Lung Cancer Screening with Low-Dose Helical CT in Korea: Experiences at the Samsung Medical Center

To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with >or=45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (>or=20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.

Predictors for Benign Solitary Pulmonary Nodule in Tuberculosis-Endemic Area

BACKGROUND: Solitary pulmonary nodule (SPN) may show different pre- sentation in tuberculosis (TB)-endemic countries. The aim of this study was to identify clinical and radiological predictors favoring benign or malignant SPN in TB-endemic region. METHODS: Two hundred one SPNs in 201 consecutive Korean patients were included (< 3 cm in diameter, all confirmed by pathology or bacteriology, 93 benign and 108 malignant diseases). For clinical parameters, age, sex, smoking status and amount, and past history of pulmonary tuberculosis and diabetes mellitus were investigated retrospectively. For radiological parameters, size, location, margin characteristics, presence of calcification, pleural tag, surrounding satellite nodule, cavitation, internal low attenuation, open bronchus sign, surrounding ground-glass opacity, enhancement pattern of the SPNs and mediastinal lymph node (LN) enlargement were analyzed on chest CT scans. RESULTS: Patients with a older age (60.7+/-9.6 vs 56.2+/-13.1, p=0.008) and more than 40-pack years smoking (27.8% vs 14.0%, p=0.017) were more frequently related with malignant than benign SPN. On chest CT scans, spiculated margin, contrast enhancement more than 20 Hounsfield unit and presence of pleural tag and mediastinal LN enlargement were more frequently observed in malignant than benign SPNs. In contrast to previous studies, satellite lesions (21.5% vs 1.9%, p < 0.001) and cavitation (20.4% vs 5.6%, p=0.001) were more frequently seen in benign than malignant SPN. Positive predictive values of benignity were 90.9% and 76.0%, respectively, when satellite lesions and cavitation were found in cases of SPN. CONCLUSION: Satellite lesions and cavitation on chest CT scan could be useful predictors for benign SPN in TB-endemic areas.

Clinical Characteristics of Recurred Patients with Stage I ,II Non-Small Cell Lung Cancer / 결핵

BACKGROUND: Five year survival rate of postoperative stage I non-small lung cancer(NSCLC) reaches to 66%. In the remaining one third of patients, however, cancer recurs and overall survival of NSCLC remains dismal. To evaluate clinical and pathologic characteristics of recurred NSCLC, we studied patterns and factors for postoperative recurrence in patients with staged I, II NSCLC. METHOD: A retrospective analysis was performed in 234 patients who underwent radical resection for pathologic stage I, II NSCLC. All patients followed for at least one year were included in this study. RESULTS: 1) There were 177 men and 57 women. The median age was 63. The median duration of follow up was 732 days (range 365~1,695 days). The overall recurrence rate was 26.5% and the recurrence occurred at 358.8 +/- 239.8 days after operation. 2) The age of recurred NSCLC patients were higher (63.2 +/- 8.8 years) than that of non-recurred patients (60.3 +/- 9.8 years)(p=0.043). The recurrence rate was higher in stage II (46.9%) than in stage I (18.8%, p<0.001) NSCLC. The size of primary lung mass was larger in recurred (5.45 +/- 3.22 cm) than that of non-recurred NSCLC (3.74 +/- 1.75 cm, p<0.001). Interestingly, there were no recurrent cases when the resected primary tumors were less than 2cm. 3) Distant recurrence was more frequent than locoregional recurrence (66.1% vs. 33.9%). Distant recurrence rate was more frequent in female and adenocarcinoma. Brain metastasis was more frequent in patients with adenocarcinoma than squamous cell carcinoma (p=0.024). CONCLUSION: The tumor size and stage were two important factors for recurrence. Considering that distant brain metastasis was more frequent in patients with adenocarinoma, prospective study should follow to evaluate the effectiveness of preoperative brain imaging.

