Neural Stem Cell Differentiation Using Microfluidic Device-Generated Growth Factor Gradient

Neural stem cells (NSCs) have the ability to self-renew and differentiate into multiple nervous system cell types. During embryonic development, the concentrations of soluble biological molecules have a critical role in controlling cell proliferation, migration, differentiation and apoptosis. In an effort to find optimal culture conditions for the generation of desired cell types in vitro, we used a microfluidic chip-generated growth factor gradient system. In the current study, NSCs in the microfluidic device remained healthy during the entire period of cell culture, and proliferated and differentiated in response to the concentration gradient of growth factors (epithermal growth factor and basic fibroblast growth factor). We also showed that overexpression of ASCL1 in NSCs increased neuronal differentiation depending on the concentration gradient of growth factors generated in the microfluidic gradient chip. The microfluidic system allowed us to study concentration-dependent effects of growth factors within a single device, while a traditional system requires multiple independent cultures using fixed growth factor concentrations. Our study suggests that the microfluidic gradient-generating chip is a powerful tool for determining the optimal culture conditions.

Adequate Change Interval of Transfusion Kits during Rapid Transfusion / 대한수혈학회지

BACKGROUND: For a rapid transfusion, pressure is sometimes applied to packed red blood cells during the operation. However, there are neither standard guidelines nor reported data regarding adequate change interval of transfusion kits. The aim of this study is to present relevant data by simulating a surgical situation. METHODS: Each unit of packed red blood cells was mixed with 50 mL of normal saline. Pressure (250 mmHg) was applied to the mixed red blood cells. Each filtration time was measured without change of the transfusion kit. The weight of the mixed red blood cells was measured before and after administration. The passed blood was examined microscopically for detection of possible microaggregation. Eight transfusion sets were tested with 70 packed red blood cells. RESULTS: International guidelines have recommended replacement of the transfusion set if flow rate decreased to less than 100 mL/min. The flow rate of five transfusion sets was recorded as less than 100 mL/min. The flow rate of the third packed red blood cells decreased to less than 100 mL/min. No microaggregate was detected. CONCLUSION: Therefore, we recommended replacement of the blood filter after filtering two units of packed red blood cells with pressure under operation room circumstances.

Reduction of Perioperative Fresh Frozen Plasma Wastage and Transfusion by Quality Improvement Activity / 대한수혈학회지

BACKGROUND: Empirical use of fresh frozen plasma (FFP) in perioperative blood transfusion leads to high wastage of FFP. However, coordination of many related clinical departments is difficult. Therefore, quality improvement (QI) activities for establishment of appropriate use of FFP are needed. METHODS: Departments of surgery (all surgery departments except ophthalmology) and the departments of anesthesiology, clinical pathology, and nurses met each month from March, 2011 to October, 2011. Each department investigated the number of FFP usages, wastage, and coagulation tests. Primary measured variables and objectives were decrease of 50% of FFP wastage rate compared with the previous year and 50% increase of coagulation testing before using FFP. Secondary measured variables were total amount of FFP usage and report time for coagulation tests. RESULTS: After the QI activities (March, 2011~October, 2011), FFP wastage decreased, from 71.5 units during the second half of 2010 to 37.8 units during the second half of 2011 (-47.1%). Rate of coagulation testing before using FFP more than doubled during the second half of 2011 (57%) compared with the second half of 2010 (25%). The rate of less than 30 minutes report time for coagulation testing increased from 60% to 75%. FFP transfusion per 1,000 surgical cases decreased to from 190 units to 118 units. CONCLUSION: Rate of FFP wastage and transfusion decreased and rate of performance of the blood coagulation test was enhanced through education and training on transfusion and QI activities.

Nutrient Intake and Food Restriction in Children with Atopic Dermatitis

This study was performed to investigate the status of food restriction and the list of restricted foods in children with moderate to severe atopic dermatitis (AD), and to find out the effect of food restriction on the changes in nutrient intake and the severity of the disease. Sixty two patient children aged 12 months to 13 years presenting AD with a SCORing of Atopic Dermatitis (SCORAD) index between 20 and 50 were enrolled. The presence of food limitation, and list of restricted foods were surveyed through the caretakers and the patients were divided into 3 groups by the number of restricted food: non-restricted group, one to three restricted group, and more than three restricted group. Dietary intake was assessed for 3 months using a food frequency questionnaire (FFQ). Half of the subjects restricted foods. The restriction was higher in the order of soda, food additives, walnut, peanut, and other nuts as a single food item; and shellfish and crustacean group, processed foods, nuts, milk & dairy products, and meats as a food group. More than three restricted group ingested more fruits and less fish and meats, resulting in high consumption of vitamin C (p = 0.027). No significant difference in the ratio of nutrient intake by the number of restricted foods was observed in other nutrients. Significant improvement of AD symptom was observed in non-restricted group (p = 0.036) and one to three restricted group (p = 0.003). It is necessary to provide proper nutrition information and systematic and continuous nutrition management for balanced nutrient intake and disease improvement in children with AD.

