Current opinion in critical care
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Curr Opin Crit Care · Feb 2003
ReviewNoninvasive mechanical ventilation in acute cardiogenic pulmonary edema.
Acute cardiogenic pulmonary edema is a frequent life-threatening emergency. During the last 10 years, increasing attention has focused on the use of noninvasive ventilation to treat patients with various forms of acute respiratory failure. ⋯ However, no sustained benefit (, decreased late mortality) or benefit for less severe forms of cardiogenic pulmonary edema has been demonstrated yet. Moreover, there are still few data that support the use of a specific mode of ventilation over the others.
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Curr Opin Crit Care · Feb 2003
ReviewWhere are we with recruitment maneuvers in patients with acute lung injury and acute respiratory distress syndrome?
Reduction of tidal volume to limit plateau pressure currently is recommended for the ventilatory management of acute respiratory distress syndrome. However, sufficient evidence now exists to support the fact that excessive reduction in tidal volume may result in harmful alveolar derecruitment depending on the level at which positive end-expiratory pressure is set. ⋯ Moreover, apart from physiologic studies suggesting a potential benefit of recruitment maneuver in terms of recruitment and gas exchange, no data are yet available that demonstrate the ability of such a maneuver to improve outcome. In this article, we discuss the physiologic rules governing recruitment and derecruitment and review articles that provide new insights in the field of recruitment maneuver.
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Curr Opin Crit Care · Feb 2003
ReviewExtubation failure: magnitude of the problem, impact on outcomes, and prevention.
Extubation failure, defined as the need for reinstitution of ventilatory support within 24 to 72 hours of planned endotracheal tube removal, occurs in 2 to 25% of extubated patients. The pathophysiologic causes of extubation failure include an imbalance between respiratory muscle capacity and work of breathing, upper airway obstruction, excess respiratory secretions, inadequate cough, encephalopathy, and cardiac dysfunction. Compared with patients who tolerate extubation, those who require reintubation have a higher incidence of hospital mortality, increased length of ICU and hospital stay, prolonged duration of mechanical ventilation, higher hospital costs, and an increased need for tracheostomy. ⋯ Risk factors for extubation failure include being a medical, multidisciplinary, or pediatric patient; age greater than 70 years; a longer duration of mechanical ventilation; continuous intravenous sedation; and anemia. Tests designed to assess for upper airway obstruction, secretion volume, and the effectiveness of cough can help to improve prediction of extubation failure. Rapid reinstitution of ventilatory support in patients who fail extubation may improve outcome.
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Curr Opin Crit Care · Feb 2003
ReviewHigh-frequency oscillatory ventilation in adults with acute respiratory distress syndrome.
The last decade has seen increased appreciation of ventilator-induced lung injury. The understanding that the process of mechanical ventilation can itself damage lungs has spurned the search for ventilation strategies that are more lung protective. ⋯ In the past year, a number of provocative and exciting studies have been published that contribute significantly to our understanding of high-frequency oscillatory ventilation, its role in preventing and reducing ventilator-induced lung injury, and its use in the support of adult patients with lung injury. In this article, we discuss the current understanding of high-frequency oscillatory ventilation and highlight the most recent literature addressing its application in adult patients with acute respiratory distress syndrome.
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Mechanical ventilation is a supportive lifesaving therapy that can potentially cause lung injury if periodic alveolar overdistension, or cyclic collapse, and reopening occur. The use of a low tidal volume with moderate to high positive end-expiratory pressure improves the survival of patients with acute lung injury and acute respiratory distress syndrome. Positioning the patient with the "good lung down" and using differential ventilation with selective positive end-expiratory pressure are the two currently accepted ventilatory strategies to be applied in patients with severe unilateral lung injury. ⋯ In unilateral lung injury, ventilatory strategies that allow recruitment of injured lung and that avoid overdistension of uninjured lung parenchyma should be applied. Experimental studies have shown that the use of selective tracheal gas insufflation and partial liquid ventilation facilitates low tidal volume with appropriate gas exchange while reducing cyclic lung stretch and shear stresses. Further studies are needed to determine future applications of these therapies in humans.