Respiratory care
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Although effective in the neonatal population, exogenous pulmonary surfactant has not demonstrated a benefit in pediatric and adult subjects with hypoxic lung injury despite a sound physiologic rationale. Importantly, neonatal surfactant replacement therapy is administered in conjunction with low fractional FIO2 while pediatric/adult therapy is administered with high FIO2 . We suspected a connection between FIO2 and surfactant performance. Therefore, we sought to assess a possible mechanism by which the activity of pulmonary surfactant is adversely affected by direct oxygen exposure in in vitro experiments. ⋯ The characteristics of pulmonary surfactant were adversely affected by short-term exposure to oxygen. Specifically, surface tension studies revealed that short-term exposure of surfactant film to high concentrations of oxygen expedited the frangibility of pulmonary surfactant, as shown with the δA. This suggests that reductions in pulmonary compliance and associated adverse effects could begin to take effect in a very short period of time. If these findings can be demonstrated in vivo, a role for reduced FIO2 during exogenous surfactant delivery may have a clinical benefit.
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The evidence indicates that risk factors other than smoking are important in the development of COPD. It has been postulated that less traditional risk factors (eg, exposure to coal and/or biomass smoke) may interact with smoking to further increase COPD risk. This analysis evaluated the effect of exposure to biomass and smoking on COPD risk in a primary care setting in Latin America. ⋯ Subjects with COPD from primary care had a higher exposure to biomass and smoking compared with non-COPD subjects. Smoking and biomass are both risk factors for COPD, but they do not appear to have an additive effect.