Comparison of the renal safety between carbon dioxide absorbent products under sevoflurane anesthesia: a pilot study / 대한마취과학회지

BACKGROUND: The chemical reaction of carbon dioxide absorbent and sevoflurane is known to produce compound A. However, carbon dioxide absorbents are not controlled by the Food and Drug Administration, but are treated as industrial products in some nations. Moreover, carbon dioxide absorbents differ in their capacities to produce compound A, because their chemical compositions differ. In this study, we compared the renal safety between carbon dioxide absorbent products in patients under sevoflurane anesthesia. METHODS: Eighty patients with no preexisting renal disease undergoing elective gynecologic surgery were randomly assigned to receive sevoflurane or isoflurane anesthesia with one of four carbon dioxide absorbent products (Sodasorblime(R), Sodalyme(R), Sodasorb(R), Spherasorb(R)) at the same fresh gas flow of 2 L/min. The renal safety was evaluated by changes of blood urea nitrogen (BUN), creatinine and urine N-acetyl-b-glucoseaminidase (NAG)-creatinine ratio at 24 hours and 72 hours after surgery from preoperative level. RESULTS: There was no significant difference in the renal safety indicators between carbon dioxide absorbents during sevoflurane anesthesia (P > 0.05). However, the BUN and urine NAG-creatinine ratios at 72 hours after surgery were higher in isoflurane anesthesia in some carbon dioxide absorbent groups (P = 0.03 and 0.04, respectively). CONCLUSIONS: We could not find significant differences of renal safety indicators with carbon dioxide absorbents. Although the adverse effect of carbon dioxide absorbents on renal function was not proved, consideration should be given to their contol by the regulation on their efficacy and safety because carbon dioxide absorbents can produce compound A.

A survey on informed consent process for epidural analgesia in labor pain in Korea / 대한마취과학회지

BACKGROUND: There is a legal obligation to explain the procedure and use of epidural analgesia in labor primarily due to the possibility of potential risks and associated complications. The present study details on the survey carried out to ascertain the current status of obtaining informed consent (IC) for explaining the epidural analgesia in labor. METHODS: The present study is based on a survey through a telephone questionnaire that covered all the hospitals in Korea where the anesthesiologists' belonged to and are registered with Korean Society of Anesthesiologists. The questionnaire included questions pertaining to administration of epidural analgesia to a parturient, information on different steps of obtaining an IC, whether patient status was evaluated, when the consent was obtained, and the reasons behind, if the consent had not being given. RESULTS: A total of 1,434 respondents took part in the survey, with a response rate of 97% (1,434/1,467). One hundred seventy-four hospitals had conducted epidural analgesia on the parturient. The overall rate of obtaining IC for epidural analgesia during labor was 85%, of which only 13% was conducted by anesthesiologists. The rate of evaluating preoperative patient status was 74%, of which 45% was conducted by anesthesiologists. Almost all of the consent was obtained prior to the procedure. CONCLUSIONS: The rate of obtaining IC for epidural analgesia in labor is relatively high (85%) in Korea. However, it is necessary to discuss the content of the consent and the procedure followed for obtaining IC during the rapid progress of labor.

Bloody cerebrospinal fluid during replacement of descending thoracic aorta: A case report / 대한마취과학회지

Cerebrospinal fluid (CSF) drainage is a routinely used adjunct to thoracoabdominal aortic surgery which may reduce the incidence of preoperative paraplegia by improving spinal cord perfusion. However, this procedure infrequently causes complications. Bloody or bloody-tinged CSF may be associated with intracranial or spinal hematoma. We present herein a case of bloody CSF during the replacement of the descending thoracic aorta.