The Clinical Characteristics of Diffuse Alveolar Hemorrhage : A Retrospective Study of 21cases / 결핵

BACKGROUND: Diffuse alveolar hemorrhage (DAH) is rare but often fatal. To determine the clinical manifestations of DAH, its etiology, clinical course and prognosis were studied. METHODS: A retrospective analysis was performed in 21 patients that were diagnosed as DAH. Diagnosis of DAH was based on the presence of the "classical triad" of hemoptysis, anemia, and rapidly progressive infiltrates on chest X-ray and a finding of bronchoalveloar lavage or lung biopsy. RESULTS: Thirteen patients (61.9%) had collagen vascular diseases (CVDs) as underlying disease and 10 patients had systemic lupus erythematosus. Females were more prevalent in CVD than in non-collagen vascular disease (NCVD). Otherwise, there were no significant differences between the two groups in terms of clinical manifestations. Dyspnea (95.2%), cough (76.2%), hemoptysis (61.9%), and fever (33.0%) were frequent symptoms. The initial creatinine level was higher in CVD than in NCVD (3.27±3.15 mg/dl vs. 1.19±0.94 md/dl, p=0.030). The corresponding drop in hemoglobin level was 2.69±1.26 g/dl. Maximal drop in hemoglobin preceded the progression of infiltrates on the chest radiograph by 1.38±4.22 days. The mortality rate was higher in the patients with NCVD than in those with CVD (50.0% vs. 23.1%). CONCLUSION: The DAH can occur not only in patients with CVD but also in those with NCVD. Higher creatinine level CVD in patients is associated with renal involvement in conjunction with DAH. The maximal drop in hemoglobin preceeding the progression of infiltrates on the chest radiograph suggests that the drop in hemoglobin is important for diagnosing DAH.

A Case of Pulmonary Mucormycosis Presenting as an Endobronchial Mass / 결핵

Pulmonary mucormycosis is an opportunistic infection in patients with severe underlying illness such as immunocompromised diseases or uncontrolled diabetes mellitus. While patients with leukemia and lymphoma usually resent with diffuse parenchymal disease, diabetic patients usually have a localized endobronchial disease involving central airways. We report upon a case of pulmonary mucormycosis in diabetes mellitus patient presenting as an endobronchial mass, which was cured with antifungal therapy, rigid bronchoscopic mass removal and right pneumonectomy.

A Case of Rifampicin Induced Pseudomembranous Colitis / 결핵

Pseudomembranous colitis, although uncommon, is an important complication of antibiotics that is related to a variety of deleterious effects on the gastrointestinal tract. Rifampicin is one of the 1st line agents in the treatment of tuberculosis and a large number of patients are exposed to its potential adverse effects. We report upon a patient that had diarrhea due to pseudomembranous colitis after receiving antitubeculous medication, and which was probably caused by rifampicin. A 77-year-old man was admitted with diarrhea of three weeks duration. One month previously, he suffered from left pleuritic chest pain and left pleural effusion was noticed at chest X-ray. One week prior to the onset of diarrhea, he was started on empirically isoniazid, rifampicin, ethambutol and pyrazynamide as antituberculous medication. On admission, he complained of diarrhea, left pleuritic chest pain, dyspnea and sputum. On physical examination, breathing sound was decreased in the left lower lung field and bowel sound increased. Pleural biopsy revealed chronic granulomatous infalmmation, which was compatible with tuberculosis. Sigmoidoscopy showed whitish to yellowish pseudomembrane with intervening normal mucosa, and his stool was positive for C.difficle toxin. He was diagnosed as pseudomembranous colitis and treated with oral metronidazole and vancomycin. The diarrhea did not recur after reinstitution of the anti-tuberculous medication without rifampicin. In patients with severe diarrhea receining anti-tuberculous medication, rifampicin induced pseudomembranous colitis should be excluded.

Comparison of Two Methods of Recruiting the Acutely Injured Lung / 결핵

BACKGROUND: To evaluate the efficacy of two methods of obtaining lung recruitment to reduce ventilator-induced lung injury(VILI). METHODS: Fifteen New-Zealand white rabbits were ventilated in the pressure-controlled mode maintaining constant tidal volume(10 ml/kg) and fixed respiration rate. Lung injury was induced by repeated saline lavage (PaO2 < 100 mmHg) and pressure-volume curve was drawn to obtain Pflex. Then the animals were randomly assigned to three groups and ventilated for 4 hours. In the control group(n=5), positive end-expiratory pressure(PEEP) was applied at a level less than Pflex by 3 mmHg throughout the study. In the recruitment maneuver(RM) group(n=5), RM(CPAP of 22.5 mmHg, for 45 seconds) was performed every 15 minutes in addition to PEEP level less than Pflex by 3 mmHg. In the Pflex group, PEEP of Pflex was given without RM. Parameters of gas exchange, lung mechanics, and hemodynamics as well as pathology were examined. RESULTS: 1) Both the control and RM groups showed decreasing tendency in PaO2 with time to show significantly decreased PaO2 at 4 hr compared to 1hr(p<0.05). But in the Pflex group, PaO2 did not decrease with time(p<0.05 vs other groups at 3, 4 hr). PaCO2 did not show significant difference between the three groups. 2) There was no significant difference in static compliance and plateau pressure. Mean blood pressure and heart rate also did not show any significant difference in the three groups. 3) In the pathologic exam, Pflex group had significantly less neutrophil infiltration than the control group(p<0.05). The difference in hyaline membrane score also showed borderline significance among groups(p=0.0532). CONCLUSION: Recruiting the injured lung may be important in decreasing VILI. Recruitment maneuver alone, however, may not be enough to minimize VILI.

