How Does a Plethysmography Work?
A plethysmography is a test that measures systolic blood pressure. As the heart pumps blood, it creates pressure on the walls of the arteries. When your doctor takes your blood pressure, he uses a test that measures the amount of pressure that is being forced on the walls of the arteries. The results of blood pressure tests come in the form of two numbers, for example 115/72 (“115 over 72,” when speaking). The first number, the systolic number, indicates the systolic blood pressure, or the maximum amount of pressure that the heart creates when it contracts. The second number measures diastolic blood pressure and indicates the force in your arteries when your heart is at rest. During a plethysmography, a blood pressure cuff is placed on each arm, with a third blood pressure cuff wrapped around the upper leg. As the test proceeds, the medical caregiver notes differences in pressure between the arms and various parts of the leg. By comparing differences between blood pressure in the extre
