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Decreased Time Constant Effects
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Decreased Time Constant Effects
Pretest
Short inspiratory and expiratory times may be appropriate in the acute phase of respiratory distress syndrome because of decreased time constant.
A.True
B.False
Post Test
Short inspiratory and expiratory times may be appropriate in the acute phase of respiratory distress syndrome because of decreased time constant.
A.True
B.False
Answer: A
Because high maximal lung volume appears to correlate best with lung injury, selection of an appropriate peak inspiratory pressure and the functional residual capacity (or operating lung volume) are critical for the prevention of lung injury during pressure-limited ventilation. With the recognition that large tidal volumes lead to lung injury, relatively small tidal volumes now are recommended. Studies in healthy infants report a tidal volume range of 5-8 cc/kg, while infants with respiratory distress syndrome have tidal volumes of 4-6 cc/kg. Insufficient data are available to recommend a specific size of tidal volume in those infants. Infants with severe pulmonary disease should be ventilated with small tidal volumes because lung heterogeneity and unexpanded alveoli lead to overdistention and injury of the most compliant alveoli if a normal tidal volume is used. Maintenance of an adequate functional residual capacity also is necessary.
reproduced by permissiom from emedicine.com |
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