Pulmonary pharmacology & therapeutics
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Pulm Pharmacol Ther · Jan 2007
Randomized Controlled TrialCapsaicin exposure elicits complex airway defensive motor patterns in normal humans in a concentration-dependent manner.
The airway defensive response to tussive agents, such as capsaicin, is frequently assessed by counting the number of cough sounds, or expulsive events. This method does not identify or differentiate important respiratory events that occur in the respiratory muscles and lungs, which are critical in assessing airway defensive responses. The purpose of this study was to characterize the airway defensive behaviours (cough and expiration reflex) to capsaicin exposure in humans. ⋯ At higher concentrations (>50 microM) ER's with one or more expulsive events (ER1) appeared, and the number of CR's with three or more expulsive events (CR3) increased. The decrease in EMG activation and airflow measurements with each successive expulsive event suggests a decline in power and shear force as the number of expulsive events increased. Therefore, the airway defensive response to capsaicin is a complex motor pattern that functions to coordinate ER's and CR's with differing numbers of expulsive events possibly to prevent aspirations and keep air moving to promote clearance.
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Pneumonia with secondary pleural infection causes considerable morbidity and mortality. Intrapleural instillation of fibrinolytic agents to dissolve fibrinous adhesions is intended to improve pleural fluid drainage and prevent pleural loculations. ⋯ Pending future clinical trials, fibrinolytic therapy may be used selectively in patients who fail drainage with appropriately sized, image-guided chest tubes if reasons exist to delay or avoid definitive surgical drainage. The scope of this article is to systematically review evidence for the efficacy of intrapleural fibrinolytic therapy in the treatment of PPE and PE with emphasis on controlled trials and present some of the future perspectives.
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Management guidelines for asthma emphasize a stepwise approach in treating this disease based on daytime symptoms, nighttime symptoms, and lung function assessed by peak expiratory flow or forced expiratory volume at 1s (FEV(1)). Although improvement of lung function is a key goal in managing asthma, clinicians often see patients who may have achieved a normal FEV(1) with guideline-recommended treatment but continue to experience limitations in their daily activities. ⋯ Alternate assessment measures are therefore often needed to assess asthma control and achieve a successful treatment outcome. This review will provide practical guidance relevant to the clinical assessment of asthma control.
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Coughing can be both voluntarily induced and involuntarily initiated by activation of vagal afferent nerves innervating the airways and lungs. Centrally, cough is regulated at the level of the brainstem through integration of vagal afferent nerve input by relay neurones in the nucleus tractus solitarius (nTS). ⋯ Peripherally, both neuronal and non-neuronal elements in the airways regulate the excitability of the vagal afferent nerve terminals regulating cough. These multiple levels of integration and encoding of the cough reflex may render this defensive respiratory response highly susceptible to modulation both by disease processes and through therapeutic intervention.
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Acid is an important mediator in the pathogenesis of cough. Inhalation of exogenous acid triggers cough and endogenous acid may contribute to cough in respiratory diseases. Acid directly stimulates vagal bronchopulmonary sensory nerves that regulate the cough reflex. ⋯ The receptors underlying acid sensitivity of vagal sensory nerves are incompletely understood. The role of TRPV1 has been established but the roles of acid-sensing ion channels (ASIC) and other receptors await more definitive investigation. Here, we provide a brief overview of the cough-related acid-sensitive sensory pathways and discuss the mechanisms of acid sensitivity.