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Diagnostic Evaluation of the BioFire® Meningitis/Encephalitis Panel: A Pilot Study Including Febrile Infants Younger than 90 Days (BioFire® Meningitis/Encephalitis Panel의 진단적 유용성 평가: 90일 미만 발열영아에서의 예비 연구)

  • Kim, Kyung Min;Park, Ji Young;Park, Kyoung Un;Sohn, Young Joo;Choi, Youn Young;Han, Mi Seon;Choi, Eun Hwa
    • Pediatric Infection and Vaccine
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    • v.28 no.2
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    • pp.92-100
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    • 2021
  • Purpose: Rapid detection of etiologic organisms is crucial for initiating appropriate therapy in patients with central nervous system (CNS) infection. This study aimed to evaluate the diagnostic value of the BioFire® Meningitis/Encephalitis (ME) panel in detecting etiologic organisms in cerebrospinal fluid (CSF) samples from febrile infants. Methods: CSF samples from infants aged <90 days who were evaluated for fever were collected between January 2016 and July 2019 at the Seoul National University Children's Hospital. We performed BioFire® ME panel testing of CSF samples that had been used for CSF analysis and conventional tests (bacterial culture, Xpert® enterovirus assay, and herpes simplex virus-1 and -2 polymerase chain reaction) and stored at -70℃ until further use. Results: In total, 72 (24 pathogen-identified and 48 pathogen-unidentified) CSF samples were included. Using BioFire® ME panel testing, 41 (85.4%) of the 48 pathogen-unidentified CSF samples yielded negative results and 22 (91.7%) of the 24 pathogen-identified CSF samples yielded the same results (enterovirus in 19, Streptococcus agalactiae in 2, and Streptococcus pneumoniae in 1) as those obtained using the conventional tests, thereby resulting in an overall agreement of 87.5% (63/72). Six of the 7 pathogen-unidentified samples were positive for human parechovirus (HPeV) via BioFire® ME panel testing. Conclusions: Compared with the currently available etiologic tests for CNS infection, BioFire® ME panel testing demonstrated a high agreement score for pathogen-identified samples and enabled HPeV detection in young infants. The clinical utility and cost-effectiveness of BioFire® ME panel testing in children must be evaluated for its wider application.

Evaluation of the usefulness of Halcyon VMAT treatment plan through comparison with tomotherapy in bilateral breast cancer radiation therapy. (양측 유방암 방사선치료 시 토모테라피와의 비교를 통한 Halcyon VMAT 치료계획의 유용성 평가)

  • LIM JUN TAEK;PARK JU YOUNG;PARK SU YEON;JEON SEONG JIN;PARK TAE YANG;HWANG DA JIN
    • The Journal of Korean Society for Radiation Therapy
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    • v.34
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    • pp.83-92
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    • 2022
  • Purpose: To evaluate usefulness of Tomotherapy and Halcyon VMAT treatment in radiation therapy for bi-breast cancer Materials and Methods: For 10 patients with bi-breast cancer, volumetric modulated arc therapy(VMAT) treatment plan was established using helical Tomotherapy(Accuray. USA) with field width of 5.0-cm and pitch of 0.287, and Halcyon(Varian Medical System, Palo Alto, CA, Version 3.0 USA) of 6arc and 8arc. Prescribed dose was 42.4 Gy/16, and V 40.3Gy of Planning Target Volume(PTV) was 90%. The quality of plan was evaluated by comparing the dose to tumor and normal organs, and the efficiency was evaluated by comparing total MU and beam on time. Results: About three treatment plans(Tomotherapy, Halcyon 6Arc VMAT, Halcyon 8Arc VMAT) , the mean homogeneity index(H.I) of PTV were 1.07, 1.10, 1.11, and the mean conformity index(C.I) of PTV were 1.21, 1.16, 1.17, respectively. The average value of the dose assessment item for a normal organ is V 5Gy(%) of both lung was 36.3, 31.2, 29.7, and V 15Gy(%) were 18.6, 15.5, 14.6, respectively. The mean heart dose(Gy) were 4.17, 2.69, 2.51. Total MU were (7498.6, 2494.2, 2471.5), and beam on time(sec) were 462.5, 195.4, 198.0. Conclusion: Halcyon VMAT showed similar quality of treatment plan compared to helical Tomotherapy, while also protecting normal organs. In addition, the efficiency of radiotherapy increased due to a decrease in Beam On Time and MU.

