Tracheoesophageal Fistula with Tracheal Dilatation in a Patient with a Tracheostomy Using a Home Mechanical Ventilator / 대한내과학회지

Patients with tracheostomies requiring prolonged home mechanical ventilation are increasing in number rapidly. A tracheoesophageal fistula is a relatively unusual complication, but this case resulted in a fatal outcome. We describe a tracheoesophageal fistula with tracheal dilation in a 72-year-old female who had a prolonged tracheostomy and nasogastric tube, using a home mechanical ventilator. On enhanced CT images, the tracheostomy tube was well located within the trachea with no abnormal finding. However, chest enhanced CT images obtained 5 months later showed marked circumferential wall thickening of the trachea with tiny ulceration, a markedly increased diameter of the tracheal lumen, and a tracheoesophageal fistula. In patients using home mechanical ventilators, the location and cuff pressure of the tracheostomy tube and the nasogastric tube should be evaluated routinely.

COPD Patients with Exertional Desaturation Are at a Higher Risk of Rapid Decline in Lung Function

PURPOSE: A recent study demonstrated that exertional desaturation is a predictor of rapid decline in lung function in patients with chronic obstructive pulmonary disease (COPD); however, the study was limited by its method used to detect exertional desaturation. The main purpose of this study was to explore whether exertional desaturation assessed using nadir oxygen saturation (SpO2) during the 6-minute walk test (6MWT) can predict rapid lung function decline in patients with COPD. MATERIALS AND METHODS: A retrospective analysis was performed on 57 patients with moderate to very severe COPD who underwent the 6MWT. Exertional desaturation was defined as a nadir SpO2 of or =50 mL. Patients were divided into rapid decliner (n=26) and non-rapid decliner (n=31) groups. RESULTS: A statistically significant difference in exertional desaturation was observed between rapid decliners and non-rapid decliners (17 vs. 8, p=0.003). No differences were found between the groups for age, smoking status, BODE index, and FEV1. Multivariate analysis showed that exertional desaturation was a significant independent predictor of rapid decline in patients with COPD (relative risk, 6.8; 95% CI, 1.8 to 25.4; p=0.004). CONCLUSION: This study supports that exertional desaturation is a predictor of rapid lung function decline in male patients with COPD.

Association of body mass index with airway hyperresponsiveness and lung function in adult asthmatics

PURPOSE: Obesity is commonly regarded as a risk factor for asthma development, poor asthma control, and poor response to asthma therapy. However, its relationships are not always consistent. Gender difference has been reported to influence asthma severity and asthma control. We investigated the contribution of obesity to airway hyperresponsiveness (AHR) and lung function before and after treatment in adult asthmatics. METHODS: The medical records of a total of 323 adult asthmatics were analyzed retrospectively. Asthma was diagnosed based on the positive result of methacholine bronchial provocation test (PC20 or =12% and 200-mL improvement in forced expiratory volume in 1 second after inhalation of a bronchodilator). Follow-up spirometry was performed in 113 patients after at least 3 months of asthma treatment with controller medication. Percent change between spirometry before and after treatment was defined as {[(value after treatment-value before treatment)/value before treatment]x100}. Body mass index (BMI, weight [kg]/height [m2]) was categorized into underweight (30) according to the world health organization classification. RESULTS: BMI did not show any significant correlation with PC20 value of methacholine provocation test and each lung function parameter before and after treatment. When we divided the study subjects according to gender and age, BMI was negatively correlated with PC20 value only in female adult asthmatics under 65 years old (r=-0.024, P=0.036). CONCLUSION: Obesity is positively correlated with the intensity of AHR in female adult asthmatics. Gender seems to differentially contribute to the relationship between BMI and AHR.

A Case of Spontaneous Remission Organizing Pneumonia after Resection of Thymoma / 대한내과학회지

Thymoma is a rare neoplasm associated with a number of autoimmune disorders and tumors. Organizing pneumonia is a reaction of the lung to various injuries. A feature of organizing pneumonia is plugs of granulation tissue within the lumens of small airways, or alveoli. Causes of organizing pneumonia include various disorders and conditions; however, thymoma with organizing pneumonia located in both lungs is very rare. We report a case of resolving organizing pneumonia after thymoma resection. Our case is the first to demonstrate that resolving organizing pneumonia can occur after thymoma resection, as has been speculated by many researchers.

