Retrograde Aortic Dissection during Ascending Aortic Aneurysm Surgery : A case report

Aortic dissection during cardiopulmonary bypass for aortic aneurysm surgery is a rare complication. If unrecognized in early time, it would be a fatal consequence. Neurological sequelae remain a well-recognized complication of cardiac surgery. Monitoring of cerebral oxygenation may be a useful technique for identifying vulnerable periods for the development of neurological injury. We report the experience of the decreasing left radial blood pressure and left rSO2 which caused by retrograde aortic dissection during the ascending aortic aneurysm replacement surgery.

The Effect of Cigarette Smoking on Propofol EC50 of Airway Obstruction during Target Controlled Infusion of Propofol / 대한마취과학회지

BACKGROUND: Airway obstruction is a main cause of respiratory complications during sedation. The aim of this study was to identify the effect of smoking on the target plasma concentration of propofol (EC50) of airway obstruction during target controlled infusion (TCI) of propofol. METHODS: Thirty healthy male adults scheduled for lower extremity surgery under regional anesthesia were randomly allocated to one of five target plasma concentrations (CP) of propofol: 1.0, 2.0, 3.0, 4.0, 5.0microgram/ml (n = 6 for each concentration). After performing regional anesthesia, oxygen was supplied and ETCO2 was measured. All patients received propofol TCI with the assigned CP. The occurrence of airway obstruction was observed until 5 minutes after effect site concentration (CE) reached CP. When hypoxemia, apnea or total airway obstruction was observed, ventilation was assisted with 100% oxygen. The CP, smoking history, snoring history, age, body mass index, Mallampati's classification and thyromental distance were regarded as independent variables. The relationship of airway obstruction and the variables was analyzed with logistic regression with Wald-forward method. By the equation of the probability of airway obstruction 'P = 1/(1 + e-z)', we estimated the propofol EC50 of airway obstruction in smokers and nonsmokers. RESULTS: The result of logistic regression was as following: z (airway obstruction) = -5.557 + 2.128 x CP [microgram/ml] + 3.625 x smoking (CP: P = 0.007, smoking: P = 0.047). The propofol EC50 of airway obstruction of non-smokers and smokers was 2.6 (1.5-9.4)microgram/ml and 0.9 (-9.3)microgram/ml, respectively. CONCLUSIONS: The propofol EC50 of airway obstruction of smokers was lower than that of nonsmokers.

The Influences of 6% HES (130/0.4) Solution on Hemostasis / 대한마취과학회지

BACKGROUND: Hydroxyethyl starches (HES) solutions are the most commonly used colloids for treating hypovolemia and expanding plasma, but they compromise platelet function and reduce the level of coagulation factors. As opposed to other HES solutions, 6% HES (130/0.4) solution may influence hemostasis minimally due to its low mean molecular weight and degree of substitution. This study was designed to establish the safety of HES (130/0.4) infusion in the presence of massive blood loss. METHODS: Twelve healthy adult patients scheduled for spine surgery were enrolled in this study. Before the induction of general anesthesia, all patients underwent acute normovolemic hemodilution (ANH), which was independent of surgical stress and other confounding factors. While approximately 30% of the estimated blood volume was procured, the blood deficit was replaced with the same volume of 6% HES (130/0.4) solution. Hematocrit, platelet count, factor VIII activity and plasma fibrinogen concentration were determined and thrombelastography was performed to evaluate the hemodilution effect and hemostatic impairment before and after ANH. Statistical testing was conducted to analyze the effect of HES on hemostasis. RESULTS: Hematocrit, platelet count, factor VIII activity and plasma fibrinogen concentrations decreased significantly (P < 0.05 respectively) after the ANH. On comparing pre-ANH and post-ANH thrombelastographic findings, the R time was shortened (P = 0.045), the alpha angle increased (P = 0.01) and MA decreased (P = 0.003) significantly. CONCLUSIONS: Summarizing, little effect was observed on the hemostatic system when 20 ml/kg of 6% HES (130/0.4) solution was infused. HES (130/0.4) solution as used to maintain normovolemia during ANH may be free from bleeding risk.