The Crisis of AIDS and responses of South African Churches in the task of new national building (새로운 민주주의 국가건설의 과제 속에 직면한 AIDS와 이에 대한 교회의 반응과 과제: 남아프리카 공화국을 중심으로)

  • Kim, Dae-Yoong
    • Journal of the Korean Association of African Studies
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    • v.29
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    • pp.27-53
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    • 2009
  • At the start of the new century, South Africa probably had the largest number of HIV-infected people of any country in the world. The only nation that comes close is India with a population of one billion people compared to South Africa's figure of 57 million. The tragedy is that this did not have to happen. South Africa was aware of the dangers posed by AIDS as early as 1985. In 1991, the national survey of women attending antenatal clinics found that only 0.8percent were infected. In 1994, when the new government took power, the figure was still comparatively low at 7.6 %. The 2004 figure which has been published is 26.5%. This article tracks the epidemic globally, in the region and in South Africa. I explain some of the basic concepts around the disease and look at what may happen with respect to numbers. The situation is bad, and the number of people falling ill, dying and leaving families will rise over next few years. This will impact on South Africa in a number of important ways. This article assesses the demographic, economic and social consequences of the epidemic. It disposes of a number of myths and present the real facts. The AIDS in South Africa is not related to individuals only. It warns that AIDS in Africa is becoming a community and systemic problem. The acuteness of the problem does not stem merely from the fact that communities are affected, or could even be wipe out by the end of this decade, but from the fact that AIDS will place incredible burdens and obligations upon medical services, health care and religious communities such as churches. The facts confront churches' mission with the important question: who is going to take care of all the patients and where? The reality is that people dying of AIDS will have to be cared for at home by relatives and friends. A further question that arises is whether our people are prepared for this. AIDS was considered to be a homo-plague and the hunt was on for a scapegoat in the light of the fatal implication of the disease. At present we are in the strategic phase where we all realize that it will be of no avail to scare people with the ominous threat of AIDS AIDS destroys the optimism of our achievement ethics. This exposure of the culture of optimism is also an exposure of the so-called 'human basic fear which accuses Christianity that their concept of sin is a damper on man's search for liberation and basic need to be freed from all Imitation. AIDS is also a test for our ecclesiastical genuineness and the sincerity of our mission sensibility. It poses the question: How unconditional is Christian love? Is there room for the AIDS sufferer in the community of believers, despite the fact he is an acknowledged homosexual? The question to put to the church is whether the community of believers is an exclusive to put to the koinonia which excludes homosexuals. They may be welcome on principle, but in actual fact are not acceptable to the church community. As South Africa enters the new century, it is clear that the epidemic is not having a measurable impact. However, the impact of AIDS is gradual, subtle and incremental. The author's proposal of what is currently most needed in South Africa is that the little things will make a difference. It's about doing lots of little things better at grassroots level, with the emphasis on doing. There are so many community, churches and NGOs initiatives worth building on and intensifying. One must not underestimate the therapeutic value of working together in small groups to overcome a problem

From a Defecation Alert System to a Smart Bottle: Understanding Lean Startup Methodology from the Case of Startup "L" (배변알리미에서 스마트바틀 출시까지: 스타트업 L사 사례로 본 린 스타트업 실천방안)

