Applicability of hypotension prediction index to surgical patients

Lee Kichang,정기태 조선대학교 의학연구원 2022 Medical Bilogical Science and Engineering Vol.5 No.2

Intraoperative hypotension, which frequently occurs during surgery, can lead to unfavorable results. However, general blood pressure monitoring has limitations in continuously detecting hypotension in a patient, and there is a risk of not recognizing the presence of hypotension. Even short-term hypotension can damage major organs. The hypotension prediction index (HPI) indicates the likelihood that a patient will develop hypotension within the next 5 to 15 minutes in a hemodynamically stable state without hypotension. The HPI algorithm was developed to calculate the probability of hypotension using a machine-learning algorithm to characterize continuous arterial pressure waveforms in 1,334 surgical and critically ill patients. HPI provides parameters for determining the cause of hypotension (preload, contractility, or afterload), such as stroke volume variability, dP/dtmax, and dynamic arterial elastance. Although there is still no standard protocol for preventing or treating hypotension using HPI values, predicting the risk continuously and the cause of hypotension during surgery in real-time may help prevent harmful hypotension during surgery. In this review, we introduce the concept of HPI and discuss whether it can be applied in actual clinical practice.

PERFORMANCE ANALYSIS OF TANDEM HEAT PUMP USING SEA WATER SOURCE

Kichang Chang,Youngjin Baik,Hosang Ra,Gilbong Lee,Hyungkee Yoon,Hyunju Kim,Hosaeng Lee 한국신재생에너지학회 2013 AFORE Vol.2013 No.-

Erratum: Quality Evaluation of Ultrasonographic Equipment Using an ATS-539 Multipurpose Phantom in Veterinary Medicine

Lee, Youngjin,Cho, Young-kwon,Lee, Kichang The Korean Society of Veterinary Clinics 2022 한국임상수의학회지 Vol.39 No.4

Appropriate depth for the esophageal stethoscope placement for temperature monitoring - a pilot study

Kichang Lee,Tae Won Lim,Ki Tae Jung 조선대학교 의학연구원 2024 Medical Bilogical Science and Engineering Vol.7 No.1

Automated Segmentation of Cerebellum Using Brain Mask and Partial Volume Estimation Map

Lee, Dong-Kyun,Yoon, Uicheul,Kwak, Kichang,Lee, Jong-Min Hindawi Publishing Corporation 2015 Computational and mathematical methods in medicine Vol.2015 No.-

<P>While segmentation of the cerebellum is an indispensable step in many studies, its contrast is not clear because of the adjacent cerebrospinal fluid, meninges, and cerebra peduncle. Thus, various cerebellar segmentation methods, such as a deformable model or a template-based algorithm might exhibit incorrect segmentation of the venous sinuses and the cerebellar peduncle. In this study, we propose a fully automated procedure combining cerebellar tissue classification, a template-based approach, and morphological operations sequentially. The cerebellar region was defined approximately by removing the cerebral region from the brain mask. Then, the noncerebellar region was trimmed using a morphological operator and the brain-stem atlas was aligned to the individual brain to define the brain-stem area. The proposed method was validated with the well-known FreeSurfer and ITK-SNAP packages using the dice similarity index and recall and precision scores. As a result, the proposed method was significantly better than the other methods for the dice similarity index (0.93, FreeSurfer: 0.92, ITK-SNAP: 0.87) and precision (0.95, FreeSurfer: 0.90, ITK-SNAP: 0.93). Therefore, it could be said that the proposed method yielded a robust and accurate segmentation result. Moreover, additional postprocessing with the brain-stem atlas could improve its result.</P>

AMESim 을 이용한 종방향 휠로더 모델 개발

진기창(Kichang Jin),박태호(Taeho Park),이형철(Hyeongcheol Lee),이종찬(Jongchang Lee),오창은 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

A wheel loader is frequently used in the construction site for uploading materials into trucks. Recently, the longitudinal wheel loader model is needed to analyze fuel consumption, fuel emission, and dynamics of wheel loader. Although a number of researches have focused on each component such as transmission, torque converter, and bucket, few researches have been done on the longitudinal wheel loader model. In this research, the wheel loader is analytically modeled and programmed by AMESim. The developed model contains engine, torque converter, transmission, differential, wheel, vehicle and external digging force. The longitudinal wheel loader model is validated by comparing the simulation results with the measured experimental results under the V-loading cycle. Therefore, the developed model well represents the actual basic function of each component and the power flow of the wheel loader.

