The Pulmonary Artery Catheter
141
capillary hydrostatic pressure is higher than the wedge pressure,
a normal
wedge pressure measurement will not rule out the diagnosis of hydrostatic pul-
monary edema.
Therefore, the use of a normal wedge pressure as a diag-
nostic criterion for ARDS should be abandoned.
THERMODILUTION CARDIAC OUTPUT
The ability to measure cardiac output increases the monitoring capacity
of the PA catheter from 2 parameters (i.e., central venous pressure and
wedge pressure) to at least 10 parameters (see Tables 8.1 and 8.2), and
allows a physiologic evaluation of cardiac performance and systemic
oxygen transport.
3
1
2
Time
Temp
Proximal Port
Injection
Thermistor
Output
Injectate mixes
with Blood
FIGURE 8.5
The thermodilution method of measuring cardiac output. See text for
explanation.
