Thu18November0755PM 3

Damping of a monitored arterial waveform can give rise to inaccurate blood pressure interpretation.

Which one of the following statements corresponds to the readings taken from a damped arterial waveform?

(Please select 1 option)

The systolic pressure is lower and the diastolic pressure higher with the same mean Correct

The systolic and diastolic pressures are lower with the same mean

The systolic pressure and diastolic pressure are higher with a higher mean

The systolic pressure and diastolic pressure are lower with a lower mean

The systolic pressure is higher and the diastolic lower with a normal mean

Explanation

Damping is a progressive decrease in the amplitude of oscillations due to dissipation of energy.

If the transducer is underdamped, resonance of the measuring system is likely to occur. The amount of damping that is applied is the damping factor (D).

When the system is:

Undamped, D=0

Critically damped, D=1

Optimally damped, D=0.64.

A 'damped' arterial line trace will have a low systolic, high diastolic and normal mean pressure reading.

Damping can result from air bubbles, blood (with higher viscosity) or blood clots in the tubing or arterial cannula. The diaphragm of the transducer or the tubing may be too compliant. Other causes include kinks, constrictions or too many injection ports in the tubing.

A resonant arterial trace will tend to have a raised systolic, low diastolic and normal mean pressure, that is, over-read.

Resonance occurs when the driving force frequency coincides with the resonant frequency of the system. This may occur if the tubing is too long or stiff. The diaphragm of the transducer may also be is too stiff or non-compliant.

Answer Statistics

1

75%

2

13%

3

2%

4

5%

5

7%

Times answered: 254