Resp Care
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Noninvasive positive-pressure ventilation (NPPV) delivers air at a high flow, which is associated with airway mucosal drying and impaired airway functioning. ⋯ NPPV delivers air with a low relative humidity, especially with high inspiratory pressure. Addition of a heated humidifier increases the relative and absolute humidity to levels acceptable for nonintubated patients, with minimal effect on delivered pressure. Consideration should be given to heated humidification during NPPV, especially when airway drying and secretion retention are of concern.
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With a high-frequency percussive ventilator and a mechanical lung model, to measure tidal volume (V(T)), pulsatile pressure amplitude (difference between peak and nadir pulsatile pressure [DeltaP];), and mean airway pressure (P (aw)) at various pulsatile frequencies, pulsatile inspiratory-expiratory ratios (I:E(p)), and pressures (measured at the interface between the pulse-generator and the endotracheal tube [P(vent)]). ⋯ During high-frequency percussive ventilation, the pulsatile frequency is inversely related to V(T). Partial cuff deflation reduces the delivered F(IO(2)).