Awareness during General Anesthesia due to Vaporizer Malfunction: A case report / 대한마취과학회지

We report a case of awakening during general anesthesia due to a vaporizer malfunction. The sevoflurane vaporizer had a hole through which approximately 20% of fresh gas escaped. The gas in the common gas outlet contained only 60% of the sevoflurane stated on the vaporizer setting. Moreover, the gas monitor module was out of order, and the heart rate and blood pressure were stable. As a result, we were unaware of the low sevoflurane concentration. The leakage through the hole could not be detected with the commonly used low-pressure system leak checking method. The implication of this case is that unexpected awakening can occur in patients with stable vital signs with an inhalation anesthesia. Therefore, more attention is needed to detect the level of patient awareness.

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.

Survey of Institutional Review Board Approval and Informed Consent in Clinical Research of Korean Anesthetic Society / 대한마취과학회지

BACKGOUND: All medical research requires approval of the institutional review board ( IRB ) and informed consent from the research participants in advance. But there are reports of low rates of IRB approval in major anesthesia journals. The purpose of the study is to investigate IRB approval and informed consent rates of Korean anesthetic field researches and provide suggestion. METHODS: We reviewed 11 years data from Korean journal of anesthesiology and obtained the number and percentage of IRB approved papers, informed consents and verbal consents. RESULTS: The total number and percentage of IRB approved papers has increased to 60% and so as cases with informed consents over the past 11 years. But the ratio is still under 25%. The ratio of informed consent against verbal consent is also increasing. CONCLUSIONS: The number of IRB approved and informed consented papers have increased. But the proportion is still not satisfying or low. Changes in understandings of the clinical researchers with education of research ethics and systemic establishment are needed.

Analysis of the Description of Ventilator Parameters in Recent Papers Relating Artificial Ventilation Using Anesthesia Machine / 대한구급학회지

BACKGROUND: Procedures in medical papers should be described in sufficient detail to allow other researchers to reproduce the results. The apparatus including anesthesia machine should be given, too. Anesthesia machine has dramatically improved as bioengineering has developed. There are several ventilator settings in modern anesthesia machines. However, it seems that only a few ventilator settings are described even though modern ventilators are used in research. The purpose of this study is to investigate that how many ventilator parameters were described in the papers of the Korean Journal of Anesthesiology from 2001 to 2006. METHODS: All of papers with human general anesthesia were reviewed except case reports, and papers regarding only induction or intubation procedures. Recruited articles were grouped into papers with strongly related to respiratory parameters (STP), and into ones with slightly related to them based on the research topics. The description of following categories was counted in each paper; the type of anesthesia machine, tidal volume, respiratory rate, inspiratory:expiratory ratio, mode of ventilation, pressure set in pressure targeted ventilation, positive end expiratory pressure, inspiratory pause, and inspiratory rising rate. RESULTS: The description rate of each parameters in STP were 36% in the type of anesthesia machine, 66% in tidal volume, 54% in respiratory rate, and 24% in inspiratory:expiratory ratio. The other settings were seldomly mentioned. CONCLUSIONS: Description on the ventilator parameters was sometimes missed. We should describe adequate ventilator settings to reproduce the results because the modern anesthesia machine has additional ventilator options.

Statistical Analysis of Mortality Associated with Anesthesia and Surgery in a Hospital from 2000 to 2004 / 대한구급학회지

BACKGROUND: Surgical patients should be provided adequate information on operation. The information on mortality is extremely important among them. The purposes of this study are to investigate the recent mortality associated with anesthesia and surgery, and to get a logistic regression model of mortality based on patient information. METHODS: We collected all of the anesthetic cases except local anesthesia during 5 years (between 2000 and 2004) in a hospital. All deaths within 7 days after anesthesia were retrieved. These data were analyzed in terms of age, gender, department in charge, time point after anesthesia, elective or emergency surgery, type of anesthesia, operation name, and diagnosis. The combined effects of the variables on the mortality were evaluated with logistic regression. The causes of death were also analyzed. RESULTS: There were 155 deaths among 74,458 patients under anesthesia. Age less than 1 year old or greater than 80 years old, male gender, department of thoracic surgery, emergency operation, cardiovascular surgery, and diseases for transplantation had higher mortality than their counterparts. Regression model was followed with assignment of '1' for the above mentioned categories. Other categories were designated by '0'. Log[p (death)/{1-p (death)}] = -9.15+1.03xage+0.66xsex+0.79xdepartment+2.77xemergency+2.52 xdiagnosis+0.89xoperation The leading cause of death was sepsis (21.9%). CONCLUSIONS: The average of mortality within 7 days after anesthesia was 21 per 10,000 anesthetic cases (0.21%). Estimated mortality based on logistic regression ranged from 0.01% to 10.25% depending on patient information.