  • Sunkyung Park;Ju-Young Park
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.5
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    • pp.91-107
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    • 2023
  • Lean startup is a concept that combines the words "lean," meaning an efficient way of running a business, and "startup," meaning a new business. It is often cited as a strategy for minimizing failure in early-stage businesses, especially in software-based startups. By scrutinizing the case of a startup L, this study suggests that lean startup methodology(LSM) can be useful for hardware and manufacturing companies and identifies ways for early startups to successfully implement LSM. To this end, the study explained the core of LSM including the concepts of hypothesis-driven approach, BML feedback loop, minimum viable product(MVP), and pivot. Five criteria to evaluate the successful implementation of LSM were derived from the core concepts and applied to evaluate the case of startup L . The early startup L pivoted its main business model from defecation alert system for patients with limited mobility to one for infants or toddlers, and finally to a smart bottle for infants. In developing the former two products, analyzed from LSM's perspective, company L neither established a specific customer value proposition for its startup idea and nor verified it through MVP experiment, thus failed to create a BML feedback loop. However, through two rounds of pivots, startup L discovered new target customers and customer needs, and was able to establish a successful business model by repeatedly experimenting with MVPs with minimal effort and time. In other words, Company L's case shows that it is essential to go through the customer-market validation stage at the beginning of the business, and that it should be done through an MVP method that does not waste the startup's time and resources. It also shows that it is necessary to abandon and pivot a product or service that customers do not want, even if it is technically superior and functionally complete. Lastly, the study proves that the lean startup methodology is not limited to the software industry, but can also be applied to technology-based hardware industry. The findings of this study can be used as guidelines and methodologies for early-stage companies to minimize failures and to accelerate the process of establishing a business model, scaling up, and going global.

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Early Recurrence of Breast Cancer after the Primary Treatment: Analysis of Clinicopathological and Radiological Predictive Factors (유방암 일차치료 후 조기 재발: 임상병리학적 및 영상의학적 예측인자 분석)

  • Sun Geun Yun;Yeong Yi An;Sung Hun Kim;Bong Joo Kang
    • Journal of the Korean Society of Radiology
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    • v.81 no.2
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    • pp.395-408
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    • 2020
  • Purpose To evaluate the value of clinicopathologic factors and imaging features of primary breast cancer in predicting early recurrence after the primary treatment. Materials and Methods We enrolled 480 patients who had been followed-up after breast-conserving surgery and adjuvant therapy from January 2010 to December 2014 at our hospital. Early recurrence was defined as recurrence within 3 years after completion of primary treatment, and univariate and multivariate logistic regression analyses were performed to determine the clinicopathologic and imaging predictive factors of early recurrence. Results In the univariate analysis, among the clinicopathologic factors, advanced stage (p = 0.021), high histologic grade (p < 0.001), estrogen receptor negative (p = 0.002), high Ki-67 proliferation index (p = 0.017), and triple-negative breast cancer (p = 0.019), and among the imaging features, multifocality (p < 0.001), vessels in the rim on Doppler ultrasonography (US) (p = 0.012), and rim enhancement (p < 0.001) on magnetic resonance imaging of the breast were significantly associated with early recurrence. In the multivariate analysis, advanced stage [odds ratio (OR) = 3.47; 95% confidence interval (CI) 1.12-10.73; p = 0.031] and vessels in the rim on Doppler US (OR = 3.32; 95% CI 1.38-8.02; p = 0.008) were the independent predictive factors of early recurrence. Conclusion Vascular findings in the rim of the primary breast cancer on Doppler US before treatment is a radiologic independent predictive factor of early recurrence after the primary treatment.

A Study of the New Positioning Guide Based on the Correlation between the Orbit Meatus Line and Mandibular Body Angle in Paranasal Sinus Parietoacanthial Projection(Water's Method) (코곁굴 두정비극방향 검사 시 안와이공선과 아래턱뼈 몸통각도의 상관관계를 이용한 새로운 자세잡이 기준에 관한 연구)

