• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.593-598
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• 2018

Computational fluid dynamics was used to develop a heat-recovery ventilator for preventing freezing in cold weather. An optimal internal return damper was applied, and a prototype was made for frost and freezing experiments. A total of 16 models were used to design the optimal internal return damper with the maximum exhaust recirculation ratio. The exhaust recirculation ratio of the exhaust air to the outdoor air was 59.9-62.3%. The tests showed that frost and freezing did not occur at outdoor air temperatures of $-15^{\circ}C$ or higher in both exhaust recirculation operation and normal operation. However, at an outdoor air temperature of $-20^{\circ}C$, no freezing occurred in the outdoor air area when the internal return damper was opened by 45 degrees. Heat recovery ventilators for preventing cold weather frost and freezing should be operated in two operation modes: normal and exhaust recirculation mode. An operating algorithm was developed for the heat-recovery ventilator operating in normal mode when the outdoor temperature is higher than $-15^{\circ}C$ and recirculation mode when the temperature is lower.

• Neonatal Medicine
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• v.18 no.1
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• pp.153-157
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• 2011

Pneumopericardium is a rare form of neonatal air leakage. Tension pneumopericardium is much more infrequent, but can cause a cardiovascular deterioration with high mortality up to 80% and neurodevelopmental morbidity in half of the cases. We report two cases of preterm infants who successfully recovered from tension pneumopericardium that developed during mechanical ventilator assistance. The patients displayed a sudden increase in oxygen demand and subsequent cardiovascular deterioration. Immediate needle aspiration of the pneumopericardium performed after checking X-ray images rescued each of patient. Since the clinical symptoms are non-specific, clinicians' suspicion is most important when patients show sudden refractory cardiovascular collapse, especially in ventilator-assisted neonates. This life threatening complication demands instant diagnosis and intervention.

• Journal of The Korean Society of Clinical Toxicology
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• v.16 no.2
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• pp.86-92
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• 2018

Purpose: Cardiovascular or respiratory complications of acute intoxication are the most common causes of mortality. Advanced cardiac life support (ACLS) or specific antidotes help manage these cardiac or respiratory complications in acute intoxication. On the other hand, some cases do not respond to ACLS or antidotes and they require some special treatment, such as extracorporeal life support (ECLS). ECLS will provide the chance of recovery from acute intoxication. This study examined the optimal timing of ECLS in acute intoxication cases. Methods: This paper is a brief report of a case series about ECLS in acute poisoning. The cases of ECLS were reviewed and the effects of ECLS on the blood pressure and serum lactate level of the patients were analyzed. Results: A total of four cases were reviewed; three of them were antihypertensive agent-induced shock, and one was respiratory failure after the inhalation of acid. The time range of ECLS application was 4.8-23.5 hours after toxic exposure. The causes of ECLS implementation were one for recurrent cardiac arrest, two for shock that did not respond to ACLS, and one for respiratory failure that did not respond to mechanical ventilator support. Three patients showed an improvement in blood pressure and serum lactate level and were discharged alive. In case 1, ECLS was stared at 23.5 hours post toxic exposure; the patient died due to refractory shock and multiple organ failure. Conclusion: The specific management of ECLS should be considered when a patient with acute intoxication does not recovery from shock or respiratory failure despite ACLS, antidote therapies, or mechanical ventilator support. ECLS improved the hemodynamic and ventilator condition in complicated poisoned patients. The early application of ECLS may improve the tissue perfusion state and outcomes of these patients before the toxic damage becomes irreversible.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.736-741
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• 2008

Background: Pneumonia continues to be the most common major infection in trauma patients. Despite the advances in prevention, diagnosis, and treatment for pneumonia, it remains a major cause of morbidity and mortality. The aim of this retrospective study is to identify the risk factors and clinical features of ventilator-associated pneumonia among chest trauma patients. Material and Method: The study population consisted of 78 mechanically ventilated patients admitted to the ICU of Chonnam National University Hospital between January, 2001, and December, 2006. The patients were divided into two groups: those with pneumonia (Group I) and without pneumonia (Group II). Clinical predictors of the occurrence and mortality for ventilator associated pneumonia were analyzed. Result: There were 57 men and 21 women, with a mean age of $48.3{\pm}19.9$ years. Almost half of the patients, 48.7% (38 of 78), had pneumonia. The mortality rate was 21.0% (8 of 38) in Group I and 2.5% (1 of 40) in Group II. The predictors of ventilator-associated pneumonia were the duration of mechanical ventilation (17.4 days vs 6.5 days, p<0.001), the mean stay in the ICU (21.7 days vs 9.7 days, p<0.001), the use of inotropics due to hemodynamic instability (63.1% vs 25.0%, p=0.001), and the serum level of CRP ($11.3{\pm}7.8$ vs $6.4{\pm}7.3$, p=0.006). Conclusion: Posttraumatic ventilator-associated pneumonia was significantly related with the duration of mechanical ventilation, the mean stay in ICU, and the use of inotropics due to hemodynamic instability. The serum level of CRP at admission was higher in the pneumonia group. Morbidity and mortality can be reduced by early identification of predictive factors for developing pneumonia in chest trauma patients.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1272-1276
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• 2009

