Current Respiratory Medicine Reviews - Volume 6, Issue 2, 2010

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Aerosol drug administration using helium-oxygen mixtures as a carrier gas has been advocated in the treatment of severe airway obstruction. Helium's low density has been shown to reduce resistance of gas flow through restricted airways passages, work of breathing, and minute ventilation requirements. Thus, it improves aerosol delivery in patients with acute airway obstruction, during both spontaneous breathing and mechanical ventilation. Although heliox has been shown to improve deposition of particles into the lung, the clinical evidence supporting the benefit of heliox is mixed. This review of the literature from 1934 - 2009 includes a brief review of the history of use of heliox in respiratory medicine, its physical properties and how they relate to the potential effects, limitations, and practical considerations associated with heliox-driven aerosol drug administration in acute and critically ill patients.

Sleep disturbances are common in chronic obstructive pulmonary disease (COPD) and are often associated with sleep disordered breathing in the form of nocturnal oxygen desaturation, obstructive sleep apnea (OSA), and hypoventilation. The respiratory changes during sleep in COPD have profound effects on sleep quality and quality of life. In addition, the physiologic alterations that result from the disordered breathing likely aggravate certain COPD-related complications, such as pulmonary hypertension, and possibly may increase mortality. Recently, the focus on specific clinical phenotypes such as upper lobe predominant emphysema, frequent exacerbators, and presence of peripheral muscle dysfunction have advanced the approaches to therapy that are affecting outcomes. It is likely that patients with coexistent COPD and sleep disordered breathing (the overlap syndrome) define another clinical phenotype that have a significant impact on the natural history of the disease. Studies have shown a high prevalence of OSA among patients with COPD and that such patients have a higher mortality despite treatment. This effect could perhaps be mediated via mechanisms involving comorbidities, including cardiovascular disease and metabolic syndromes. Current interventions, like supplemental oxygen, positive airway pressure support, and lung volume reduction improve the well being and survival of some patients with COPD, but the optimal therapy for the COPD overlap phenotype remains to be determined.

In the last three decades, an increasing number of pathogens resistant to common antibiotics have been a serious threat to public health worldwide. Pleuromutilin, its derivatives and others natural products are important in the fight against pathogen resistant to common antibiotics, such as in respiratory diseases. The aim of the current review is to highlight the most important pleuromutilin derivatives described in the literature between the years of 2007 and 2009.

A great variability may be noted among different countries in the selection of the primary choice in the antimicrobial agents for the treatment of community-acquired pneumonia (CAP), even for the cases considered as at a low-risk class. This fact may be due to many microbial causes of CAP and specialties involved, as well as different health-care systems effecting on the availability or cost of antibiotics. However, many countries or regions adopt some of the guidelines or design their own recommendations regardless of the local data, probably because of the scarcity of such data. This is the reason why we have developed a guideline for the initial treatment of CAP by 2002 upon the basis of several local evidences in South America (Consensur I). However, several issues deserve to be currently rediscussed as follows: i). Certain clinical scores other than the Physiological Severity Index (PSI) have become more popular in clinical practice (i.e. CURB-65, CRB-65) ii). Some pathogens have emerged in the region, such as community-acquired Staphylococcus aureus (CA-MRSA) and Legionella spp, iii). New evidences on the performance of the rapid test for the etiologic diagnosis in CAP have been reported (e.g., urinary Legionella and pneumococcus antigens), iv). New therapeutic considerations needs to be approached (i.e. dosage reformulation, duration of treatment, emergence of novel antibiotics and clinical impact of combined therapy) and finally, v). the real clinical impact of the penicillin-resistant S. pneumoniae in CAP. Like in the first version of the Consensur (Consensur I), the various current guidelines have helped to organize and stratify the present proposal, Consensur II.

This article reviews the epidemiological evidence on the effects of dietary nutrients on lung function, respiratory symptoms, mortality and risk of developing chronic obstructive pulmonary disease (COPD). Published articles are located by searching several electronic databases using the relevant key words without any restriction on publication date. Article reference lists are also searched for relevant papers. A total of 23 articles are included for the present review. Intakes of antioxidants namely vitamin C, vitamin E and beta-carotene are found to be positively associated with lung function. High levels of dietary fiber appear to be beneficial to lung function while lowering the risk of COPD and respiratory symptoms. Increase intake of flavonoids may enhance lung function and reduce respiratory symptoms, but evidence in relation to COPD mortality is lacking. Recent studies also suggested that some n-3 and n-6 fatty acids may offer protection against COPD risk and mortality. For other nutrients such as vitamins A and B6, carotenoids, soy isoflavones, magnesium and selenium, limited results are available and conclusions cannot be drawn. In view of the emerging evidence, further research is required to ascertain the role of dietary nutrients on COPD.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive mediastinal staging tool for lung cancer but also a diagnostic tool for mediastinal lesions near the airway. This review focuses primarily on the technique of linear probe EBUS-TBNA itself, training and financial issues, indications and performance, and pros and cons compared to other mediastinal sampling techniques. As such, it is relevant to centres considering to establish an EBUS-TBNA service. EBUS-TBNA is the most commonly used for staging non-small cell lung cancer (NSCLC), particularly bulky mediastinal lymphadenopathy and enlarged N2 or N3 disease on CT, but is also used for the diagnosis of unexplained mediastinal lymphadenopathy of other causes. For staging when radical treatment is contemplated, many centres still perform mediastinoscopy and this should be done in order to corroborate negative EBUS-TBNA results in this setting or when the pre-test clinical probability of lung cancer is high. EBUS-TBNA may be used in the future for staging, when the mediastinal nodes are normal according to radiological staging and also in re-staging. EBUS-TBNA can be learned with appropriate training and mentorship; it offers numerous advantages over mediastinoscopy and can reduce costs by avoiding mediastinoscopy (and the required peri-operative support) in many cases.

Cough is among the most common complaints for which patients seek medical attention, yet available therapies are woefully inadequate. Better and more effective cough suppressants are desperately needed, as currently available antitussives are limited by inconsistent efficacy and bothersome or intolerable side effects. As research in the field of cough continues to grow, inhalation cough challenge, which allows the measurement of cough reflex sensitivity and its modulation by pharmacological and other interventions, will assume ever greater importance. The ability of inhalation cough challenge to measure cough reflex sensitivity in a safe and reproducible manner has been clearly demonstrated in several decades of clinical experience. To assure quality data from cough challenge studies, careful consideration of study populations, as well as meticulous attention to the methodology of the cough challenge procedure, are essential.