  • Yong-Min Son;Han-Yong Kim;Young-Cheol Joo
    • Journal of the Korean Society of Radiology
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    • v.18 no.4
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    • pp.335-344
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    • 2024
  • In this study, we aim to investigate the correlation between the lateral images of Korean skulls and the angle between the OML and the Body of the Mandible. Additionally, we seek to provide criteria for the ease of positioning in clinical settings and establish standardized imaging procedures for the PNS Water's view examination. This study was conducted on a total of 202 patients who visited the radiology department of a general hospital and examined the skull lateral radiography. In addition to the patient images, skull phantoms were also utilized, and images were obtained using GC85A and EOS equipment. In this research, abbreviations related to the angle of the Body of Mandible were defined using PACS on lateral images. Measurements were taken for various angles, including ramus of mandible angle(RIA), accurate OML angle(TIA), OML and IR Angle(OIA), total mandibular length(TML), ramus height(RH), the angle between the pogonion, gonion, and condylion(MA). The validity of these measurements was confirmed using the skull phantom in the study. The age-specific average range for RIA was 22.67° to 26.04°, with measurements of 23.14° for males and 24.78° for females. The age-related mean ranges for TIA and OIA were 35.98° to 38.31° and 72.27° to 75.25°, respectively. For males, TIA was 36.74° and OIA was 72.73°, while for females, TIA was 36.43° and OIA was 73.38°. The age-dependent measurements for TML and RH ranged from 85.73 mm to 89.60 mm and 62.60 mm to 70.87 mm, respectively. Male values were 90.54 mm and 70.78 mm, while female values were 85.13 mm and 61.54 mm for TML and RH, respectively. The age-specific average range for MA was 55.95° to 58.63°, with measurements of 57.96° for males and 57.76° for females. Correlation analysis revealed a positive correlation between RIA and OIA, as well as between RIA and TIA. Based on the results of this study, which indicate a positive correlation between the angle of the Body of Mandible and the OML, it can be inferred that adjusting the mandible vertically to align with the imaging receptor may contribute to more accurate image acquisition during PNS Water's view examination. Therefore, it is believed that there is value in utilizing this relationship as a criterion for establishing new positioning standards, which could enhance the utility of a new positioning guide.

Pipetting Stability and Improvement Test of the Robotic Liquid Handling System Depending on Types of Liquid (용액에 따른 자동분주기의 분주능력 평가와 분주력 향상 실험)

  • Back, Hyangmi;Kim, Youngsan;Yun, Sunhee;Heo, Uisung;Kim, Hosin;Ryu, Hyeonggi;Lee, Guiwon
    • The Korean Journal of Nuclear Medicine Technology
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    • v.20 no.2
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    • pp.62-68
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    • 2016
  • Purpose In a cyclosporine experiment using a robotic liquid handing system has found a deviation of its standard curve and low reproducibility of patients's results. The difference of the test is that methanol is mixed with samples and the extractions are used for the test. Therefore, we assumed that the abnormal test results came from using methanol and conducted this test. In a manual of a robotic liquid handling system mentions that we can choose several setting parameters depending on the viscosity of the liquids being used, the size of the sampling tips and the motor speeds that you elect to use but there's no exact order. This study was undertaken to confirm pipetting ability depending on types of liquids and investigate proper setting parameters for the optimum dispensing ability. Materials and Methods 4types of liquids(water, serum, methanol, PEG 6000(25%)) and $TSH^{125}I$ tracer(515 kBq) are used to confirm pipetting ability. 29 specimens for Cyclosporine test are used to compare results. Prepare 8 plastic tubes for each of the liquids and with multi pipette $400{\mu}l$ of each liquid is dispensed to 8 tubes and $100{\mu}l$ of $TSH^{125}I$ tracer are dispensed to all of the tubes. From the prepared samples, $100{\mu}l$ of liquids are dispensed using a robotic liquid handing system, counted and calculated its CV(%) depending on types of liquids. And then by adjusting several setting parameters(air gap, dispense time, delay time) the change of the CV(%)are calcutated and finds optimum setting parameters. 29 specimens are tested with 3 methods. The first(A) is manual method and the second(B) is used robotic liquid handling system with existing parameters. The third(C) is used robotic liquid handling system with adjusted parameters. Pipetting ability depending on types of liquids is assessed with CV(%). On the basis of (A), patients's test results are compared (A)and(B), (A)and(C) and they are assessed with %RE(%Relative error) and %Diff(%Difference). Results The CV(%) of the CPM depending on liquid types were water 0.88, serum 0.95, methanol 10.22 and PEG 0.68. As expected dispensing of methanol using a liquid handling system was the problem and others were good. The methanol's dispensing were conducted by adjusting several setting parameters. When transport air gap 0 was adjusted to 2 and 5, CV(%) were 20.16, 12.54 and when system air gap 0 was adjusted to 2 and 5, CV(%) were 8.94, 1.36. When adjusted to system air gap 2, transport air gap 2 was 12.96 and adjusted to system air gap 5, Transport air gap 5 was 1.33. When dispense speed was adjusted 300 to 100, CV(%) was 13.32 and when dispense delay was adjusted 200 to 100 was 13.55. When compared (B) to (A), the result increased 99.44% and %RE was 93.59%. When compared (C-system air gap was adjusted 0 to 5) to (A), the result increased 6.75% and %RE was 5.10%. Conclusion Adjusting speed and delay time of aspiration and dispense was meaningless but changing system air gap was effective. By adjusting several parameters proper value was found and it affected the practical result of the experiment. To optimize the system active efforts are needed through the test and in case of dispensing new types of liquids proper test is required to check the liquid is suitable for using the equipment.

