Estandarización de la prueba de capacidad de difusión de monóxido de carbono: Chilean Society of Respiratory Diseases guidelines / Standardization of the single-breath diffusing capacity

Since its introduction in clinical practice carbon monoxide diffusing capacity (DLCO), has been widely used in respiratory diseases, being the most common test utilized after spirometry in pulmonary function laboratories. It represents the entire diffusion process including transport through the alveolar-capillary barrier and hemoglobin binding. Its high affinity with hemoglobin and its near zero partial pressure in plasma determines that CO transfer depends specifically on diffusion. Common respiratory and cardiac diseases such as emphysema, interstitial lung diseases, lung damage by drugs, arterial pulmonary hypertension and cardiac failure, among others show a reduced DLCO. Recent theories considering red blood cells as the main factor involved in resistance to diffusion, suggest that DLCO may reflect the status of lung microcirculation. For example, in cardiac failure, DLCO does not improve in parallel with lung volume, even with cardiac stabilization or cardiac transplantation. Despite its wide utilization, DLCO measurement presents standardization and reproducibility difficulties. International guidelines and task forces recommend using representative values of the target population. After analyzing the available information a group of experts from the Pulmonary Function Commission of the Chilean Society of Respiratory Diseases has proposed guidelines for measurement techniques, quality control, equipment calibration and interpretation of results.

Desde la introducción en la práctica clínica de la prueba de difusión con monóxido de carbono (CO) a mediados del siglo pasado, su utilización ha sido ampliamente difundida en la evaluación de diversas enfermedades respiratorias, de hecho se le considera la prueba más utilizada luego de la espirometría. Desde el punto de vista conceptual aporta información global de todo el proceso de difusión, que incluye el paso a través de la barrera alvéolo capilar y su unión con la hemoglobina. Gracias a la elevada afinidad del CO por la hemoglobina y a la particularidad de que la presión parcial de CO en el plasma es prácticamente cero, la transferencia del CO depende sólo de su difusión. Patologías respiratorias y cardíacas habituales como el enfisema pulmonar, las enfermedades pulmonares intersticiales, el compromiso pulmonar por drogas neumotóxicas, la hipertensión arterial pulmonar y la insuficiencia cardíaca congestiva, entre otras, cursan con disminución de la capacidad de difusión de CO (DLCO). Un nuevo desafío plantean las hipótesis recientes que postulan que la resistencia a la difusión del monóxido de carbono depende principalmente del glóbulo rojo, por lo que ésta podría consistir en una representación de la microcirculación. Como ejemplo, en la insuficiencia cardíaca congestiva, el deterioro de la DLCO no mejora en conjunto con los volúmenes pulmonares, ni cuando estos pacientes se estabilizan o se trasplantan. Si bien se trata de una técnica de laboratorio ampliamente utilizada, aún presenta problemas de estandarización y reproducibilidad. En este documento de consenso, un grupo de estudio de la Comisión de Función Pulmonar de la Sociedad Chilena de Enfermedades Respiratorias, ha efectuado una revisión de este método, con las correspondientes proposiciones de técnicas de medición, control de calidad, calibración e interpretación.

Dificultades en la elección de una ecuación de referencia para la interpretación de los resultados de capacidad de difusión de monóxido de carbono / Difficulties in the selection of a reference equation for the interpretation of the results of DLCO

Introduction: In the absence of national reference equations, the ATS recommends comparing the results of the diffusion capacity of healthy subjects in a representative sample of the population with international equations and choosing among them, the one that provides the lowest sum of the residues. Objective: To compare reference equations available in the literature and identify which best meets the selection criteria. Methods: We reviewed 10 reference equations, for each one we calculated the sum of the residues for a sample of 71 healthy subjects and described the characteristics that affect the variability of each one. Results: Since 1985 we have used the single breath method. Only Thompson et al prediction equations 2008 were obtained with instantaneous reading of CO. Equations with the lowest sum of residues (Miller, Roca and Cotes) include smokers and former smokers. Conclusions: We need an equation in non-smokers with methodology that ensures low variability.

