What does zeroing set the device to?

• A. The device’s previous reading
• B. Atmospheric pressure
• C. Patient-specific baseline pressure
• D. Calibration mode

Answer: (B)

Zeroing sets the device’s pressure sensor to a reference of atmospheric pressure. This aligns the sensor output so that when no cuff pressure is applied, the display reads zero. With this baseline, all subsequent cuff pressures are measured as pressure above ambient, eliminating offsets from sensor drift and environmental pressure. This is essential for accurate systolic and diastolic readings, because without zeroing the readings could be biased by ambient pressure or sensor offset. It is different from using the previous reading or a patient-specific baseline, and it is not the same as entering calibration mode.