Current opinion in pulmonary medicine
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Ozone (O3) is an air pollutant produced by sunlight-driven reactions involving the oxides of nitrogen and volatile organic compounds. The population of many large metropolitan areas in the US is exposed to high levels of O3, particularly in the summer months. Individuals exposed to O3 levels in human experiments at higher than common ambient levels develop reversible reductions in lung function often associated with symptoms, such as airway hyperreactivity and lung inflammation. ⋯ Defining the adverse effects of chronic exposure to ambient levels of O3 on lung function and disease have been challenging, in part due to the presence of co-pollutants, such as particulate matter. The US Environmental Protection Agency's 1997 revised standard for O3 (0.08 ppm averaged over 8 hours) is designed to provide better protection to susceptible individuals. The revised standard is being implemented following the failure of court challenges.
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Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States, and it accounts for approximately 500,000 hospitalizations for exacerbations each year. New definitions of acute COPD exacerbation have been suggested, but the one used by Anthonisen et al. is still widely accepted. It requires the presence of one or more of the following findings: increase in sputum purulence, increase in sputum volume, and worsening of dyspnea. ⋯ There is no role for mucolytic agents or chest physiotherapy in the acute exacerbation setting. Noninvasive positive pressure ventilation might benefit a group of patients with rapid decline in respiratory function and gas exchange. It has the potential to decrease the need for intubation and invasive mechanical ventilation and possibly decrease in-hospital mortality.
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Conditions associated with airflow obstruction are often over- and underdiagnosed. Prevalence estimates of undiagnosed airflow obstruction (UDAO) range from 3 to 12%. UDAO is a nonspecific physiologic abnormality that may be caused by a number of factors (eg, cigarette smoking) and can be the manifestation of many different disorders. ⋯ While cigarette smoking is associated with UDAO, a substantial proportion of persons have never smoked, particularly among women. Few studies suggest that this condition is associated with increased morbidity and mortality. While there is currently no evidence to support screening for UDAO, case-finding may have a role among persons with respiratory symptoms, who have ever smoked, with a family history of respiratory disease, or with occupational exposures to dusts or fumes.