Introducción: En ausencia de ecuaciones de referencia nacionales, la ATS recomienda comparar los resultados de capacidad de difusión de monóxido de carbono de sujetos sanos en una muestra representativa de la población, con ecuaciones internacionales y escoger entre estas, aquella que presente la menor suma de los residuos. Objetivo: Comparar las ecuaciones de referencia disponibles en la literatura e identificar cuál cumple mejor los criterios de selección. Método: Revisamos 10 ecuaciones de referencia; calculamos la suma de los residuos de cada una de ellas para una muestra de 71 sujetos sanos y describimos las características que inciden en la variabilidad de cada una. Resultados: Desde 1985 se ha utilizado el método de respiración única. Sólo las ecuaciones de Thompson y cols. 2008fueron obtenidas con lectura instantánea. Las ecuaciones que presentan menor suma de residuos (Miller, Roca y Cotes) incluyen fumadores y ex fumadores. Conclusiones: Es necesaria una ecuación nacional en sujetos sanos no fumadores, con metodología que asegure baja variabilidad.

Test de respiración única para la capacidad de difusión de monóxido de carbono (DLCO) y su interpretación en enfermedades autoinmunes. Aplicación en la práctica clínica -Segunda Parte- / Single breath carbon monoxide diffusing capacity (DLCO) test and its interpretation in autoimmune diseases. Application in clinical practice Part -II-

El test de respiración única ha probado por si mismo ser una parte esencial del tamizaje de rutina de la función pulmonar, y de igual valor que la espirometría. A pesar de 100 años de investigación, aún no existe certeza sobre la relativa importancia de las membranas alveolo-capilares vs los eritrocitos como los pasos que sean delimitantes en el transporte global del monóxido de carbono del gas hacia la sangre, pero esto es solo un problema cuantitativo. La naturaleza esencial del test de DLCO ya ha sido elucidada, siendo F.J.W. Roughton y R.E. Forster los mayores protagonistas en esta descripción. La interpretación de la DLCO, en conjunto con la espirometría y los volúmenes pulmonares, pueden contribuir en la evaluación de enfermedades pulmonares subyacentes y, en el campo reumatológico es esencial su conocimiento puesto que ofrece la posibilidad de establecer un diagnóstico diferencial y un seguimiento cercano de los pacientes con enfermedades autoinmunes con manifestaciones pulmonares. El test de espiración única para la capacidad de difusión de monóxido de carbono, la espirometría y los gases arteriales son los test de función pulmonar más ampliamente utilizados para la evaluación y tratamiento de pacientes.

The single breath DLCO (TLCO) has proved as an essential part of the routine pulmonary function screen, similar to spirometry. In spite of nearly 100 years research, there is still concern over the relative importance of the alveolarcapillary membranes versus the red cells as rate limiting steps in the overall transfer of carbon monoxide from gas to blood, but this is only a quantitative problem. The essential nature of the DLCO has already been elucidated by F.J.W. Roughton and R.E. Forster having played the major roles. Interpreting the DLCO, in conjunction with spirometry and lung volumes assessment, may assist in diagnosing the underlying disease and in the Rheumatology field it is essential it's knowledge because it offers the possibility of establish the differential diagnosis and a close follow-up of the patients with pulmonary manifestations in autoimmune diseases.

Importancia de la corrección de la KCO informada computarizada en pacientes con volumen alveolar disminuído / Importance to adjust computerized informed KCO in patients with low alveolar volume

