Ki-Soo Kim

A Structural Model of Stress, Motivation, and Academic Performance in Medical Students

Objective The purpose of the present study was 1) to identify factors that may influence academic stress in medical students and 2) to investigate the causal relationships among these variables with path analysis. Methods One hundred sixty medical students participated in the present study. Psychological parameters were assessed with the Medical Stress Scale, Minnesota Multiphasic Personality Inventory, Hamilton Depression Scale, Beck Depression Inventory, and Academic Motivation Scale. Linear regression and path analysis were used to examine the relationships among variables. Results Significant correlations were noted between several factors and Medical Stress scores. Specifically, Hamilton Depression Scale scores (β=0.26, p=0.03) and amotivation (β=0.20, p=0.01) and extrinsically identified regulation (β=0.27, p<0.01) response categories on the Academic Motivation Scale had independent and significant influences on Medical Stress Scale scores. A path analysis model indicated that stress, motivation, and academic performance formed a triangular feedback loop. Moreover, depression was associated with both stress and motivation, and personality was associated with motivation. Conclusion The triangular feedback-loop structure in the present study indicated that actions that promote motivation benefit from interventions against stress and depression. Moreover, stress management increases motivation in students. Therefore, strategies designed to reduce academic pressures in medical students should consider these factors. Additional studies should focus on the relationship between motivation and depression.

Embolization versus surgical resection of pulmonary sequestration: clinical experiences with a thoracoscopic approach.

PURPOSEnThe goal of this study was to compare the safety and efficacy of treatment for pulmonary sequestration (PS) by transcatheter arterial embolization (TAE) versus surgical resection and to consider the role of a thoracoscopic approach.nnnMETHODSnA retrospective review involving 73 children (≤ 15 years of age) with PS between 2002 and 2011 was performed.nnnRESULTSnForty-two patients were managed with TAE, and 31 underwent surgery alone. Their presenting symptoms were pneumonia (n=11), pneumothorax (n=2), pneumomediastinum (n=1) and respiratory distress (n=6).Fifty-three (72.6%) were asymptomatic. The average age at treatment was 17.0 ± 44.4 and 31.3 ± 41.7 months for the TAE and surgery groups, respectively. In the TAE group, complete regression was observed in only 3 patients, 4 showed no regression, and 35 (83.3%) had residual lesions. Four patients developed sepsis or other blood vessel complications after TAE. The results of resection via thoracotomy versus a thoracoscopic approach were evaluated in 34 patients, including 3 who underwent the operation after TAE. Twenty-seven patients underwent thoracotomy, and 7 underwent thoracoscopic resection. There were no significant differences between the groups except time to chest tube removal, which was shorter in the thoracoscopic group (p=0.046). Complications included a wound infection in 1 patient after thoracotomy.nnnCONCLUSIONSnWe believe that even in asymptomatic patients, all PSs should be resected because of the risk of infection, the low rate of natural regression, complications after TAE, and to exclude other pathology. Our experience also shows that thoracoscopic resection of PS is feasible, efficacious, and safe in newborns and infants.

Neonatal pulmonary sequestration: clinical experience with transumbilical arterial embolization.

Pulmonary sequestration (PS) is a rare congenital malformation of the lower respiratory tract. The exact natural course of PS is not well understood and there are no well‐established treatment guidelines for antenatally diagnosed PS. The aim of this study was to describe clinical outcomes in neonates with PS and to evaluate the efficacy of transumbilical arterial embolization (TUE). From 1998 to 2006, total 30 neonatal cases were included. Serial antenatal ultrasound in 26 cases found 6 (23%) regressed lesions, all of which were demonstrated on postnatal chest CT. Six (20%) cases were classified as mixed‐type (combined cystic) lesions. Surgery was performed early (during initial hospitalization) in two cases and lately (after the neonatal period) in four cases. TUE was performed for 17 (57%) cases of intrapulmonary PS. Follow‐up images obtained a median of 19 months (range, 4–51) after TUE demonstrated complete (9, 53%), partial (5, 29%), and no (3, 18%) regression. The regression rate was significantly higher in solid‐type lesions (13/13, 100%) than in mixed‐type (1/4, 25%) (Pu2009=u20090.006). Complications included transient hypertension (two cases, 12%), post‐embolization fever (two cases, 12%) and migration of a microcoil (one case, 6%), without long‐term morbidities. Natural courses could be observed in 10 cases of extralobar PS and regression was observed in 2 cases (20%) during a median follow‐up of 12 months (range, 6–45). A well‐designed comparative study is warranted to evaluate the long‐term efficacy and safety of TUE. Pediatr Pulmonol. 2008; 43:404–413.

