LUNG WATER
The need to detect pulmonary edema has led to a variety of techniques
for the early detection of increased lung water. Chest radiography, although it
has a relatively low sensitivity (a 35% increase in extravascular lung water is required
for the diagnosis of definite pulmonary edema), remains the gold standard. Techniques
such as Compton scattering,[245]
[246]
magnetic resonance imaing,[247]
[248]
positron emission tomography,[249]
double-indicator
dilution using indocyanine green and a thermal marker[250]
[251]
or heavy water (i.e., deuterium oxide [D2
O]),
[252]
[253]
multiple
inert gases,[254]
[255]
and impedance plethysmography[256]
have been useful
research tools but have not entered routine clinical use.