La disminución del factor de transferencia de monóxido de carbono (TLCO) y del Volumen Alveolar (VA) no es uniforme. Los informes de los equipos computadorizados entregan un valor de KCO que no toma en cuenta este detalle.Objetivo: Realizar el cálculo de KCO a través de la corrección de Stam (J Apply Physiol 1994) y compararlas con las informadas por el software de un equipo de laboratorio pulmonar computadorizado reconocido (Collins).Material y Método: Fueron incluídos pacientes consecutivos derivados al Laboratorio Pulmonar de la Unidad para realizar una prueba de TLCO por enfermedad intersticial pulmonar entre Enero y Junio de 2008. Se realizaron las pruebas según recomendacionesATS/ERS por el método de respiración única y con el método de toma de muestra de Ogilvie. Se analizó la KCO según lo informa el software del equipo Collins Plus/SQL System (1995Warren Collins), y luego se lo recalculó corregida según el cálculo de Stam (J Apply Physiol 1994). Se incluyó en este análisis si tenían <80% del volumen alveolar predicho. Resultados: Fueron evaluados 15 pacientes (media edad: 57.5 ± 12.9 años, sexo femenino 66.7%) con enfermedad intersticial.La media de VA fue 3.5±0.8 L(64.3±11.6%). La media de KCO informada a través del software fue 4.2± 1.3ml/min/mmHg/L. La media de KCO corregida fue 3.7 ± 1.2ml/min/mmHg/L (Δ 11.8±3.8, rango: 6.8%-21.1%). Se observó una relación lineal y negativa entre el %VA y el delta de KCO corregida/informada (r2= -0.99). La elección de diferentes tablas de valores normales de VA altera hasta 12% el valor de la misma, pero la KCO corregida se altera en grado mínimo (3%). Conclusiones: Cuando el VA está disminuído, se debe realizar la corrección del informe computadorizado de la KCO, porque se observa una diferencia promedio del 12%, sobreestimando la real KCO del paciente. Otros factores, como la tabla de valores predictivos de VA, influencia muy poco la corrección de KCO.

The decrease of the Transfer Factor of the Lung for Carbon Monoxide (TLCO) and the Alveolar Volume (VA) is not uniform. Software of lung computed machine informs the carbon monoxide transfer coefficient TLCO/VA (KCO) by calculating the ratio without adjusting for that assumption. Objectives: To calculate KCO using a correction by the Stam´s equation (J Apply Physiol1994), to compare the corrected KCO with the result informed by the software of Collins lung laboratory equipment, and to evaluate the impact of using different predictive tables of VA in the estimates of KCO. Materials: Consecutive patients with intersticial lung disease who attended the LungLaboratory to perform the TLCO between January and June 2008 were included in the study. TLCO was performed according to ATS/ERS recommendations by the single-breathand Ogilvie methods. KCO was calculated by the software of Collins Plus/SQL System (1995 Warren Collins), and then recalculated by Stam´s equation. Only patients withless than 80% of VA predictive value were included. Results: 15 patients with interstitial lung disease were evaluated (age: 57.53 ± 12.93 years old, female: 66.66%). The mean VA was 3.55 ±0.83 L (64.33 ±11.56%) and the mean KCO informed by software was 4.17 ±1.31 ml/min/mmHg/L. The corrected KCO was 3.76 ±1.33 ml/min/mmHg/L(Δ 11.84 ±3.84, range: 6.82%-21.1%). It was observed a negative and lineal relation between %VA and Δ KCO corrected/informed (R2= -0.99). The election of different tables of VA normal values distorts up to12% the individualvalues, but the corrected KCO is little modified (3%). Conclusion: When the VA is reduced, the correction of the KCO must be performed, to avoid on average a 12% overestimate. Other factors such as the election of VA predictive tables have little influence on the KCO correction.

Test de respiración única para la capacidad de difusión de monóxido de carbono (DLCO) y su interpretación en enfermedades autoinmunes. Historia y bases fisiológicas / Single breath carbon monoxide diffusing capacity (DLCO) test and its interpretation in autoimmune diseases. History and physiological basis

El test de respiración única para la capacidad de difusión de monóxido de carbono (DLCO) tiene una larga historia desde su nacimiento por Krogh y Krogh en 1909 hasta la primera publicación, describiendo una técnica estandarizada para la medición de la capacidad de difusión (DLCO) por Ogilvie en 1957. El test de DLCO fue inicialmente ideado como una herramienta fisiológica para evaluar el concepto (ahora abandonado) de que el pulmón, al igual que la vejiga natatoria de algún pez marino de agua profunda, podía secretar oxígeno en contra del gradiente normal de tensión provisto por el aire inspirado. El test de DLCO fue introducido como una prueba clínica por Marie Krogh en 1915, pero la medida nunca engranó debido a que los métodos de medición del monóxido de carbono eran muy engorrosos. En los años cincuenta con la introducción del medidor infrarrojo de monóxido de carbono (CO) (desarrollado en Alemania en la Segunda Guerra Mundial), el interés en el test de DLCO revivió y varios métodos para realizar el test de DLCO en pacientes con enfermedades pulmonares se aplicaron, usándose étodos en estado estable, la respiración única y las técnicas de reinhalación.

