Expert review of respiratory medicine
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Expert Rev Respir Med · Aug 2010
ReviewPros and cons of recruitment maneuvers in acute lung injury and acute respiratory distress syndrome.
In patients with acute lung injury and acute respiratory distress syndrome, a protective mechanical ventilation strategy characterized by low tidal volumes has been associated with reduced mortality. However, such a strategy may result in alveolar collapse, leading to cyclic opening and closing of atelectatic alveoli and distal airways. Thus, recruitment maneuvers (RMs) have been used to open up collapsed lungs, while adequate positive end-expiratory pressure (PEEP) levels may counteract alveolar derecruitment during low tidal volume ventilation, improving respiratory function and minimizing ventilator-associated lung injury. ⋯ The efficiency of RMs may be affected by different factors, including the nature and extent of lung injury, capability of increasing inspiratory transpulmonary pressures, patient positioning and cardiac preload. Current evidence suggests that RMs can be used before setting PEEP, after ventilator circuit disconnection or as a rescue maneuver to overcome severe hypoxemia; however, their routine use does not seem to be justified at present. The development of new lung recruitment strategies that have fewer hemodynamic and biological effects on the lungs, as well as randomized clinical trials analyzing the impact of RMs on morbidity and mortality of acute lung injury/acute respiratory distress syndrome patients, are warranted.
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Endobronchial ultrasound (EBUS) is an evolving diagnostic tool in respiratory medicine that allows the bronchoscopist to see beyond the airway. The radial probe EBUS was first introduced to evaluate the central airway structure. With advances in technology, the small radial probes can now visualize and assist transbronchial biopsies of peripheral lung nodules without exposure to radiation. ⋯ EBUS-TBNA has access to all of the mediastinal lymph nodes accessible by mediastinoscopy as well as N1 nodes. EBUS-TBNA is primarily used for lymph-node staging and diagnosis of lung cancer, but is also used for the diagnosis of unexplained mediastinal and hilar lymphadenopathy. It is a minimally invasive approach that is safe and has a good diagnostic yield.
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Although mechanical ventilation (MV) is a life-saving intervention for patients with acute respiratory distress syndrome (ARDS), it can aggravate or cause lung injury, known as ventilator-induced lung injury (VILI). The biophysical characteristics of heterogeneously injured ARDS lungs increase the parenchymal stress associated with breathing, which is further aggravated by MV. ⋯ Several attempts have been made to identify clinical surrogate measures of lung stress/strain (e.g., density changes in chest computed tomography, lower and upper inflection points of the pressure-volume curve, plateau pressure and inflammatory cytokine levels) that could be used to titrate MV. However, uncertainty about the topographical distribution of stress relative to that of the susceptibility of the cells and tissues to injury makes the existence of a single 'global' stress/strain injury threshold doubtful.
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Expert Rev Respir Med · Jun 2010
ReviewPirfenidone: antifibrotic agent for idiopathic pulmonary fibrosis.
Idiopathic pulmonary fibrosis (IPF) is a devastating disease with rare incidence but high mortality, and the pathogenesis of which is still poorly understood. Available treatment options have been empirically applied but evidence-based benefits have not yet been confirmed. Pirfenidone is an antifibrotic agent that is potentially effective for IPF treatment. ⋯ The efficacy is demonstrated in patients with mild-to-moderate impairment of pulmonary functions, but not confirmed for patients with severe impairment. Major adverse events are photosensitivity and anorexia, but the treatment was generally safe and well tolerated. In this article, the usefulness and limitations of pirfenidone in IPF treatment are discussed to determine its potential for the management of IPF progression.