Effects of aging on accompanying intermittent hypoxia in a bleomycin-induced pulmonary fibrosis mouse model.

BACKGROUND/AIMS: Obstructive sleep apnea (OSA) is prevalent in older patients with idiopathic pulmonary fibrosis (IPF); however, it is underrecognized. OSA is characterized by intermittent hypoxia (IH) and sleep fragmentation. In this study, we evaluated the effects of IH in an older mouse model of bleomycin-induced lung fibrosis. METHODS: Bleomycin-induced mice (C57BL/6, female) were randomly divided into four groups of young vs. old and room air (RA)-exposed vs. IH-exposed. Mice were exposed to RA or IH (20 cycles/h, FiO2 nadir 7 ± 0.5%, 8 h/day) for four weeks. The mice were sacrificed on day 28, and blood, bronchoalveolar lavage (BAL) fluid, and lung tissue samples were obtained. RESULTS: The bleomycin-induced IH-exposed (EBI) older group showed more severe inflammation, fibrosis, and oxidative stress than the other groups. The levels of inflammatory cytokines in the serum and BAL fluid increased in the EBI group. Hydroxyproline levels in the lung tissue increased markedly in the EBI group. CONCLUSION: This study demonstrates the possible harmful impact of OSA in an elderly mouse model of lung fibrosis. This study further suggests that older patients with IPF and OSA may be more of a concern than younger patients with IPF. Further research is required in this area.

Associations among sleep-disordered breathing, sleep quality, and lung cancer in Korean patients.

PURPOSE: Intermittent hypoxia and sleep fragmentation, two main features of sleep-disordered breathing (SDB), have been shown to increase the aggressiveness of lung cancer, mainly in animal and in vitro studies. However, the association between SDB and lung cancer has not been well described in human studies. In this study, we investigated the associations among SDB, sleep quality, and lung cancer in Korean patients. METHODS: Patients with histologically diagnosed lung cancer performed a home sleep apnea test. Sleep questionnaires including the Epworth Sleepiness Scale (ESS), Insomnia Severity Index, and Pittsburgh Sleep Quality Index were also administered. Clinical information related to lung cancer was collected during the study. RESULTS: Sixty-nine patients were enrolled, 31 of whom were poor sleepers. The overall prevalence of SDB was 57% and that of moderate to severe SDB was 27%. Underlying chronic obstructive pulmonary disease (COPD) and smoking history were significantly more frequent in patients with moderate to severe SDB compared to patients without or with mild SDB. No significant differences were observed in the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), or time with oxygen saturation < 90% (T90) according to cancer cell types, mutations, stages, and survival. However, small-cell lung cancer patients showed a trend toward higher AHI, ODI, and T90 values. CONCLUSION: The prevalence of SDB and proportion of poor sleepers were high in Korean patients with lung cancer. Paying more attention to sleep status may be helpful for patients with COPD, a smoking history, and small-cell lung cancer.

Monocyte distribution width (MDW) as a useful indicator for early screening of sepsis and discriminating false positive blood cultures.

BACKGROUND: Severe sepsis and septic shock are the leading cause of in-hospital death. As sepsis progresses, expression and activity of endogenous mediators of inflammation change. Early detection of biomarkers can play a role in sepsis screening and in improvement of patient outcomes. Recent studies suggest that increase in monocyte volume may be helpful in early detection of sepsis. Therefore, we evaluated the utility of monocyte distribution width (MDW) for the early assessment of sepsis compared with the blood culture and other inflammatory biomarkers. METHODS: Medical records of 1,404 patients (aged ≥19 years) who were admitted to the emergency department owing to clinically suspected infectious disease and requested blood cultures from Oct 2019 to Jan 2021 were reviewed. The patients were grouped based on Sepsis-3 criteria. They had undergone other laboratory tests to evaluate their clinical status. MDW was analyzed using DxH900 hematology analyzer (Beckman Coulter, Brea, California, USA). To determine the diagnostic performance of MDW, C-reactive protein (CRP), and procalcitonin (PCT) for sepsis, the area under the curve (AUC) of receiver operating characteristics curves and their sensitivity and specificity were measured. RESULTS: Among 1,404 patients, 520 patients were designated the sepsis group based on Sepsis-3 criteria. In the sepsis group, MDW value was 24.1 (median, IQR 21.6-28.1); AUC values for MDW, CRP, and PCT were 0.67 (95% CI, 0.64-0.69), 0.66 (95% CI, 0.63-0.68), and 0.75 (95% CI, 0.72-0.77), respectively. For diagnosis of the sepsis, the cut-off value of MDW was 21.7 (sensitivity 74% and specificity 54%). Measured values of MDW were higher for the blood culture positive group than that of the blood culture contamination group (P<0.001, 95% CI, -5.9 to -3.0) or blood culture negative group (P<0.001, 95% CI = -5.8 to -4.2). CONCLUSIONS: MDW is a new hematological parameter that is simultaneously calculated during complete blood cell counting by Beckman Coulter hematology analyzer. MDW is expected to serve as a useful indicator for early screening of sepsis in conjunction with CRP and PCT. MDW is especially useful for sepsis assessment in patients with a suspected infection. MDW can also assist in discriminating false positive blood cultures.

