하악골에서 발생한 원발성 Ewing씨 육종 1례

고중화,전상훈,오영택,최진혁 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.2

치과용 니켈-티타늄 합금의 갈바닉 부식

최창혁,최기열,이중배 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

The purpose of this study was to evaluate the galvanic corrosion behavior of NT by coupling with other dental alloys in artificial saliva. The variation of galvanic current and common potential (mixed potential) were monitored as a function of time, and interpreted in terms of the electrochemical properties of each alloy. The effects of adding some constituents such as acid or chloride to the ordinary composition of artificial saliva were also estimated. For most cases of coupling, the significant current was observed only at early stage for several seconds or several minutes, then gradually diminished. The current value was affected by the excessive amount of acid or chloride added to artificial saliva, depending on their aggressiveness on each alloy ; the current was increased in the couples with HG, LG, VT, and decreased in the couples with AM and G2. The results were more complicated in the couples with AP and TC, where some mixed reaction occurred. The common potential was always between two corrosion potentials of alloys involved in the couple, and did not exceed the breakdown potential of alloy acted as anode except the case of coupling with AM in acid-containing artificial saliva. The coupling with AM was found to be the most susceptible to galvanic corrosion.

우리 민속음악의 현대화에 관한 연구

김현중 / 김용래 / 윤경구 / 최종석 / 권혁남 공주교육대학교 초등연구원 1978 公州敎大論叢 Vol.14 No.2

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선인장 양심실 보조장치의 설계 및 임상적용을 위한 평가

민병구,박찬영,최재순,이혁수,황창모,김삼성,윤걸중,김종원,선경,이경갑,정종태,김원곤 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.1

현재 개발되고 있는 맥동형 이식형 인공심장은 완전이식형 인공심장과 좌심실보조장치 뿐이다. 좌심실보조장치를 장착한 환자의 10~15%가 우심실의 보조를 필요로하고 완전이식형 인공심장의 장착을 위해서는 자연심장을 제거해야하는 상황에서 이식형 양심실보조장치에 대한 필요성이 대두되고 있다. 본 연구진은 완전이식형 인공심장으로 개발된 한국형 인공심장을 개선하여 양심 실 보조장치를 개발하였다. 양심실보조장치는 이동형 작동기식 미케니즘을 이용하고 있으며 에너지 변환장치와 감속기로 구성된 작동기와 혈액주머니, 그리고 내장형 제어기로 구성되어 있다. 선인장 펌프로 명명된 KAH350은 캐뉼라의 연결을 위한 커넥터를 포함하여 길이 177mm, 폭 164mm, 높이 67 이고 무게 780g이며 최대 심박출량은 5L/min 이다. 양심실보조장치로 개발된 선인장펌프는 좌심실보조장치로도 응용이 가능하다. 이식적합성과 생체적합성을 평가하기 위하여 좌심실보조장치로 5회, 양싱실보조장치로 6회의 동물실험을 수행하였다. 각각 최장 28일간 생존하였으며 11회의 동물실험중 장치의 결함에 의한 것이 3회 있었는데 이들은 모두 전자장치의 결함과 방수처리문제였다. 현재 이식적합성과 일박출량을 향상시킨 KAH400모델이 개발중이다. The types of pulsatile implantable artificial hearts that are on the way of development and have been developed are totally implantable artificial heart and implantable left ventricular assist device (LVAD). Approximately 10% to 15% of all patients Implanted with wearable VADs have required right heart support with another device. And it is reluctant to patient who should remove his or her own heart to be implanted with total artificial heart. These situations drive the development of implantable bi-ventricular assist device (BVAD). The Korean BVAD was develophed by modifying the moving actuator type Korean artificial heart. This electro-mechanical BVAD comprises actuator including energy converter and reduction gear train, blood sacs, and internal motor and energy controllers. The KAH350 which is named as 'Cactus Pump' is 177mm in length, 164mm in width, and 67mm in thickness including connectors and nuts. The weight and maximum cardiac output of Cactus Pump is 780g and 5L/min, respectively. The Cactus Pump that was developed as BVAD could be used as LVAD by attaching compliance caps on the 2 ports of one ventricle. The animal experiments were undergone 5 times for LVAD, and 6 times for BVAD. The best records were 28 days survival in both applications. There were 3 times of device failure and they were all associated with electrical connection and hermetic sealing. The KAH400 that has improved anatomical fitting characterisitcs and stroke volume is on development.