Effect of Furosemide on Ductal Closure and Renal Function in Indomethacin-Treated Preterm Infants during the Early Neonatal Period

Background: Furosemide is known to increase renal prostaglandin synthesis. However, its influence on ductal closure and renal toxicities of indomethacin in preterm infants has not been conclusive, especially during the early neonatal period. Objectives: To identify the effects of furosemide after indomethacin administration on the rate of patent ductus arteriosus (PDA) closure and renal function in preterm infants. Methods: 68 infants (gestational age <34 weeks and birth weight <2,000 g) receiving indomethacin therapy (one course: 0.2–0.1–0.1 mg/kg q 12 h, mostly started <48 h after birth) were randomly assigned to the furosemide (n = 35) or control (n = 33) group. Each indomethacin dose was followed by furosemide (1.0 mg/kg) or placebo. The primary (PDA closure) and secondary (acute renal failure (ARF) and others) outcomes were assessed. Renal parameters before and 0–12 and 24–36 h after the first course of indomethacin were also investigated. Results: In an intention-to-treat analysis, there were no differences in the PDA closure rate between the furosemide (29/34) and the control (27/29) group (p = 0.437). The incidence of ARF (serum creatinine >1.6 mg/dl) was greater in the furosemide group (20/34) than in the control group (3/29) (p < 0.001). Compared with the control group, serum creatinine and cystatin C levels and fractional excretion of sodium were significantly increased in the furosemide group for 24–36 h after indomethacin therapy (p < 0.01). There were no between-group differences in mortality and other neonatal morbidity rates. Conclusions: Use of furosemide in combination with indomethacin increased the incidence of ARF but did not affect the PDA closure rate in preterm infants.

Magnetic resonance imaging in the evaluation of the lumbar herniated intervertebral disc

SummaryTwo hundred and eleven patients with lumbar disc herniation at 242 levels were divided into 5 groups by their appearances on magnetic resonance imaging (MRI), and the findings at operation were compared to assess the accuracy of the MRI classification. There were no negative explorations. There was 92% sensitivity, 91% specificity and 92% accuracy for MRI in distinguishing protruded discs from other forms of lumbar disc herniation. For sequestrated discs there was 92% sensitivity, 99% specificity and 97% accuracy. In the extruded subligamentous type there was 71% sensitivity, 82% specificity and 79% accuracy, and 52% sensitivity, 92% specificity and 81% accuracy in the extruded transligamentous type. The overall accuracy of MRI predicting the types of herniated lumbar intervertebral disc was 85%. High resolution MRI is sensitive in detecting disc disease and specific in characterizing various subgroups of disc herniation, especially those which are sequestrated.RésuméDeux cent onze patients atteints de hernie discale lombaire, confirmée par imagerie par résonance magnétique (IRM) et représentant 242 niveaux, ont été répartis en cinq groupes. Le diagnostic IRM a été comparé aux constatations opératoires afin dévaluer de façon prospective la précision diagnostique de la classification IRM. Il ny a pas eu dexploration discale négative. Pour la distinction entre protrusion et autres types de hernie discale, la sensibilité, la spécificité et lexactitude de lIRM ont été respectivement de 92%, 91% et 92%. Pour la séquestration discale, la sensibilité a été de 92%, la spécificité de 99% et lexactitude de 97%. En ce qui concerne lextrusion sous-ligamentaire, on a noté une sensibilité de 71%, une spécifité de 82% et une exactitude de 79%, tandis que pour les extrusions trans-ligamentaires la sensibilité a été de 52%, la spécifité de 92% et lexactitude de 79%. Lexactitude moyenne pour la prévision du type de hernie discale a donc été de 85%. LIRM de haute résolution est donc très efficace pour la détection des lésions discales et leur classification.