Impacts of the COVID-19 pandemic on sleep center operations and sleep apnea treatment in Korea: A multicenter survey.

ABSTRACT: The coronavirus disease-2019 (COVID-19) pandemic has not only changed the lives of people around the world but also affected all areas of the healthcare system, including sleep medicine. However, no studies in Korea have investigated the status of domestic sleep centers and their challenges during the pandemic.An online survey was performed from December 2020 to January 2021. Hospitals that belonged to sleep-related academic societies and were considered well managed were included in this survey. The questionnaire focused on changes in sleep center operations, infection control policies, and patient treatment since the start of the COVID-19 pandemic. Telemedicine and future directions for sleep medicine services were also investigated.Of the 20 sleep centers that responded, 80% were at university hospitals with more than 500 inpatient beds. During the third wave of the COVID-19 pandemic in Korea (November-December 2020), the routine operating schedule of the sleep study room was reduced in 30% of the sleep centers compared to November-December 2019 (before COVID-19). The number of type 1 polysomnographies performed decreased in 85% of the sleep centers. In contrast, in-lab positive airway pressure (PAP) titrations decreased in 40%, remained unchanged in 35%, and increased in 25%. With respect to prescriptions, 30% of the sleep centers increased the number of prescriptions for auto-titrating continuous PAP. However, 60% of the sleep centers reported no change in the rate of fixed continuous PAP and auto-titrating continuous PAP prescriptions. All sleep centers that participated in this survey agreed that the need for documented infection control regulations will continue after the COVID-19 pandemic. Since the beginning of the pandemic, 30% of the centers have tried telemedicine. However, respondents expressed concern about telemedicine, citing a number of practical issues.Compared to countries where the COVID-19 pandemic was severe, Korea had less impact of COVID-19 on the sleep center operations and sleep apnea treatment. Infection and quality control in the sleep study room are important and inevitable issues, and regulation within each institution is necessary. Further research and discussion are needed regarding telemedicine and home sleep apnea test in Korea.

Utilization of a rapid response team and associated outcomes in patients with malignancy.

BACKGROUND: Recent advances in diagnosis and treatment have improved long-term outcomes in cancer patients. As a result, the requirement for a rapid response team (RRT) for cancer patients is also increasing. This study aimed to analyze utilization of an RRT and the associations between related factors and mortality in a population of cancer patients. METHODS: This retrospective cohort study included hospitalized patients at a single academic medical center in Seoul, Korea, who required RRT activation during a 6-year period from June 2013 to December 2018. RESULTS: Overall, 164 of the 457 patients who met the above criteria were cancer patients, and they had a significantly higher Charlson comorbidity score than the non-cancer patients (5.0 vs. 7.0, P<0.001). A significantly larger proportion of cancer patients required intensive care unit transfer (51.8% vs. 41.0%, P=0.032). Cancer patients also had significantly higher in-hospital mortality compared with other patients (39.6% vs. 10.9%, P<0.001). Furthermore, presence of cancer was independently associated with in-hospital mortality (adjusted odds ratio [OR], 2.09; 95% confidence interval [CI], 1.11 to 3.93). Among cancer patients, higher Acute Physiology and Chronic Health Evaluation (APACHE) II at the time of RRT activation was significantly associated with in-hospital mortality regardless of malignancy (adjusted OR, 1.08; 95% CI, 1.01 to 1.15). CONCLUSIONS: Cancer patients requiring RRT activation have significantly higher rates of inhospital mortality than patients not using RRT. Higher severity score at the time of RRT activation in patients with malignancy was significantly associated with in-hospital mortality.