POSTER PRESENTATION 1: Resuscitation/Airway Management : PS1-2 ; A Study about Lens Fogging of Portable Video Laryngoscopes in Cold Environment

( Hyuk Joong Choi ) 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2

When equipment mounted with lenses that have been in cold environment is exposed abruptly to warm environment, the condensation of moisture on the surface of the lenses happens due to temperature difference. Video laryngoscopes, which were developed recently and are being used widely in operating rooms, emergency rooms, and many other hospital environments, also have a lens. Because the video laryngoscope is inserted inside the body that is warm and highly humid, condensation is highly likely to happen. The authors attempted to examine the degree of condensation in portable video laryngoscopes used in cold environment outside hospital where temperature difference from the body temperature is large. An airway management model (Ambu Airway Trainer, Ambu Corp.) was positioned in a thermohydrostat set at temperature 37°C and humidity 95% similar to the environment of the human throat. We exposed McGrath Mac (Aircraft medical Ltd.UK) and Glidescope Ranger (Verathon Inc. USA) to a refrigerator at 0°C for an hour. Then, taking out and switching the power on immediately, we inserted them at once into the airway management model in the thermohydrostat and videotaped the images on the screens of the video laryngoscopes. Then, the images of the video laryngoscopes were compared. Videotaping was done for 30 seconds just after inserting the video laryngoscope blade. The same experiment was repeated 5 times in order to see if the image on the screen was the same among the experiments. Before the experiments, anti-condensation solution was applied to the LCD screens of the two video laryngoscopes in order to prevent condensation. In both McGrath Mac and GlideScoep Ranger, condensation happened from just after the insertion of the laryngoscope blade. The degree of condensation in McGrath Mac was mild enough to identify the anatomical structure of the glottis, and the same level of condensation was maintained for over 30 seconds. On the other hand, condensation in Glidescope Ranger was so heavy just after the insertion of the laryngoscope blade that the anatomical structure of the glottis could not be identified at all. After about 5 seconds, however, the visual field was improved as much as that in McGrath Mac, and after about 10 seconds, condensation disappeared completely. McGrath Mac is sufficiently usable in cold environment. For GlideScope Ranger, however, it took about 5 seconds after the laryngoscope was turned on until the visual field was sufficiently clear for intubation. Considering this characteristic, it is recommended to turn on the laryngoscope at least 10 seconds before intubation when using GlideScope in cold environment.

Korean Symposium 7: Airway and Resuscitation : KS7-1 ; Rethinking about Rapid Sequence Intubation; Review of Respiratory Physiology and Latest Medical Literature