Impact of fetal echocardiography on trends in disease patterns and outcomes of congenital heart disease in a neonatal intensive care unit.

Background: Congenital heart disease (CHD) is the most common developmental malformation and the leading cause of neonatal mortality and morbidity. The introduction of fetal echocardiography has made prenatal diagnosis of CHD possible. Objective: This study was conducted to investigate the impact of fetal echocardiography on the changing disease patterns and outcomes of CHD. Methods: A retrospective analysis of data from infants with CHD admitted to the neonatal intensive care unit (NICU) of the Asan Medical Center during the time periods was performed. Period I (1994–1996) was considered representative of a period before the introduction of fetal echocardiography, while period II (2004–2006) represented a period of more extensive application of fetal echocardiography. Results: A total of 164 patients were admitted to the NICU during period I and 320 during period II. The number of infants prenatally diagnosed with CHD was 5 of 164 (3.0%) in period I and 219 of 320 (68.4%) in period II (p < 0.05). The overall accuracy of fetal diagnosis was approximately 92%. Of the 3 CHD categories, there was a greater proportion of infants with ‘significant’ heart disease in period II than I (47 vs. 32%; p < 0.05). In contrast, there was a smaller proportion of infants with ‘simple’ heart defects in period II than I (22 vs. 40%; p < 0.05). The proportion of infants with ‘complex’ heart disease was similar in both periods (28% in period I and 31% in period II). The 1-year survival rate of patients with CHD has improved remarkably with time (70.1% in period I to 88.8% in period II). Multivariate analysis showed prenatal diagnosis and planned delivery in a tertiary NICU are factors affecting CHD outcomes, especially when defects are ‘complex’ (p < 0.01). Conclusion: Fetal echocardiography has resulted in an increased frequency of prenatal CHD diagnosis, has altered the disease patterns observed in the NICU, and has resulted in better 1-year outcomes.

Novelty-seeking and avoidant coping strategies are associated with academic stress in Korean medical students

High levels of stress and depression in medical students is raising concern. In this study, we sought to identify coping strategies and other factors influencing academic stress in medical students. We enrolled 157 students from the University of Ulsan College of Medicine, Korea, in November, 2010. We used the Medical Stress Scale, Temperament and Character Inventory, Hamilton Depression Scale, Beck Depression Inventory, and Coping Response Inventory to assess psychological parameters. We used Pearsons correlation and linear regression analyses to analyze the data. Novelty-seeking, self-directedness, cooperativeness, coping strategy, and depression scale scores all correlated significantly with stress level. Linear regression analysis indicated that students who are novelty-seeking, likely to use avoidant coping strategies, and unlikely to use active-cognitive and active-behavioral strategies tend to have higher stress levels. Reduction of stress in medical students may be achieved through evaluation of coping strategies and personality features and use of interventions to promote active coping strategies.