Hemodynamic Changes Using Esophageal Doppler during a Thoracoscopic Thoracic Sympathicotomy in Primary Hyperhidrosis / 대한마취과학회지

BACKGROUND: Among the treatments for hyperhidrosis, thoracoscopic sympathicotomy is comparatively easy and simple to operate, so complications rarely occur. Since the thoracic sympathetic nerve controls the cardiovascular system, there should be hemodynamic changes after the operation. However, little study has been done up on describing the overall hemodynamic changes occurring during operation. Therefore, we examined hemodynamic changes by Esophageal Doppler. METHODS: This research was conducted on thirteen patients with hyperhidrosis, from 15 to 50 years who were group 1 or 2, according to the American Society of Anesthesiologists (ASA) classification, and were without heart disease, respiratory disease or esophageal disease. Induction was done using TCI Diprivan 4.5microgram/ml, vecuronium 0.1 mg/kg at maintained with 50% nitrous oxide. Hemodynamic parameters such as heart rate, mean arterial pressure and cardiac output and tissue oximeter were examined after anesthesia was induced, and CO2 given, that is, immediately before thoracic sympathicotomy and after thoracic sympathicotomy. RESULTS: The mean heart rate was 89 +/- 12 beats/min just before thoracic sympathicotomy, after surgery this decreased statistically. Mean tissue oxygen saturation in the arm was 77 +/- 10% just after surgery, and this was a significant increase compared with that before surgery (P<0.05). Cardiac output by esophageal doppler decreased statistically after induction. CONCLUSIONS: During thoracoscopic thoracic sympathicotomy in primary hyperhidrosis, the heart rate decreased, cardiac output using esophageal doppler showed a significant decrease at each time, and there was not any differences between each time.

The Changes of Coagulation State among ABO Blood Types during Acute Normovolemic Hemodilution / 대한마취과학회지

BACKGROUND: Improvement of coagulation function by acute normovolemic hemodilution (ANH) is well evidenced in modern medical practice. It has been reported that there are fixed differences in the plasma concentrations of von Willebrand factor and factor VIII according to ABO blood types. Therefore, the changes of coagulation state among ABO blood types during ANH are expected but have not yet been studied. This study was designed to establish the changes of coagulation state among ABO blood types during ANH by intraoperative thrombelastography (TEG). METHODS: Fifty one healthy adult patients scheduled for spine surgery were enrolled in this study. All patients were grouped by ABO blood types and underwent ANH after the induction of general anesthesia. While autologous blood (25% of EBV) was procured, warmed 0.9% saline, 3 times the blood volume deficit, was infused to maintain normovolemia. Platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), factor VIII activity and TEG were performed to evaluate coagulation state before and after ANH. Statistical analysis was conducted to determine the dilutional effects and intergroup differences. RESULTS: Improvement of coagulation function after ANH was visible only by TEG, and not by PT, APTT or factor VIII activity. Fourteen of fifteen patients with type O blood showed decreased factor VIII activity to under the normal limit after ANH. In patients with blood type O, changes of APTT (P = 0.093, P = 0.086) and factor VIII activity (P = 0.001, P = 0.004) during ANH were remarkable in comparison with blood type B and AB. CONCLUSIONS: ANH enhances coagulation function evaluated by means of TEG. No difference was observed in terms of the changes of coagulation state among ABO blood types during ANH. However, ANH should be instituted cautiously in patients with type O blood because there is a possibility of impairing factor VIII activity.

