• Pediatric Infection and Vaccine
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• v.22 no.2
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• pp.75-80
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• 2015

Purpose: Ventilator-associated pneumonia (VAP) is a serious threat in critically ill pediatric patients. Data regarding Stenotrophomonas maltophilia VAP in pediatric population is limited. We evaluated the clinical data of S. maltophilia associated VAP in critically ill pediatric patients. Methods: A retrospective chart review was performed in pediatric patients 18 years old or younger who developed S. maltophilia associated VAP at Samsung Medical Center, Seoul Korea from January 2008 to December 2012. Results: A total of 31 patients were identified S. maltophilia associated VAP. Median age was 8 months (range, 0.5 month to 16.6 years) and 13 patients were male (40.6%). Underlying illnesses were cardiologic diseases (n=11, 34.4%), hematologic oncologic malignancies (n=7, 25%), neurologic diseases (n=4, 12.5%), pulmonary diseases (n=3, 9.4%), and others (n=4, 12.5%). The median duration of ventilator use before S. maltophilia VAP diagnosis was 14 days (range, 4-256 days). Overall mortality at 30 days was 12.5% (4/32). Conclusions: S. maltophilia should be also considered as a possible pathogen for VAP in critically ill pediatric patients. Empiric antibiotic choice should include agents that are active against S. maltophilia in patients who are deteriorating on broad spectrum beta-lactam antimicrobial agents.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.112.2-112.2
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• 2011

PVT(Photovoltaic Thermal) 모듈은 태양광과 태양열 에너지를 동시 이용이 가능한 모듈로서 태양광전지(PV, Photovoltaic)모듈에 열교환기를 접합한 형태로 전기에너지뿐만 아니라 열에너지를 동시에 생산할 수 있는 시스템이다. 기존 PV 모듈은 일사량이 많으면 전력 생산량이 증가하는 동시에 PV모듈의 온도가 상승함에 따라 발전 효율이 감소하는 문제점이 있으며 일반적으로 $25^{\circ}C$이상 조건에서 모듈 온도가 $10^{\circ}C$ 증가할수록 발전효율의 약 4~5% 정도 감소하는 것으로 보고되고 있다. PVT 모듈은 기존 태양광모듈에 열교환기를 접합하여 냉각함으로써 PV모듈의 온도를 낮추어 발전효율을 증가시키는 동시에 부가적으로 발생하는 온수를 직접이용하거나 다양한 계통의 보조 열원으로 이용할 수 있는 장점이 있다. 본 연구에서는 수치해석기법(CFD)을 활용하여 PV모듈 냉각 및 온수 발생을 위한 열교환기를 설계하였으며 다양한 형상의 열교환기에 대해 유동해석을 수행하여 최적의 열흡수효율을 갖는 열교환기의 형상을 설계하였다. 또한 최적 설계된 PVT 모듈을 제작하여 실제 태양과 유사한 광원을 갖는 인공태양조건에서의 실내 실험을 통해 PVT 모듈의 성능을 검증하였으며 또한 실제 노상에 설치하여 ASHRAE 93-77의 실험기준과 ECN의 PVT 집열기 성능측정 가이드라인에 따라 옥외 시험평가를 하여 PVT 모듈의 성능 검증을 하였다. 최적 설계된 PVT모듈에 대한 성능평가 결과 기존 PV 모듈보다 발전효율이 약 15%(기존 발전효율 대비) 향상된 결과를 확인하였다.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.44-49
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• 2009

