There are a number of things that could be causing you to get higher values. It is possible the blood pressure of the person being measured, is, in fact, higher than believed. Blood pressure is a very dynamic vital sign and responds quickly to both physiological and psychological stimuli. Changes of 40mmHg or more on systolic values are quite common. Make sure the patient has rested for at least 2-3 minutes before taking their BP. Second, make sure you are using an appropriately sized cuff.