Application of a New Spirometric Reference Equation and Its Impact on the Staging of Korean Chronic Obstructive Pulmonary Disease Patients

PURPOSE: A new spirometric reference equation was recently developed from the first national chronic obstructive pulmonary disease (COPD) survey in Korea. However, Morris' equation has been preferred for evaluating spirometric values instead. The objective of this study was to evaluate changes in severity staging in Korean COPD patients by adopting the newly developed Korean equation. MATERIALS AND METHODS: We evaluated the spirometric data of 441 COPD patients. The presence of airflow limitation was defined as an observed post-bronchodilator forced expiratory volume in one second/forced vital capacity (FEV1/FVC) less than 0.7, and the severity of airflow limitation was assessed according to GOLD stages. Spirometric values were reassessed using the new Korean equation, Morris' equation and other reference equations. RESULTS: The severity of airflow limitation was differently graded in 143 (32.4%) patients after application of the new Korean equation when compared with Morris' equation. All 143 patients were reallocated into more severe stages (49 at mild stage, 65 at moderate stage, and 29 at severe stage were changed to moderate, severe and very severe stages, respectively). Stages according to other reference equations were changed in 18.6-49.4% of the patients. CONCLUSION: These results indicate that equations from different ethnic groups do not sufficiently reflect the airflow limitation of Korean COPD patients. The Korean reference equation should be used for Korean COPD patients in order to administer proper treatment.

Bronchoscopic Ethanolamine Injection Therapy in Patients with Persistent Air Leak from Chest Tube Drainage / 결핵및호흡기질환

BACKGROUND: Chest tube drainage (CTD) is an indication for the treatment of pneumothorax, hemothroax and is used after a thoracic surgery. But, in the case of incomplete lung expansion, and/or persistent air leak from CTD, medical or surgical thoracoscopy or, if that is unavailable, limited thoracotomy, should be considered. We evaluate the efficacy of bronchoscopic injection of ethanolamine to control the persistent air leak in patients with CTD. METHODS: Patients who had persistent or prolonged air leak from CTD were included, consecutively. We directly injected 1.0 mL solution of 5% ethanolamine oleate into a subsegmental or its distal bronchus, where it is a probable air leakage site, 1 to 21 times using an injection needle through a fiberoptic bronchoscope. RESULTS: A total of 15 patients were enrolled; 14 cases of spontaneous pneumothorax [idiopathic 9, chronic obstructive pulmonary disease (COPD) 3, post-tuberculosis 2] and one case of empyema associated with broncho-pleural fistula. Of these, five were patients with persistent air leak from CTD, just after a surgical therapy, wedge resection with plication for blebs or bullae. With an ethanolamine injection therapy, 12 were successful but three (idiopathic, COPD and post-tuberculosis) failed, and were followed by a surgery (2 cases) or pleurodesis (1 case). Some adverse reactions, such as fever, chest pain and increased radiographic opacities occurred transiently, but resolved without any further events. With success, the time from the procedure to discharge was about 3 days (median). CONCLUSION: Bronchoscopic ethanolamine injection therapy may be partially useful in controlling air leakage, and reducing the hospital stay in patients with persistent air leak from CTD.

Infection Rate of Chlamydia pneumoniae in Patients with Chronic Cough / 결핵및호흡기질환

BACKGROUND: Persistent cough has recently been found to be associated with Chlamydia pneumoniae infection. We aimed to investigate the infection rate of C. pneumonia in adult patients with chronic cough. METHODS: We recruited 68 patients with persistent cough lasting in excess of 3 weeks, who visited Kangdong Sacred Heart Hospital from January 2005 to August 2005. On the first visit, chest and paranasal sinuses radiography, skin prick test of common allergens, and induced sputum samples for C. pneumoniae were performed in all of patients. Further evaluation for diagnosis included a methacholine provocation test and eosinophil counts in induced sputum. RESULTS: The most common cause of chronic cough was upper airway cough syndrome (UACS) (26.5%), followed by eosinophilic bronchitis (20.6%) and cough variant asthma (16.2%). Idiopathic chronic cough was the cause in 33.8% of patients. The mean duration of cough was 11.7 months. C. pneumoniae was isolated by polymerase chain reaction (PCR) from one patient who had upper respiratory air way syndrome. CONCLUSION: Chlamydia pneumoniae appears to have a minor role as a cause of chronic cough in patients.

