Extravascular Lung Water Measurement
Extravascular lung water (EVLW) is the term used to describe water within the lungs but outside the pulmonary vasculature. Excessive EVLW volume is a common and serious feature of critical illness. However, clinical assessment of the extent of pulmonary capillary leakage is difficult and inconsistent [1, 2]. Traditional methods of reducing EVLW volume include the use of loop diuretics and vasodilator drugs. The choice of these interventions is very much at the discretion of the clinician; pharmacological therapy is titrated to achieve a subjective clinical improvement rather than a quantitative EVLW volume target. The critically ill patient may also require fluid resuscitation to correct hypovolemia and to maintain oxygen delivery to the major organs. However, in the presence of increased pulmonary capillary permeability or impaired myocardial function, the administration of large volumes of intravenous fluid is associated with a significant risk of pulmonary edema. Effective fluid resuscitation, therefore, involves a fine balance between the harmful effects of inadequate tissue oxygen delivery on the one hand and excessive EVLW volume on the other.
KeywordsAcute Lung Injury Mean Transit Time Extravascular Lung Water Indicator Dilution Intrathoracic Blood Volume
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