Table 1. Overview of monitoring methods.
| Method | Examples of
commercial name |
Calibrated or not | Major advantages | Major disadvantages |
|---|---|---|---|---|
| Invasive methods | ||||
| Pulmonary artery
catheter |
Calibrated | Direct measurements
in right atrium and pulmonary circulation |
Delay in determining CO,
most invasive, and risks involved |
|
| Less-invasive methods | ||||
| Transpulmonary
thermodilution |
PiCCO
®
VolumeView ®/EV1000 ® LiDCO ® |
Calibrated | Intermittent and
continuous CO, added variables |
Need for specialized arterial
and central venous line, LIMITS (PiCCO ® system) |
| Ultrasound flow
dilution |
COstatus ® | Calibrated | Continuous CO, added
variables, can detect intracardiac shunts |
Requires AV loop |
| Pulse contour and
pulse pressure variation |
FloTrac
®/Vigileo
®
ProAQT ®/Pulsioflex ® LiDCOrapid ®/pulseCO ® Most Care ®/PRAM |
Non-calibrated | Continuous CO | Lack accuracy in unstable
patients or during use of vasoactive drugs |
| Partial CO
2
-rebreathing |
NiCO ® | Non-calibrated | No need for
intravascular devices |
Only in sedated patients
under volume control ventilation, interference from pulmonary disease |
| Transesophageal
echocardiography |
Operator dependent | Real-time images of the
cardiac structures and blood flow |
Learning curve, (low) risk of
complications |
|
| Esophageal Doppler | Operator dependent | Real-time CO and
afterload data, added variables |
Risk of dislocation | |
| Non-invasive methods | ||||
| Transthoracic
echocardiography |
Operator dependent | Direct measurement of
CO and visualization of cardiac structures |
Ultrasound characteristics
often suboptimal in ICU patients |
|
| Non-invasive pulse
contour systems |
T-line
®
ClearSight ®/Nexfin ®/ Physiocal ® CNAP ®/VERIFY ® |
Non-calibrated | Non-invasive, simple
tool |
Less accurate, needs more
validation |
| Bioimpedance | Non-calibrated | Simple tool, providing
data concerning CO and fluid overload |
Changes intrathoracic fluid
content and SVR influence measurements |
|
| Estimated continuous
cardiac output ® |
esCCO ® | Non-calibrated | Uses widely available
variable to estimate CO |
Is only estimate, inadequate
accuracy |
| Ultrasonic cardiac
output monitoring ® |
USCOM ® | Non-calibrated | Short learning curve
and only few risks |
Only estimate, uses standard
valve areas which can differ in patients |
AV loop, arteriovenous fistula; CO, cardiac output; ICU, intensive care unit; SVR, systemic vascular resistance.