Purpose : Early surfactant treatment and minimal ventilation, bronchopulmonary dysplasia needed prolonged oxygen supplement is a problem. This study aimed to report the effects of early surfactant treatment and minimal ventilation on the prevention of bronchopulmonary dysplasia in respiratory distress syndrome. Methods : We retrospectively studied 139 premature newborn infants (gestational age, 36 weeks; birth weight, 1,500 gm) admitted to the neonatal intensive care unit of Daegu Fatima Hospital between January 2001 and December 2006. We analyzed the occurrence of bronchopulmonary dysplasia with respect to ventilator care and surfactant treatment. Results : The incidence of bronchopulmonary dysplasia was significantly higher with prolonged ventilator care, moderate to severe respiratory distress syndrome, and low Apgar score (P<0.001). Despite early surfactant treatment and minimal ventilation, mild bronchopulmonary dysplasia occurs in a considerable number of patients with mild respiratory distress syndrome. The patient group with low Apgar scores required ventilator care for a prolonged period (P=0.020). Conclusion : Early surfactant treatment and minimal ventilation shortens the duration of ventilator care; however, the preventive effects on bronchopulmonary dysplasia are limited. Therefore, not only early surfactant treatment and minimal ventilation but also appropriate management in the delivery room is essential.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.803-810
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• 1999

Background : The patient's work of breathing(WOBp) during assisted ventilation may vary according to many factors including ventilatory demand of the patients and applied ventilatory setting by the physician. Pressure-controlled ventilation(PCV) which delivers gas with decelerating flow may better meet patients' demand to improve patient-ventilator synchrony compared with volume-controlled ventilation(VCV) with constant flow. This study was conducted to compare the difference in WOBp in two assisted modes of ventilation, PCV and VCV with constant flow. Methods : Ten patients with respiratory failure were included in this study. Initially, the patients were placed on VCV with constant flow at low tidal volume($V_{T,\;LOW}$)(6-8 ml/kg) or high tidal volume($V_{T,\;HIGH}$)(10-12 ml/kg). After a 15 minute stabilization period, VCV with constant flow was switched to PCV and pressure was adjusted to maintain the same tidal volume($V_T$) received on VCV. Other ventilator settings were kept constant. Before changing the ventilatory mode, WOBp, $V_T$, minute ventilation($V_E$), respiratory rate(RR), peak airway pressure (Ppeak), peak inspiratory flow rate(PIFR) and pressure-time product(PTP) were measured. Results : The mean $V_E$ and RR were not different between PCV and VCV during the study period. The Ppeak was significantly lower in PCV than in VCV during $V_{T,\;HIGH}$. HIGH ventilation(p<0.05). PIFR was significantly higher in PCV than in VCV at both $V_T$ (p<0.05). During $V_{T,\;LOW}$ ventilation, WOBp and PTP in PCV($0.80{\pm}0.37\;J/min$, $164.5{\pm}74.4\;cmH_2O.S$) were significantly lower than in VCV($1.06{\pm}0.39J/mm$, $256.4{\pm}107.5\;cmH_2O.S$)(p<0.05). During $V_{T,\;HIGH}$ ventilation, WOBp and PTP in PCV($0.33{\pm}0.14\;J/min$, $65.7{\pm}26.3\;cmH_2O.S$) were also significantly lower than in VCV($0.40{\pm}0.14\;J/min$, $83.4{\pm}35.1\;cmH_2O.S$)(p<0.05). Conclusion : During assisted ventilation, PCV with decelerating flow was more effective in reducing WOBp than VCV with constant flow. But since individual variability was shown, further studies are needed to confirm these results.

• Clinical and Experimental Pediatrics
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• v.50 no.12
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• pp.1200-1205
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• 2007

Purpose : We performed this study to investigate the outcome of surfactant replacement therapy (SRT) in above nearterm neonates who were required mechanical ventilatory care due to meconium aspiration pneumonia (MAP), respiratory distress syndrome (RDS) or other severe pneumonia (PN). Methods : 48 patients, gestational period ${\geq}36weeks$, who were admitted in NICU of Dongsan Medical Center, Keimyung University between July 1999 and June 2004 were enrolled. They were divided into three groups, MAP group (15 cases), RDS group (27 cases) and PN group (6 cases). All patients were received SRT and evaluated several clinical data (gestational age, oxygen index, duration of ventilator care) and outcome (complications and mortality rate) between pre-SRT and post-SRT. The mean dose of surfactant (modified bovine surfactant, Newfacten, Yuhan Co., Seoul, Korea) was 120 mg/kg. Results : Among each groups, mean pre-SRT OI was higher in MAP group ($21{\pm}3.2$) than other groups, mean duration (days) of ventilatory care and oxygen therapy were similar distributions. Compared with pre-SRT values, significant improvements (P<0.05) in mean values for FiO2 and oxygenation index were documented at 12 hours after SRT. Early complications (persistent pulmonary hypertension of newborm, pneumothorax) and survival rate were lower in MAP group. Within RDS group, earlier SRT (given before 12 hours of life) revealed significantly lower early complication rate than later SRT (given after 12 hours of life) (13.3% vs 58.3%, P<0.05) Conclusion : Our study suggested that SRT seems to be an effective therapy in above nearterm neonates with severe pulmonary disease, and earlier SRT tends to reduce complications in RDS group than later therapy.

