Shock Syndromes I
Device or
Category
Obtainable
Parameters
Advantages
Limitations
Pulmonary artery
catheter (PAC)
Measured: PASP,
PADP, mPAP,
PAOP, CO, and CI
by thermodilution
or continuous
measurement (copper
filament adapted
catheter), Svo2
Calculated: PVR,
SVR, CO, and CI by
Fick equation, SV
| • | Only method available |
|---|
to directly measure
pulmonary artery
pressures
| • | Direct measurement of |
|---|
CO and Svo2 (may be
available as continuous
variables)
| • | Outcomes data supporting superiority |
|---|
to CVC lacking
| • | May cause arrhythmias |
|---|---|
| • | Assumes right heart function |
approximates left heart function
(usually, but not always, true)
| • | Fick CO calculation typically uses an |
|---|
estimated value for Vo2, which may
be falsely low in a patient with septic
shock and underestimate CO
| • | Valvular abnormalities may make |
|---|
values inaccurate (particularly mitral
stenosis, mitral regurgitation, tricuspid
regurgitation, or aortic regurgitation)
| • | Correct catheter tip location (lung |
|---|
zone 3) needed for accurate readings
Echocardiography
Cardiac chamber
size and function,
pericardial
appearance (and
presence of fluid),
IVC collapsibility/
distensibility, ejection
fraction, RVSP (an
estimate of PASP),
LVOT VTI (to
calculate CO/CI)
| • | Noninvasive |
|---|
(transthoracic)
| • | Visualization of |
|---|
ventricular function
instead of presumed
function based on CO
| • | IVC collapsibility |
|---|
can predict fluid
responsiveness
| • | Subjectivity of user assessment |
|---|---|
| • | Not done continuously; therefore, |
cannot detect acute changes or must
be repeated when the patient’s status
changes
| • | May have limited visibility/windows |
|---|
depending on patient body habitus or
positioning
Esophageal
Doppler (ODM
II, CardioQ,
HemoSonic 100)
CO, CI, SV, flow time
| • | Ease of use |
|---|---|
| • | May be used to |
determine fluid
responsiveness
| • | Assumptions used by the device |
|---|
may not be valid in the setting of
hemodynamic instability (fixed
partition of blood flow to cephalic
vessels and descending aorta, constant
aortic cross-sectional area)
| • | Accuracy depends on position (need |
|---|
for frequent repositioning)