The Effects of Dantrolene on Hypoxic-Ischemic Injury in the Neonatal Rat Brain

BACKGROUND:The pathophysiology of brain damage from hypoxia or ischemia has been ascribed to various mechanisms and cascades. Intracellular calcium overload and a calcium excitotoxic cascade have been implicated. It has been suggested that disturbances of endoplasmic reticulum calcium homeostasis are involved in the induction of neuronal cell injury. Two types of intracellular Ca2+-release channels, involving the ryanodyne receptor and the inositol (1,4,5)-triphosphate receptor, are essential for Ca2+ signaling in cells. Dantrolene, which is used for the treatment of malignant hyperthermia syndrome, has been reported to inhibit Ca2+ release through ryanodyne receptors from the endoplasmic reticulum into the cytosol. We designed this study to investigate the neuroprotective effects of dantrolene on hypoxic-ischemic brain damage in the neonatal rat brain. METHODS:Seven-day-old Sprague-Dawley rats were assigned into two groups; control group (n = 69) and dantrolene group (n = 60). Dimethyl sulfoxide was administered intracerebroventricularly in the control group, and dantrolene in dimethyl sulfoxide was similarly administered to the dantrolene group, before hypoxic-ischemic brain injury (HII). HII was induced by the ligation of the common carotid artery under isoflurane anesthesia, followed by exposure to about 2.5 h of hypoxia (oxygen concentration was maintained at 7%-8%). 1H magnetic resonance spectroscopy was performed 1 day after HII. This noninvasive method evaluated apoptotic processes in the brain after HII. Morphologic score analyses and the calculated percentage of infarct areas after 2,3,5-triphenyltetrazolium chloride staining 14 days after HII were also used to evaluate the effects of dantrolene on HII. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) staining was performed 1 day after HII using 24 more rats. RESULTS:The lipid/creatine ratios in the right hemispheres in the dantrolene group 1 day after HII were significantly lower than those of the control group (P < 0.05). There was no significant difference between the two groups in the N-acetylaspartate/creatine ratios. The gross morphologic scores were lower in the dantrolene group than in the control group (P < 0.05), and infarct area (%) after 2,3,5-triphenyltetrazolium chloride staining was less in the dantrolene group than in the control group (P < 0.05) 14 days after HII. Further work with 24 rats showed no significant difference, however, in the number of TUNEL positive cells on the two groups. CONCLUSIONS:Our results show that dantrolene, administered intracerebroventricularly before HII, had a neuroprotective effect in HII model of the neonatal rat brain.

Scoring Method for Early Prediction of Neonatal Chronic Lung Disease Using Modified Respiratory Parameters

In our previous study, we have demonstrated that peak inspiratory pressure over birth weight (PIP/kg) and mean airway pressure over birth weight (MAP/kg) were more significant risk factors for the development of neonatal chronic lung disease (CLD) than PIP and MAP. We aimed to develop a scoring method using the modified respiratory variables (SMUMRV) to predict CLD at early postnatal period. From 1997 to 1999, a retrospective review was performed for 197 infants <1,500 g for the development of the SMUMRV based on statistical analysis. From 2000 to 2001, calculated scores on day 4, 7 and 10 of life were obtained prospectively for 107 infants <1,500 g. Predictive values and the area under the receiver operator characteristic curve (AUC) were determined and compared with the result of the previous regression model. Gestational age, birth weight, 5 min Apgar score, PIP/kg at 12 hr of age, fractional inspired oxygen (FiO2), MAP/kg, modified oxygenation index and ventilatory mode were selected as parameters of SMUMRV. No significant differences of AUCs were found between the SMUMRV and the Yoder model. It is likely that our scoring method provides reliable values for predicting the development of CLD in very low birth weight infants.

Epidemiology of respiratory syncytial virus infection in infants born at less than thirty-five weeks of gestational age.

Background: The aims of this study were to observe the respiratory syncytial virus (RSV) hospitalization rate and to identify the risk factors for hospitalization for RSV infection among infants in Korea born at <35 weeks of gestational age and who had not previously received palivizumab. Methods: We conducted a study over a 2.5-year period (between April 2007 and September 2009) that included premature infants (<35 weeks of gestational age) who underwent follow-up during 1 year after discharge from the neonatal intensive care unit. Demographic information was collected for each subject at baseline, and the reasons for hospitalization were obtained during the 1-year follow-up period. Results: The study population included 1022 subjects who completed follow-up interviews. Eight hundred seventeen infants were included in analysis for RSV hospitalization. Excluded from the study were 167 subjects with chronic lung disease who had received palivizumab prophylaxis and 38 subjects who were not tested for RSV. The overall incidence of RSV hospitalization in the group that did not receive palivizumab was 4.5% (37 of 817 patients). Independent risk factors associated with RSV hospitalization were multiple gestation (P = 0.022) and longer duration of mechanical ventilation in the neonatal intensive care unit (P = 0.039). Conclusion: This study showed the epidemiology and risk factors of RSV hospitalization in preterm infants in Korea. RSV infection was one of the main causes of hospitalization after discharge from the neonatal intensive care unit in patients born at <35 weeks of gestational age.