• 대한의용생체공학회:의공학회지
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• 제13권3호
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• pp.209-216
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• 1992

A new experimental technique is proposed to localize the flow limiting segment(FLS) during forced expiration. The present technique is based on the pressure drip across FLS and a consequent change in airway resistance, which can provide an accurate and objective location of FLS. During forced expiratory maneuver artificially induced by a strong negative pressure (-100mmHg) applied at the trachea in an anesthetized open chest dog, airway resistance( R) was calculated from air flow and airway pres- sure signals at various airway locations and lung volumes, At the lung volumes above 10 % VC, FLS located in the trachea 6cm lower from the larynx. With the lung volume decreased below 8% VC, FLS jumped upstream to End-3rd generation of the airway. These results were similar with the previous reports from excised dog lungs, which demonstrated the validity of the present technique. Since the present technique provides a more objective measure of FLS location, it would be useful in future studies of expiratory flow limitation.

• Journal of Preventive Medicine and Public Health
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• 제19권2호
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• pp.314-321
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• 1986

Forced vital capacities (FVC's) and forced expiratory volumes in one second $(FEV_{1.0}'s)$ of 26 pneumoconiosis patients were checked at admission and were followed up for 10 months through hospitalization. FVC's and $FEV_{1.0}'s$ were slightly improved in 10 months after admission. The improvement of FVC's was statistically significant. In the group of large opacities in chest radiographs, FVC's and $FEV_{1.0}'s$ were lower than those values in small opacity group at admission but improved more progressively. Similar finding was noted in the group of emphysema; those values were lower at admission but improved more progressively than those of non-emphysema group.

• 보험의학회지
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• 제33권2호
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• pp.8-11
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• 2014

Pulmonary function test is a group of tests which are composed of measurement for lung function. Thy are spirometry, blood-gas analysis, lung volumes, exercise test, diffusion capacity, and bronchial challenge test. In this article, I will review the pulmonary function test and it's application in terms of clinical aspect and insurance medicine. The standard spirometric indicies are forced vital capacity(FVC), forced expiratory volume at 1 second(FEV1), and the ratio of FEV1 over FVC(FEV1/FVC). If the value of FEV1/FVC less than 70%, the examinee has obstructive ventilatory dysfunction.

• Korean Journal of Radiology
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• 제22권10호
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• pp.1719-1729
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• 2021

Objective: Emphysema and small-airway disease are the two major components of chronic obstructive pulmonary disease (COPD). We propose a novel method of quantitative computed tomography (CT) emphysema air-trapping composite (EAtC) mapping to assess each COPD component. We analyzed the potential use of this method for assessing lung function in patients with COPD. Materials and Methods: A total of 584 patients with COPD underwent inspiration and expiration CTs. Using pairwise analysis of inspiration and expiration CTs with non-rigid registration, EAtC mapping classified lung parenchyma into three areas: Normal, functional air trapping (fAT), and emphysema (Emph). We defined fAT as the area with a density change of less than 60 Hounsfield units (HU) between inspiration and expiration CTs among areas with a density less than -856 HU on inspiration CT. The volume fraction of each area was compared with clinical parameters and pulmonary function tests (PFTs). The results were compared with those of parametric response mapping (PRM) analysis. Results: The relative volumes of the EAtC classes differed according to the Global Initiative for Chronic Obstructive Lung Disease stages (p < 0.001). Each class showed moderate correlations with forced expiratory volume in 1 second (FEV₁) and FEV₁/forced vital capacity (FVC) (r = -0.659-0.674, p < 0.001). Both fAT and Emph were significant predictors of FEV₁ and FEV₁/FVC (R² = 0.352 and 0.488, respectively; p < 0.001). fAT was a significant predictor of mean forced expiratory flow between 25% and 75% and residual volume/total vital capacity (R² = 0.264 and 0.233, respectively; p < 0.001), while Emph and age were significant predictors of carbon monoxide diffusing capacity (R² = 0.303; p < 0.001). fAT showed better correlations with PFTs than with small-airway disease on PRM. Conclusion: The proposed quantitative CT EAtC mapping provides comprehensive lung functional information on each disease component of COPD, which may serve as an imaging biomarker of lung function.

