Shock Syndromes I

In general, less invasive devices are desired, but they often have limited accuracy in estimating

hemodynamic parameters compared with invasive devices.

When further hemodynamic assessment is indicated, echocardiography is the preferred modality to

initially evaluate the type of shock as opposed to more invasive approaches.

Some ICU monitors can display additional hemodynamic parameters (e.g., automated PPV from an

arterial catheter) without additional equipment or devices.

Bioimpedance uses electrodes on the skin or an endotracheal tube to estimate the CO through

mathematical modeling of the impedance by the body to electrical current flow induced by cyclic changes

in blood flow during the cardiac cycle. Bioreactance improves on bioimpedance models by analyzing

the variations in the whole frequency spectra of the oscillating current instead of only variations in

amplitude changes. This increases the signal-to-noise ratio and improves device performance.

Device or

Category

Obtainable

Parameters

Advantages

Limitations

Noninvasive BP

monitoringa

familiarity

monitoring

dysfunction

Arterial BP

catheter

measurement in shock

than noninvasive

methods

blood gas sampling

and DBP measurements (MAP still

accurate)

circulation (may result in decreased

distal arterial perfusion)

Central venous

catheter (CVC)

CVP/RAP, Scvo2

than a PAC

as a continuous

measurement

tion of highly osmotic

and caustic agents

end-diastolic pressure

fluid responsiveness

in the chapter)