What is the general effect of using a cuff that is too narrow?

• A. Values tend to be higher than true BP
• B. Values tend to be lower than true BP
• C. No effect on measured BP
• D. Only diastolic values are affected

Answer: (A)

Using a cuff that is too narrow causes the blood pressure readings to be higher than the true values. A narrow cuff doesn’t apply pressure as evenly or effectively around the arm, so more cuff pressure is needed to occlude the brachial artery. When you measure and then release pressure, the inflated pressure you rely on to mark systolic and diastolic points ends up being artificially elevated. That’s why a cuff that’s too narrow tends to give falsely high readings for both systolic and diastolic blood pressure. To avoid this, choose a cuff with a width about 40% of the arm’s circumference and ensure the bladder encircles about 80% of the arm.