Clinical Features and Treatment Response in 18 Cases with Idiopathic Nonspecific Interstitial Pneumonia / 결핵

BACKGROUND: Nonspecific interstitial pneumonia (NSIP) has been reported recently to show much better response to medical treatment and better prognosis compared with idiopathic UIP. However, clinical characteristics of idiopathic NSIP discriminating from UIP have not been defined clearly. METHOD: Among 120 patients with biopsy-proven diffuse interstitial lung diseases between July 1996 and March 2000 at Samsung Medical Center, 18 patients with idiopathic NSIP were included in this study. Retrospective chart review and radiographic analysis were performed. RESULTS: 1) At diagnosis, 17 patients were female and average age was 55.2 +/-8.4 years (44~73 years). The average duration from development of respiratory symptom to surgical lung biopsy was 9.9+/-17.1 months. Increase in bronchoalveolar lavage fluid lymphocytes (23.0 +/-13.1%) was noted. On HRCT, ground glass and irregular linear opacity were seen but honeycombing was absent in all patients. 2) Corticosteroids were initially given to 13 patients of whom medication was stopped in 3 patients due to severe side effects. Further medical therapy was impossible in 1 patient who experienced streroid-induced psychosis. Herpes zoster (n=3), tuberculosis (n=1), avascu lar necrosis of hip (n=1), cataract (n=2) and diabetes mellitus (n=1) developed during prolonged corticosteroid administration. Of 7 patients receiving oral cyclophosphamide therapy, hemorrhagic cystitis hindered one patient from continuous medication. 3) After medical treatment, 14 of 17 patients improved and 3 patients remained stable (mean w-up ; 24.1+/-11.2 months). FVC increased by 20.2 +/-11.2% of predicted value and the extent of ground glass opacity on HRCT decreased significantly (15.7+/-14.7%). 4) Of 14 patients who had stopped medication, 5 showed recurrence of NSIP and 2 aggravated during steroid tapering. All patients with recurrence showed deterioration within one year after completion of initial treatment. CONCLUSION: Since idiopathic NSIP has unique clinical profiles and shows a good prognosis, differential diagnosis from UIP and aggressive medical treatment are needed.

Clinical differential diagnosis of usual interstitial pneumonia from nonspecific interstitial pneumonia / 결핵

BACKGROUND: Nonspecific interstitial pneumonitis (NSIP) is most likely to be confused with usual interstitial pneumonitis (UIP). Unlike patients with UIP, the majority of patients with NSIP have a good prognosis, with most patients improving after treatment with corticosteroids. Therefore it is clinically important to differentiate NSIP from UIP. UP to now, the only means of differentiating these two diseases was by means of surgical lung biopsy. American Thoracic Society (ATS) proposed a clinical diagnostic criterial for UIP to provide assistance to clinicians in its diagnosis without surgical lung biopsy. This study is aimed to investigate whether there were clinical and radiological differences between NSIP and UIP, and the usefulness of ATS clinical diagnostic criteria for UIP in Korea. METHODS: we studied 60 patients with UIP and NSIP confirmed by surgical lung biopsy. Clinical manifestations, pulmonary function test, arterial blood gas analysis, bronchoalveolar lavage (BAL), and high resolution computed tomography (HRCT) were evaluated and analyzed by Chi-square test or t-test. The clinical criteria for UIP proposed by ATS were applied to all patients with idiopathic interstitial pneumonia. RESULTS: Forty-two patients with UIP and 18 with NSIP were pathologically identified. Among the 18 patients with NSIP (M : F = 1 : 17), the mean age was 55.2± 8.4 (44~73)yr. Among the 42 patients with UIP (M : F = 33 : 9), the mean age was 59.5±7.1 (45~74) yr (p=0.0460. Fever was more frequent in NSIP (39%) (p=0.034), but clubbing was frequently observed in UIP (33%) (p=0.023). BAL lymphocytosis was more frequent (23%) (p=0.0001) and CD4/CD8 ratio was lower in NSIP (p=0.045). On HRCT, UIP frequently showed honeycomb appearance (36 of 42 patients) through not in NSIP (p=0.0001). Six of 42 UIP patients (14.3%) met the ATS clinical criteria for IPF, and 3 of 16 NSIP patients (18.8%) met the diagnostic criteria. CONCLUSION: Being a relatively young female and having short duration of illness, fever, BAL lymphocytosis, low CD4/CD8 ratio with the absence of clubbing and honeycomb appearance in HRCT increase the likelihood of the illness being NSIP. The usefulness of ATS clinical diagnostic criteria for UIP may be low in Korea.

