Mechanical ventilation is an important strategy to manage patients with respiratory ailments in the acute as well as chronic setups. To be able to do so, we need a good understanding of the physiology of the respiratory system and the disease pattern. Two major components of the lung physiology are compliance and resistance and these define time constants (TCs). Compliance is the measure of distensibility of lungs. It is the change in pressure by the change in volume. Resistance is the opposing force that is created when air flows in the airway. Compliance and resistance together produce an entity called TC. TC defines the amount of time taken in seconds for the lung unit to fill or empty. TCs normally vary within the lungs and do more so in the diseased lungs. This article gives an overview of TCs and its components for the better understanding of the reader.

Pulmonary diseases have known to exert significant human sufferings with high death toll globally. The association between periodontitis and pulmonary diseases is still in its infancy and needs attention. Poor oral health has shown to influence pulmonary health as well as the course of the diseases associated with this system. Numerous studies have emphasized that resident microorganisms of lungs are primarily the habitants of oral cavity. It could be due to the aspiration of oral periodontopathic bacteria into the lungs, thereby initiating the inflammatory process. Added to this, the inflammatory mediators elaborated from the inflamed periodontium in case of periodontal diseases may spread via blood to other organs such as lungs causing infections. Numerous studies have highlighted the beneficial role of periodontal therapy in improving lung function with a decreased frequency of exacerbations, reduced risk of adverse respiratory events, and morbidity, especially in chronic obstructive pulmonary disease patients. Medically compromised dentate patients admitted in intensive care units owing to their inability to maintain oral hygiene properly have increased propensity of acquiring respiratory infections. The present review focuses on emphasizing the relationship between periodontitis and pulmonary diseases with the available published literature utilizing PubMed and Google Scholar databases in the last four decades.

Talc powder is widely used for different purposes worldwide. Effects of talc on the human health is a concern as it has many chemical components. This review is an attempt to present the relevant researches in this field and to summarize the current updates about the topic. Talcum powder exposure has been shown to be a reason in the development of mesotheliomas and carcinoma of the lung in women. Regular cosmetic powders can get attached to larger particles that would deposit in the upper airways of the human respiratory system. The alveolar region is the second most exposed region of the respiratory system. Deposition levels in the tracheobronchial region is the lowest. Cosmetic talc powder, used regularly by women worldwide, can cause detrimental effects on different organ systems of the human body. Awareness on its harmful effects to the users may be useful to reduce the usage to some extent.

Background: Pleural effusion is common clinical entity in day-to-day clinical practice. There are various etiologies for pleural effusion. Among those tubercular pleural effusion, parapneumonic effusion, malignant effusion, and congestive heart failure were the most common causes of pleural effusion. Here, we have done a retrospective study to see the etiology of pleural effusion in our tertiary care center. Patients and Methods: This retrospective study conducted in a tertiary care center over 1 year period. A total of 63 patients were included in this study after verifying in patient records of all patients who were admitted with exudative pleural effusion. The demographic data collected and complete history was obtained. Investigations such as complete hemogram, random blood sugar; renal function tests, serum proteins, chest x-ray, and pleural fluid analysis and investigations such as ultrasonogram of the chest and abdomen, echocardiogram, computed tomography scan of chest, fine-needle aspiration cytology, and pleural biopsy reports (if done) were collected. Results: Among the study participants, 40 were male and 23 were female patients with male-to-female ratio of 1.7:1. Mean age of the study population was 48.8 ± 18.7 years. The most common presenting symptom was dyspnea (84%) followed by cough (80%), fever (65%), and chest pain (43%). The most frequent cause of pleural effusion was tuberculosis in 38% of patients, followed by parapneumonic effusion (28.5%) and malignant pleural effusion (22.2%). Three patients had chylothorax, two patients had pancreatic pleural effusion and the diagnosis was unknown in two patients. Mean ± standard deviation (SD) adenosine deaminase (ADA) value of the study population was 45.3 ± 28.1. Mean ± SD of ADA values in tuberculous, parapneumonic, and malignant pleural effusion was 54.5 ± 16.8, 65.2 ± 30.7, and 18.2 ± 11.0, respectively. Conclusions: Tuberculosis is one of the common causes of exudative effusions along with parapneumonic effusions and malignancy. Pleural fluid ADA levels are highly sensitive with good specificity for the diagnosis of etiology of tubercular effusions. However in view of high levels of ADA in pleural fluid in parapneumonic effusions also, other measures such as clinical evaluation, lymphocyte to neutrophil ratio, and glucose levels are necessary to separate both these entities.