호소수를 원수로 사용하는 정수장의 소독부산물 생성 특성 및 제어 방안

이기창(Kichang Lee),제갈봉창(Bongchang Gegal),최일환(Ilhwan Choi),이원태(Wontae Lee) 大韓環境工學會 2015 대한환경공학회지 Vol.37 No.5

본 연구는 경상북도 지역에서 호소수를 원수로 사용하는 한 정수장의 원수 및 공정별 처리수의 자연유기물질(NOM) 및 소독부산물(DBPs) 생성특성을 조사하고 정수공정내 DBPs 제어방안을 제시하였다. Fluorescence excitation-emission matrix(FEEM) 분석결과 원수의 NOM은 토양과 미생물의 복합기원에 의한 것으로 밝혀졌다. NOM의 분자량크기 및 분획제거 특성은 liquid chromatography-organic carbon detector (LC-OCD)를 이용하여 분석하였다. 대체로 휴믹물질과 저분자량 유기물질 분획이 많았고, 고분자량물질은 저분자량물질보다 응집·침전공정에서 제거가 용이한 것으로 나타났다. 전염소주입 후 정수공정별로 진행될수록 반응시간이 길어져 DBPs 농도가 증가하였으며 생성된 DBPs는 일반적인 정수처리로 제거되지 않았다. THMs은 chloroform이 74%로 주종을 이루었으며 bromodichloromethane (22%)와 dibromochloromethane (4%)도 발생했다. HAAs는 dichloroacetic acid (50%)와 trichloroacetic acid (48%)가 주종을 이루었고 dibromoacetic acid (2%) 등 브롬계열은 농도가 낮거나 발생되지 않았다. HANs은 dichloroacetonitrile (60%), bromochloroacetonitrile (30%), dibromoacetonitrile (10%)이 발생되었다. 실험기간 동안 해당 정수장에서 DBPs 발생은 용존유기물농도와 수온보다 전염소주입농도에 큰 영향을 받은 것으로 나타났고, 염소주입농도의 조절로 DBPs 생성농도를 이전에 비해 16~44% 감소시킬 수 있었다. This study investigated the influence of characteristics of natural organic matter (NOM) on the formation of disinfection by-products (DBPs), and proposed the control strategies of DBPs formation in a drinking water treatment plant using lake water in Gyeongsangbuk-do. The fluorescence excitation-emission matrix analysis results revealed that the origins of NOM in raw waters to the plant were a mixture of terrestrial and microbial sources. Molecular size distributions and removals of NOM fractions were evaluated with a liquid chromatography-organic carbon detector (LC-OCD) analysis. Humic substances and low molecular weight organics were dominant fractions of NOM in the raw water. High molecular weight organics were relatively easier to remove through coagulation/precipitation than low molecular weight organics. The concentrations of DBPs formed by pre-chlorination increased through the treatment processes in regular sequence due to longer reaction time. Chloroform (74%) accounts for the largest part of trihalomethanes, followed by bromodichloromethane (22%) and dibromochloromethane (4%). Dichloroacetic acid (50%) and trichloroacetic acid (48%) were dominant species of haloacetic acids, and brominated species such as dibromoacetic acid (2%) were minimal or none. Dichloroacetonitrile (60%) accounts for the largest part of haloacetonitriles, followed by bromochloroacetonitrile (30%) and dibromoacetonitrile (10%). The formation of DBPs were reduced by 16~44% as dosages of pre-chlorine decreased. Dosages of pre-chlorine was more contributing to DBPs formation than variations of dissolved organic contents or water temperature.