Preoperative Evaluation for the Prediction of Postoperative Mortality and Morbidity in Lung Cancer Candidates with Impaired Lung Function / 결핵

BACKGROUND: The evaluation of candidates for successful lung resection is important. We studied to Our study was conducted to determine the preoperative predictors of postoperative mortality and morbidity in lung cancer patients with impaired lung function. METHOD: Between October 1, 1995 to August 31, 1997, 36 lung resection candidates with FEV1 of less than 2L or 60% predicted due to lung cancer were included prospectively. Age, sex, weight loss, hematocrit, serum albumin, EKG and concomitant illness were considered as systemic potential predictors for a successful lung resection. Smoking history, presence of pneumonia, dyspnea scale(1 to 4), arterial blood gas analysis with room air breathing, routine pulmonary function test were also included for the analysis. In addition, predicted postoperative(ppo)pulmonary factors such as ppo-FEV1, ppo-diffusing capacity(DLco), predicted postoperative product(PPP) of ppo-FEV1% x ppo-DLco% and ppo-maximal O2 uptake(VO2max) were also measured. RESULTS: There were 31 men and 5 women with the median age of 65 years (range 44 to 82) and a mean FEV1 of 1.78 +/-0.06L. Pneumonectomy was performed in 14 patients, bilobectomy in 8, lobectomy in 14. Pulmonary complications developed in 10 patients, cardiac complications in 3, other complications (empyema, air leak, bleeding) in 4. Twelve patients were managed in the intensive care unit for more than 48 hours. Two patients died within 30 days after operation. The ppo-VO2max was less than 10 mg/kg/min in these two patients. MVV was the only predictor for the pulmonary complications. However, there was no predictors for the post operative death in this study.

The Role of Resectional Surgery for the Treatment of Localized Multi-drug Resistant Pulmonary Tuberculosis / 결핵

BACKGROUND: Surgery may have a role when medical treatment alone is not successful in patients with multi-drug resistant (MDR) pulmonary tuberculosis (PTB). To document the role of resection in MDR PTB, we analyzed 4 years of our experience. METHODS: A retrospective review was performed on thirteen patients that underwent pulmonary resection for MDR PTB between May 1996 and February 2000. All patients had organisms resistant to many of the first-line drugs including isoniazid (INH) and rifampicin (RFP). RESULTS: The thirteen patients were 37.5±12.4 years old (mean±S.D.)(M:F=5:8), and their sputum was culture positive even with adequate medication for prolonged periods (109.7±132.0 months), resistant to 2-8 drugs including isoniazid and rifampin. All patients had localized lesion(s) and most (92.3%) had cavities. At least 3 sensitive anti-TB medications were started before surgery in all patients according to the drug sensitivity test. The preoperative FE1 was 2.37±0.83 L. Lobectomy was performed in 11 patients and pleuropneumonectomy in two. Postoperative mortality did not occur, but pneumonia occurred as a complication in one (7.7%). After 41.5±58.9 days (range 1~150 days) follow up, negative conversion of sputum culture was achieved in all patients within 5 months. Only one patient (7.7%) recurred 32 months after lung resection. CONCLUSION: When medical treatment alone is not successful, surgical resection can be a good treatment option in patients with localized MDR PTB.

