When placing an arterial line, if the patient's left ventricle is 20cm above the transducer, what is the patient's true blood pressure if the monitor reads 120/80?

To determine the true blood pressure when an arterial line is placed, it is essential to consider the hydrostatic effect of the height difference between the patient's heart and the transducer. When the left ventricle is 20 cm above the transducer, the pressure reading must be corrected upward due to gravitational influences on the blood column.

A general rule of thumb is that for every 1 cm of height difference, the arterial blood pressure is affected by approximately 0.74 mmHg. In this scenario, since the left ventricle is 20 cm above the transducer, this would translate to an increase in blood pressure of about 14.8 mmHg (20 cm multiplied by 0.74 mmHg/cm).

Thus, to find the true blood pressure, you would add this correction to the measured blood pressure of 120/80. The systolic pressure would adjust from 120 mmHg to approximately 135 mmHg (120 + 14.8), and the diastolic pressure would adjust from 80 mmHg to about 95 mmHg (80 + 14.8). These calculations lead to a corrected blood pressure of approximately 135/95, which aligns with one of the other options provided.