• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.115-122
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• 2021

Oral cancer surgery typically consists of resection of lesion, neck dissection and reconstruction, and it has an impact on the position of hyoid bone. Therefore, morphological change of airway can occur since the geometric parameter of airway is correlated with the hyoid bone. Airflow is affected by geometry of the airway. In this study, flow characteristics were compared between pre- and post-surgery models by both particle image velocimetry (PIV) and numerical simulation. 3D model of upper airway was reconstructed based on CT data. Velocity is accelerated by the reduced channel area, and vortex and recirculation region are observed in pre- and post-surgery models. For the post-surgery model, high pressure distribution is developed by significantly decreased hydraulic diameter, and the longitudinal flow stream is also interrupted.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.215-221
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• 2019

The respiratory medical device is a medical device that delivers optimal oxygen or a certain amount of humidification to a patient by delivering artificial respiration to a patient through a machine when the patient has lost the ability to breathe spontaneously. These include respirators for use in chronic obstructive pulmonary disease and anesthesia or emergency situations, and positive airway pressure devices for treating sleep apnea, and as the population of COPD (chronic obstructive pulmonary disease) and elderly people worldwide surge, the market for the respiratory medical devices it is getting bigger. As the demand for both airway pressure devices, there is a problem that the ventilator standard is applied because the reference standard has not been established. Therefore, the boundaries between the items are blurred due to the purpose, intended use, and method of use overlapping similar items in a respiratory medical device. In addition, for both airway pressure devices, there is a problem that the ventilator standard is applied because the reference standard has not been established. Therefore, in this study, we propose clear classification criteria for the respiratory medical devices according to the purpose, intended use, and method of use and provide safety and performance evaluation guidelines for those items to help quality control of the medical devices. And to contribute to the rapid regulating and improvement of public health. This study investigated the safety and performance test methods through the principles of the respiratory medical device, national and international standards, domestic and international licensing status, and related literature surveys. The results of this study are derived from the safety and performance test items in the individual ventilator(ISO 80601-2-72), the International Standard for positive airway pressure device (ISO 80601-2-70), The safety and performance of humidifiers (ISO 80601-2-74) and the safety evaluation items related to home healthcare environment (IEC 60601-1-11), In addition, after reviewing the guidelines drawn up through expert consultation bodies including manufacturers and importers, certified test inspection institutions, academia, etc., the final guidelines were established through revision and supplementation. Therefore, in this study, we propose guidelines for evaluating the safety and performance of the respiratory medical device in accordance with growing technology development.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.443-448
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• 2015

Obstructive sleep apnea (OSA) is a syndrome characterized by the repetitive episodic collapse of the upper airway. Maxillomandibular advancement surgery is one of the most effective surgical treatment methods in treating obstructive sleep apnea. The advancement of both maxill and mandible can enlarge the cross-sectional areas and volumes of the postero-superior airway. The purpose of this study is to analyze flow patterns in the upper airway before and after maxillomandibular advancement surgery. Here, we analyzed flow phenomena of inspiration and expiration to prevent obstructive sleep apnea patient from happening side effect. Modeling of the upper airway carried out from clinical CT scanned images. We used time-dependent values for boundary condition. CFD analyses were performed and evaluated section of minimum area (SMA), compared with patient inside upper airway before and after maxillomandibular advancement surgery in SMA, and negative pressure effects. The study showed the greatest enlargment of the section of minimum cross-sectional area. Moreover, the velocity and the negative airway pressure were decreased. According to the result of this study, the maxillomandibular advancement surgery stabilizes the airflow in the postero-superior airway of OSA patients.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.532-535
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• 2004

Acute fulminating pulmonary edema was developed in 20 year old female following an acute airway obstruction due to a burglary attack on neck with bare hands. The pathogenesis of pulmonary edema is related to the alveolar and capillary damage induced by the severe negative pressure generated by attempting to inspire against the closed upper airway. This female responded to fluid restriction and oxygen supply. To our knowledge, pulmonary edema caused by man has never been reported in the literature.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.119-130
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• 1996