Perfluorocarbon Does Not Inhibit Chemokine Expression in Airway Epithelial Cells / 결핵

BACKGROUND: Liquid ventilation is associated with decreased inflammatory response in an injured lung. This study was performed to investigate if whether perfluorocarbon (PFC) can decrease chemokine expression in airway epithelial cells. METHODS : A549 cells were used for airway epithelial cells and perfluorodecalin for PFC. To expose cells to PFC, lower chamber of Transwell a plate was used. This study was performed in two parts. In the first part, we examined whether PFC could decrease chemokine expression in airway epithelial cells through inhibition of other inflammatory cells. Peripheral blood mononuclear cells (PBMC's) were isolated and stimulated with lipopolysaccharide (LPS, 10 mg/mL) for 24 hours with or without exposure to PFC. Then A549 cells were stimulated with conditioned media (CM) containing the culture supernatants of PBMC . After 24 hours, the expressions of interleukin-8 (IL-8) and RANTES were measured. In the second part of the study, we studied whether PFC could directly suppress chemokine expression in airway epithelial cells. A549 cells were stimulated for 24 hours with interleukin-1b and/or tumor necrosis factor-a with or without exposure to PFC (,)and then the chemokine expression was measured. Northern analysis was used to measure the mRNA expression (,) and ELISA was used for immunoreactive protein measurements in culture supernatant. RESULTS: 1. IL-8 and RANTES mRNA expression and immunoreactive protein production were increased significantly by CM from LPS-stimulated PBMC in A459 cells compared with CM from unstimulated PBCM(p<0.05) (,)but exposure of PFC had no significant effect on either mRNA expression immunoreactive protein expression. 2. IL-8 and RANTES mRNA expression and immunoreactive protein production were increased significantly by IL-1b and TNF-a in A549 cells(p<0.05)(,)but exposure of PFC had no significant effect on either mRNA expression or immunoreactive protein production. CONCLUSION: Decreased chemokine expression of airway epithelial cells may not be involved in decreased inflammatory response observed in liquid ventilation. Further studies on possible mechanisms of decreased inflammatory response are warranted.

A Case of Giant Cell Interstitial Pneumonia / 결핵

Giant cell interstitial pneumonia, a synonym of (for) hard metal pneumoconiosis, is a unique form of pulmonary fibrosis resulting from an exposure to hard metal dust. A case of biopsy-proved giant cell interstitial pneumonia in the absence of appropriate history of exposure to hard metal dust is reported. The patient presented with clinical features of chronic interstitial lung disease or idiopathic pulmonary fibrosis. He worked in a chemical laboratory at a fertilizer plant(,)where he had been exposed to various chemicals such as benzene and toluene. He denied having any other hobby in his house or job at work which may have exposed him hard metal dust(.) High-resolution CT scan revealed multi-lobar distribution of ground glass opacity with peripheral and basal lung predominance. The retrieved fluid of bronchoalveolar lavage contained asbestos fiber and showed neutrophil predominance. Surgical lung biopsy was performed for a definite diagnosis. Lung specimen showed alveolar infiltration of numerous multinucleated giant cells with mild interstitial fibrosis. Upon detailed examination of the lung tissue, one asbestos body was found. An analysis for mineral contents in lung tissue was performed. Compared to with the control specimen, the amount of cobalt and several hard metal components in the lung tissue of this patient was ten times higher. We speculated that the inconsistency between occupational history and the findings of pathologic and mineralogical analyses could be explained by the difference in individual immunologic reactivity to hard metal dust despite the relatively small amount of unrecognized environmental exposure (ED: It's hard to understand what this phrase is trying to say).

Bronchoscopy and Surgical Lung Biopsy for the Diagnosis and Management of Pulmonary Infiltrates in Immunocompromised Hosts / 결핵

BACKGROUND: Pulmonary infiltrate in immunocompromised hosts has many infectious and non- infectios etiologies. To evaluate the diagnostic yield and therapeutic implication of two invasive diagnostic methods, such as bronchoscopy and surgical lung biopsy, we performed retrospective analysis of these patients. METHODS: All immunocompromised patients admitted to Samsung Medical Center from October 1995 to August 1998 who underwent bronchoscopy and/or surgical lung biopsy for the diagnosis of pulmonary infiltrates were included in this study. Confirmative diagnostic yield, the rate of changed therapeutic plan and patients' survival were investigated. RESULTS: Seventy-five episodes of pulmonary infiltrates developed in 70 patients(M : F = 46 : 24, median age 51). Underlying diseases of patients were hematologic malignancy(n=30), organ transplantatio n(n=11), solid tumor(n=12), connective tissue disease(n=6) and others. Confirmative diagnosis was made in total 53 cases (70.7%), of which 70.2% had infectious etiology. Diagnostic yields of bronchoscopy, bronchoalveolar lavage(BAL), transbronchial lung biopsy(TBLB) and surgical lung biopsy were 35.0%(21/60), 31.4%(16/51), 25.0%(9/36) and 80.0%(20/25). Therapeutic plan was changed in 40%(24/60) of patients after bronchoscopy and in 36%(9/25) of patients after surgical lung biopsy. More patients survived (84.4% vs 60.5%, p=0.024) when therapeutic plan was changed after invasive diagnostic study. CONCLUSION: Bronchoscopy and surgical lung biopsy are helpful for the therapeutic implication of pulmonary infiltrates in immunocompromised hosts. Large-scale prospective case-control study may further clarify their limitation and usefulness.

