Respiratory care
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Oxidative stress occurs when imbalances exist between the production of oxygen free radicals and endogenous antioxidants that neutralize their harmful effects, causing irreversible tissue damage. Oxygen free radicals readily interact with DNA, proteins, and lipids, instigating conformational changes to cellular structures and leading to derangement and dysfunction. Oxidative stress is a key feature in the pathology of COPD. As disease progression occurs, supplemental oxygen is often warranted to ameliorate dyspnea. It has been established that supplemental oxygen at > 0.60 FIO2 is an instigator of oxidative stress. We sought to determine whether chronic exposure to low-flow domiciliary oxygen served as a mechanism of ongoing oxidative stress in this patient population. This study serves to inform best practices for low-flow domiciliary oxygen therapy. ⋯ In subjects diagnosed with advanced COPD, chronic exposure to supplemental oxygen therapy at concentrations ≤ 36% did not appear to induce oxidative stress based on EBC IsoF levels. Our findings do not substantiate that chronic exposure to supplemental oxygen at concentrations < 36% instigates oxidative stress, and, therefore, changes to current domiciliary oxygen therapy prescription practices are not warranted.
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Chronic hypoxemia in patients with COPD is a limiting factor that is associated with disease progression and significantly contributes to decreased physical activity. Although correction of hypoxemia results in physiological improvements, oxygen therapy may be related to social isolation and inactivity. However, few studies have objectively investigated the level of physical activity in daily life (PADL) in these patients. The objective of this study was to compare the level of PADL in subjects with COPD on home oxygen therapy and in subjects with no oxygen therapy, and to investigate whether home oxygen therapy is associated with the level of PADL. ⋯ Subjects with COPD using oxygen at home showed reduced level of PADL. The results indicate that oxygen therapy is associated with severe physical inactivity and may be a predictor of the level of PADL.
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Pediatric patients treated with noninvasive ventilation (NIV) are frequently given aerosol therapy. Limited pediatric data are available on the efficiency of aerosol delivery efficiency. We evaluated the effect of different nebulizers, positions in the single-limb ventilator circuit, and ventilator settings on the efficiency of aerosol delivery in a model of pediatric NIV. We hypothesized that using a vibrating mesh nebulizer, placing the nebulizer after the circuit leak, and not using the highest inspiratory positive airway pressure would increase aerosol delivery efficiency. ⋯ In a model of pediatric NIV using a single-limb circuit, aerosol delivery devices were more efficient when placed after the exhalation port of the ventilator circuit. Vibrating mesh nebulizers were more efficient than jet nebulizers.