The purpose of this study is to introduce wasted heat recovery heat exchanger for different kind of material in HVAC systems in field. For the purpose of estimating the large volume rotary heat exchanger and cross flow plate heat exchanger in heat recovery ventilator.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.951-954
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• 1995

Diagnostic procedures in pregnant wowen is limited and is usually delayed, especially so if she is on mechanical ventilation. A 28-year-old pregnant woman with severe dyspnea was referred to our hospital under the impression of miliary tuberculosis. The respiratory failure was so severe that patient had to be managed with mechanical ventilator under clinical impression of overwhelming pneumonia or pulmonary tuberculosis. But the patient's conditions deteriorated. Bronchoscopy and blind transbronchial lung biopsy performed to determine the nature of the etiology, and to our surprise, revealed squamous cell carcinoma of the lung.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.893-897
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• 2009

Purpose : Advances in neonatal intensive care have improved the survival rate of low-birth-weight infants, but mild bronchopulmonary dysplasia (BPD) with the accompanying need for prolonged oxygen supplement remains problematic. Maternal chorioamnionitis and neonatal ventilator care affect the development of BPD. This study aimed to examine whether maternal chorioamnionitis or neonatal ventilator care affect the development of BPD dependently or independently. Methods : We performed a retrospective study of 158 newborn infants below 36 weeks of gestational age and 1,500 gm birth weight admitted to the neonatal intensive care unit of Daegu Fatima Hospital between January 2000 and December 2006. We analyzed the incidence of BPD according to maternal chorioamnionitis and neonatal ventilator care. Result : Histologic chorioamnionitis was observed in 50 of 158 infants (31.6%). There were no significant differences in the development of BPD (P=0.735) between the chorioamnionitis (+) and chorioamnionitis (-) groups. In the multiple regression analysis, ventilator care (OR=7.409, 95% CI=2.532-21.681) and neonatal sepsis (OR=4.897, 95% CI=1.227-19.539) affected the development of BPD rather than maternal chorioamnionitis (OR=0.461, 95% CI=0.201-1.059). Conclusion : Ventilator care or neonatal sepsis may play a role in the development of BPD rather than maternal chorioamnionitis.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.359-362
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• 2013

Chronic hypoventilation due to injury to the brain stem respiratory center or high cervical cord (above the C3 level) can result in dependence to prolonged mechanical ventilation with tracheostomy, frequent nosocomial pneumonia, and prolonged hospitalization. Diaphragm pacing through electrical stimulation of the phrenic nerve is an established treatment for central hypoventilation syndrome. We performed chronic phrenic nerve stimulation for diaphragm pacing with the spinal cord stimulator for pain control in a quadriplegic patient with central apnea due to complete spinal cord injury at the level of C2 from cervical epidural hematoma. After diaphragmatic pacing, the patient who was completely dependent on the mechanical ventilator could ambulate up to three hours every day without aid of mechanical ventilation during the 12 months of follow-up. Diaphragm pacing through unilateral phrenic nerve stimulation with spinal cord stimulator was feasible in an apneic patient with complete quadriplegia who was completely dependent on mechanical ventilation. Diaphragm pacing with the spinal cord stimulator is feasible and effective for the treatment of the central hypoventilation syndrome.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.137-143
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• 2017

An axial fan has competitive advantages that can make air flow more straight and longer and produce larger air volume than the other kinds of fans. In those reasons, axial fans are widely used for ventilator, 4D cinema, duct, and so on. But, as it was designed and manufactured without any mathematical analysis or computer simulations, it is difficult to develop the performance of axial fans. Actually the axial fan is designed and manufactured in industry by imitation or traditional method. Flow velocity and volume of axial fan are changed by pitch angle, frame, the number of blade, camber angle, and chord length. In this paper, the performance of axial fan was analyzed and by computer program known as CFD. Finally, we have designed a new axial fan whose velocity and volume is improved. The performance of new axial fan is also compared with the of conventional fans experimentally.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1200-1206
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• 2003

Purpose : This study was conducted for the use of nasal continuous positive airway pressure (CPAP), by comparing the early use of non-invasive nasal CPAP with low intermittent mandatory ventilation(low IMV) and endotracheal CPAP in weaning a mechanical ventilator from infants with moderate respiratory distress syndrome(RDS). Methods : Thirty infants in the study group, with moderate RDS from November 2001 to June 2002, were administered surfactants and treated with the mechanical ventilator, and applied the nasal CPAP in weaning. Thirty infants of the control group, from January 1999 to September 2001, were applied low IMV and endoctracheal CPAP in weaning. Results : There were no significant differences in the characteristics, the severity of clinical symptoms, the initial laboratory findings and settings of the mechanical ventilator. After weaning, the study group showed no significant changes in $PaCO_2$. However, the control group showed a slight $CO_2$ retension after one and 12 hours. Twenty eight infants(93.3%) of the study group and 24 infants(80%) of the control group were successfully extubated. The primary cause of failure was apnea. There were no significant differences in the duration of weaning and the mechanical ventilator treatment between the groups. Complications in weaning were related to the fixation of nasal CPAP and the mechanical problems caused by endotracheal tube. Conclusion : Aggressive weaning is possible for moderate RDS, in which the nasal CPAP was used without the low IMV and the endotracheal CPAP process. It had no difficulties. In conclusion, the nasal CPAP is an adequate weaning method for moderate RDS.