Preservation of Pulmonary Function after Sleeve Lobectomy in Patients with Lung Cancer / 결핵

BACKGROUND: Sleeve lobectomy of the main bronchus has been proposed to spare lung tissue in patients who cannot tolerate pneumonectomy because of impaired lung function. The purpose of this study was to evaluate whether sleeve lobectomy can preserve lung function as expected from preoperative evaluation of lung function in patients with non-small cell lung cancer. METHOD: Between January 1995 and March 1998, 15 patients with non-small cell lung cancer who underwent sleeve resection were evaluated. Preoperative evaluations included spirometry and quantitative lung perfusion scan, from which predicted postoperative FEV1 was calculated. At least 3 months after operation follow up spirometry and bronchoscopy were performed. Predicted FEV1 was compared with measured postoperative FEV1. RESULT: Fourteen men and one woman, with median age of 58 years, were reviewed. The diagnosis was squamous cell carcinoma in 13 patients and adenocarcinoma of lung in 2 patients. Our results showed a excellent preservation of pulmonary function after sleeve lobectomy. Correlation between the predicted (mean, 2180 +/- 570mL) and measured FEV1 (mean, 2293 +/- 499mL) was good ( r = 0.67, P< 0.05 ). Furthermore, patient with low FEV1 (<2L) showed improved lung function after sleeve lobectomy. CONCLUSION: These findings indicated a complete recovery of the reimplanted lung lobes after sleeve lobectomy. Therefore, this technique could be safely used in lung cancer patients with impaired lung function.

Difference in Patient's Work of Breathing Between Pressure-Controlled Ventilation with Deccelerating Flow and Volume-Controlled Ventilation with Constant Flow during Assited Ventilation / 결핵

BACKGROUND: The patient's work of breathing(WOBp) during assisted ventilation may vary according to many factors including ventilatory demand of the patients and applied ventilatory setting by the physician. Pressure-controlled ventilation(PCV) which delivers gas with decelerating flow may better meet patients' demand to improve patientventilator synchrony compared with volume-controlled ventilation(VCV) with constant flow. This study was conducted to compare the difference in WOBp in two assisted modes of ventilation, PCV and VCV with constant flow. METHODS: Ten patients with respiratory failure were included in this study. Initially, the patients were placed on VCV with constant flow at low tidal volume(VT,LOW)(6-8 ml/kg) or high tidal volume(VT,HIGH)(10-12 ml/kg). After a 15 minute stabilization period, VCV with constant flow was switched to PCV and pressure was adjusted to maintain the same tidal volume(VT) received on VCV. Other ventilator settings were kept constant. Before changing the ventilatory mode, WOBp, VT, minute ventilation(VE), respiratory rate(RR), peak airway pressure (Ppeak), peak inspiratory flow rate(PIFR) and pressure-time product(PTP) were measured. RESULTS: The mean VE and RR were not different between PCV and VCV during study period. The Ppeak was significantly lower in PCV than in VCV during VT,HIGH ventilation(p<0.05). PIFR was significantly higher in PCV than in VCV at both VT (p<0.05). During VT,LOW ventilation, WOBp and PTP in PCV(0.80?0.37 J/min, 164.5?74.4 cmH2O.S) were significantly lower than in VCV(1.06+/-0.39J /min, 256.4+/-107.5 cmH2O.S)(p<0.05). During VT,HIGH ventilation, WOBp and PTP in PCV(0.33+/-0.14 J/min, 65.7+/-26.3 cmH2O.S) were also significantly lower than in VCV(0.40+/-0.14 J/min, 83.4+/-35.1 cmH2O.S)(p<0.05). CONCLUSION: During assisted ventilation, PCV with deccelerating flow was more effective in reducing WOBp than VCV with constant flow. But since individual variability was shown, further studies are needed to confirm these results.

