Resp Care
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Pulmonary function, in HIV infected patients, has been associated with reduction in pulmonary ventilation parameters. ⋯ AIDS subjects, in our study, had reduced parameters of maximal respiratory pressures and spirometry. The frequent dysfunction of respiratory muscles might be due to the association of multiple factors and not a particular one; moreover, smoking was independently associated with abnormal airway function. Pulmonary function tests should be implemented as an essential part of the medical assistance to AIDS patients.
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Current published guidelines on spirometry interpretation suggest an elevated FVC and FEV(1) > 100% of predicted with an obstructive ratio may represent a physiological variant. There is minimal evidence whether this finding can be indicative of symptomatic airways obstruction. ⋯ A normal FEV(1) > 90% of predicted with obstructive indices may not represent a normal physiological variant, as 28% of patients were found to have underlying AHR. These findings suggest that clinicians should evaluate for AHR, especially in symptomatic patients, even if the FEV(1) is > 90% of predicted.
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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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Ventilatory inefficiency increases ventilatory demand; corresponds to an abnormal increase in the ratio of minute ventilation (V_dot(E)) to CO(2) production (V_dot(CO(2))); represents increased dead space, deregulation of respiratory control, and early lactic threshold; and is associated with expiratory flow limitation that enhances dynamic hyperinflation and may limit exercise capacity. ⋯ Ventilatory inefficiency correlates with a reduction in exercise capacity in COPD patients. Including this parameter in the evaluation of exercise limitation in this patient population may mean a contribution toward the understanding of its pathophysiology.