Intermittent hypoxia exacerbates tumor progression in a mouse model of lung cancer.

The purpose of this study was to evaluate whether obstructive sleep apnea (OSA)-related chronic intermittent hypoxia (CIH) influences lung cancer progression and to elucidate the associated mechanisms in a mouse model of lung cancer. C57/BL6 mice in a CIH group were exposed to intermittent hypoxia for two weeks after tumor induction and compared with control mice (room air). Hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF) and metastasis-related matrix metalloproteinases (MMP) were measured. The expression levels of several hypoxia-related pathway proteins including HIF-1α, Wnt/ß-catenin, the nuclear factor erythroid 2-related factor 2 (Nrf2) and mammalian target of rapamycin-ERK were measured by western blot. The number (P < 0.01) and volume (P < 0.05) of tumors were increased in the CIH group. The activity of MMP-2 was enhanced after CIH treatment. The level of VEGF was increased significantly in the CIH group (p < 0.05). ß-catenin and Nrf2 were translocated to the nucleus and the levels of downstream effectors of Wnt/ß-catenin signaling increased after IH exposure. CIH enhanced proliferative and migratory properties of tumors in a mouse model of lung cancer. ß-catenin and Nrf2 appeared to be crucial mediators of tumor growth.

Effects of long term normobaric hyperoxia exposure on lipopolysaccharide-induced lung injury.

Purpose/Aim of the study: Prolonged exposure to hyperoxia can cause injury to normal lung tissue. However, patients with acute hypoxic respiratory failure are frequently exposed to very high oxygen levels. This study investigated the effects of long term normobaric hyperoxia exposure in a mouse model of acute severe lung injury (SLI).Meterials and Methods: C57BL/6J mice were injected intratracheally with lipopolysaccharide (LPS, 4 mg/kg) to induce acute lung injury. After 2 h, mice were divided into two groups, and then exposed to room air or hyperoxic conditions for 48 h. Animals in the hyperoxia group were placed within their cages in a Plexiglass chamber with an atmosphere of 95% O2 maintained constant using an oxygen analyzer. After exposure to normoxia (N) or hyperoxia (H) for 48 h, the left lungs were collected for tissue paraffin block or oxidative stress assay. One lobe of the right lung was collected for lung/body weight ratio. The lung injury score and the mean linear intercept were evaluated in hematoxylin and eosin -stained lungs. The biochemical tests were performed by using ELISA assay.Results: Lung injury scoring, lung/body weight, and mean linear intercept were not significantly different between the N + LPS (NLPS) and H + LPS (HLPS) groups. Similar trends were observed in hydroxyproline and transforming growth factor-ß (TGF-ß) levels. Total cell and neutrophil counts in bronchoalveolar lavage fluid showed no significant differences between NLPS and HLPS groups. Histological analyses demonstrated more severe lung injury and fibrosis in the NLPS group than in the HLPS group. In addition, interleukin (IL)-1ß was significantly decreased in the HLPS group compared to the NLPS group. Other inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and IL-6, showed similar trends. The malondialdehyde (MDA) level was significantly lower in the HLPS group than in the NLPS group.Conclusions: Exposure to hyperoxia did not augment lung injury in the LPS-induced lung injury model, and some indicators even showed better outcomes. These results suggest that long-term high-oxygen therapy in patients with SLI has low risk of lung injury.

Normobaric hyperoxia inhibits the progression of lung cancer by inducing apoptosis.