Short-Term Efficacy of Steroid and Immunosuppressive Drugs in Patients with Idiopathic Pulmonary Fibrosis and Pre-treatment Factors Associated with Favorable Response / 결핵

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a diffuse inflammatory and fibrosing process that occurs within the interstitium and alveolus of the lung with invariably poor prognosis. The major problem in management of IPF results from the variable rate of disease progression and the difficulties in predicting the response to therapy. The purpose of this retrospective study was to evaluate the shortterm efficacy of steroid and immunosuppressive therapy for IPF and to identify the pre-treatment determinants of favorable response. METHOD: Twenty patients of IPF were included. Diagnosis of IPF was proven by thoracoscopic lung biopsy and they were presumed to have active progressive disease. The baseline evaluation in these patients included clinical history, pulmonary function test, bronchoalveolar lavage (BAL), and chest high resolution computed tomography (HRCT). Fourteen patients received oral prednisolone treatment with initial dose of 1mg/kg/day for 8 to 12 weeks and then tapering to low-dose prednis olone (0.5mg/kg/day). Six patients who previously had experienced significant side effects to steroid received 2mg/kg/day of oral cyclophosphamide with or without low-dose prednisolone. Follow-up evaluation was performed after 6 months of therapy. If patients met more than one of followings, they were considered to be responders: (1)improvement of more than one grade in dyspnea index, (2)improvement in FVC or TLC more than 10% or improvement in DLco more than 20% (3) decreased extent of disease in chest HRCT findings. RESULT: One patient died of extrapulmonary cause after 3 month of therapy, and another patient gave up any further medical therapy due to side effect of steroid. Eventually medical records of 18 patients were analyzed. Nine of 18 patients were classified into responders and the other nine patients into nonresponders. The histopathologic diagnosis of the responders were all nonspecific interstitial pneumonia (NSIP) and that of nonresponders were all usual interstitial pneumonia (UIP) (p<0.001). The other significant differences between the two groups were female predominance (p<0.01), smoking history (p<0.001), severe grade of dyspnea (p<0.05), lymphocytosis in BAL fluid (23.8+/-16.3% vs 7.83+/-3.6%, p < 0.05), and less honeycombing in chest HRCT findings (0% vs 9.22+/-2.3%, p < 0.001). CONCLUSION: Our results suggest that patients with histopathologic diagnosis of NSIP or lymphocytosis in BAL fluid are more likely to respond to steroid or immunosuppressive therapy. Clinical results in large numbers of IPF patients will be required to identify the independent variables.

Clinical Course of Untreated Sarcoidosis / 결핵

BACKGROUND: Sarcoidosis, uncommon in Korea, has variable clinical course, ranging from benign self-limited recovery to life-long disability regardless of corticosteroid therapy. The purpose of this st udy is to observe the clinical course of untreated sarcoidosis. METHODS: Twenty four patients who were confirmed as sarcoidosis by tissue diagnosis were included. For average 12month follow-up periods, subjective symptoms, radiologic findings, and parameters of pulmonary function test(FVC, FEV1, DLco) were evaluated every 3months compared between corticosteroid treated (n=5) and non-treated (n=19) patients. 'Deterioration' was defined if patients met more than one of followings (1) decrement in any parameters of pulmonary function test (2) worsening in the degree of dyspnea (3) increase in radiologic extents, and (4) newly developed extrapulmonary sarcoidosis. 'Stable' was defined as no significant interval changes in every parameters. 'Improvement' was defined as decrement of extension of the radiologic lesions without deterioration. RESULTS: Among 19 untreated sarcoidosis patient, one deteriorated, 14 improved (13 of them showed complete resolution in radiology), and 4 were remained stable. On the other hand, five corticosteroid treated patients, uveitis was developed in one, 2 improved, and 2 remained stable. CONCLUSION: These findings suggest that patient with sarcoidosis, especially those without serious extrapulmonary disease, has stable clinical course and would not need corticosteroid therapy.