( Hyuk Joong Choi ) 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2

Severe hypoxic patients who desperately require preoxygenation will impede its provision. Hypoxia and hypercapnia can lead to severe agitation. It can make these patients to rip off their preoxygenation masks. This situation often leads to precipitous attempts at intubation without adequate preoxygenation. Standard RSI method consists of the simultaneous administration of a sedative and a paralytic agent and the provision of no ventilations during intubation attempt. This sequence can be broken to allow for adequate preoxygenation without risking gastric insufflation or aspiration; this is so-called “delayed sequence intubation” (DSI). DSI consists of the administration of sedative agents and followed by preoxygenation before the administration of a paralytic agent. It is similar with the procedural sedation. The patients will be calm, but they can breathe spontaneously. When you use the DSI method, the Ketamine is recommended to use as sedative agent. Ketamine does not blunt spontaneous respirations or airway reflexes during dissociative period. A dose of 1-2 mg/kg by slow intravenous push is recommended. This can make the patient calm within 30 seconds. Then we can do preoxygenation with non-rebreathing mask. If there is shunt, using a non-invasive mask hooked up to ventilator with a CPAP setting of 5-15 cm H20 may be needed. After a saturation of > 95% is achieved, then we can administrate the paralytic agents. After the 45-60 seconds, the patient will be apneic state, then we can intubate the patient. The Ketamine can raise blood pressure, so it is not desirable in patient with hypertension. Dexmedetomidine (alpha-2 agonist) can be an alternative in this situation. A dose of 1 mcg/kg administered over 10 minutes will lead to a sedated patient who will accept preoxygenation after 3-5 minutes in most cases. DSI method can give more oxygen to the patients before intubation, sometimes it improve the patient’s respiratory parameters that intubation can be avoided. It is DSI’s another advantage. If we deem that intubation is still necessary at this point, we can proceed with standard RSI by administering a conventional sedation agent (e.g. etomidate or additional ketamine) in combination with a paralytic, as the patient has already been appropriately preoxygenated. In conclusion, DSI can makes outcome better rather than RSI. However, this can achieved in carefully selected situations. For safe DSI, we have to improve our airway assessment and planning includes oxygen status and predictors of difficult preoxygenation as well as difficult airway.

POSTER PRESENTATION 2: Radiology/Procedures/Education/Administration/QIImportant : PS2-60 ; Mastery Learning of Cardiopulmonary Resuscitation Skills by Medical Students Using Simulation Technology

( Hyuk Joong Choi ),( Tae Ho Lim ),( Wonhee Kim ) 대한응급의학회 2014 대한응급의학회 학술대회초록집 Vol.2014 No.2

CPR education using hi-fi simulation technique is known to produce generally higher education effects than education based on lectures or using lo-fi simulation technique. However, little has been known about difference in the effect of simulation education among individual CPR techniques. Thus, the authors attempted to see if there was any difference in achievement among individual CPR techniques after mastery learning using hi-fi simulation technique. For this study, we had 101 senior medical students, who were participating in the practice course of the Department of Emergency Medicine, complete the basic life support course as prerequisite learning, and presented the goals of learning to them. Then grouping them into teams with 4-6 members, we provided each team with learning materials including videos so that they had unsupervised learning for advanced life support. After two days, each team experienced a cardiac arrest situation using hi-fi simulation technique without separate education. During the simulation, feedback was provided through formative evaluation, and in debriefing, the students were induced to find problems by themselves, to make specific learning plans to solve the problems by themselves, and to have cooperative learning by team. Two days after that, a cardiac arrest situation was presented so that the students would treat, and individual students’ performance was evaluated. The evaluation used 25 items in the practical test used for the Training of In-hospital Cardiac Arrest by the Korean Advanced Life Support of the Korean Association of Cardio-Pulmonary Resuscitation. After the evaluation, the evaluation items were categorized into basic life support technique, leadership, arrhythmia treatment, and post-resuscitation treatment and the students’ achievement was analyzed. The achievement of each item was converted into 0-100 scale for comparison. The median of the students’ overall achievement of the 25 items was 88. The items showing the highest achievement were those related to the recognition and treatment of arrhythmia, and the median was 87. The items showing the lowest achievement was those related to post-resuscitation treatment, and the median was 50. In small group analysis, there was no statistically significant difference according to gender and school system (2+4 year system vs. 4+4 year system). Among the items of basic life support, the achievement of swift rotation of chest compression with other team members was low. Among the leadership items, instructing the prevention of hyperventilation, finding reversible cause, and summarizing the current situation/asking team members’ opinions showed relatively low achievement. In the items related to treatment for each cardiac arrest rhythm, recognizing and coping with pulseless electrical activity was relatively low. In the items related to post-resuscitation treatment, instructing therapeutic hypothermia showed low achievement. In the results of CRP education that applied simulation technique and mastery learning, there was a significant difference in achievement among individual CPR techniques.