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The Comparative Analysis of the Titer of Seroconversion Rate Through the Natural Antibody and Antibody after Vaccination of Hepatitis A (A형 간염의 자연항체와 예방접종을 통한 항체 생성률의 역가 비교분석)

  • Kwon, Won Hyun;Kim, Kyung Hwa;Cho, Kyung A;Moon, Ki Choon;Kim, Jung In;Lee, In Won
    • The Korean Journal of Nuclear Medicine Technology
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    • v.17 no.2
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    • pp.95-100
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    • 2013
  • Purpose: Since 2008, hepatitis A patients was rapidly increasing. So, Most of the health checkup examinees were interested in whether hepatitis A antibody was a lot. thereby The number of tests was increasing. In recent years, Antibody test results in the range of cut-off values were increased. According to the cause analysis, most examinees had a hepatitis A vaccine. This study was conducted to classify hepatitis A antibody as natural antibody and antibody after vaccination and compared the titer for seroconversion rate based on cut-off values. Materials and Methods: For a month in August 2012, First, We surveyed 185 health examinees and classified 119 health examinees who had acquired natural antibody. Second, for employees who were inoculated against hepatitis at our hospital, We classified into 53 primary inoculators and 59 secondary inculators. when the standard of cut-off value was 1, The seroconversion rate was compared the titer divided by 0.90-1.10 (${\pm}$), 0.60-0,89 (1+), 0.30-0.59 (2+), 0.01-0.29 (3+) and we compared the titer for seroconversion rate by each manufacturer after vaccination. Results: When the standard of cut-off value was 1, the titer of 119 health examinees who had acquired natural antibody was 0.90-1.10 (${\pm}$): 0%, 0.60-0.89 (1+): 0%, 0.30-0.59 (2+): 4.2%, 0.01-0.29 (3+): 96% and the titer of <0.60 ($${\geq_-}2+$$) was 100%. The titer of 53 primary inoculators was 0.90-1.10 (${\pm}:59.1%$), 0.60-0.89 (1+): 18.1%, 0.30-0.59 (2+): 18.1%, 0.01-0.29 (3+): 4.6% and the seroconversion rate was 45.3%. The titer of $${\geq_-}0.60$$ ($${\leq_-}1+$$) was 77.3%. The titer of 59 secondary inoculators was 0.90-1.10 (${\pm}:1.9%$), 0.60-0.89 (1+): 15.4%, 0.30-0.59 (2+): 36.54%, 0.01-0.29 (3+): 46.2% and the seroconversion rate was 88.1%. The titer of <0.60 ($${\geq_-}2+$$) was 82.7%. When we compared the titer for seroconversion rate by each manufacturer after vaccination, the seroconversion rate of 53 primary inoculators was BNIBT: 20.8% (${\pm}:24.5%$), GB: 15.7% (${\pm}:7.8%$), RIAKEY: 94.3% (${\pm}:3.8%$), ROCHE: 83% (${\pm}:0%$), ABBOTT: 73.1% (${\pm}:5.8%$) and the seroconversion rate of 59 secondary inoculators was BNIBT : 86.4% (${\pm}:1.7%$), GB: 88.5% (${\pm}:1.9%$), RIAKEY: 100% (${\pm}:0%$), ROCHE: 98.3% (${\pm}:0%$), ABBOTT: 98.2% (${\pm}:0%$). Conclusion: The study show that the titer of natural immune antibodies is higher than the titer of vaccination and the titer of secondary inoculation is mainly higher than the titer of primary inoculation. Consequently, if we know the titer of hepatitis A antibodies, it will help to give resullt reports. And then, when we compared the titer and the seroconversion rate by each manufacturer, There was a very distinct difference. As the test subjects inoculate against hepatitis A (HAV), it is considered BNIBT, GB will occur false negative rate and RIAKEY, ROCHE, ABOTT will occur false positive rate.