Comparison of the Prevalence of Chronic Obstructive Pulmonary Disease Diagnosed by Lower Limit of Normal and Fixed Ratio Criteria

The Global Initiative of Chronic Obstructive Lung Disease (GOLD) guidelines define chronic obstructive pulmonary disease (COPD) in subjects with FEV1/FVC or =65, 14.9% and 31.1%, respectively. In conclusion, the prevalence of COPD by LLN criterion was significantly lower in elderly compared to fixed ratio of FEV1/FVC. Implementing LLN criterion instead of fixed ratio of FEV1/FVC may reduce the risk of over-diagnosis of COPD in elderly people.

Semi-quantitative Procalcitonin Assay in Critically ill Patients with Respiratory infections / 결핵및호흡기질환

BACKGROUND: Serum procalcitonin level has been considered prognostic during sepsis and septic shock. We investigated the significance of procalcitonin in critically ill patients with respiratory infections. METHODS: The patients who had radiographically diagnosed diffuse lung infiltrations were enrolled on a prospective basis. Bronchoalveolar lavage (BAL) fluid for the purpose of quantitative cultures (> or =10(4) cfu/mL) was obtained from all patients. Serum procalcitonin levels determined by PCT-Q kit were measured on BAL day and classified as follows; 10.0 ng/mL. We analyzed the patient's characteristics according to outcome; favorable or unfavorable, defined as death. RESULTS: Patients from the following categories were included: medical 17 (47.2%), surgical 9 (25%), and burned 10 (27.8%). APACHE II scores on admission to intensive care unit were 11.5+/-6.89 and 11 (30.6%) had unfavorable outcomes. A procalcitonin level > or =0.5 ng/mL was in 17 (47.2%) of all. On univariate analysis, the frequencies of burn injury, mechanical ventilation, multiple organ failure, and a procalcitonin level > or =0.5 ng/mL were more often increased in patients with unfavorable outcomes than in those with favorable outcomes (p or =0.5 ng/mL was more sensitive in predicting VAP than unfavorable outcome. CONCLUSION: A higher procalcitonin level seems to be associated with VAP, but further study is required to know that procalcitonin would be a prognostic marker in critically ill patients with respiratory infections.

A Case of Partial Spontaneous Regression of Non-Small Cell Lung Cancer / 결핵및호흡기질환

Spontaneous regression is extremely rare in lung cancer and this in spite of its global high incidence. So far, less than 30 such cases have been reported in the literature. We report here on the case of a 68-year-old man who had the diagnosis of adenocarcinoma and in absence of any medical therapy, he had a partial spontaneous regression of tumor.

A Study to Validate the Pretest Probability of Malignancy in Solitary Pulmonary Nodule / 결핵및호흡기질환

BACKGROUND: Solitary pulmonary nodules (SPN) are encountered incidentally in 0.2% of patients who undergo chest X-ray or chest CT. Although SPN has malignant potential, it cannot be treated surgically by biopsy in all patients. The first stage is to determine if patients with SPN require periodic observation and biopsy or resection. An important early step in the management of patients with SPN is to estimate the clinical pretest probability of a malignancy. In every patient with SPN, it is recommended that clinicians estimate the pretest probability of a malignancy either qualitatively using clinical judgment or quantitatively using a validated model. This study examined whether Bayesian analysis or multiple logistic regression analysis is more predictive of the probability of a malignancy in SPN. METHODS: From January 2005 to December 2008, this study enrolled 63 participants with SPN at the Kangnam Sacred Hospital. The accuracy of Bayesian analysis and Bayesian analysis with a FDG-PET scan, and Multiple logistic regression analysis was compared retrospectively. The accurate probability of a malignancy in a patient was compared by taking the chest CT and pathology of SPN patients with <30 mm at CXR incidentally. RESULTS: From those participated in study, 27 people (42.9%) were classified as having a malignancy, and 36 people were benign. The result of the malignant estimation by Bayesian analysis was 0.779 (95% confidence interval [CI], 0.657 to 0.874). Using Multiple logistic regression analysis, the result was 0.684 (95% CI, 0.555 to 0.796). This suggests that Bayesian analysis provides a more accurate examination than multiple logistic regression analysis. CONCLUSION: Bayesian analysis is better than multiple logistic regression analysis in predicting the probability of a malignancy in solitary pulmonary nodules but the difference was not statistically significant.

