Sun28November0628PM 41

A transducer is an electrical device that converts one form of energy into another.

The output of a transducer that directly measures arterial blood pressure is assumed to be in direct proportion to any change. Transducers are subject to zero offset and gradient drift.

In the context of an arterial pressure transducer, which of the following are the most appropriate calibration values to compensate for gradient drift?

(Please select 1 option)

0 mmHg and 200 mmHg Correct

760 mmHg and 1000 mmHg

200 mmHg and 760 mmHg

0 mmHg and 120 mmHg

0 mmHg and 100 mmHg

Explanation

A calibration is a comparison between two measurements. In the context of blood pressure measurement the displayed value is proportional to the true value.

Measuring systems are subject to both gradient and offset drift, that is, the degree to which a displayed reading changes with time when the true value is constant. A two-point calibration should be performed at regular intervals to prevent gradient drift. The values of 0 mmHg and 200 mmHg are within the physiological range of measurement and are therefore the most appropriate values.

The establishment of the "zero" value is the concept of making hydrostatic measurements with fluid-filled systems relative to a reference value, usually atmospheric pressure (760 mm Hg), and then examining the change from that value. The process of "zeroing" involves opening the fluid column on the measuring device to the atmosphere and setting the system such that atmospheric pressure is the starting value.

The zero-reference against atmospheric pressure is the low known value of a two-point calibration. Zero offset drift occurs more readily than gradient drift. For this reason "zeroing" should be performed more regularly than a two point calibration.

Answer Statistics

1

61%

2

10%

3

11%

4

11%

5

9%

Times answered: 225