THE EFFECT OF CATHETER-DIRECTED ETHANOL SCLEROTHERAPY ON OVARIAN RESERVE IN PATIENTS WITH RECURRENT ENDOMETRIOSIS: COMPARATIVE ANALYSIS WITH PRIMARY ENDOMETRIOSIS

( Yeojin Lee ),( Jae Kyung Lee ),( Sanghwa Kim ),( Yeon Ju Lee ),( Kichang Han ),( Man-deuk Kim ),( Heeyon Kim ),( Seok Kyo Seo ) 대한산부인과학회 2022 대한산부인과학회 학술대회 Vol.108 No.-

Objective: Although the surgical treatment remains gold standared in endometrioma, ovarian reserve is injured after the hemostasis and excision of the cyst. Catheter-directed ethanol sclerotherpy is known to affect the ovarian function less, increase efficacy, and reduce complications. This study aims to investigate the changes in ovarian reserve after catheter-directed ethanol sclerotherpy in recurrent endometrioma. Methods: Electronic medical records and pictures in patients with endometrioma who underwent catheter-directed ethanol sclerotherpy were obtainted in single institution from August 2014 to April 2022. Patient with aged >18 years old and AMH level >1.0 and <5.0 were enrolled in the study and age, BMI, cyst diameter, unilaterality, number of loculation and AMH level and CA-125 level before and after 1month, 6month, 1year and 2year of sclerotherapy were obtained. Results: 139 patients were enrolled in the study under IRB. There was significant differnece in AMH level before sclerotherapy in primary and recurrent endometrioma(2.68 vs. 2.04, p-value=0.011). However, there was no statistically significant difference in delta value of AMH after sclerotherapy in primary and recurrent endometrioma in 1month, 6month, 1year and 2year after sclerotherpy(91.78% vs. 96.14%, 74.75% vs. 81.58%, 83.98% vs. 65.79%, 97.08% vs. 52.52%, with p-value=0.593, 0.695, 0.217, 0.069, respectively). Also, this results were consistent regardless of unilaterality and loculation and CA-125 level showed no differerence between primary and recurrent endometrioma on every 1month, 6month, 1year and 2year after sclerotherpy. Conclusion: The effect of Catheter-directed ethanol sclerotherpy on ovarian reserve is not inferior in recurrent endometrioma compared to primary endometrima. Since sclerotherapy is known to less deteriorate the ovarian function than surgical removal of endometrioma, clinician could consider this as the first-line therapy in patient with recurrent endometrioma.

Comparison of dental radiography and computed tomography: measurement of dentoalveolar structures in healthy, small-sized dogs and cats

Seunghee Lee,Kichang Lee,Hyeona Kim,Jeongsu An,Junho Han,Taekwon Lee,Hogyun Jeong,Youngkwon Cho 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.5

Background: Dental diseases are common in dogs and cats, and accurate measurements of dentoalveolar structure are important for planning of treatment. The information that the comparison computed tomography (CT) with dental radiography (DTR) is not yet reported in veterinary medicine. Objectives: The purpose of this study was to compare the DTR with CT of dentoalveolar structures in healthy dogs and cats, and to evaluate the CT images of 2 different slice thicknesses (0.5 and 1.0 mm). Methods: We included 6 dogs (2 Maltese and 1 Spitz, Beagle, Pomeranian, mixed, 1 to 8 years, 4 castrated males, and 2 spayed female) and 6 cats (6 domestic short hair, 8 months to 3 years, 4 castrated male, and 2 spayed female) in this study. We measured the pulp cavity to tooth width ratio (P/T ratio) and periodontal space of maxillary and mandibular canine teeth, maxillary fourth premolar, mandibular first molar, maxillary third premolar and mandibular fourth premolar. Results: P/T ratio and periodontal space in the overall dentition of both dogs and cats were smaller in DTR compared to CT. In addition, CT images at 1.0 mm slice thickness was generally measured to be greater than the images at 0.5 mm slice thickness. Conclusions: The results indicate that CT with thin slice thickness provides more accurate information on the dentoalveolar structures. Additional DTR, therefore, may not be required for evaluating dental structure in small-sized dogs and cats.

하이브리드 굴삭기의 상위제어기 개발을 위한 MILS 환경 구축

진기창(Kichang Jin),박태호(Taeho Park),이지호(Jiho Lee),정유석(Yuseuk Jung),권영민(Youngmin Kwon),이형철(Hyoungcheol Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

The hybrid excavator is designed and constructed by replacing the hydraulic components of the conventional hydraulic excavator with the electric components. The target hybrid excavator of this research is the compound hybrid excavator replacing only the swing part with the electric motor. This paper presents dynamic modeling of the compound hybrid excavator including an engine, a generator, ultra capacitors, hydraulic components and the swing part. The developed model is programmed with the AMESim and validated by the experimental data.