Chest
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Comparative Study
Medication nebulizer performance. Effects of diluent volume, nebulizer flow, and nebulizer brand.
Medication nebulizers are commonly used to delivery aerosolized medications to patients with respiratory disease. We evaluated output and respirable aerosol available to the patient (inhaled mass) for 17 medication nebulizers using a spontaneous breathing lung model. ⋯ The performance of medication nebulizers is affected by fill volume, flow, and nebulizer brand. When they are used for research applications, the nebulizer characteristics must be evaluated and reported for the conditions used in the investigation.
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To compare pressure-controlled inverse ratio ventilation (PCIRV) with volume-controlled ventilation with positive end-expiratory pressure (VCV PEEP) at equal levels of end-expiratory alveolar pressure. The primary focus of the study was on pulmonary epithelial permeability. Histologic and gravimetric indicators of lung injury were also studied. ⋯ The observations reported in this article imply that PCIRV causes an alteration in lung epithelial or membrane function in comparison to VCV PEEP. This functional difference is most likely caused by the large time-adjusted lung volume produced by pressure control in combination with a prolonged inspiration. It remains to be established whether this early functional effect of PCIRV is relevant with regard to structural lung injury in mechanically ventilated subjects.
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It is occasionally desirable for patients with a tracheostomy tube to breathe through their native airway. We hypothesized that capped tracheostomy tubes with cuffs deflated would create substantial additional resistance to airflow without fenestration but would provide minimal resistance to airflow when the tube had a fenestration. ⋯ The effort required to move gas across the native airway in the absence of a fenestration may be substantial. If a patient is to breathe through a native airway, a fenestrated tube should be used unless the tracheostomy tube is a No. 4.