The single breath test of carbon monoxide (CO) uptake has a long history /from its birth by Krogh and Krogh in 1909 to the first publication describing a standardized technique for the diffusing capacity measurement (DLCO) by Ogilvie in 1957. The DLCO was devised originally as a physiological tool to test the notion (now abandoned) that the lung, like the swim bladder of some deep-sea fish, could secrete oxygen against the normal tension gradient provided by inspired air. The DLCO was introduced as a clinical test by Marie Krogh in 1915, but the measurement never caught on because methods of measuring carbon monoxide were so cumbersome. In the 1950s, with the introduction of the infra-red CO meter (developed in Germany, in World War II) interest in the DLCO revived, and several different methods for measuring DLCO in patients with pulmonary diseases were in use various steady state methods, the single breath and rebreathing techniques.

Compromiso pulmonar en esclerosis sistémica / Lung involvement in systemic sclerosis

El objetivo del estudio fue determinar las características clínicas de los pacientes con esclerodermia y compromiso pulmonar y evaluar si existen factores clínicos predictores de mayor riesgo de enfermedad intersticial. Se estudiaron en forma retrospectiva 40 pacientes con esclerodermia. Fueron divididos en 2 grupos: capacidad de difusión del monóxido de carbono (DLCO) normal (n = 22) y DLCO disminuida (n = 18, 45%). Los pacientes con DLCO disminuida no fueron diferentes en edad (51.1 más o menos 13.5 vs. 53.5 más o menos 9.3 años, p = 0.5182), sexo (varones 13.6%, p = 0.6088 ), presencia de Raynaud (86.6% vs. 85%, p = 0.6272), síndrome de ojo seco (6.2% vs. 10.5%, p = 1.0000) prevalencia de enfermedad difusa (94.1% vs. 83.3%, p = 0.6026) o de dilatación esofágica. El tiempo de evolución de la enfermedad no fue diferente. La sensibilidad de la disnea para detectar una DLCO alterada fue 46.6% con una especificidad del 90% y la de la caída de la saturación de O2 (SaO2) del 71.4% y 80% respectivamente. Los pacientes con DLCO baja tuvieron mayor prevalencia de anticuerpos anti-Scl 70 positivos (5/9 vs. 0/11, p = 0.0081) y de incapacidad ventilatoria restrictiva aunque en 56.7% de los pacientes con DLCO disminuida la capacidad pulmonar total (CPT) era normal. La presencia de hipertensión pulmonar medida por ecocardiograma Doppler fue idéntica (11/13 vs. 10/11, p = 1.0000). Los pacientes con DLCO disminuida tuvieron una prevalencia muy superior de tomografía computada de tórax con evidencias de compromiso intersticial (82.3% vs. 5.8%, p menor o igual a 0.0001). En conclusión, nuestros datos sugieren que la disminución de la DLCO es un hallazgo, muy frecuentemente asociado a TAC de tórax con compromiso intersticial y que no hay variables clínicas que permitan predecir su anormalidad.

The objective of this study was to determine clinical predictors of interstitial lung disease in patients with systemic sclerosis (SSc) and pulmonary involvement as defined by presence of a decreased diffusing capacity for carbon monoxide (DLCO). Forty subjects with SSc were retrospectively evaluated. Patients were categorized according to their level of DLCO (less than or more than or equal to 80% of predicted). Sensitivity of dyspnea to detect a decreased DLCO was 46.6% and specificity 90%, whereas oxygen desaturation showed a sensitivity of 71.4% and a specificity of 80%. Patients with decreased DLCO (n = 18) were not different in age (51.1 more or less than 13.5 vs. 53.5 more or less than 9.3 y, p = 0.5182), sex (male 13.6%, p = 0.6088), prevalence of Raynaud (86.6% vs. 85%, p = 0.6272), sicca syndrome (6.2% vs. 10.5% p = 1.0000) diffuse cutaneous involvement (94.1% vs. 83.3%, p = 0.6026) or esophageal dilatation. The duration of symptoms since diagnosis was no different. Prevalence of pulmonary hypertension assessed by Doppler echocardiography or abnormal nailfold capillaroscopic findings were identical in both populations. Patients with low DLCO had a significatly higher prevalence of anti topoisomerase antibodies. (5/9 vs. 0/11, p = 0.0081) and restrictive lung disease. Patients with low DLCO showed a significantly higher prevalence of abnormal HRCT findings suggestive of ILD (82.3% vs. 5.8%, p less than or equal to 0.0001). We conclude that a low DLCO is a frequent finding in SSc patients, strongly associated with HRCT signs of ILD. We have not found clinical factors predictive for a low DLCO.