• 대한통합의학회지
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• 제10권1호
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• pp.149-155
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• 2022

Purpose : This study investigated the effects of wearing a mask and different mask filters on the respiratory function of stroke patients. Methods : A total of 15 stroke patients were selected according to the inclusion and exclusion criteria. The respiratory functions were compared between participants with and without masks and among respiratory functions with three different mask filters. The order of using masks was non-wearing masks, Dental masks, KF80 masks, and KF94 masks; the difference in respiratory volumes among these conditions were measured. For accuracy of the measurement, sufficient education on the respiratory measurement method was provided to the researcher, and the heart rate of the participants was estimated to confirm their stability before the measurements. To ensure accuracy, the subjects were educated on the researchers' respiratory measurement methods. Each measurement was followed by 10 min breathing stability before replacing the next mask. Results : The results of this study showed that the difference in respiratory functions, including forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁), and maximal voluntary ventilation (MVV), in stroke patients was statistically significant among different masks (p<.05). Afterwards, the values of FVC, FEV₁, and MVV in stroke patients wearing masks were significantly lower than those of the non-masked control group (p<.05). The difference in respiratory functions with different mask filters showed no statistical significance (p<.05). Conclusion : This study showed that participants wearing any of the masks presented a lower respiratory function than that of those without using masks; additionally, no difference in respiratory functions was observed with differences in mask filters. Therefore, wearing a mask for a prolonged period is confirmed to affect breathing in stroke patients with weak respiratory function.

• The Korean Journal of Physiology
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• 제15권1호
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• pp.37-43
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• 1981

장기간(長期間)의 체력단련(體力鍛鍊)이 폐기능(肺機能)에 미치는 영향(影響)을 알아보고자 운동선수군(運動選手群) 24명(名)과 비운동선수군(非運動選手群) 12(名)에 대(對)하여 실시(實施)한 본(本) 연구(硏究)의 결과(結果)를 요약(要約)하면 다음과 같다. 호흡수(呼吸數), 일회호흡량(一回呼吸量) 폐활량(肺活量)은 실시군(實施群)과 비실시군(非實施群) 사이에 유의(有意)한 차이(差異)가 없었으나, 최대환기능(最大換氣能)은 선수군(選手群)이 $148.1{\pm}3.01\;L/min$, 비선수군(非選手群)이 $1118.3{\pm}9.1\;L/min$ 로서 선수군(選手群)에서 비선수군(非選手群)에 비(比)해 유의하게(p<0.01) 높았다. 초시폐활량(秒時肺活量)은 선수군(選手群)이 $3.310{\pm}0.070\;L$, 비선수군(非選手群)이 $2.279{\pm}0.104\;L$였고, $FEV_1%$는 선수군(選手群)이 $83.63{\pm}1.29%$, 비선수군(非選手群)이 $75.33{\pm}1.75%$로서 둘 다 선수군(選手群)에서 비선수군(非選手群)에 비(比)해 유의하게(p<0.01)높았다. $FEF_{\;0.2{\sim}1.2}L$는 선수군(選手群)이 $297.7{\pm}13.5\;L/min, 비선수군(非選手群)이 $222.7{\pm}15.0\;L/min$였고, $FEF_{\;25{\sim}75}%$는 선수군(選手群)이 $3.543{\pm}0.109\;L/sec$, 비선수군(非選手群)이 $2.719{\pm}0.142\;L/sec$로서 둘다 선수군(選手群)에서 비선수군(非選手群)에 비(比)해 유의하게(p<0.01)높았다. 이상(以上)의 결과(結果)를 종합(綜合)하면 선수군(選手群)과 비선수군(非選手群) 사이에 폐용적(肺容積)은 별차이(別差異)가 없으나, 최대환기능(最大換氣能), 초시폐활량(秒時肺活量), $FEV_1%$, $FEF_{\;0.2{\sim}1.2}L$, $FEF_{\;25{\sim}75}%$등(等)은 선수군(選手群)이 비선수군(非選手群)에 비(比)해 유의하게(p<0.01) 높은 측정치(測定値)를 나타내었으며, 이것은 선수군(選手群)에서 비선수군(非選手群)에 비(比)해 호흡근(呼吸筋)의 힘이 더 강(强)하거나, 폐(肺) 및 흉곽(胸廓)의 용압률(容壓率)이 더 크기 때문인 것으로 사료(思料)된다.

