Respiratory care
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Most patients on long-term oxygen therapy use stationary oxygen delivery systems. It is not uncommon for guidelines to instruct patients to use tubing lengths no longer than 19.68 ft (6 m) when using an oxygen concentrator and 49.21 ft (15 m) when using cylinders. However, these concepts are not based on sufficient evidence. Thus, our objective was to evaluate whether a 98.42-ft (30-m) tubing length affects oxygen flow and FIO2 delivery from 1 cylinder and 2 oxygen concentrators. ⋯ Tubing length of 98.42 ft (30 m) may be used by patients for home delivery oxygen with flows up to 5 L/min, as there were no important changes in flows or FIO2.
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The effect of leaks on volume-targeted pressure support noninvasive ventilation mode has only been tested with continuous simulated leaks. The objective of the study was to assess the influence of random leaks occurring either during inspiration or expiration. ⋯ The introduction of random leaks influences the performance of commercial ventilators with single-limb circuits and intentional leak. The decrease in delivered VT with inspiratory leaks reaches a magnitude that may have clinically important impacts.
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The role of exhaled H2S as a marker of airway inflammation and its relationship with COPD severity remain to be determined. ⋯ Exhaled levels of H2S were lower in subjects with eosinophilia. Increased levels of exhaled H2S predicted a non-eosinophilic phenotype in our study population.