Effects of woodsmoke exposure on airway inflammation in rural Guatemalan women.

BACKGROUND: More than two-fifths of the world's population uses solid fuels, mostly biomass, for cooking. The resulting biomass smoke exposure is a major cause of chronic obstructive pulmonary disease (COPD) among women in developing countries. OBJECTIVE: To assess whether lower woodsmoke exposure from use of a stove with a chimney, compared to open fires, is associated with lower markers of airway inflammation in young women. DESIGN: We carried out a cross-sectional analysis on a sub-cohort of participants enrolled in a randomized controlled trial in rural Guatemala, RESPIRE. PARTICIPANTS: We recruited 45 indigenous women at the end of the 18-month trial; 19 women who had been using the chimney stove for 18-24 months and 26 women still using open fires. MEASUREMENTS: We obtained spirometry and induced sputum for cell counts, gene expression of IL-8, TNF-α, MMP-9 and 12, and protein concentrations of IL-8, myeloperoxidase and fibronectin. Exhaled carbon monoxide (CO) and 48-hr personal CO tubes were measured to assess smoke exposure. RESULTS: MMP-9 gene expression was significantly lower in women using chimney stoves. Higher exhaled CO concentrations were significantly associated with higher gene expression of IL-8, TNF-α, and MMP-9. Higher 48-hr personal CO concentrations were associated with higher gene expression of IL-8, TNF- α, MMP-9 and MMP-12; reaching statistical significance for MMP-9 and MMP-12. CONCLUSIONS: Compared to using an open wood fire for cooking, use of a chimney stove was associated with lower gene expression of MMP-9, a potential mediator of airway remodeling. Among all participants, indoor biomass smoke exposure was associated with higher gene expression of multiple mediators of airway inflammation and remodeling; these mechanisms may explain some of the observed association between prolonged biomass smoke exposure and COPD.

Severe H1N1-Associated acute respiratory distress syndrome: A case series.

BACKGROUND: Acute respiratory distress syndrome resulting from novel influenza A virus (H1N1) infection remains uncommon. METHODS: We describe the clinical profiles of adult patients with acute respiratory distress syndrome due to microbiologically confirmed H1N1 admitted to a medical intensive care unit in San Francisco, California over a 2-month period. RESULTS: Between June 1 and July 31, 2009, 7 patients (age range: 25-66 years; 4 patients under the age of 40 years; 6 male; 1 pregnant) were diagnosed with H1N1, with 5 of 6 (83%) having initial false-negative rapid testing. All developed respiratory failure complicated by acute respiratory distress syndrome, with 4 additionally developing multiorgan dysfunction. All were managed with a lung protective ventilator strategy (average number of days on the ventilator: 16), and 4 patients also required additional rescue therapies for refractory hypoxemia, including very high positive end-expiratory pressure, inhaled epoprostenol, recruitment maneuvers, and prone positioning. Despite these measures, 3 patients (43%) ultimately died. CONCLUSIONS: Clinicians should be vigilant for the potential of H1N1 infection to progress to severe acute respiratory distress syndrome in a variety of patient demographics, including younger patients without baseline cardiopulmonary disease. A high degree of suspicion is critical, especially with the relative insensitivity of rapid testing, and should prompt empiric antiviral therapy.

Case report: a case of wood-smoke-related pulmonary disease.

CONTEXT: Biomass serves as a major fuel source for >50% of the world's population. The global burden of disease attributed to indoor air pollution from biomass combustion accounts for approximately 3% of worldwide disability-adjusted life-years lost. This is due to pneumonia in children and chronic obstructive pulmonary disease and lung cancer in women. CASE PRESENTATION: A 53-year-old man from Mexico was referred to the pulmonary clinic for evaluation of chronic productive cough and pulmonary nodules. In his youth, he worked at a charcoal plant in Mexico, where he burned wood and was exposed to massive amounts of smoke. His evaluation revealed thickened bronchovascular bundles with nodules on thoracic computed tomography, dark black plaques in large airways on bronchoscopy, and carbon-laden macrophages and fibrotic scars on lung biopsy. DISCUSSION: The patient was diagnosed with "hut lung," a term that refers to the noninfectious, nonmalignant respiratory manifestations of chronic, high-level exposures to biomass smoke. This is the first reported case of hut lung associated with charcoal production. This case highlights that histopathologic abnormalities of the lung parenchyma may be present in patients with only mild symptoms and that clinical progression is likely a function of both the duration and intensity of exposure. RELEVANCE TO CLINICAL PRACTICE: As residents of lesser developed countries continue to be exposed to high levels of biomass smoke at work or at home and continue to immigrate to developed countries, it is important that health care providers in developed countries be aware of biomass-smoke-related pulmonary disease.