What does an Underdamped arterial line mean?

Underdamping (defined as when the oscillations are too pronounced and can lead to a false high systolic or a false low diastolic pressure). Causes include: Catheter whip or artefact. Stiff non-compliant tubing.

What is a square test on an arterial line?

The Square Wave Test When you squeeze the fast flush valve, you let the transducer taste some of the 300mmHg in the pressurized saline bag. This produces a waveform that rises sharply, plateaus, and drops off sharply when the flush valve is released again. This is the “square wave”.

What does the square wave test measure?

The primary utilization of the square wave test is with arterial lines – those invasive monitoring cannulations which reside within the lumen of a systemic artery – and can be transduced to reveal a beat by beat graphic of luminal arterial tension.

What does the Dicrotic notch on an arterial waveform indicate?

The dicrotic notch, or incisura, which interrupts the arterial downslope, represents the closure of the aortic valve, which occurs just moments after the start of diastole. At the end of diastole, the waveform reaches its nadir.

What does Overdamped mean?

over damping: the condition in which damping of an oscillator causes it to return to equilibrium without oscillating; oscillator moves more slowly toward equilibrium than in the critically damped system.

What causes catheter whip?

Resonance or whip causes falsely increased systolic readings and falsely decreased diastolic readings. It occurs when the system’s frequency of oscillation (i.e., heart rate) matches the system’s natural frequency of vibration causing whip in the signal.

What is Dicrotic notch?

The dicrotic notch is a prominent and distinctive feature of the pressure waveform in the central arteries. It is universally used to demarcate the end of systole and the beginning of diastole in these arteries.

How do you know if you are Overdamped?

Solution. An overdamped system moves slowly toward equilibrium. An underdamped system moves quickly to equilibrium, but will oscillate about the equilibrium point as it does so. A critically damped system moves as quickly as possible toward equilibrium without oscillating about the equilibrium.

How does an under damped square wave test work?

Last, an under-damped waveform is where there is “ringing” or multiple oscillations / vibrations that follow the square wave test. A waveform that is under-damped will appear saltatory in nature causing variations in the systolic and diastolic blood pressure values.

What causes the square wave test in a transducer?

The Square Wave Test When you squeeze the fast flush valve, you let the transducer taste some of the 300mmHg in the pressurized saline bag. This produces a waveform that rises sharply, plateaus, and drops off sharply when the flush valve is released again. This is the “square wave”.

How does a square wave test work on a catheter?

Squarewave test is when you flush the line and observe the wave form on the monitor. It should be perfect square with 1-2 oscilation. A square wave test checks the dynamic response of the entire catheter monitoring kit transducer system.

How is square wave testing can assure accuracy?

Square wave testing can have a direct impact on the validity and accuracy of the hemodynamic values which are obtained from the invasive monitoring device. It is imperative that critical care clinicians be competent in understanding not only the purpose of square wave testing, but how to interpret its results.