Hypoxia is a critical characteristic of solid tumors with respect to cancer cell survival, angiogenesis, and metastasis. Hyperoxic treatment has been attempted to reverse hypoxia by enhancing the amount of dissolved oxygen in the plasma. In this study, we evaluated the effects of normobaric hyperoxia on the progression of lung cancer to determine whether oxygen toxicity can be used in cancer therapy. Following a tail vein injection of the Lewis lung carcinoma cells, C57BL/6J mice were exposed to a 24-h normobaric hyperoxia/normoxia cycle for two weeks. In addition, A549 lung cancer cells were incubated in a normobaric hyperoxia chamber for a 24-h period. As a result, the size and number of tumors in the lung decreased significantly with exposure to normobaric hyperoxia in the mouse model. Cell viability, colony-forming ability, migration, and invasion all decreased significantly in A549 cells exposed to normobaric hyperoxia and the normal control group exposed to normobaric hyperoxia showed no significant damage. Oxidative stress was more prominent with exposure to normobaric hyperoxia in cancer cells. A549 cells exposed to normobaric hyperoxia showed a significantly higher cell apoptosis ratio compared with A549 cells without normobaric hyperoxia exposure and normal human lung cells (BEAS-2B cells). The Bax/Bcl-2 mRNA expression ratio also increased significantly. Changes in the key regulators of apoptosis were similar between in vivo and in vitro conditions. The p-ERK level decreased, while the p-JNK level increased, after normobaric hyperoxia exposure in A549 cells. This study demonstrated the role of normobaric hyperoxia in inhibiting lung cancer. Normal tissue and cells showed no significant hyperoxic damage in our experimental setting. The anti-tumor effect of normobaric hyperoxia may due to the increased reactive oxygen species activity and apoptosis, which is related to the mitogen-activated protein kinase pathway. Impact statement Normobaric hyperoxia (NBO) is a feasible therapy for cancer with a low complication rate. Although NBO may be beneficial in cancer treatment, very few studies have been conducted; thus, the evidence is thin. This is the first study to clearly demonstrate morphological changes in lung cancer with NBO exposure and to investigate the underlying mechanisms both in vivo and in vitro. This study will arouse interest in NBO treatment and promote further research.

Nonspecific Bronchoprovocation Test.

Bronchial asthma is a disease characterized by the condition of airway hyper-responsiveness, which serves to produce narrowing of the airway secondary to airway inflammation and/or various spasm-inducing stimulus. Nonspecific bronchoprovocation testing is an important method implemented for the purpose of diagnosing asthma; this test measures the actual degree of airway hyper-responsiveness and utilizes direct and indirect bronchoprovocation testing. Direct bronchoprovocation testing using methacholine or histamine may have superior sensitivity as these substances directly stimulate the airway smooth muscle cells. On the other hand, this method also engenders the specific disadvantage of relatively low specificity. Indirect bronchoprovocation testing using mannitol, exercise, hypertonic saline, adenosine and hyperventilation serves to produce reactions in the airway smooth muscle cells by liberating mediators with stimulation of airway inflammatory cells. Therefore, this method has the advantage of high specificity and also demonstrates relatively low sensitivity. Direct and indirect testing both call for very precise descriptions of very specific measurement conditions. In addition, it has become evident that challenge testing utilizing each of the various bronchoconstrictor stimuli requires distinct and specific protocols. It is therefore important that the clinician understand the mechanism by which the most commonly used bronchoprovocation testing works. It is important that the clinician understand the mechanism of action in the testing, whether direct stimuli (methacholine) or indirect stimuli (mannitol, exercise) is implemented, when the testing is performed and the results interpreted.

Factors associated with plasma IL-33 levels in patients with chronic obstructive pulmonary disease.

BACKGROUND: Interleukin (IL)-33 promotes T helper (Th)2 immunity and systemic inflammation. The role of IL-33 in asthma has been widely investigated. IL-33 has also been suggested to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study investigated the clinical significance and usefulness of plasma IL-33 level in patients with COPD. METHODS: A total of 307 patients with stable COPD from 15 centers, who were in the Korean Obstructive Lung Disease cohort, were enrolled in this study. Plasma IL-33 levels were measured by enzyme-linked immunosorbent assay. We analyzed the association between IL-33 level and other clinical characteristics related to COPD. We also examined the features of patients with COPD who exhibited high IL-33 levels. RESULTS: IL-33 levels varied, but were very low in most patients. Eosinophil count was significantly correlated with a plasma IL-33 level. In addition, old age and current smoking were related to a low IL-33 level. Significantly more patients with a higher IL-33 level had chronic bronchitis compared with those with a low IL-33 level. CONCLUSION: Plasma IL-33 level in patients with stable COPD was related to eosinophil count and chronic bronchitis phenotype. Further studies are needed to identify the precise mechanisms of IL-33/ST2 pathway in patients with COPD.

