Question

A patient's blood pressure is being monitored through an indwelling arterial line. At inception of the monitoring, the transducer was level with the heart and the system was zeroed. Since then, the patient has moved his arm, which has raised the transducer. Which of the following effect will this have on reported pressures?

1) systolic and diastolic pressures will be erroneously low
2) systolic pressures will be erroneously low while diastolic pressures will be erroneously high
3) pressures will remain accurate
4) systolic and diastolic pressures will be erroneously high

Answer 1

Raising the transducer above the level of the heart when monitoring a patient's blood pressure through an indwelling arterial line will result in both systolic and diastolic pressures being erroneously reported as low due to the effects of gravity. option 1 is correct.

Step-by-step explanation:

When the patient moves their arm and raises the transducer above the level of the heart, it will affect the reported pressures from an indwelling arterial line. Since the transducer should be at the level of the heart to accurately reflect the true blood pressure, if it is raised, the pressure readings will be artificially lowered.

This occurs because the pressure transducer measures the pressure relative to its position; lifting the transducer higher means the blood pressure has to overcome additional gravitational force to reach that level, which makes the measured pressure lower than the actual pressure. Therefore, both the systolic and diastolic pressures will be erroneously low.