Respiratory care
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High-frequency oscillatory ventilation (HFOV) can improve ventilation-perfusion matching without excessive alveolar tidal stretching or collapse-reopening phenomenon. This is an attractive feature in the ventilation of patients with ARDS. However, two recent large multi-center trials of HFOV failed to show benefits in this patient population. The following review addresses whether, in view of these trails, HFOV should be abandoned in the adult population?
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Airway pressure release ventilation (APRV) was originally described as a mode to treat lung-injured patients with the goal to maintain a level of airway pressure that would not depress the cardiac function, deliver mechanical breaths without excessive airway pressure, and to allow unrestricted spontaneous ventilation. Indeed, based on its design, APRV has technological features that serve the goals of safety and comfort. Animal studies suggest that APRV leads to alveolar stability and recruitment which result in less lung injury. ⋯ Finally, we do not have evidence that APRV (as originally described) improves relevant clinical outcomes of patients with ARDS. For APRV to become the primary mode of ventilation for ARDS, it will require development of sound protocols and technological enhancements to ensure its performance and safety. For now, APRV does have a greater potential for adversely affecting patient outcome than improving it; unless definitive data are forthcoming demonstrating outcome benefits from the use of APRV in ARDS, there is no reason to consider this approach to ventilatory support.
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Oxygen is both lifesaving and toxic. Appropriate use of oxygen aims to provide a balance between the two effects. ⋯ The role of hyperoxemia in mechanically ventilated patients, in the face of non-toxic inspired oxygen concentrations, is less clear. This paper will review the data for and against the use of conservative oxygen targets and the avoidance of hyperoxemia in mechanically ventilated patients.
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Intermittent mandatory ventilation (IMV) was introduced nearly 50 years ago. Despite the initial fanfare and early adoption by many, the role of IMV continues to be questioned. ⋯ Spontaneous breathing, however, has a number of salutatory effects on gas exchange, the distribution of ventilation, and hemodynamics. These issues will be explored in light of a growing body of evidence.