The Pulmonary Artery Catheter
143
fluid passes through the shunt, thereby creating an abbreviated thermod-
ilution curve similar to the high-output curve in the middle panel of
Figure 8.6. In left-to-right shunts, the thermodilution curve is abbreviat-
ed be-cause the shunted blood increases the blood volume in the right
heart chambers, and this dilutes the indicator solution that is injected.
HEMODYNAMIC PARAMETERS
The PA catheter provides a wealth of information on cardiovascular func-
tion and systemic oxygen transport. This section provides a brief de-
scription of the hemodynamic parameters that can be measured or de-
rived with the PA catheter. These parameters are included in Table 8.1.
Body Size
Hemodynamic parameters are often expressed in relation to body size,
FIGURE 8.6
Thermodilution curves for a low cardiac output
(upper panel)
, a high cardiac
output
(middle panel)
, and tricuspid insufficiency
(lower panel).
The sharp inflection in each
curve marks the end of the measurement period. CO
=
cardiac output.
