Accurate Blood Pressure Measurement: What is it? Why is it important? Why is it so difficult to obtain a reliable measurement?

Similar to the pressure created by water flowing through a garden hose, blood pressure refers to the force exerted by circulating blood on the walls of our arteries and blood vessels. Blood pressure is commonly measured by inflating a cuff on the upper arm and watching the pressure indicated by a blood pressure gauge while listening to the Korotkoff sounds at the brachial artery with a stethoscope. The cuff must first be inflated enough to stop all the blood from flowing through the artery. Then, as the pressure in the cuff is gradually released with a valve, the occlusion of the artery is reduced. The point at which blood begins to flow again is signaled by the first Korotkoff sound. This is an indication of the peak blood pressure in the arteries and is referred to as systolic blood pressure. Continued reduction of the pressure in the cuff eventually allows the blood to flow completely unobstructed again. This point is signaled by the disappearance of the Korotkoff sounds and is considered a reliable indication of diastolic blood pressure.