Articles: mechanical-ventilation.
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The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. ⋯ A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H2O PEEP in mild ARDS, 10-15 cm H2O PEEP in moderate ARDS, and 15-20 cm H2O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation.
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Comparative Study
Pressurized Metered-Dose Inhalers Versus Nebulizers in the Treatment of Mechanically Ventilated Subjects With Artificial Airways: An In Vitro Study.
The primary focus of previous aerosol research during mechanical ventilation was the endotracheal tube (ETT). Consequently, there are limited data in the literature on the delivery of inhaled medications administered with different aerosol devices in mechanically ventilated patients with a tracheostomy tube (TT). The purpose of this study was to quantify and compare the efficiency of aerosol devices in a lung model of an intubated and mechanically ventilated adult with a TT. ⋯ Aerosol drug delivery via a TT was greater than with an ETT, whereas the delivery efficiency of a pMDI via either airway was greater than that of a jet nebulizer.
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Indian J Crit Care Med · Nov 2015
Critical illness associated with 2013-2014 influenza A (H1N1): Postpandemic characteristics, presentation and outcomes.
The United States experienced a postpandemic outbreak of H1N1 influenza in 2013-2014. Unlike the pandemic in 2009 clinical course and outcomes associated with critical illness in this postpandemic outbreak has been only sparsely described. ⋯ Compared to the 2009-2010 pandemic, the 2013-2014 H1N1 strain affected older patients with more underlying co-morbid cardio-pulmonary diseases. The patients had worse oxygenation indices and rescue modalities such as prone ventilation, inhaled epoprostenol and ECMO, were used more consistently as compared to the 2009 pandemic.
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Pulse pressure variations (PPV) are mainly influenced by ventilation. The impact of sedation on PPV is not known. The aim of the study was to test the influence of sedation on pulse pressure variation in mechanically ventilated critically ill patients and to compare PPV in critically ill and brain dead patients. Beside the absolute value of PPV, the adjusted values of pulse pressure were used to eliminate influence of ventilation. ⋯ Deeper sedation increases values of adjusted pulse pressure variation.
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In respiratory distress, lung airways become flooded with liquid and may collapse due to surface-tension forces acting on air-liquid interfaces, inhibiting gas exchange. This paper proposes a mathematical multiscale model for the mechanical ventilation of a network of occluded airways, where air is forced into the network at a fixed tidal volume, allowing investigation of optimal recruitment strategies. The temporal response is derived from mechanistic models of individual airway reopening, incorporating feedback on the airway pressure due to recruitment. ⋯ However, the time taken for complete ventilation of the network increases significantly as the network becomes more heterogeneous, leading to increased stresses on airway walls. The model predicts that the most peripheral airways are most at risk of ventilation-induced damage. A positive-end-expiratory pressure reduces the total recruitment time but at the cost of larger stresses exerted on airway walls.