Importance of Carbon Monoxide Transfer Coefficient (KCO) Interpretation in Patients with Airflow Limitation / 결핵및호흡기질환

BACKGROUND: The single-breath carbon monoxide diffusion capacity (DLCO) and the per unit alveolar volume (KCO; DLCO/VA) gave discordant values when there was an abnormal alveolar volume (VA). However, the clinical significance of the discordant values in patients with airflow limitation has not been examined. This study investigated the DLCO and KCO changes after improving the airflow limitation. METHOD: The baseline DLCO and KCO with lung volume were measured in patients with an airflow obstruction. The effective alveolar volume was measured using the single-breath CH4 dilution method. The patients divided into two groups according to the baseline values: (1) increased KCO in comparison with the DLCO (high discordance) (2) decreased or not increased KCO in comparison with the DLCO (low discordance). The diffusion capacity and lung volume were measured after treatment. RESULTS: There was no significant difference in the baseline lung volumes including the FEV1 and FVC between the two groups. The FEV1 and FVC were significantly increased in the high discordance group compared with the low discordance group after treating the airflow limitation. The DLCO and alveolar volume were significant higher in the high discordance group compared with the low discordance group while the TLC was not. CONCLUSION: The discordance between the DLCO and KCO could be translated into an airflow reversibility in patients with an airflow limitation

Five-year Observation of the Effects of Spa Therapy for Patients with Pulmonary Emphysema, Evaluated by %Low Attenuation Area (%LAA) of the Lungs on High-resolution CT, %DLco and %Residual Volume (RV) / 日本温泉気候物理医学会雑誌

The effects of long-term spa therapy were studied in 10 patients with pulmonary emphysema: five patients had long-term spa therapy for 5 years (group A), and another 5 patients had not spa therapy for the same 5 years (group B). There were no significant differences in %FVC, %FEV 1.0, %LAA of the lung on HRCT, %DLco and %RV between the two groups. 1. The LAA of the lung on HRCT slightly, but did not significantly increase in patients with spa therapy for 5 years. In patients without spa therapy, the %LAA of the lung significantly increased after 4-(61.1%) (p<0.01) and 5-year observation (65.5%) (p<0.001) compared with the initial value (52.2%). 2. The %DLco and %RV values slightly decreased in patients with spa therapy, but the decrease in the two parameters was not significant. 3. The %DLco significantly decreased (67.2% to 49.0%), and the %RV also significantly increased (175.4% to 230.6%) after 5-year observation in patients without spa therapy. The results obtained here suggest that spa therapy for pulmonary emphysema should start as early as possible when the diagnosis of the disease is decided, and the therapy should be continued as long as possible.

Long-term Spa Therapy Prevents the Progressive Pathological Changes of the lung in Patients with Pulmonary Emphysema / 日本温泉気候物理医学会雑誌

Clinical effects of spa therapy for patients with pulmonary emphysema (PE) were evaluated by observing changes in %LAA of the lung on HRCT, %RV, %FVC, %FEV 1.0, and %DLco values after the long-term therapy. The subjects in this study 16 patients with PE. The subjects were divided into two groups according to the extent of %LAA<-950 HU of the lung on HRCT: %LAA<50% (N=6) and 50%≤%LAA (N=8). 1. Spa therapy significantly improved %LAA (42.5% at the initial stage to 36.3% 24 months after spa therapy), %RV (202.1% to 156.1%) and %DLco 71.0% to 85.7%), but not %FVC and %FEV 1.0, in patients with PE of %LAA<50%, however, significant. Improvement of these parameters was not observed in patients without spa therapy. 2. Spa therapy did not improve the values of %LAA, %RV, and %DLco, as well as %FVC and %FEV 1.0, in patients with PE of 50%≤%LAA. These parameters tended to decrease in the patients of 50%≤%LAA. These results suggest that spa therapy improves %LAA and parameters related to pulmonary function when they are at early stage of PE, however, the therapy was not remarkably effective for these parameters when they were at advanced stage of PE.