We review the factors which regulate the depth and composition of the human airway surface liquid (ASL). These include secretion from airway submucosal glands, ion and fluid transport across the surface epithelium, goblet cell discharge, surface tension and transepithelial gradients in osmotic and hydrostatic pressure. We describe recent experiments in which we have used low temperature scanning electron microscopy of rapidly frozen specimens to detect changes in depth of ASL in response to submucosal gland stimulation. We also present preliminary data in which X-ray microanalysis of frozen specimens has been used to determine the elemental composition of ASL.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.18-26
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• 2000

Objectives: To investigate the airway narrowing patterns by multi-level airway pressure(MAP) monitoring during sleep and to evaluate the value of CT scan taken during waking and sleep apneic periods to identify the level of airway narrowing(LAN) in patients with obstructive sleep apnea syndrome(OSAS). Methods: Eleven patients with OSAS underwent a night polysomnography with continuous MAP monitoring by 4-sensor(placed at nasopharynx, caudal-uvula, hypopharynx, esophagus) or 2-sensor(placed at caudal-uvula and esophagus) catheter. All patients had cine CT at five levels of high retro and alatal, low retropalatal, retroglossal, epiglottis and hypopharynx during awake and sleep periods. In each patient, LAN determined by CT scan($LAN_{CT}$) during sleep apnea was compared with LAN by MAP monitoring($LAN_{MAP}$). Results: MAP monitoring showed that four patients(36%) had a single pattern of LAN while the other seven patients(64%) showed two or more different LANs in different apneic episodes. Velopharynx was the most common level of frequently observed airway narrowing during sleep apnea(63.6%). However, a single pattern of airway narrowing was more frequent(72.7%) in airway CT during sleep apnea. Velopharynx was the most common narrowest level also in apneic CT(66%). In comparing $LAN_{CT}$ with $LAN_{MAP}$, the $LAN_{CT}$ of five patients(45.5%) were high-concordant, those of another five(45.5%) low-concordant, and that of one(9%) discordant with $LAN_{MAP}$. Conclusions: Cine CT scan during the awake state or sleep apnea may not reflect the LAN correctly in OSAS because most patients showed two or more different airway narrowing patterns during different episodes of sleep apnea in each patient.

• The Journal of the Korean dental association
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• v.53 no.1
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• pp.47-56
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• 2015

Obstructive sleep apnea (OSA), most common respiratory disorder of sleep, is characterized by intermittent partial or complete occlusions of the upper airway due to loss of upper airway dilating muscle activity during sleep superimposed on a narrow upper airway. Termination of these events usually requires arousal from sleep and results in sleep fragmentation and hypoxemia, which leads to poor quality of sleep, excessive daytime sleepiness, reduced quality of life and numerous other serious health consequences Untreated OSAS can cause various problems such as hypertension, diabetes, stroke, cardiac disease, daytime sleepiness. Various treatments are available, including non-surgical treatment such as medication or modification of life style, surgical treatment, continuous positive airway pressure (CPAP) and oral appliance (OA). Oral appliance is known to be effective in mild to moderate OSA, also genioglossus muscle advancement (GA) or maxillomandibluar advancement (MMA) is a good option for OSA patients with muscular or skeletal problems. Although the prevalence of OSA is increasing, the proportion of the patient treated by dentist is still very law. Dentists need to understand the mechanism of OSA and develop abilities to treat OSA patients with dental problems. The purpose of this paper is to give a brief overview about OSA and the dentist's role in OSA patients.

