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Lung mechanics in hypervolemic pulmonary edema.
Journal of Applied Physiology
|April 1, 1975
Summary
Extravascular thermal volume of the lung (ETVL) can indicate pulmonary edema stages. Lung mechanics monitoring alongside ETVL offers a less invasive method for assessing lung water compared to traditional double indicator dilution techniques.
Area of Science:
- Physiology
- Pulmonary Medicine
- Critical Care Medicine
Background:
- Extravascular thermal volume of the lung (ETVL) is a double indicator dilution technique used to measure pulmonary edema.
- A less invasive monitor for pulmonary edema is needed.
Purpose of the Study:
- To evaluate ETVL and lung mechanics as less invasive monitors of pulmonary edema.
- To correlate anatomic changes with physiologic measurements of ETVL and central blood volume (CBV).
Main Methods:
- Pulmonary edema was induced in dogs by dextran circulation overload.
- Phases of edema (congestion, interstitial, alveolar) were defined based on ETVL and CBV.
- Mechanical ventilation with varying end-tidal pressures (CPPV) was applied during alveolar edema.
Main Results:
- Pulmonary resistance increased with alveolar edema.
- Lung compliance decreased proportionally to increased lung water.
- Controlled positive pressure ventilation (CPPV) did not reduce lung water but improved functional residual capacity (FRC) and PaO2.
Conclusions:
- ETVL and lung mechanics provide insights into pulmonary edema.
- Lung compliance changes correlate with lung water but are difficult to predict precisely.
- CPPV can improve oxygenation in edematous lungs without affecting lung water levels.