Does Propofol Improve Postischemic Myocardial Dysfunction by Reducing the Postischemic Adhesion of Polymorphonuclear Neutrophils? / 대한마취과학회지

BACKGROUND: Fluid replacement after hemorrhage usually results in hemodilution, and hemodilution leads to increased cerebral blood flow, which is known to be beneficial to the outcome of ischemic brain damage. However, the effect of hemodilution may be different in patients with head injuries and increased intracranial pressure (ICP). The aim of this study was to evaluate the effects of normovolemic hemodilution on cerebral blood flow (CBF), brain tissue oxygen tension (PbtO2), and the severity of cryogenic brain injury, and to determine the acceptable limit of hemodilution during cryogenic brain injury. METHODS: Thirty New Zealand white rabbits were anesthetized with O2-N2O-isoflurane. Cryogenic brain injury (1 cm in diameter) was produced by applying liquid nitrogen on the surface of the right parietal bone for 90 seconds. Sixty minutes after cryogenic brain injury, acute normovolemic hemodilution was induced with 10% pentastarch for 30 minutes. In group I (n = 7), hemodilution was not induced. In groups II (n = 7), III (n = 8), and IV (n = 8), the hemoglobin concentrations were adjusted to 9-10, 6-7 and 3-4 g/dl, respectively. Mean arterial pressure, central venous pressure and ICP were measured, and local CBF and PbtO2 of the right parietal subcortex were continuously monitored. The rabbits were euthanized 150 minutes after brain injury, and the brains were removed and sectioned coronally through the center of the lesion. The extent of brain injury in the coronal plane was measured by light microscopic examination. The posterior part of the brain was divided into two halves and the water fraction of each part was measured by the dry-weight method. Data obtained were compared by the Kruskal-Wallis test or by repeated measures ANOVA. The difference was considered significant when P <0.05. RESULTS: No differences were observed in mean arterial pressure, central venous pressure or rectal temperature. However, significant differences were found in ICP, CBF and PbtO2 among the groups. ICP was significantly higher in group IV than in groups I and II. The CBF values of groups III and IV were higher than those of group I. The values of PbtO2 of group IV were lower than those of groups I and II. Normovolemic hemodilution, of up to 6-7 g/dl of hemoglobin, led to an abrupt increase in CBF and a subsequent increase in ICP. Hemodilution, of up to 3-4 g/dl of hemoglobin, decreased brain tissue oxygen tension significantly. No differences in the brain water fractions and the extent of cryogenic injury were found among the groups. CONCLUSIONS: It is concluded that the acceptable limit of acute normovolemic hemodilution in cryogenic brain injury is 9-10 g/dl of hemoglobin, as ICP and CBF do not increase and PbtO2 does not deteriorate.

Coagulopathy Detected with a Thrombelastography during ANH after Induction of General Anesthesia: A case report / 대한마취과학회지

Thrombelastography (TEG) performed by an anesthesiologist provides a rapid assessment of coagulation at the bedside. TEG analyzing coagulation status of native whole blood is a more accurate test with a relatively good sensitivity and specificity than PT and aPTT. We experienced an unexpected coagulopathy during the perioperative period. The case was a 47-year-old male patient with blood type O who underwent elective spine surgery. Perioperative coagulation tests (PT, aPTT, BT, CT, etc.) were within normal limits. Anesthesia was induced with propofol 90 mg, vecuronium 8 mg and alfentanil 0.5 mg and maintained with 1.0 1.5 vol% enflurane and 50% N2O in O2. Then we performed acute normovolemic hemodilution (ANH) with monitoring pre- and post-hemodilutional TEG. Hemostasis was revealed as abnormal by a pre-hemodilution TEG (CI = -11.06) and post-hemodilution TEG (CI = -13.06). We managed this coagulopathy with blood components and drugs on the basis of a follow-up TEG so that abnormal hemostasis and TEG findings improved (CI = -4.35). We report a case where undetected coagulopathy was revealed and treated successfuly with TEG.