Evaluation of Lung Permeability in Patients with Connective Tissue Disease using 99mTc-DTPA Aerosol Scintigraphy / 대한류마티스학회지

OBJECTIVE: The association between the connective tissue diseases and lung diseases is well established. DLCO and 99mTc-DTPA aerosol scintigraphy are used for evaluation of the alvelolar-capillary permeability. This study evaluated the changes in permeability of alveolar-capillary membrane and the utility of the 99mTc-DTPA aerosol clearance to detect lung involvement in patients with connective tissue diseases. METHODS: The patient group consisted of the patients with any proven connective tissue diseases (27 rheumatoid arthritis, 17 systemic lupus erythematosus, 7 other connective tissue diseases) and the control group consisted of healthy 12 persons. The patients and controls were non-smokers and had no concomitant diseases that could affect the result (diabetes, any lung diseases etc). Chest X-ray, spirometric measurements of lung volumes, flow idices, diffusing capacities and 99mTc-DTPA aerosol scintigraphy were performed in the patient group and control group. 99mTc-DTPA aerosol (1110 MBq) was used with the aero-vent jet nebulizer as a lung delivery system. Patients in sitting position inhaled for 5 minutes at normal tidal oral breathing, Scintigraphic data were recorded using the Picker Prism 2000 gamma cammera, 15 frames of the lung were obtained as the area of interest anteriorly and posteriorly (120 msec at each frame, for 30 minutes). 99mTc-DTPA clearance rate was calculated as the time to half clearance (T1/2). RESULTS: The mean clearance rates of 99mTc-DTPA were 64.0+/-24.1 min (RA 70.7+/-26.2 min, SLE 61.6+/-14.0 min, Others 43.9+/-24.7 min), and 47.0+/-10.3 min in the patient group and the control group respectively. Significant correlation was not found between the pulmonary clearance rate of 99mTc-DTPA and other parameters (disease duration, ESR, CRP, DLCO and FEV1/FVC). CONCLUSION: 99mTc-DTPA clearance in the patient group (RA, SLE, others) was significantly decreased than that in control group (p<0.05). In the patient group with normal chest X-ray, 99mTc-DTPA clearance in the connective tissue disorders was significantly decreased than control group (p<0.05). We suggest that 99mTc-DTPA aerosol scintigraphy may be one of useful technique for early detection of the lung involvement in the connective tissue disorders.

Evaluation of Lung Permeability in Patients with Connective Tissue Disease using 99mTc-DTPA Aerosol Scintigraphy / 대한류마티스학회지

OBJECTIVE: The association between the connective tissue diseases and lung diseases is well established. DLCO and 99mTc-DTPA aerosol scintigraphy are used for evaluation of the alvelolar-capillary permeability. This study evaluated the changes in permeability of alveolar-capillary membrane and the utility of the 99mTc-DTPA aerosol clearance to detect lung involvement in patients with connective tissue diseases. METHODS: The patient group consisted of the patients with any proven connective tissue diseases (27 rheumatoid arthritis, 17 systemic lupus erythematosus, 7 other connective tissue diseases) and the control group consisted of healthy 12 persons. The patients and controls were non-smokers and had no concomitant diseases that could affect the result (diabetes, any lung diseases etc). Chest X-ray, spirometric measurements of lung volumes, flow idices, diffusing capacities and 99mTc-DTPA aerosol scintigraphy were performed in the patient group and control group. 99mTc-DTPA aerosol (1110 MBq) was used with the aero-vent jet nebulizer as a lung delivery system. Patients in sitting position inhaled for 5 minutes at normal tidal oral breathing, Scintigraphic data were recorded using the Picker Prism 2000 gamma cammera, 15 frames of the lung were obtained as the area of interest anteriorly and posteriorly (120 msec at each frame, for 30 minutes). 99mTc-DTPA clearance rate was calculated as the time to half clearance (T1/2). RESULTS: The mean clearance rates of 99mTc-DTPA were 64.0+/-24.1 min (RA 70.7+/-26.2 min, SLE 61.6+/-14.0 min, Others 43.9+/-24.7 min), and 47.0+/-10.3 min in the patient group and the control group respectively. Significant correlation was not found between the pulmonary clearance rate of 99mTc-DTPA and other parameters (disease duration, ESR, CRP, DLCO and FEV1/FVC). CONCLUSION: 99mTc-DTPA clearance in the patient group (RA, SLE, others) was significantly decreased than that in control group (p<0.05). In the patient group with normal chest X-ray, 99mTc-DTPA clearance in the connective tissue disorders was significantly decreased than control group (p<0.05). We suggest that 99mTc-DTPA aerosol scintigraphy may be one of useful technique for early detection of the lung involvement in the connective tissue disorders.