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The Study in Objectification of the diagnosis of Sasang Constitution(According to Analysis of the Past Questionnaires) (사상체질진단(四象體質診斷)의 객관화(客觀化)에 관한 연구(硏究)(기존(旣存) 설문지(說問紙)의 분석(分析)을 중심(中心)으로))

  • Kim, Young-woo;Kim, Jong-won
    • Journal of Sasang Constitutional Medicine
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    • v.11 no.2
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    • pp.151-183
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    • 1999
  • The object of this study was 200 patients who had been treated in the Oriental Medical Hospital at Dong Eui Medical Center during 9 months from Jan. 1999 to sept. 1999. We proceeded the judgment of Sasang Constitution according to 'Questionnaire of Sasang Constitution Classification (I)', and 'Questionnaire of Sasang Constitution Classification II(QSCCII)' and the diagnosis by a medical specialist. The following conclusion were made in comparison with Sasang Constitution and Questionnaire. 1. We selected the 84 subjects what had the statistical value out of the 196 subjects('Questionnaire of Sasang Constitution Classification (I)' had the 71 subjects and 'Questionnaire of Sasang Constitution Classification II(QSCCII)', had the 121 subjects). And we selected again the 73 subjects('Questionnaire of Sasang Constitution Classification (I)', had the 33 subjects and 'Questionnaire of Sasang Constitution Classification II (QSCC II)' had the 40 subjects) out of the 84 subjects, because it had a repeated subjects. 2. We made the Questionnaire what has the 85 subjects, including the subjects what was approved its statistical value by 'A CLINICAL STUDY OF THE JUDGMENT OF SASANG CONSTITUTION ACCORDING TO QUESTIONNAIRE' and 'A CLINICAL STUDY OF THE TYPE OF DISEASE AND SYMPTOM ACCORDING TO SASANG CONSTITUTION CLASSIFICATION'. The subject what ask the physique and the body form was 7, the subject what ask the external appearance and the posture was 7, the subject what ask the habit and the character was 3, the subject what ask the physiology and the pathology was 3, the subject what ask the phenomenon that he has frequency was 4, the subject what ask the eating was 3, the subject what ask the symptom that he has frequency was 14, the subject what ask the work and the qualities-defects was 6, the subject what ask the friendly intercourse was 7, the subject what ask the usual mind was 5, the subject what ask the emotional inclination was I, the subject what ask the behavioral inclination was 10, the subject what ask the character was 15. 3. In the new Questionnaire, the subject what has relevance to Soyang was 84, the subject what has relevance to Soeum was 87, the subject what has relevance to Taeeum was 70. And we made the point of subject with the statistical ratio. The total point of Soyang was 7785.04, the total point of Soeum was 7742.80, the total point of Taeeum was 7746.60. 4. As a result of judgment of Sasang Constitution between the clinical diagnosis by a medical specialist and the new Questionnaire, the diagnostic accuracy of new Questionnaire was 73.33%. The diagnostic accuracy of Soyang was low, the others was high. And the Taeyang was excepted.

