The Evolution of Blood Pressure Measuring

The patient’s arm should be on a table, resting at heart level, as well as their back supported and feet flat on the floor. Then, a blood pressure cuff is wrapped around the upper part of the arm, with the bottom of the cuff just above the elbow and against bare skin. With advanced technology, some digital blood pressure cuffs automatically inflate and measure the pulse. However, for manual measuring, a health care professional will slowly let air out of the cuff while listening to your pulse and blood flow with a stethoscope and will record the measurement once the test is finished.

If you’re a nurse, you know the drill. You’ve learned how to do the blood pressure test and have probably done it thousands of times. At this point, you could probably do it in your sleep. But, have you ever stopped to wonder how the first blood pressure test was taken? Or, what kinds of tools were used on the first reading for a test? Especially for the younger generation, it’s easy to take technology for granted and not fully understand where it all began. So, let’s go back to the beginning.

History of Measuring Blood Pressure

If you’re in the medical field, you should be pretty familiar with a sphygmomanometer since it’s most likely that you use it almost every day. A sphygmomanometer is the official name for the tool used to measure blood pressure. The tool consists of an inflatable rubber cuff, a measuring unit that includes some type of gauge, and a mechanism for inflating the cuff. To measure the pressure in your blood vessels, the gauge uses a unit of measurement called millimeters of mercury (mmHg).

However, long before the sphygmomanometer was invented, the Chinese were the first to recognize and theorize the complex system of how blood circulated through our bodies. According to American Diagnostic Corporation, there was even evidence around that suggested that Indian scholars had developed some knowledge of the circulatory system back then.

By the 1600’s, a doctor named William Harvey developed a deeper understanding of this system, and began teaching about circulation in 1615. In 1628, he published his famous work that soon became the foundation for the study of the circulatory system. And once there was a correlation between heart rate and pulse, this paved the way to discovering blood volume and blood pressure.

In 1733, Reverend Stephen Hales recorded the first ever blood pressure measurement by inserting a long glass tube upright into an artery of a horse. This allowed him to observe the increase in pressure as blood was forced up the tube.

The first sphygmomanometer was invented in 1881 by Samuel Siegfried Karl Ritter von Basch, and included a rubber bulb that was filled with water to restrict blood flow in the artery. The bulb was also connected to a mercury column to help with an accurate reading. The device was improved in 1896 by Scipione Riva-Rocci, which included a cuff that could be wrapped around the arm to apply even pressure.

Although the design has generally stayed the same, modern blood pressure measurement was not developed until 1905 when Dr. Nikolai Korotkoff discovered that there was a difference between systolic blood pressure and diastolic blood pressure. Since then, further improvements have been made to the sphygmomanometer, but the concept of how blood pressure is measured has remained the same. Blood pressure machines are so important and so commonly used that there are now at-home blood pressure tests that people can use at a moments notice. You can even order them off national and local online stores, without a medical prescription or recommendation. And some even link up to your computer or smartphone, making it easy to transfer data to medical records or keep a recording for your own personal files.

Measuring one’s blood pressure is widely accepted as an important vital sign when diagnosing a patient. But do you know exactly why this is? When someone is entering the emergency room, going into labor, or just having a routine check-up, checking someone’s blood pressure is part of the process.

What are you monitoring for?

Many individuals don’t even know they have high blood pressure, which is why having a test done to rule out any irregularities or complications is important. Having high blood pressure can mean you’re at a higher risk for heart disease or even having a stroke.

If you are 18 years or older and have normal blood pressure levels with no heart disease risk factors, the Mayo Clinic suggests that you should have a test done at least once every two to five years. If you are 40 years old or older or are younger with an increased risk of high blood pressure, you should have the test done every year. People who have chronic health conditions, such as high or low blood pressure or heart disease, may need to be checked more often.

If you’re a healthcare professional, then you should already know the main “dos” and “don’ts” for taking a blood pressure test. However, it never hurts to refresh your memory! The correct way to measure blood pressure is:

• Don’t eat or drink anything 30 minutes before taking your blood pressure
• Empty your bladder before your reading
• Sit in a comfortable chair with your back supported for at least 5 minutes before your reading
• Put both feet flat on the ground and keep your legs uncrossed
• Rest your arm with the cuff on the table at chest height
• Make sure the blood pressure cuff is snug but not too tight; the cuff should be against your bare skin, not over clothing
• Do not talk while your blood pressure is being measured

After the test is taken, a doctor, nurse or technician can give you the results. As previously mentioned, the blood pressure test is measured in millimeters of mercury (mmHg), and has two numbers. The top number, which is called “systolic”, is the pressure of blood flow when your heart muscle contracts and pumps blood. The bottom number, called the “diastolic”, is the pressure measured between heartbeats.

While having high blood pressure isn’t very good, it is something that can be managed and can be improved upon by making a few lifestyle changes. If you have high blood pressure, you can reduce your sodium intake, eat healthier foods, limit your consumption of alcohol, quit smoking, lose weight, and exercise regularly. And if these lifestyle changes don’t do the job, your doctor may recommend medication.

So, after reading this blog, you can be sure to know you’re getting your blood pressure checked properly the next time you visit the doctors. You also shouldn’t be afraid to ask questions about your results and what they mean. After all, getting your blood pressure checked is one way to make sure you are maintaining the healthiest version of yourself.