Clinical Course of Usual Interstitial Pneumonia / 결핵

BACKGROUND: Idiopathic pulmonary fibrosis(IPF) is a fatal progressive fibrous disease of the lung of unknown etiology. Recently it has been classified into several distinct entities of the basis of pathologic and clinical characteristics, ie : usual interstitial pneumonia(UIP), desquamative interstitial pneumonia(DIP), acute interstitial pneumonia(AIP), bronchiolitis obliterans with organizing pneumonia(BOOP), and nonspecific interstitial pneumonia(NSIP). IPF is now applied only for UIP, which has the worst prognosis. The previous reports of 3-5 year median survival apears to be overoptimistic because other types with better prognosis like NSIP or BOOP might have been included. Therefore, this study was performed to determine the clinical course and the prognostic factors of UIP as diagnosed by surgical lung biopsy. METHODS: The subjects were 72 UIP patients (age 58.2±11.6 years, M:F=45:27, median follow up period:18.1 months (0.7-103.6) diagnosed by surgical lung biopsy at the Asan Medical Center (68 patients) and the Paik Hospital in Seoul (4 patients). Clinical scores (level of dyspnea:1-20 points), radiologic score (honey-combing : HC score 0-5 points, ground glass : GG score 0-5 points), and physiologic scores (FVC:1-12 points, FEV1:0-3 points, TLC:0-10 points, DDLC:0-5 points, AaDO2:0-10 points) were summed into a total CRP score. RESULTS: 1) The one year survival rate was 78.3%, while the rate for three year survival was 58.1%, and the median survival period was 42.5 months. 2) Short term (1 year) prognosis : The patients who died within one year of diagnosis (14 patients) had the higher initial total CRP score (28.6±8.3 vs. 16.6±9.7) than those who lived longer than one year (46 patients). The difference in the total CRP score was attributed to the symptom score (8.4±2.1 vs. 5.7±3.9) and the physiologic score (15.7±7.1 vs. 6.7±5.7) including FVC, DLCO, and AaDO2. 3) Long-term (3 year) prognosis : The total CRP score (12.2±6.7 vs. 28.7±7.9:including symptom score, FVC, DLCO, and AaDO2) at the time of diagnosis were also different for the long-term survivors and those who lived less than 3 years. 4) Cox regression analysis showed LCO (≥60%) (Hazard ratio:4.56, 95% CI:2.30-16.04) was the independent prognostic factors of UIP (P<0.05). CONCLUSION: These results suggest that DLCO at the time of diagnosis seem to be a prognostic markers of biopsy-proven UIP.

Gas diffusion effect on Nifedipine in coal workers pneumoconiosis by radio-opacity size / 예방의학회지

Carbon monoxide diffusing capacity(DLco) was evaluated before and after nifedipine administration in coal workers' pneumoconiosis by the size of radioopacity. Nifedipine was administered to 18 men and 17 men of small round opacity group and large opacity group respectively. Placebo was administered to 19 men and 15 men of small and large opacity group respectively. In large opacity group DLco was increased after nifedipine administration. But, it was not significant statistically(0.05 < p < 0.01). In other groups, there were no significance difference between and after medication.