Incidence of Immunoglobulin G Subclass Deficiencies in Patients with Bronchiectasis and the Clinical Characteristics of Patients with Immunoglobulin G Subclass Deficiency and Bronchiectasis / 결핵및호흡기질환

BACKGROUND: There are various etiologies causing bronchiectasis, but the cases without definite causes account for a quite high proportion. It is also uncertain that immunoglobulin G subclass deficiency (IgGSD) is associated with bronchiectasis. Therefore, we tried to measure the frequency of IgGSD in patients with bronchiectasis of unclear etiology, and to observe the clinical features of those patients with bronchiectasis and IgGSD. METHODS: For the outpatients of a university hospital who were diagnosed as bronchiectasis by chest CT, we produced comprehensive history taking and physical examinations, and finally selected 31 patients with bronchiectasis of unclear etiology. RESULTS: Two patients had total immunoglobulin G deficiency. The frequency of IgGSD was comparatively high (n=14). When we compared IgGSD group to normal immunoglobulin G subclass group, there were no significant differences in sex, age, and the frequency of sinusitis, bronchial asthma, and the abnormal lung function. CONCLUSION: In cases of bronchiectasis without definite causes, it can be considered to measure the level of immunoglobulin G subclass. It is also probably worthwhile to further evaluate the relationship between IgGSD and bronchiectasis.

A Trial of Aerosolized Colistin for the Treatment of Nosocomial Pneumonia due to Multidrug-resistant Acinetobacter baumannii / 결핵및호흡기질환

BACKGROUND: Recently, multidrug-resistant (MDR) A. baumannii has been implicated for a significant proportion of nosocominal pneumonia in many intensive care units (ICUs), and its acquisition may increase mortality and the length of stay in the ICU. Aerosolized colistin has been successfully used in patients with cystic fibrosis, but there is a lack of data regarding the use of aerosolized colistin in patients with nosocomial pneumonia. METHODS: We conducted the present study to assess the effectiveness of aerosolized colistin for the treatment of MDR A. baumannii nosocomial pneumonia. We retrospectively reviewed the medical records of 10 patients who had been hospitalized in the medical ICU and had received aerosolized colistin as a therapy for MDR A. baumannii pneumonia. RESULTS: The mean duration of aerosolized colistin therapy was 12.7+/-2.4 days. Nine (90%) of 10 patients showed a favorable response to the therapy. Follow-up cultures were available for all patients, and the responsible pathogen was completely eradicated. One patient suffered from bronchospasm, which resolved after treatment with nebulized salbutamol. CONCLUSION: Our results corroborate previous reports that aerosolized colistin may be an effective and safe choice for the treatment of nosocomial pneumonia caused by MDR A. baumannii. Larger prospective controlled clinical studies are warranted to validate further the effectiveness and safety of aerosolized colistin therapy.

A Case of Secondary Organizing Pneumonia Occurring in Therapy for Lung Abscess / 결핵및호흡기질환

The patient is a 62-year-old man with known diabetes mellitus who presented with a two-weeks-history of dyspnea, cough, and fever. He was diagnosed with a lung abscess in the right upper lobe and was treated with intravenous antibiotics. The patient's clinical and radiological findings improved within seven days after medical treatment. However, newly developed ground-glass opacity and infiltrations were observed in the right lower lung. Fourteen days after admission, the patient's symptoms and imaging finding became aggravated despite trestment with susceptible antibiotics for lung abscess. Trans-bronchial lung biopsy (TBLB) was performed in the lateral basal segment of the right lower lobe of the lung. A histologic photomicrograph showed organizing pneumonia, also called bronchiolitis obliterans with organizing pneumonia(BOOP), that became more definite as the terminal bronchioles and alveoli became occluded with masses of inflammatory cells and fibrotic tissue. The clinical symptoms and radiograph findings resolved quickly with prednisone treatment. We report a case of secondary organizing pneumonia diagnosed after TBLB following lung abscess treatment and provide a review of the literature.

A Case of Tracheostomy Induced Bilateral Tension Pneumothorax / 결핵및호흡기질환

Tracheostomy is one of the oldest surgical procedures in medical history. The indications for a tracheostomy include the relief of an upper airway obstruction, long-term mechanical ventilation, and decreased airway resistance to help wean the patient from mechanical ventilator support. Unfortunately, tracheostomy is also associated with a number of problems including, bleeding, infection, pneumothorax, and tracheal stenosis. A pneumothorax is an uncommon complication of a tracheostomy, and can result from direct injury to the pleura or positive pressure ventilation through a dislocation of the tracheostomy tube. We report an uncommon case of a tracheostomy-induced bilateral tension pneumothorax with a review of the literature.