Epidemiology and Clinical Characteristics of Rapid Response Team Activations.

BACKGROUND: To ensure patient safety and improvements in the quality of hospital care, rapid response teams (RRTs) have been implemented in many countries, including Korea. The goal of an RRT is early identification and response to clinical deterioration in patients. However, there are differences in RRT systems among hospitals and limited data are available. METHODS: In Seoul St. Mary's Hospital, the St. Mary's Advanced Life Support Team was implemented in June 2013. We retrospectively reviewed the RRT activation records of 287 cases from June 2013 to December 2016. RESULTS: The median response time and median modified early warning score were 8.6 minutes (interquartile range, 5.6 to 11.6 minutes) and 5.0 points (interquartile range, 4.0 to 7.0 points), respectively. Residents (35.8%) and nurses (59.1%) were the main activators of the RRT. Interestingly, postoperative patients account for a large percentage of the RRT activation cases (69.3%). The survival rate was 83.6% and survival was mainly associated with malignancy, Acute Physiology and Chronic Health Evaluation-II score, and the time from admission to RRT activation. RRT activation with screening showed a better outcome compared to activation via a phone call in terms of the intensive care unit admission rate and length of hospital stay after RRT activation. CONCLUSIONS: Malignancy was the most important factor related to survival. In addition, RRT activation with patient screening showed a better outcome compared to activation via a phone call. Further studies are needed to determine the effective screening criteria and improve the quality of the RRT system.

Prevalence of chronic cough and possible causes in the general population based on the Korean National Health and Nutrition Examination Survey.

Although chronic cough is very common, its prevalence and causes have been rarely reported in the large general population including smokers. This study aimed to identify the prevalence of possible causes of chronic cough and their clinical impact.From Korean National Health and Nutrition Examination Survey (KNHANES) data including 119,280 adults aged over 40 years, 302 individuals with chronic cough were recruited irrespective of smoking status. Data from questionnaire, laboratory tests including spirometry, chest radiographs, and otorhinolaryngologic examination were analyzed.The prevalence of chronic cough in adults was 2.5% ±â€Š0.2%. Current smokers occupied 47.7% ±â€Š3.8% of study population and 46.8% ±â€Š3.9% of the subjects showed upper airway cough syndrome (UACS). Based on spirometry, chronic obstructive pulmonary disease (COPD) was identified in 26.4% ±â€Š3.5%. Asthma explained for 14.5% ±â€Š2.8% of chronic cough. Only 4.1% ±â€Š1.6% showed chronic laryngitis suggesting gastro-esophageal reflux-related cough. Abnormalities on chest radiography were found in 4.0% ±â€Š1.2%. Interestingly, 50.3% ±â€Š4.5% of study subjects had coexisting causes. In multivariate analysis, only current smoking (odds ratio [OR] 3.16, P < 0.001), UACS (OR 2.50, P < 0.001), COPD (OR 2.41, P < 0.001), asthma (OR 8.89, P < 0.001), and chest radiographic abnormalities (OR 2.74, P = 0.003) were independent risk factor for chronic cough. This pattern was not different according to smoking status excepting the prevalence of COPD.Smoking, COPD, and chest radiographic abnormalities should be considered as causes of chronic cough, along with UACS and asthma. Gastro-esophageal reflux-related cough is not prevalent in study population.

Therapeutic effect of budesonide/formoterol, montelukast and N-acetylcysteine for bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation.

BACKGROUND: Bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic stem cell transplantation (HSCT) is currently treated with systemic corticosteroids despite poor efficacy and side effects. This study investigated the therapeutic effect of budesonide/formoterol, montelukast and n-acetylcysteine, which are suggested as treatment options for BOS after HSCT. METHODS: After diagnosis of BOS, 61 patients were treated with budesonide/formoterol, montelukast and n-acetylcysteine for 3 months. Pulmonary function test and COPD assessment test (CAT) were performed before and after the combination therapy. Therapeutic response was evaluated by changes in forced expiratory volume in 1 s (FEV1) or CAT score. RESULTS: After 3 months of combination treatment, mean FEV1 increased by 220 mL (p < 0.001) and residual volume decreased by 200 mL (p =0 .005). Median CAT score also significantly decreased from 15.5 to 11.0 (p = 0.001). The overall response rate to combination therapy was 82 %. Comparing the no-response group and the response group, the forced vital capacity (% predicted) decline between pre-HSCT and BOS diagnosis was significantly greater in the response group (p = 0.036). CONCLUSION: Combination treatment with budesonide/formoterol, montelukast and n-acetylcysteine significantly improved lung function and respiratory symptoms in patients with BOS after allogeneic HSCT without serious side effects.