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Comparison of Single-Breath and Intra-Breath Method in Measuring Diffusing Capacity for Carbon Monoxide of the Lung (일산화탄소 폐확산능검사에서 단회호흡법과 호흡내검사법의 비교)

  • Lee, Jae-Ho;Chung, Hee-Soon;Shim, Young-Soo
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.4
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    • pp.555-568
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    • 1995
  • Background: It is most physiologic to measure the diffusing capacity of the lung by using oxygen, but it is so difficult to measure partial pressure of oxygen in the capillary blood of the lung that in clinical practice it is measured by using carbon monoxide, and single-breath diffusing capacity method is used most widely. However, since the process of withholding the breath for 10 seconds after inspiration to the total lung capacity is very hard to practice for patients who suffer from cough, dyspnea, etc, the intra-breath lung diffusing capacity method which requires a single exhalation of low-flow rate without such process was devised. In this study, we want to know whether or not there is any significant difference in the diffusing capacity of the lung measured by the single-breath and intra-breath methods, and if any, which factors have any influence. Methods: We chose randomly 73 persons without regarding specific disease, and after conducting 3 times the flow-volume curve test, we selected forced vital capacity(FVC), percent of predicted forced vital capacity, forced expiratory volume within 1 second($FEV_1$), percent of forced expiratory volume within 1 second, the ratio of forced expiratory volume within 1 second against forced vital capacity($FEV_1$/FVC) in test which the sum of FVC and $FEV_1$ is biggest. We measured the diffusing capacity of the lung 3 times in each of the single-breath and intra-breath methods at intervals of 5 minutes, and we evaluated which factors have any influence on the difference of the diffusing capacity of the lung between two methods[the mean values(ml/min/mmHg) of difference between two diffusing capacity measured by two methods] by means of the linear regression method, and obtained the following results: Results: 1) Intra-test reproducibility in the single-breath and intra-breath methods was excellent. 2) There was in general a good correlation between the diffusing capacity of the lung measured by a single-breath method and that measured by the intra-breath method, but there was a significant difference between values measured by both methods($1.01{\pm}0.35ml/min/mmHg$, p<0.01) 3) The difference between the diffusing capacity of the lung measured by both methods was not correlated to FVC, but was correlated to $FEV_1$, percent of $FEV_1$, $FEV_1$/FVC and the gradient of methane concentration which is an indicator of distribution of ventilation, and it was found as a result of the multiple regression test, that the effect of $FEV_1$/FVC was most strong(r=-0.4725, p<0.01) 4) In a graphic view of the difference of diffusing capacity measured by single-breath and intra-breath method and $FEV_1$/FVC, it was found that the former was divided into two groups in section where $FEV_1$/FVC is 50~60%, and that there was no significant difference between two methods in the section where $FEV_1$/FVC is equal or more than 60% ($0.05{\pm}0.24ml/min/mmHg$, p>0.1), but there was significant difference in the section, less than 60%($-4.5{\pm}0.34ml/min/mmHg$, p<0.01). 5. The diffusing capacity of the lung measured by the single-breath and intra-breath method was the same in value($24.3{\pm}0.68ml/min/mmHg$) within the normal range(2%/L) of the methane gas gradient, and there was no difference depending on the measuring method, but if the methane concentration gradients exceed 2%/L, the diffusing capacity of the lung measured by single-breath method became $15.0{\pm}0.44ml/min/mmHg$, and that measured by intra-breath method, $11.9{\pm}0.51ml/min/mmHg$, and there was a significant difference between them(p<0.01). Conclusion: Therefore, in case where $FEV_1$/FVC was less than 60%, the diffusing capacity of the lung measured by intra-breath method represented significantly lower value than that by single-breath method, and it was presumed to be caused largely by a defect of ventilation-distribution, but the possibility could not be excluded that the diffusing capacity of the lung might be overestimated in the single-breath method, or the actual reduction of the diffusing capacity of the lung appeared more sensitively in the intra-breath method.

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