Background: Asthma is a long-term inflammatory disorder of the airways characterized by wheezing, dyspnea, and cough. For the last few decades, inhalational devices have been used in the management of the disease, but compliance remains the problem. Higher doses of oral medications used with prominent side effects precluded the use of oral beta-agonist bronchodilators, and the search for an ideal beta-adrenergic bronchodilator continues. This study was conducted for evaluation of the role of oral bambuterol in the management of bronchial asthma. Aims and Objectives: Our study aimed to evaluate the potency and effectiveness of oral bambuterol in the management of the disease in fifty patients followed up over 2 weeks with objective assessment of symptom scores and changes in the frequency of rescue bronchodilator after 2 weeks of treatment. Side effects, if any, were documented for all patients. Methods: The study was conducted on fifty patients with chronic bronchial asthma. They were given 10 mg of bambuterol once daily orally for 14 days. Pulmonary function tests were performed at days 1, 7, and 14. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and peak expiratory flow rate (PEFR) were measured. Patients were assessed for symptom score and side effects at days 1, 7, and 14. Results: After completion of the study, significant improvement in the symptom score, FVC, FEV1, and PEFR was obtained with minimal side effects. Conclusion: Bambuterol 10 mg oral tablet once a day provides significant improvement in pulmonary function tests and effectively reduces asthmatic symptoms with minimal side effects.

Introduction: Dyspnea associated with pulmonary arterial hypertension (PAH) requires supplemental oxygen to maintain oxygen saturation. Many researches related to oxygen therapy in chronic obstructive pulmonary disease and cor pulmonale are available, but the effect of long-term oxygen therapy (LTOT) has not been explored in PAH patients. Aim: This study aimed to determine the effect of LTOT in patients diagnosed with PAH. Methodology: All adult patients with PAH, primary or secondary to respiratory disease who require LTOT, were included in the study. The following parameters were collected: age, gender, severity of PAH based on echocardiogram, body mass index, comorbidities, type of oxygen therapy device, amount and duration of oxygen usage, mortality, frequency of readmission, oxygenation, and vital sign parameters. Results: This was a retrospective study which included 332 participants diagnosed to have PAH after detailed echocardiogram assessment. Out of these, 32 participants were prescribed LTOT at the time of discharge. At the time of discharge, there was a significant improvement in all the vital signs and oxygenation variables. The increase in oxygenation, hemoglobin, and reduced respiratory rate after LTOT was statistically significant (P < 0.001). During follow-up after 1 year, 26 (81.3%) participants survived, 3 participants (9.4%) expired, and 3 participants (9.4%) were lost to follow-up. Conclusion: The use of oxygen therapy is beneficial in patients with PAH in terms of improvement in oxygenation and reduction in hospital readmission. Survival at 1 year is 81% in patients using LTOT.

Background: Dyspnea is highly distressing experience of breathlessness that limits the activities of daily living and affects an increasingly large group of patients with respiratory diseases such as chronic obstructive pulmonary disease (COPD). Aims: The aim of our study was to investigate the prevalence of dyspnea and its associated factors in patients with COPD. Patients and Methods: This cross-sectional study was carried out among 221 COPD patients of Tribhuvan University Teaching Hospital, Nepal. Patients\' dyspnea was assessed using the modified Medical Research Council Dyspnea Scale and Dyspnea 12 Questionnaire. Patient's anxiety and depression were measured using Hospital Anxiety and Depression Scale, and COPD Assessment Test (CAT) was used to measure the impact of COPD. Mann-Whitney and Kruskal-Wallis test were used to find out the association between variables. Multiple regression analysis was used to find out the most significant factor associated with dyspnea. Results: Out of 221 patients, almost all (92.8%) patients had some degrees of dyspnea. Dyspnea was statistically significantly associated with age (P < 0.001), education (P < 0.001), marital status (P < 0.001), type of family (P = 0.009), working status (P < 0.001), duration of illness (P < 0.001), history of previous hospitalization (P < 0.001), status of hospitalization in the last year (P < 0.001), domiciliary oxygen therapy (P < 0.001), other comorbidities (P < 0.001), anxiety (P < 0.001), and depression (P < 0.001). Conclusions: This study concludes that dyspnea is highly prevalent in COPD, and duration of illness, depression, and CAT score were the most significant factors associated with dyspnea in patients with COPD.

Introduction: Diabetes mellitus (DM) is an important and common comorbid condition associated with chronic obstructive pulmonary disease (COPD). The exact prevalence of DM in COPD patients among the Indian population is unknown. Coexisting DM is associated with poor outcome in COPD patients and has a significant impact on lung function and severity of the disease. Aim: The aim of this study was to determine the prevalence of type 2 DM in COPD patients attending tertiary care hospital and to assess its impact on the severity of the disease and exacerbation. Patients and Methods: A cross-sectional study was done at a tertiary care center in Davangere from July to December 2016. Convenience sampling was used to study 412 patients attending the hospital for consultation. An interview schedule consisting of sociodemographic details and GOLD criteria 2015 to diagnose COPD and the World Health Organization criteria for DM was used. Results: The prevalence of DM was 23.05% (95) among 412 COPD patients studied. Thirty-five (8.49%) patients were newly diagnosed with DM. The prevalence in mild, moderate, severe, and very severe COPD was 14.73%, 18.94%, 36.84%, and 29.47%, respectively. DM group patients had a significant decline in lung function compared to non-DM group (mean forced expiratory volume 1% - 45.92 ± 4.22 v/s 56.64 ± 3.58, P = 0.001), and the majority of patients with DM (29.47%) were in exacerbation when compared to nonDM group (16.71%). Conclusion: The prevalence of DM is high in COPD patients, and significant numbers are newly detected. Hence, it is crucial to screen all COPD patients for DM routinely. Further diabetics tend to have more severe COPD when compared to nondiabetics.