• Physical Therapy Rehabilitation Science
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• v.7 no.1
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• pp.18-22
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• 2018

Objective: This study aimed to investigate the effect of different-sized airways of the inspiratory muscle trainer (IMT) on maximal inspiratory pressure (MIP) and the rating of perceived exertion, as measured by the modified Borg scale (m-Borg). Design: Cross-sectional study. Methods: Twenty healthy subjects (10 men, 10 women) volunteered for the study. The spirometry was used to measure MIP. The trial order of the three spirometry conditions was chosen randomly. After measuring the MIP and before taking the final break, each of the conditions were immediately measured using the m-Borg. All subjects used the IMT with an airway diameter of 5-, 6-, and 7-mm. Results: The MIP significantly decreased with the decreasing airway diameter of the IMT (p<0.001), and the differences in all three conditions (7- and 6-mm, 6- and 5-mm, and 7- and 5-mm airways) were significant (p<0.05). The RPE significantly increased with the decreasing airway diameter of the IMT (p<0.001), and the differences in all three conditions (7- and 6-mm, 6- and 5-mm, and 7- and 5-mm airways) were significant (p<0.05). Conclusions: Decreasing the airway diameter of the IMT decreased the MIP and increased the m-Borg. In regards to physical exercise within the clinical setting, the m-Borg could be a useful as a prior monitoring method to prevent dyspnea for patients with narrowed airways (blocked with secretion or sputum in pulmonary disease) and the different-sized airways of the IMT could be applied as a useful tool to improve MIP for prevention of pulmonary disease.

• Journal of Veterinary Science
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• v.21 no.2
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• pp.27.1-27.10
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• 2020

The efficacies of a supraglottic airway device (SGAD) and an endotracheal tube (ETT) in cats under general anesthesia with volume-controlled ventilation (VCV) were compared. Thirty healthy cats were randomly allocated for airway control using either an SGAD or an ETT. Five tidal volumes (6, 8, 10, 12, and 14 mL/kg) were randomly tested, and respiratory rates were adjusted to achieve a minute ventilation of 100 mL/kg/min. The dose of propofol necessary to insert the SGAD or ETT, the static respiratory pressure, leakage during VCV, and end tidal CO₂ (ETCO₂) were recorded. Dosages of propofol and static respiratory measurements for the SGAD and ETT groups were compared using a t-test. The distribution of leakages and hypercapnia (ETCO₂ > 45 mmHg) were compared using Fisher's exact test. A significance level of p < 0.05 was established. No significant difference in dose of propofol was observed between the SGAD and ETT groups (7.1 ± 1.0, 7.3 ± 1.7 mg/kg; p = 0.55). Static resistance pressure of the SGAD (22.0 ± 8.1 cmH₂O/L/sec) was significantly lower than that of the ETT (36.6 ± 12.9 cmH₂O/L/sec; p < 0.01). Of the 75 trials, leakage was more frequent when using an SGAD (8 events) than when using an ETT (1 event; p = 0.03). Hypercapnia occurred more frequently with SGAD (18 events) than with ETT (3 events; p < 0.01). Although intubation with an ETT is the gold standard in small animal anesthesia, the use of an SGAD can reduce airway resistance and the work of breathing. Nonetheless, SGAD had more dead space and the tidal volume for VCV needs adjustment.

• Tuberculosis and Respiratory Diseases
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• v.44 no.6
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• pp.1433-1439
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• 1997

Bronchial foreign body is not a rare disease in children and it is urgently necessary to remove this foreign body from the airway to relive life or to prevent further damages and complications. But the innate small size of airways in infants makes it difficult to access by interventional methods such as intubation or bronchoscopy and etc. Laryngeal mask airway is a new way of method of airway management which is relatively recently introduced into medical practice. It gives way to access to airways without reducing the size of airway or incresing airway pressure during procedure through it and have many other advantages compared to the previous traditional endotracheal intubation, especially in infants. We successfully removed a case of bronchial foreign body, peanut, via laryngeal mask airway during fiberoptic bronchoscopy and by this method we can avoid the unnecessary tracheostomy in this 1 year old infant.