• Child Health Nursing Research
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• v.17 no.2
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• pp.145-152
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• 2011

Purpose: To evaluate the efficacy of Optimal humidification during Nasal Continuous Positive Airway Pressure (nCPAP) for Extremely Low Birth Weight Infant (ELBWI). Methods: The study design was a pre-test-post-test nonequivalent nonsynchronized quasi-experimental design. The participants were 218 ELBWI on nCPAP (experimental group: 102 and control group: 116). Data collection was conducted from January 2005 to April 2010. In order to measure and analyze the nCPAP duration, reintubation and nasal condition, Chi-square test and t-test were used. Results: Hypothesis 1, that the duration with nCPAP in the experimental group is longer than that of the control group and hypothesis 2-3, that the rate of reintubation and nasal problems in the experimental group are lower than the control group, were all supported as there were statistically significant differences between two groups. Conclusion: The findings suggest that the Optimal humidification in this study is an efficient intervention because it helps increase the last time of nCPAP with ELBWI and minimize complications. It is expected that Optimal humidification is beneficial and helpful in preventing and caring for respiratory problems in these infants.

• Clinical and Experimental Pediatrics
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• v.52 no.3
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• pp.310-314
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• 2009

Purpose : Pneumothorax is an important factor responsible for increased mortality and morbidity in neonates. Here, we compared the clinical findings and prognosis for neonatal pneumothorax induced by respiratory distress syndrome (RDS) and pneumonia. Methods : Between January 2001 and December 2005, 80 patients with neonatal pneumothorax induced by RDS and pneumonia and admitted to the NICU of Dongsan Medical Center, Keimyung University, were enrolled. They were assigned to the RDS group (30 cases) or the pneumonia group (50 cases). Admission records for gestational age, onset day of life, rate of ventilatory care and thoracostomy, and prognosis were retrospectively reviewed and statistically analyzed for both groups. Results : The mean gestation age was significantly shorter in the RDS group (32.3 weeks) than in the pneumonia group (38.1 weeks) (P<0.001), and the mean onset day of life were later in the RDS group (4.6 days) than in the pneumonia group (1.8 days) (P<0.05). Rates of ventilatory care and thoracostomy were higher for the RDS group than for the pneumonia group (100% vs. 44%, and 66.7% vs. 48%, respectively). Total mortality rates and pneumothorax specific mortality rates were higher for the RDS group than for the pneumonia group (46.7% vs. 18%, P<0.01 and 33.3% vs. 16%, P<0.05, respectively). After logistic regression analysis, preterm significantly increased the mortality rate (OR 7.44, 95% CI: 1.99-27.86, P<0.005), but bilateral involvement (OR 1.17, 95% CI: 0.82-1.67, P>0.5) and the RDS group itself (OR 1.70, 95% CI: 0.52-5.54, P>0.3) did not increase mortality rates significantly. Conclusion : Our study suggests that neonatal pneumothorax in the RDS group tends to have a later onset, higher mortality rate, and needs a higher rate of thoracostomy than the pneumonia group. However, after logistic analysis, only preterm significantly and independently increased the mortality rate.