Pharmacokinetic Profiles of Isoniazid and Rifampicin in Korean Tuberculosis Patients / 결핵

BACKGROUND: Isoniazid(INH) and rifampicin(RFP) are the most effective anti-tuberculosis drugs which make the short-course chemotherapy possible. Although prescribed dosages of INH and RFP in Korea are different from those recommended by American Thoracic Society, there has been few study about pharmacokinetic profiles of INH and RFP in Korean patients who receive INH, RFP, ethambutol(EMB) and pyrazinamide(PZA) simultaneously. METHODS: Among the patients with active tuberculosis from Dec. 1997 to July 1998, we selected 17 patients. After an overnight fast, patients were given INH 300mg, RFP 450mg, EMB800mg and PZA 1500mg daily. Blood samples for the measurement of plasma INH(n=15) and RFP(n=17) level were drawn each at 0, 0.5, 1, 1.5, 2, 4, 6, 8 and 12hrs, and urine was also collected. INH and RFP level in the plasma and the urine were measured by high-performance liquid chromatography(HPLC). Pharmacokinetic parameters such as peak serum concentration(Cmax), time to reach to peak serum concentration(Tmax), half-life, elimination rate constant(Ke), total body clearance(CLtot), nonreanl clearance(CLnr), and renal clearance(CLr) were calculated. RESULTS: 1) Pharmacokinetic parameters of INH were as follows: Cmax; 7.63 +/- 3.20 micro gram /ml, Tmax; 0.73 +/- 0.22hr, half-life;2.12 +/- 0.84hrs, Ke;0.83 +/- 0.15hrs-1, CLtot;17.54 +/- 8.89L/hr, CLnr; 14.74 +/- 8.35L/hr, CLr; 2.79 +/- 1.31L/hr 2) Pharmacokinetic parameters of RFP were as follows : Cmax; 8.93 +/- 3.98 micro gram/ml, Tmax;1.76 +/- 1.13hrs, half-life;2.27 +/- 0.54hrs, Ke;0.32 +/- 0.08hrs-1, CLtot;14.63 +/- 6.60L/hr, CLr;1.04 +/- 1.55L/hr, CLnr;13.59 +/- 6.21L/hr. 3) While the correlation between body weight and Cmax of INH was not statistically significant (gamma=-0.514, p value >0.05), Cmax of RFP was significantly affected by body weight of the patients(gamma=-0.662, p value <0.01). CONCLUSION: In Korean patients with tuberculosis, 300mg of INH will be sufficient to reach the ideal peak blood level even in the patients over 50kg of body weight. However, 450mg of RFP will not be the adequate dose in the patients who weigh over 50~60kg.

Efficacy of the Antibiotics Chosen by ATS Guideline in the Treatment of Korean Patients with Community-acquired Pneumonia Admitted to a Tertiary Hospital / 결핵

BACKGROUND: In 1993, American Thoracic Society (ATS) recommended a guideline for the initial management of adults with community-acquired pneumonia(CAP). However, etiologic organisms and medical system in Korea seem to be different from those in Western countries. Retrospective analysis was done to evaluate the efficacy of antibiotics chosen by ATS guideline in the treatment of Korean patients with CAP admitted to a tertiary university medical center. METHODS: Hospitalized patients with CAP at Samsung Medical Center from April 1997 through March 1998 were retrospectively reviewed. Patients who fulfilled all of the following criteria were included in this study : (1) fever >or=38degrees C (2) purulent sputum (3) pulmonary infiltrates on chest X-ray. Patients were classified as : 1) ATS group ; patients whose initial antibiotics were chosen by ATS guideline 2) Non-ATS overuse group ; additional antibiotics administered more than those of ATS guideline, and 3) Non-ATS underuse group ; initial antibiotics were insufficient to ATS guideline. Response of empirical antibiotics and etiologic organisms of 3 groups were identified. RESULTS: Sixty-four patients were enrolled. Thirty-six patients were classified into ATS group, 10 patients Non-ATS overuse group, and 18 patients Non-ATS underuse group. Thirty-three patients of 36 ATS group, 9 patients of 10 Non-ATS overuse group, and 14 patients of 18 Non-ATS underuse group showed improvement by initial empirical antibiotics. There was no statistical difference in antibiotic response between 3 groups (p>0.05). S. pneumoniae (12.5%), K. pneumoniae(9.4%), and P. aeruginosa(4.7%), Mycoplasma(3.1%) were the most commonly isolated organisms. In 18 patients with severe CAP, P. aeruginosa was isolated only in 1 patient and Legionella organism not isolated. CONCLUSION: Initial empirical antibiotics chosen by ATS guideline were effective in the management of Korean patients with CAP admitted to a tertiary hospital. However well-designed large-scale prospective study is needed to identify etiologic organisms and choose an adequate initial empirical antibiotics in Korean adults patient with severe CAP.