• Tuberculosis and Respiratory Diseases
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• 제40권5호
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• pp.548-557
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• 1993

연구배경 : 기관지 확장증은 비가역적 병변으로 만성적이고 반복적인 폐기관지의 감염으로 인하여 많은 예에서 만성기관지염, 폐기종 및 기관지천식등이 동반되는 경우가 많다. 따라서 이들에서의 폐기능도 동반되는 질환이나 침범범위등에 따라서 다양하리라 생각이 되어 기관지 확장증의 병리해부학적 형태의 차이, 그리고 호흡곤란의 정도에 따른 폐기능의 차이를 조사하였다. 방법 : 1985년 1월부터 1991년 12월까지 경북대학병원에서 기관지 조영술사진에 의해 기관지확장증으로 확진된 93예를 대상으로 폐활량, 최대환기량, 노력성호기곡선 및 기류-용량 곡선에서 계측할 수 있는 각종지표와 closing volume을 구하여 기관지조영술상의 낭종형, 원통형 및 혼합형 등의 기관지확장증의 형태 및 Hugh-Jones의 호흡곤란의 정도에 따른 성적을 비교검토 하였다. 결과: 1) 이환된 폐구역수의 평균은 원통형(tubular), 낭종형(saccular) 및 혼합형(mixed) 에서 각각 4.7, 6.9, 7.8개였고 폐활량 및 노력성 호기곡선의 모든 계측치와 PEF를 제외한 호기류속도를 반영하는 계측치는 낭종형 및 혼합형에서 저명하게 감소하였다. 2) MVV는 낭종형 및 혼합형에서 감소하는 경향이었으며 CV/VC는 낭종형 및 혼합형에서 증가하는 경향이었다. 3) 호흡곤란의 정도가 심할수록 이환된 폐구역수는 유의하게 증가되었으며 폐환기능은 이와 비례하여 저하하였다. 결론 : 이상의 결과로 기관지확장증에서의 환기기능은 제한성환기 장애와 폐쇄성환기 장애가 동반되어 있으며 이는 호흡곤란의 정도가 심할수록, 낭종형 및 혼합형일수록 뚜렷하였다.

• Tuberculosis and Respiratory Diseases
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• 제72권1호
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• pp.8-14
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• 2012

Background: Although airway obstruction in chronic obstructive pulmonary disease (COPD) is due to pathologic processes in both the airways and the lung parenchyma, the contribution of these processes, as well as other factors, have not yet been evaluated quantitatively. We therefore quantitatively evaluated the factors contributing to airflow limitation in patients with COPD. Methods: The 213 COPD patients were aged >45 years, had smoked >10 pack-years of cigarettes, and had a post-bronchodilator forced expiratory volume in one second ($FEV_1$)/forced vital capacity (FVC) <0.7. All patients were evaluated by medical interviews, physical examination, spirometry, bronchodilator reversibility tests, lung volume, and 6-minute walk tests. In addition, volumetric computed tomography (CT) was performed to evaluate airway wall thickness, emphysema severity, and mean lung density ratio at full expiration and inspiration. Multiple linear regression analysis was performed to identify the variables independently associated with $FEV_1$ - the index of the severity of airflow limitation. Results: Multiple linear regression analysis showed that CT measurements of mean lung density ratio (standardized coefficient ${\beta}$=-0.46; p<0.001), emphysema severity (volume fraction of the lung less than -950 HU at full inspiration; ${\beta}$=-0.24; p<0.001), and airway wall thickness (mean wall area %; ${\beta}$=-0.19, p=0.001), as well as current smoking status (${\beta}$=-0.14; p=0.009) were independent contributors to $FEV_1$. Conclusion: Mean lung density ratio, emphysema severity, and airway wall thickness evaluated by volumetric CT and smoking status could independently contribute to the severity of airflow limitation in patients with COPD.

• Tuberculosis and Respiratory Diseases
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• 제80권4호
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• pp.385-391
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• 2017