• Neonatal Medicine
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• v.17 no.1
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• pp.21-33
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• 2010

Purpose : The increased survival of preterm infants in the neonatal intensive care unit recently has resulted in an increased frequency of bronchopulmonary dysplasia (BPD), especially with atypical forms. However, there have been few studies compairing classic and atypical BPD. The aim of this study was to investigate the differences between these two types of BPD. Methods : Infants with a gestational age less than 32 weeks born at the Seoul National University Hospital and Bundang Seoul National University Hospital from May 2004 to April 2007 were included. The data were categorized in 2 groups, classic and atypical BPD. We determined the incidence of BPD, and compared perinatal factors and postnatal managements between two groups. Results : Among 260 study subjects, 141 (54.2%) infants had BPD. Classic BPD infants were 64 and atypical BPD infants were 77. Comparison of differences between 2 groups, classic BPD infants were associated with respiratory distress syndrome, patent ductus arteriosus, intrauterine growth restriction, more high-frequency ventilator (HFV) use, low 1 and 5 minute Apgar scores. Atypical BPD infants were associated with antenatal steroid use, maternal premature rupture of membrane and chorioamnionitis (CAM). In multivariate analysis, more HFV use was associated with classic BPD. Antenatal steroid use, clinical CAM and histological CAM were associated with atypical BPD. Conclusion : The results of this study showed that antenatal factors (antenatal steroid use, clinical CAM, histological CAM) were associated with atypical BPD and postnatal factors (HFV used more) were associated with classic BPD. Further studies are needed for prevention and treatment of BPD.

• Fire Science and Engineering
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• v.31 no.2
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• pp.113-118
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• 2017

The purpose of this study was to compare the ventilatory volume and airway pressure using Oxylator EM-100, MicroVenT CSI-3000, OXY-LIFE II. The data were obtained from February 13 in 2017 andanalyzed using the SPSS WIN 18.0 program. The results of theventilatory volume showed the Oxylator EM-100 551.44 ml (${\pm}18.70$), MicroVenT CSI-3000 527.26 ml (${\pm}17.98$), and OXY-LIFE II 369.46 ml (${\pm}12.30$). The airway pressure showed the Oxylator EM-100 $11.89cmH_2O$ (${\pm}.41$), MicroVenT CSI-3000 $11.66cmH_2O$ (${\pm}.34$), and OXY-LIFE II $8.02cmH_2O$ (${\pm}.25$). This study will provide the basic data for an appropriate ventilation method by an oxygen supply device including Oxylator EM-100, MicroVenT CSI-3000, and OXY-LIFE II.

• Journal of Chest Surgery
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• v.39 no.7 s.264
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• pp.505-510
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• 2006

Background: Small animal cardiopulmonary bypass (CPB) model would be a valuable tool for investigating path-ophysiological and therapeutic strategies on bypass. The main advantages of a small animal model include the reduced cost and time, and the fact that it does not require a full scale operating environment. However the rat CPB models have a number of technical limitations. Effective maintenance and control of core temperature by a heat exchanger is among them. The purpose of this study is to confirm the effect of rectal temperature maintenance using a heat exchanger of cardioplegia system in cardiopulmonary bypass model for rats. Material and Method: The miniature circuit consisted of a reservoir, heat exchanger, membrane oxygenator, roller pump, and static priming volume was 40 cc, Ten male Sprague-Dawley rats (mean weight 530 gram) were divided into two groups, and heat exchanger (HE) group was subjected to CPB with HE from a cardioplegia system, and control group was subjected to CPB with warm water circulating around the reservoir. Partial CPB was conducted at a flow rate of 40 mg/kg/min for 20 min after venous cannulation (via the internal juglar vein) and arterial cannulation (via the femoral artery). Rectal temperature were measured after anesthetic induction, a ter cannulation, 5, 10, 15, 20 min after CPB. Arterial blood gas with hematocrit was also analysed, 5 and 15 min after CPB. Result: Rectal temperature change differed between the two groups (p<0.01). The temperatures of HE group were well maintained during CPB, whereas control group was under progressive hypothermia, Rectal temperature 20 min after CPB was $36.16{\pm}0.32^{\circ}C$ in the HE group and $34.22{\pm}0.36^{\circ}C$ in the control group. Conclusion: We confirmed the effect of rectal temperature maintenance using a heat exchanger of cardioplegia system in cardiopulmonary bypass model for rats. This model would be a valuable tool for further use in hypothermic CPB experiment in rats.