Resp Care
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Comparative Study
Modification of a high frequency oscillator circuit with a heated expiratory filter to prevent infectious pathogen transmission: a bench study.
High frequency oscillation is a safe and effective treatment for patients with ARDS, but poses a patient and caregiver risk when the circuit is disconnected. We modified the circuit to include a heated expiratory filter, eliminating the need for daily filter changes due to buildup of condensate. The purpose of the study was to determine if substitution of the filter resulted in a clinically important change in delivered tidal volume or amplitude. We additionally compared expiratory resistance and measured efficacy for the substituted filter. ⋯ Modifying the circuit to include a heated expiratory filter does not affect tidal volume, and the filter material remains efficacious during oscillation. Amplitude varies under some conditions. Preventing the need for daily filter changes reduces the risk of alveolar de-recruitment. This does not completely eliminate exposure to expired gases, but provides an additional layer of protection against occupational exposure and nosocomial spread of respiratory pathogens. Further testing in a clinical environment is necessary.
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Chest radiography and computed tomography (CT) have a crucial role to play in the diagnosis and management of acute respiratory distress syndrome (ARDS). The identification of pulmonary opacification is a requirement for the definition of ARDS on the chest radiograph, while CT has a role to play, not only in the diagnosis of ARDS, but also in the identification of complications. This paper reviews the radiological appearances of ARDS that have been documented for some time, and also more recent research that has identified a role for CT in directing ventilation and in prognostication.
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Air-fluid levels within emphysematous lung bullae are a relatively uncommon occurrence in patients with preexisting bullous disease, and are not commonly reported. We report 2 cases of new onset air-fluid levels in patients with underlying bullous disease with substantially different clinical presentations but with clinical improvement after medical therapy only.
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Choke points and airway wall structure in expiratory central airway collapse are poorly defined. Computed tomography, white light bronchoscopy, endobronchial ultrasound, vibration response imaging, spirometry, impulse oscillometry, negative expiratory pressure, and intraluminal catheter airway pressure measurements were used in a patient with cough, dyspnea, and recurrent pulmonary infections. Computed tomography and white light bronchoscopy identified dynamic collapse of the trachea and mainstem bronchi, consistent with severe crescent tracheobronchomalacia. ⋯ After Y-stent insertion, the choke point migrated distally. Imaging studies revealed improved airway dynamics, airway patency, and ventilatory function. Novel imaging and physiologic assessments could be used to localize choke points and airway wall structure in tracheobronchomalacia.