The Experiences of Airway Management for Anesthesia of Patients with Involved Cervical Spine Ankylosing Spondylitis / 대한마취과학회지

Ankylosing spondylitis is a chronic and systemic disease involving the axial skeleton. In patients with involved cervical spine ankylosing spondylitis, endotracheal intubation by direct laryngoscope may be difficult because they have a limitation of cervical movement and anatomical anomalies. We experienced the evaluation of thirteen patients with involved cervical spine ankylosing spondylitis by the Mallampati classification, Cormack and Lehane grade, thyromental distance and orolaryngeal angle. By Mallampati class and Cormack and Lehane grade, patients were almost class 3 or 4. Thyromental distance was 5.3 +/- 0.4 cm, and orolaryngeal angle was 90.4 +/- 8.0o.

A Comparative Study of Propofol-Fentanyl and Propofol-Ketamine Anesthesia for Spine Surgery under Somato-Sensory Evoked Potential Monitoring / 대한마취과학회지

BACKGROUND: Somato-sensory evoked potential (SSEP) monitoring has been used to help minimize neurologic morbidity during spinal surgery. However, SSEP is affected by anesthetics, technical errors and physiologic aspects. We reviewed 50 cases of spinal surgery done with total intravenous anesthesia under SSEP monitoring. METHODS: Fifty patients, ASA class I-II, free of neurologic disease and scheduled for elective spinal surgery were randomly selected for the study. All of the operations were performed under general anesthesia employing the method of total intravenous anesthesia with propofol and fentanyl (Group I, P-F) or ketamine (Group II, P-K), and monitored by SSEP. We checked the changes of blood pressure and heart rates during the operation, recorded latency and amplitude of SSEP in the pre-induction, post-induction, during screw insertion and post-distraction periods. Also, we checked the number transfers to the ICU and application of a ventilator. RESULTS: Systolic and diastolic blood pressure were increased significantly in the propofol-ketamine group (P < 0.05), but there was no difference in heart rate between both groups. In addition there were no statistical differences in latencies and amplitudes of SSEP. The number of patients transferred to the ICU and placed on a ventilator showed no statistical difference. CONCLUSIONS: We think that the combination of propofol and fentanyl or ketamine used for total intravenous anesthesia is a very useful method in spinal surgery under SSEP monitoring.

The Effect of Propofol Pretreatment on the Focal Ischemic Injury of Brain in the Rat / 대한마취과학회지

BACKGROUND: Propofol is widely used in neurosurgical anesthesia as an intravenous anesthetic agent. There have been some reports on the protective effects of propofol in cerebral ischemia. However conflicting results also exist. This study was designed to test the hypothesis that propofol pretreatment would provide protective effect on the focal cerebral ischemia-reperfusion injury. METHODS: Thirty Sprague-Dawley rats were divided into two groups; 15 for a halothane group, 15 for a propofol group. After induction of anesthesia with halothane in 100% oxygen, the tracheas were intubated and mechanical ventilation was maintained. For the entire experimental period normocapnia was maintained and scalp temperature was maintained in the range of 37 - 37.5oC. In the propofol group, propofol was infused at the rate of 2 mg/kg/min for 30 min without halothane administration prior to the ischemic period. In the halothane group, propofol was not infused. The left middle cerebral artery was occluded for 90 minutes with an intraluminal monofilament. After ischemia, perfusion was restored and rats were awakened. After 24 hours, the brain was removed and sectioned coronally and immersed in the 2% 2,3,5-triphenyltetrazolium choride solution. Percent mean infarcted area was calculated and compared between groups by Wilcoxon rank sum test. RESULTS: The percent infarcted area of halothane and propofol groups was 18.8 +/- 19.2% and 15.7 +/- 16.4%, respectively. There was no difference between groups in the aspect of percent infarcted area and physiologic variables such as mean arterial pressure, scalp temperature and serum glucose concentration. CONCLUSIONS: The pretreatment of propofol does not produce protective effect on focal cerebral ischemia compared with treatment with halothane.