Respirology : official journal of the Asian Pacific Society of Respirology
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Comparative Study
Non-invasive positive pressure ventilation during sleep at 3800 m: Relationship to acute mountain sickness and sleeping oxyhaemoglobin saturation.
Overnight oxyhaemoglobin desaturation is related to AMS. AMS can be debilitating and may require descent. Positive pressure ventilation during sleep at high altitude may prevent AMS and therefore be useful in people travelling to high altitude, who are known to suffer from AMS. ⋯ The use of positive pressure ventilation during sleep at 3800 m significantly increased the sleeping oxygen saturation; we suggest that the marked reduction in symptoms of AMS is due to this higher sleeping SaO2. We agree with the findings from previous studies that the development of AMS is associated with a lower sleeping oxygen saturation.
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Volume-assured non-invasive ventilation (NIV) theoretically guarantees minute ventilation with circuit leak compensation unlike other modes of NIV. Bench testing demonstrated that minute ventilation was maintained with varying lung compliance and resistance with minimal effect from circuit leak, confirming for the first time the core features of volume-assured NIV. ⋯ These data confirm that va-NIPPV is able to approximate a preset TgV with varying lung compliance and resistance, and that additional circuit leak has little effect on the delivered minute ventilation.
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Clinical variables and laboratory data were compared to elucidate the risk factors associated with the development of ARDS among elderly patients with community-acquired pneumonia (CAP). The predictors for ARDS appeared to differ from the determinants of severity of CAP. ARDS developed less frequently among patients aged>or=85 years. ⋯ Predictors for ARDS appeared to differ from the determinants of severity of CAP in the elderly. ARDS developed less frequently in patients aged>or=85 years and in those with oropharyngeal AP. It is important to identify subjects at high risk for ARDS upon admission and to observe them closely.
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In asthma, clinical symptoms and lung function are insensitive in reflecting the underlying airway inflammation, and monitoring of this process has only recently become available. Fractional exhaled nitric oxide (Fe(NO)) is now recognized as a reliable surrogate marker of eosinophilic airway inflammation and offers the advantage of being completely non-invasive and very easy to obtain. ⋯ It covers the relationship between Fe(NO) and the underlying eosinophilic inflammation, the pathophysiology and production of Fe(NO), technical aspects of Fe(NO) measurement and potential confounding factors in interpreting levels. Fe(NO) reference values and the role of Fe(NO) in asthma assessment, diagnosis and management are also discussed.