Sphygmomanometer. We’ve all seen one before and probably even used one before; we just did not know its name. So what is a sphygmomanometer you ask?
Merriam-Webster defines a sphygmomanometer as “an instrument for measuring blood pressure and especially arterial blood pressure.” The National Heart, Lung, and Blood Institute under the Department of Health, tells us all about how the sphygmomanometer works. Blood pressure is measured in millimeters of mercury and the two numbers recorded are systolic pressure and diastolic pressure. The American Heart Association explains the difference between systolic and diastolic pressure. Systolic pressure measures the pressure in the arteries when your heart beats while diastolic pressure measures the pressure in the arteries when your heart is resting. With the cuff wrapped around your upper arm the pump will inflate the cuff to stop the flow of blood to your artery for a few seconds. The valve, right below the pump, lets small amounts of air out to allow blood to flow again. The dial is then used to read your blood pressure. A stethoscope is also used to hear the systolic and diastolic pressure.
The history of the sphygmomanometer dates back to Galileo. He was one of the first to count his pulse while watching a pendulum. Sanctorious, a professor of medicine and contemporary of Galileo’s, used the pendulum to measure his pulse. He used different lengths of string on the pendulum until it was in sync with his pulse. Fifty years passed before any strides were made with the sphygmomanometer. Steven Hales, a clergyman and biologist, measured the blood pressure by measuring the height of a column of blood in a glass tube that was connected to the artery. Through this, he calculated the speed of circulation. Another seventy-five years would go by until Poiseuille came along. He invented the U-shaped mercurial manometer and discovered the laws for the flow of blood. Many other physicians helped with the development of the sphygmomanometer but it is Riva-Rocci who invented the sphygmomanometer we now today in roughly 1896. To read more about how Riva-Rocci’s invention worked and the history of the sphygmomanometer, click here.
The sphygmomanometer we have in our collection at the High Plains Museum, seen on the left, looks slightly
different from the ones we see in doctors’ offices today. The dial as you can see is much larger compared to todays and ours comes inside a small wood and glass display unit. This is the only one we have in our collection but we have a picture of Maxine Peter’s checking a man’s blood pressure at a health screening sponsored by the Sherman County EHU, State & County health personnel. The picture was taken in February 1975 and can be seen on the right.
A sphygmomanometer is an object that we have all had used on us at one point in our lives. It dates back to the days of Galileo and took many people to get what we know today. This is an object that has changed its look and is evolving with the help of technology. Today there are electronic sphygmomanometer’s that do not require a band to be placed on your upper arm; just a small device wrapped around your wrist and placed to your heart. While the object may look differently today it plays the same role and will continue to be an important part of health care.