Aim: The aim of this study was to assess the prevalence of obstructive airway disease (OAD) in coronary artery disease (CAD) patient's using spirometric indices. Patients and Methods: The prospective study was conducted between June 2014 and June 2015. Patients admitted to the intensive coronary care unit having a proven diagnosis of CAD (single or multiple vessel disease) on coronary angiography were undergone spirometry examination. Results: This study included a total of 80 patients of proven CAD. Sixty-one patients were male and 19 were female. The mean age of the cases was 59.29 years. In our study, 37.5% had triple-vessel disease, 33.8% had double-vessel disease, and remaining 28.8% had single-vessel disease. Eighteen patients (22.5%) were found to have OAD. On comparison of severity of OAD with the severity of CAD, no statistically significant association was found. Conclusion: It is imperative to carry out inexpensive investigations such as spirometry in all the patients with CAD so that both the conditions can be managed adequately with better outcomes.

Introduction: Laryngeal tuberculosis (TB) has shown increase in incidence in recent years and the increase in immunosuppressive conditions has altered the clinical profile of the disease. The aim of this study was to evaluate the changing trends of laryngeal TB and to highlight its site of involvement, type of lesion, and degree of involvement. Patients and Methods: This prospective study included 54 patients with a diagnosis of laryngeal TB. All patients were evaluated in terms of their age, chief complaints, lesions, and site of involvement on flexible fiber-optic bronchoscopy, and they also underwent a variety of laboratory investigations as indicated. Results: The study showed that true vocal cords + false cords + epiglottis were involved in 48.1% (n = 26), arytenoids + interarytenoid + posterior part of true cords in 24.1% (n = 13), true cords + false cords + arytenoids + interarytenoid in 18.5% (n = 10), true vocal cords alone in 5.5% (n = 3), interarytenoid in 1.8% (n = 1), and interarytenoid + arytenoid involvement was seen in 1.8% (n = 1) of patients. These lesions were categorized into four different appearances as follows: granulomatous lesions in 50% (n = 27), ulcerative lesions in 27.7% (n = 15), hyperemia and hypertrophic in 16.7% (n = 9), and papillomatous mass in 5.6% (n = 3) based on fiber-optic bronchoscopy. Conclusion: In this study, the disease was most rampant in the age group of 31-60 years, with a predilection seen in low socioeconomic groups, rural groups and in individuals addicted to smoling and alcoholism. Hoarseness and odynophagia are the major symptoms. Multiple subsites are involved, and the lesions show a predilection for the anterior part of the vocal cord.

Pleuropulmonary aspergillosis is a rare entity and usually occurs in a patient with preexisting lung disease or surgery. A 29-year-old pregnant woman with 16 weeks of gestation presented with shortness of breath, right-sided chest pain, and productive cough of 2 weeks\' duration. A chest radiograph done with abdominal shield revealed right hydropneumothorax. Intercostal drainage insertion was done under ultrasound guidance. Pleural fluid was exudative with high adenosine deaminase levels, and GeneXpert test was negative for Mycobacterium tuberculosis. Pleural fluid and sputum culture revealed significant growth of Aspergillus fumigatus. She was treated with voriconazole intravenously followed by oral route. The patient improved clinically with good lung expansion, and she delivered a normal live baby by elective cesarean section. We report this case in view of the rarity of pleuropulmonary aspergillosis occurring in a young pregnant female with no evidence of prior lung pathology.

Spontaneous esophageal-pleural fistula (EPF) is extremely rare. We present a case of a 52-year gentleman who presented with shortness of breath and decreased appetite, whose chest X-ray and ultrasonogram of thorax depicted a pleural effusion like picture. Intercostal drainage tubes were inserted to alleviate his dyspnea. Plain computerized tomography (CT) thorax initially revealed a pleural cyst, which was surgically drained. Subsequent CT thorax with contrast and barium swallow revealed EPF, which was confirmed with endoscopy. Pleural fluid analysis revealed candida as the cause of EPF. Candida as a cause of EPF that too in an nonimmunocompromised patient is very rare. Multidisciplinary approach is required to diagnose and prevent mortality in such cases.

Endobronchial tuberculosis (TB) refers to TB infection of the tracheobronchial tree. We report the case of a 62-year-old immunocompetent patient of chronic cough with normal X-ray. She did not have any systemic complaints suggestive of TB. Her diagnosis was made when she underwent bronchoscopy to look for any endobronchial cause of cough. It revealed complete caseation in the airways. Microscopically and pathologically, it was confirmed to be tubercular. The patient improved clinically on antitubercular therapy.