Smoking habits and nicotine dependence of North Korean male defectors.

BACKGROUND/AIMS: The smoking rates and patterns in the North Korean population are not well known. More than 20,000 North Korean defectors have settled in South Korea; thus, we can estimate the current North Korean smoking situation using this group. METHODS: All North Korean defectors spend their first 3 months in a South Korean facility learning to adapt to their new home. We retrospectively analyzed the results from a questionnaire conducted among North Korean male defectors in this facility from August 2012 to February 2014. RESULTS: Of 272 men, 84.2% were current smokers, 12.5% were ex-smokers, and 3.3% were non-smokers. The mean age of this group was 35.9 ± 11.3 years, and smoking initiation occurred at a mean age of 18.2 ± 4.7 years. Among the subjects, 78.1% had a family member who smoked. Of the 221 current smokers, 67.4% responded that they intended to quit smoking. Fagerström test and Kano test for social nicotine dependence (KTSND) results for current smokers were 3.35 ± 2.26 and 13.76 ± 4.87, respectively. Question 9 on the KTSND (doctors exaggerate the ill effects of smoking) earned a significantly higher score relative to the other questions and a significantly higher score in current smokers compared with non-smokers. CONCLUSIONS: The smoking rate in North Korean male defectors was higher than that indicated previously. However, interest in smoking cessation was high and nicotine dependence was less severe than expected. Further investigation is needed to identify an efficient method for North Korean smokers to stop smoking.

Effect of roflumilast, novel phosphodiesterase-4 inhibitor, on lung chronic graft-versus-host disease in mice.

Chronic graft-versus-host disease (CGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation. Roflumilast has anti-inflammatory effects and has been used in the treatment of inflammatory airway diseases. It is at present unclear whether roflumilast may have a therapeutic role in CGVHD. To test this, we used the B10.D2 → BALB/c model of CGVHD to address the therapeutic effect of roflumilast on the development of CGVHD. Lungs of animals treated with roflumilast exhibited less chronic inflammatory cell infiltration and fibrosis in the peribronchial and perivascular area versus allogeneic controls. To define the mechanism, we examined the expression of pro-inflammatory and profibrotic cytokines in the lung. Messenger RNA expression of interleukin-6 and interleukin-1ß in the lungs was significantly reduced in recipients treated with roflumilast. Similar changes were observed in profibrotic cytokines and chemokines. In addition, the percentage of Foxp3(+) regulatory T cells (Tregs), which have the potential to attenuate GVHD, increased significantly within the CD4(+) T cells with roflumilast in the lungs. In conclusion, roflumilast treatment attenuated murine lung CGVHD by blocking T-cell activation mediated by Tregs and downregulating pro-inflammatory and profibrotic cytokines, resulting in the reduction of lung inflammation and fibrosis.

Serious Complications after Self-expandable Metallic Stent Insertion in a Patient with Malignant Lymphoma.

An 18-year-old woman was evaluated for a chronic productive cough and dyspnea. She was subsequently diagnosed with mediastinal non-Hodgkin lymphoma (NHL). A covered self-expandable metallic stent (SEMS) was implanted to relieve narrowing in for both main bronchi. The NHL went into complete remission after six chemotherapy cycles, but atelectasis developed in the left lower lobe 18 months after SEMS insertion. The left main bronchus was completely occluded by granulation tissue. However, the right main bronchus and intermedius bronchus were patent. Granulation tissue was observed adjacent to the SEMS. The granulation tissue and the SEMS were excised, and a silicone stent was successfully implanted using a rigid bronchoscope. SEMS is advantageous owing to its easy implantation, but there are considerable potential complications such as severe reactive granulation, stent rupture, and ventilation failure in serious cases. Therefore, SEMS should be avoided whenever possible in patients with benign airway disease. This case highlights that SEMS implantation should be avoided even in malignant airway obstruction cases if the underlying malignancy is curable.