The Findings of Pulmonary Function Test in Patients with Inhalation Injury / 결핵및호흡기질환

BACKGROUND: The changes in the pulmonary function observed in burn patients with an inhalation injury are probably the result of a combination of airway inflammation, chest wall and muscular abnormalities, and scar formation. In addition, it appears that prolonged ventilatory support and an episode of pneumonia contribute to the findings. This study investigated the changes in the pulmonary function in patients with inhalation injury at the early and late post-burn periods. METHODS: From August 1, 2002, to August 30, 2005, surviving burn patients who had an inhalation injury were enrolled prospectively. An inhalation injury was identified by bronchoscopy within 48hours after admission. Spirometry was performed at the early phase during admission and the recovery phase after discharge, and the changes in the pulmonary function were compared. RESULTS: 37 patients (M=28, F=9) with a total burn surface area (% TBSA), ranging from 0 to 18%, were included. The initial PaO2/FiO2ratio and COHb were 286.4+/-129.6 mmHg and 7.8+/-6.6 %. Nine cases (24.3%) underwent endotracheal intubation and 3 cases (8.1%) underwent mechanical ventilation. The initial X-ray findings revealed abnormalities in, 18 cases (48.6%) with 15 (83.3%) of these being completely resolved. However, 3 (16.7%) of these had residual sequela. The initial pulmonary function test, showed an obstructive pattern in 9 (24.3%) with 4 (44.4%) of these showing a positive bronchodilator response, A restrictive pattern was also observed in 9 (24.3%) patients. A lower DLco was observed in only 4 (17.4%) patients of which 23 had undergone DLco. In the follow-up study, an obstructive and restrictive pattern was observed in only one (2.7%) case each. All the decreased DLco returned to mormal. CONCLUSIONS: Most surviving burn patients with an inhalation injury but with a small burn size showed initial derangements in the pulmonary function test that was restored to a normal lung function during the follow up period.

The Role of Respiratory Viral Infections in Exacerbation of Asthma and Chronic Obstructive Pulmonary Disease (COPD) / 결핵및호흡기질환

BACKGROUNDS: The exacerbations of asthma and chronic obstructive pulmonary disease (COPD) have been suggested to be associated with respiratory tract viral infections (RTVIs). However, the rates of virus detection in previous studies have been quite variable, with lower rates for the exacerbation of COPD. Therefore, the virus detection of patients with exacerbation of asthma and COPD were investigated. METHODS: 20 and 24 patients with exacerbation of asthma and COPD, respectively, were enrolled. Nasal and sputum samples were taken, and polymerase chain reaction (PCR) for rhinovirus and coronavirus and virus culture for influenza A, B, RSV and parainfluenza virus performed. RESULTS: The mean FEV1/FVC in the exacerbation of asthma and COPD patients were 1.9/2.9 L (65.5%) and 1.1/2.6 L (42.3%), respectively. Respiratory virus was detected in 13 (65%) patients with exacerbation of asthma and rhinovirus was detected in 9. Coronavirus, influenza A, RSV and parainfluenza virus were detected in 2, 2, 1 and 1 patients with asthma. Among patients with exacerbation of COPD, a virus was detected in 14 (58.3%) patients, with rhinovirus, coronavirus and influenza A detected in 10, 3 and 4, respectively. CONCLUSIONS: This study suggested that RTVIs may have a role in the exacerbation of COPD as well as asthma.

Clinical Investigation of Recurrent Pneumonia in Adults: Analysis of Patients From Hallym University Medical Center / 결핵및호흡기질환

BACKGROUND: Recurrent pneumonia in adults is not uncommon. However, there is no domestic data about recurrent pneumonia in adults. Therefore, we investigated the associated diseases and clinical findings of recurrent pneumonia in adults. METHODS: Among 5513 patients who were treated in five teaching hospitals of Hallym medical center?over a 5-year period, we retrospectively reviewed the medical records of the 58 who were compatible with diagnostic criteria of recurrent pneumonia. RESULTS: The number of patients with recurrent pneumonia was 58 (1.05%, 58/5513) during the 5 years. Thirty- seven patients were male and 21 were female. Mean age was 66.4 (+/-14.9) years. Median interval between each pneumonic episode was 18.5 months. Associated diseases were 25 cases of respiratory diseases, 13 of heart diseases, 13 of diabetes mellitus, 7 of lung malignancies, 11 of malignancies other than lung, 7 of neurologic disease, and 8 of miscellaneous diseases. Three cases had no underlying illness. Of the 8 cases with 2 or more times of recurrence, 4 were associated with respiratory diseases, 2 with aspiration pneumonia due to neurologic diseases, 1 with heart disease and 1 with no underlying illness. Recurrent pneumonic episodes affecting the same location were 30 of the total recurrent pneumonic episodes (30/67, 47.8%) and common associated diseases were respiratory diseases including lung malignancies. The etiology of recurrent pneumonia was Streptococcus pneumoniae, methicillin- resistant Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, atypical organisms, etc. CONCLUSION: Recurrent pneumonia in adults had a low incidence rate compared with children, but most cases had associated illness. Respiratory diseases including lung cancer were the most common associated illness of recurrent pneumonia.

