blood oxygenation and pulmonary shunt.

The Effects of Thoracic Epidural Anesthesia on Myocardial and Systemic Circulation after Coronary Artery Occlusion in Dogs / 대한마취과학회지

Thoracic epidural combined with general anesthesia is used for thoracic and upper abdominal surgery and postoperative pain control. This technique has advantages of reducing the hemodynamic demand on the heart because of cardiac sympathetic block and stable intraoperative hemodynamics, but it may have a potential hazard of reducing coronary perfusion pressure due to hypotension. Decreased coronary perfusion pressure may be critical hazard to coronary insufficiency patients, but coronary vascular resistance may be decreased also due to blockade of sympathetic coronary constriction. This study was done to investigate the effect of thoracic epidural anesthesia on myocardial and systemic circulation during coronary occlusion limiting flow to 50% of preocclusive value. Comnary occlusion of left circumflex coronary artery was achieved with hydraulic vascular occluder with blood flow meter distal to occluder in 20 dogs. Five of them were dead during preparation. Coronary stenosis was maintained for 30 minutes, then epidural anesthesia was done with 0.5% bupivacaine (bupiva group) or saline (saline group) 5 ml through the surgically introduced epidural catheter. Arterial, mixed venous and coronary sinus blood was collected for the measurement of metabolites and myocardial and systemic oxygen comsumption and extraction ratio. Hemodynamic parameters and blood samples were obtained before(control), 30 minutes after stenosis(stenosis), 15, 30, 60, 90 and 120 minutes after epidural blockade. The results were as follows; The thoracic epidural block caused decrease in blood pressure, heart rate, cardiac index, level of free fatty acid and glucose, and increase in lactic acid level of mixed veous and coronary sinus blood, myocardial oxygen extraction ratio, arterio-venous oxygen content difference, and systemic oxygen extraction ratio. In conclusion the high thoracic epidural block may cause hypotension thus decrease oxygen supply to myocardium but the degree of which is less than that of total body, in the dogs with acute coronary stenosis. The reason is that the high thoracic epidural block decrease myocardial oxygen consumption, and make effective distribution of blood flow in ischemic myocardium, but the normal myocardium has the highest oxygen extraction in the body, so the high thoracic epidural block in coronary stenosis may cause ill effect on myocardial oxygen equlibrium.

Effects of Thoracic Epidural Anesthesia on Pulmonary Hypertension Induced by Acute Diffuse Alveolar Hypoxia and N-nitro-L-arginine in Dogs / 대한마취과학회지

Thoracic epidural anesthesia has been used to manage intraoperative and postoperative pain for thoracic surgical patients with general anesthesia recently, And this combined anesthesia has been associated with less sedation, earlier ambulation, blunting of the stress response and better pain control in the post-operative period. But the effects of thoracic epidural anesthesia on pulmonary shunt, pulmonary vasoactivity and oxygenation are still unknown. The author has investigated the effects of thorarcic epidural anesthesia on pulmonary hypertension induced by acute diffuse alveolar hypoxia and N(W) -nitro-L-arginine(L-NNA) in 12 mongrel dogs. Acute diffuse alveolar hypoxia which is similar to the early stage of acute respiratory failure may induce the pulmonary hypertension. And L-NNA, inhibitor of endothelium derived relaxing factor(EDRF), may also induce pulmonary hypertension under hypoxic state. The measurements were made three times, the first was baseline at room air ventilation. Following baseline recordings, saline 4 ml(group A, n=6) or 2% lidocaine 4 ml(group B, n=6) was injected through the epidural catheter and ventilation was started with hypoxic gas mixture(10% O2, 90% N2). The seeond measurements was made 30 min after the hypoxic ventilation and third was 20 min after infusion of L-NNA(50 mg/kg mixed with distill water 50 ml, infusion rate is 50 ml/20min) under the continuous ventilation with hypoxic gas mixture. The results were as follows: 1) There were significant changes in mean pulmonary arterial pressure, pulmonary vascular resistance in group A(p<0.05) and in arterial and mixed venous oxygen tension, arterial and mixed venous oxygen content, intrapulmonary shunt in both groups(p<0.05) 30 minutes after hypoxia but there were not significant differences between groups. 2) There were significant changes in mean pulmonary arterial pressure, in group B (p<0.05) and pulmonary vascular resistance, systemic vascular resistance and mixed venous oxygen tension and content in both groups (p<0.05) 20 miniutes after infusion of L-NNA under the continuous ventilation with hypoxic gas mixture but there were not significant differences between groups. But there were significant changes in central venous pressure in group B(p<0.05) and significant differences between groups(p<0.05) at 20 miniutes after infusion of L-NNA. These results indicate that thoracic epidura1 anesthesia does not influence the pulmonary hypertension directly and does not praduce any unfavorable hemodynamic events during pulmonary hypertension induced by acute diffuse alveolar hypoxia and N(W)-nitro-L-arginine. Therefore thoracic epidural anesthesia shoud be valuable assistant to the general anesthesia for pulmonary hypertensive patients.