Three Cases of Waardenburg Syndrome Type 2 in a Korean Family

Joong Hyuk Choi,Sung-Kyun Moon,Ki Hwang Lee,Ho Min Lew,Yoon-Hee Chang 대한안과학회 2004 Korean Journal of Ophthalmology Vol.18 No.2

Waardenburg syndrome (WS) is a rare, autosomal dominant disorder characterized by sensorineural hearing loss, pigmentary disturbances of the skin, hair, and iris, and other developmental defects such as lateral displacement of both medial canthi and lacrimal puncta called dystopia canthorum. While mutations of the PAX3(paired box) gene have been identified in about 99% of WS type 1 cases, WS type 2 is a heterogeneous group, with about 15% of cases caused by mutations in microphthalmia associated transcription factor (MITF). We have experienced three cases of typical WS type 2 in a Korean family, for whom full ocular examination and genetic studies were performed. The genetic studies revealed no mutation in either PAX3 or MITF genes. The genetic basis, as yet unknown for most cases of WS type 2, might be found with further investigation.

인공타액 조건에 따른 치과용 티타늄의 갈바니부식 특성

최창혁(Chang Hyuk Choi),이중배(Joong Bae Lee),최기열(Ki Yeol Choi) 대한치과재료학회 2009 대한치과재료학회지 Vol.36 No.1

Safety and Efficacy of Everolimus-Eluting Bioresorbable Vascular Scaffold Versus Second-Generation Drug-Eluting Stents in Real-World Practice

이주명,조현성,Choi Ki Hong,Hong David,박택규,Yang Jeong Hoon,송영빈,Choi Jin-Ho,Choi Seung-Hyuk,정진옥,이종영,Choi Young Jin,Chae Jei-Keon,허승호,Bae Jang-Whan,Oh Ju-Hyeon,전국진,Kim Hyun-Joong,조병렬,Shin Doosup,Lee Seung Hun 대한의학회 2023 Journal of Korean medical science Vol.38 No.5

Background: The risk of device thrombosis and device-oriented clinical outcomes with bioresorbable vascular scaffold (BVS) was reported to be significantly higher than with contemporary drug-eluting stents (DESs). However, optimal device implantation may improve clinical outcomes in patients receiving BVS. The current study evaluated mid-term safety and efficacy of Absorb BVS with meticulous device optimization under intravascular imaging guidance. Methods: The SMART-REWARD and PERSPECTIVE-PCI registries in Korea prospectively enrolled 390 patients with BVS and 675 patients with DES, respectively. The primary endpoint was target vessel failure (TVF) at 2 years and the secondary major endpoint was patientoriented composite outcome (POCO) at 2 years. Results: Patient-level pooled analysis evaluated 1,003 patients (377 patients with BVS and 626 patients with DES). Mean scaffold diameter per lesion was 3.24 ± 0.30 mm in BVS group. Most BVSs were implanted with pre-dilatation (90.9%), intravascular imaging guidance (74.9%), and post-dilatation (73.1%) at proximal to mid segment (81.9%) in target vessel. Patients treated with BVS showed comparable risks of 2-year TVF (2.9% vs. 3.7%, adjusted hazard ratio [HR], 1.283, 95% confidence interval [CI], 0.487–3.378, P = 0.615) and 2-year POCO (4.5% vs. 5.9%, adjusted HR, 1.413, 95% CI, 0.663–3.012, P = 0.370) than those with DES. The rate of 2-year definite or probable device thrombosis (0.3% vs. 0.5%, P = 0.424) was also similar. The sensitivity analyses consistently showed comparable risk of TVF and POCO between the 2 groups. Conclusion: With meticulous device optimization under imaging guidance and avoidance of implantation in small vessels, BVS showed comparable risks of 2-year TVF and device thrombosis with DES.