Background: Men with chronic obstructive pulmonary disease, have reduced endogenous testosterone levels, but the relationship between pulmonary function and endogenous testosterone levels, is inconsistent. Testicular volume is a known indicator of endogenous testosterone levels, male fertility, and male potency. In the present study, the authors investigated the relationship, between testicular volume and lung function. Methods: One hundred and eighty-one South Korean men age 40-70, hospitalized for urological surgery, were retrospectively enrolled, irrespective of the presence of respiratory disease. Study subjects underwent pulmonary function testing, prior to procedures, and testicular volumes were measured by orchidometry. Testosterone levels of patients in blood samples collected between $7{\small{AM}}$ and $11{\small{AM}}$, were measured by a direct chemiluminescent immunoassay. Results: The 181 study subjects were divided into two groups, by testicular volume (${\geq}35mL$ vs. <35 mL), the larger testes group, had better lung functions (forced vital capacity [FVC]: $3.87{\pm}0.65L$ vs. $3.66{\pm}0.65L$, p=0.037; forced expiratory volume in 1 second [$FEV_1$]: $2.92{\pm}0.57L$ vs. $2.65{\pm}0.61L$, p=0.002; FVC % predicted: $98.2{\pm}15.2%$ vs. $93.8{\pm}13.1%$, p=0.040; $FEV_1$ % predicted: $105.4{\pm}19.5%$ vs. $95.9{\pm}21.2%$, p=0.002). In addition, the proportion of patients with a $FEV_1/FVC$ of <70%, was lower in the larger testes group. Univariate analysis conducted using linear regression models, revealed that testicular volume was correlated with FVC (r=0.162, p=0.029), $FEV_1$ (r=0.218, p=0.003), $FEV_1/FVC$ (r=0.149, p=0.046), and $FEV_1$ % predicted (r=0.178, p=0.017), and multivariate analysis using linear regression models, revealed that testicular volume was a significant predictive factor for $FEV_1$ % predicted (${\beta}=0.159$, p=0.041). Conclusion: Larger testicular volume was independently associated, with favorable indices of lung function. These results suggest that androgens, may contribute to better lung function.

• Tuberculosis and Respiratory Diseases
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• 제50권4호
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• pp.415-425
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• 2001

배 경 : 폐기종의 중증도 판정에 있어서 병리학적 기준은 기강(air space)의 확장 정도에 있으며, 이는 고해상도 전산화 촬영 (high resolution computed tomography, HRCT)에 의해 결정되는 폐기종 점수(emphysema scoring)와 좋은 상관성을 보인다는 것은 주지의 사실이다. 한편 폐기종의 주증상은 운동성 호흡곤란이므로 폐기종에 대한 임상적 평가는 운동능력의 감소를 측정하는 것이 타당하다고 알려져 있다. 그러나 대개의 경우 폐기종의 중증도 판정은 안정시 폐기능 검사에 의존하는 경우가 흔하며, 병리학적 중증도 판정과 상관성이 높다고 알려져 있는 고해상도 전산화 촬영에 의한 폐기종 점수와 운동부하 폐기능검사 지표들과의 상관성 여부에 대한 연구는 드문 실정이다. 이에 본 연구에서는 폐기종의 중증도 판정에 있어서 HRCT와 안정시 폐기능 검사 및 운동부하 폐기능 검사간에 상호 관련성을 확인하여 보았다. 방 법 : 평균 연령 $60.6{\pm}10.3$세인 14명의 폐기종 환자들을 대상으로 HRCT, 안정시 폐기능 검사(forced expiratory flow volume curve, lung volumes by He dilution method, DLco, ABGA), 그리고 점진적운동부하폐 기능검사(incremental cycle ergometer)를 시행하였으며 HRCT는 GE highlight를 이용하여 조영증강 없이 최대흡기시에 1.5mm collimation, 10mm 간격으로 폐전체를 스캔하였고, 환자마다 모든 스캔에서 density mask를 이용하여 -400 HU를 기준으로 한 총폐면적과 -900 HU를 기준으로 한 폐기종 면적을 각각 구하여 백분율로 환산하여 폐기종 점수를 구하였다. 결 과 : 평균 폐기종 점수는 $37.4{\pm}14.9%$ 이었다. 폐기종 점수와 안정시 폐기능 검사의 DLco(r=-0.75)와 $PaO_2$(r=-0.66) 사이에서만 유의한(p<0.05) 상관성이 관찰되었다. 반면 폐기종 점수와 운동부하폐기능 지표들간의 상관성은 최대 산소섭취량(r=-0.68), 혐기성 역치(V-slope method, r=-0.690), 최대운동부하(r=-0.74), 최대운동시 $O_2$ pulse(r=-0.73), 최대운동시의 생리적 사강비율 (r=0.80) 등과 높은 유의성 (p<0.01)을 나타내었다. 그러나 호흡예비율과 심박수 예비율간에서는 유의한 상관성이 없었고, pulse oxymeter로 측정한 산소포화도와의 상관성도 유의하지 않았다. 결 론 : 이상의 결과에서 폐기종의 병리학적 중증도를 잘반영한다고 알려진 HRCT 폐기종 접수는 폐기종에 의한 생리학적 장애를 잘 반영하는 운동부하 폐기능 검사의 주요 지표들과 유의한 상관성이 있음을 확인할 수 있었다.