The SOFA Score to Evaluate Organ Failure and Prognosis in the Intensive Care Unit Patients / 결핵및호흡기질환

BACKGROUND: The Sequential Organ Failure Assessment (SOFA) score can help to assess organ failure over time and is useful to evaluate morbidity. The aim of this study is to evaluate the performance of SOFA score as a descriptor of multiple organ failure in critically ill patients in a local unit hospital, and to compare with APACHE III scoring system. METHODS: This study was carried out prospectively. A total of ninety one patients were included who admitted to the medical intensive care unit (ICU) in Chuncheon Sacred Heart Hospital from May 1 through June 30, 2000. We excluded patients with a length of stay in the ICU less than 2 days following scheduled procedure, admissions for ECG monitoring, other department and patients transferred to other hospital. The SOFA score and APACHE III score were calculated on admission and then consecutively every 24 hours until ICU discharge. RESULTS: The ICU mortality rate was 20%. The non-survivors had a higher SOFA score within 24 hours after admission. The number of organ failure was associated with increased mortality. The evaluation of a subgroup of 74 patients who stayed in the ICU for at least 48 hours showed that survivors and non-survivors followed a different course. In this subgroup, the total SOFA score increased in 81% of the non-survivors but in only 21% of the survivors. Conversely, the total SOFA score decreased in 48% of the survivors compared with 6% of the non-survivors. The non-survivors also had a higher APACHE III score within 24 hours and there was a correlation between SOFA score and APACHE III score. CONCLUSION: The SOFA score is a simple, but effective method to assess organ failure and to predict mortality in critically ill patients. Regular and repeated scoring enables patient's condition and clinical course to be monitored and better understood. The SOFA score well correlates with APACHE III score.

Effects of Matrix Metalloproteinase Inhibitor on Ventilator-Induced Lung Injury in Rats / 결핵

BACKGROUND: Many inflammatory mediators and collagenases are involved in the pathogenesis of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The increase of matrix metalloproteinase-9 (MMP-9, gelatinase-B) produced mainly by inflammatory cells was reported in many ALI models and ARDS patients. Cyclic mechanical stress also can induce MMP-9 production from alveolar macrophages and connective tissue cells. In this study, the expression of MMP-9 in ventilator-induced lung injury (VILI) model and the effects of matrix metalloproteinase inhibitor (MMPI) on VILI were investigated. METHODS: Eighteen Sprague-Dawley rats were divided into three groups: low tidal volume (LVT, 7mL/Kg tidal volume, 3 cmH2O PEEP, 40/min.), high tidal volume (HVT, 30mL/Kg tidal volume, no PEEP, 40/min) and high tidal volume with MMPI (HVT+MMPI) groups. Mechanical ventilation was performed in room air for 2 hours. The 20 mg/Kg of CMT-3 (chemically modified tetracycline-3, 6-demethyl 6-deoxy 4-dedimethylamino tetracycline) was gavaged as MMPI from three days before mechanical ventilation. The degree of lung injury was measured with wet-to-dry weight ratio and acute lung injury score. Expression of MMP-9 was studied by immunohistochemical stain with a mouse monoclonal anti-rat MMP-9 IgG1. RESULTS: In the LVT, HVT and HVT + MMPI groups, the wet-to-dry weight ratio was 4.70+/-0.14, 6.82+/-1.28 and 4.92+/-0.98, respectively. In the HVT group, the ratio was significantly higher than other groups (p<0.05). Acute lung injury score measured by five-point scale was 3.25+/-1.17, 12.83+/-1.17 and 4.67+/-0.52, respectively. The HVT group was significantly damaged by VILI and MMPI protects injuries by mechanical ventilation (p<0.05). Expression of MMP-9 measured by four-point scale was 3.33+/-2.07, 12.17+/-2.79 and 3.60+/-1.95, respectively, which were significantly higher in the HVT group (p<0.05). CONCLUSION: VILI increases significantly the expression of MMP-9 and MMPI prevents lung injury induced by mechanical ventilation through the inhibition of MMP-9.