As the PAC is inserted, the following waveforms can be observed.
1. When the catheters enters the RA, a CVP tracing is seen – characterized by a and v waves.
2. As the catheter enters the RV, a sharp increase in systolic pressure is noted.
3. As the catheter is advanced to the pulmonary artery, an increment in diastolic pressure is seen as well as the presence of a dichromatic notch.
4. When the catheter is advanced further into the pulmonary artery, and wedged – a sine wave that oscillates with respiration is seen.
THE RA WAVEFORM:
The RA waveform is characterized by presence of 2 waves: a wave (contraction of the RA) and the v wave (passive filling of the RA).
The x descent represents RA relaxation, which is interrupted by the c wave which represents closure of the tricuspid valve.
The y descent follows the v wave, which signals the opening of the tricuspid valve and exit of blood from the RA to the RV.
The wave below illustrates flushing of the catheter – which results in high pressures in the transducer (1). Flushing stops, and results in fall in pressures and an overshoot (2), and a return to normal waveform.
The wave below – overshooting is absent, and the waveform is flattened, which is found in an overdamped waveform. Overdamping can be caused by a kinked catheter, air bubbles, fibrin clot.
The graph below illustrate catheter whip – where ventrcicular contractions are transmitted to the PAC.
The arrow indicates when the balloon is inflated. There is a sustained increment in pressure reading.
ACUTE MITRAL INSUFFICIENCY
Prominent v waves represent blood that enters the LA during ventricular systole due to an incompetent mitral valve.
Broad c-v waves can be seen.
Marked acute dilatation of the RV occurs. Acute dilatation is limited by the pericardium. Deep x and y descents, resembling the letter W is seen.
MEASURED HEMODYNAMICS VARIABLES:
DERIVED HEMODYNAMICS VARIABLES
OXYGEN TRANSPORT VARIABLES
Criner, G., Barnette, R. and D’Alonzo, G. (2010). Critical Care Study Guide. Dordrecht: Springer.