Diagnostic value of bronchoscopy in patients with hematologic malignancy and pulmonary infiltrates.

Pulmonary infections are a major cause of morbidity and mortality in patients with hematologic malignancy. Bronchoscopy is at present still the traditional first investigation in immunosuppressed patients that have developed pulmonary infiltrates. There is limited data available on the validity of fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) to determine the etiology of pulmonary infiltrates with concurrent hematologic malignancy. We retrospectively analyzed the microbiological results of 206 bronchoscopic examinations and treatment changes used in 187 patients with hematologic malignancy and pulmonary infiltrates. Bacteria, fungi, and viruses were found in 85 (41.3 %), 49 (23.8 %), and 55 (28.6 %) of cases, respectively, and overall yield of bronchoscopy was 65.0 %. We compared the microbiological findings with respect to neutropenia, hematopoietic stem cell transplantation (HSCT) status, and the type of malignancy. There were significantly more bacterial and viral infections detected in post-HSCT patients, and more viruses were detected in patients without neutropenia. Galactomannan (GM) was measured in 149 BAL samples. With a GM index threshold of ≥0.5, the sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) of the BAL GM assay were 93.94 %, 86.21 %, 65.96 %, and 98.04 %, respectively. Treatment was modified in 62 cases (30.1 %). There was no significant relationship of treatment modification with the underlying disease, HSCT, or neutropenia. Bronchoscopy with BAL is a valuable diagnostic tool to determine the etiology and appropriate treatment in patients with hematologic malignancy and pulmonary infiltrates. A BAL GM test is recommended when invasive pulmonary aspergillosis is suspected.

A case of pneumomediastinum and parapneumonic effusions following pharyngeal perforation caused by shouting.

Spontaneous pneumomediastinum is an uncommon disorder, and usually affects young men and has a benign course. Common triggers are asthma, the smoking of illicit drugs, the Valsalva maneuver, and respiratory infections. Most cases are usually due to alveolar rupture into the pulmonary interstitium caused by excess pressure. The air dissects to the hilum along the peribronchovascular sheaths and spreads into the mediastinum. However, pneumomediastinum following pharyngeal perforation is very rare, and has only been reported in relation to dental procedures, head and neck surgery, or trauma. We report a case of pneumomediastinum that developed in a 43-year-old patient with pharyngeal perforation after shouting. His course was complicated by mediastinitis and parapneumonic effusions.

Clinical experience of rigid bronchoscopy in single center.

BACKGROUND: The aim of this study was to analyze clinical situations requiring rigid bronchoscopy and evaluate usefulness of rigid bronchoscopic intervention in benign or malignant airway disorders. METHODS: We retrospectively reviewed 29 patients who underwent rigid bronchoscopy from November 2007 to February 2011 at St. Paul's Hospital, The Catholic University of Korea School of Medicine. RESULTS: Of the 29 patients, the most frequent underlying etiology was benign stenosis of trachea (n=20). Of those 20 patients, 16 had post-intubation tracheal stenosis (PITS), 2 had tracheal stenosis due to inhalation burn (IBTS) and other 2 had obstructive fibrinous tracheal pseudomembrane (OFTP). Other etiologies were airway malignancy (n=6), endobronchial stenosis due to tuberculosis (n=2), and foreign body (n=1). For treatment, silicone stent insertion was done in 16 cases of PITS and IBTS and mechanical removal was performed in 2 cases of OFTP. In 6 cases of malignant airway obstruction mechanical debulking was performed and silicone stents were inserted additionally in 2 cases. Balloon dilatation and electrocautery were used in 2 cases of endobronchial stenosis due to tuberculosis. In all cases of stent, airway obstructive symptom improved immediately. Granulation tissue formation was the most common complication. CONCLUSION: Tracheal stenosis was most common indication and silicone stenting was most common procedure of rigid bronchoscopy in our center. Rigid bronchoscopic procedures, at least tracheal silicone stenting, should be included in pulmonary medicine fellowship programs because it is a very effective and indispensable method to relieve critical airway obstruction which needs training to learn.