If the strain-gauge transducer is placed below the catheter, what is the expected reading?

When a strain-gauge transducer is placed below the level of the catheter, it measures the pressure exerted by the column of fluid above it plus any additional pressure from the transducer's position. This results in a reading that reflects both the actual pressure in the catheter and the hydrostatic pressure exerted by the height of the fluid column above the transducer.

If the transducer is positioned below the catheter, the pressure reading will be artificially elevated because it includes the addition of the hydrostatic pressure from the height difference. This increased reading does not accurately represent the pressure in the catheter itself, leading to the interpretation that the reading is higher than the actual pressure in the system. Understanding the effects of hydrostatic pressure is crucial in accurately interpreting hemodynamic data in clinical settings.