What is a sphygmomanometer? Structure and working principle of mechanical sphygmomanometer

Blood pressure monitor is a common medical device, used in hospitals and medical facilities, especially mechanical blood pressure monitors. Let’s find out with lassho.edu.vn what a muscle sphygmomanometer is, the structure and working principle of a muscle sphygmomanometer in this article!

What is a sphygmomanometer?

A mechanical sphygmomanometer is a medical device used to measure blood pressure based on simple operating principles. The device exerts a pressure greater than expected systolic pressure on the pulse, stopping the flow of blood, then slowly reducing the pressure.

The results obtained are systolic and diastolic blood pressure readings through listening to the movements of blood flow through the vessels. Muscle sphygmomanometers are now commonly used in hospitals, clinics and medical facilities.

Muscle sphygmomanometer is a common blood pressure measuring device in hospitals, clinics and other medical facilities

Structure of a blood pressure monitor

The muscle sphygmomanometer consists of the following main parts:

• Cuff: Made from fabric of different sizes, placed around the arm to measure blood pressure.
• Rubber ball: A device that inflates air into the cuff to create pressure to measure blood pressure.
• Meter: As a part that displays blood pressure readings, the unit of measurement is mmHg , helping users to better monitor their health.
• Stethoscope: Amplifies sound, making it easier to detect pulse sounds.

The mechanical sphygmomanometer consists of a cuff, a stethoscope, a rubber ball and a display

Working principle of mechanical sphygmomanometer

Mechanical sphygmomanometer works on the principle of measuring gas pressure in ducts . When the user squeezes the squeeze, the cuff on the arm creates pressure that blocks the flow of blood in the arteries. At this point, the machine will pump air into the cuff to create pressure and stop the blood flow completely.

When the valve is opened, the gas in the cuff is gradually reduced to create a smaller pressure. When the pressure generated by the cuff is equal to the systolic blood pressure, blood passes through the cuff and produces a sound that can be heard through the stethoscope.

The pressure the cuff creates will continue to decrease until the sound disappears . At this point, the cuff pressure is already lower than the arterial diastolic pressure. As soon as the sound disappears, the reading on the meter is also the diastolic blood pressure to be measured.

Mechanical sphygmomanometer works on the principle of measuring gas pressure in ducts

Advantages and disadvantages of mechanical sphygmomanometer

Advantage:

• Low cost: The mechanical sphygmomanometer has a selling price of about 0.3 – 1 million VND (updated in May 2023 and may change from time to time), cheaper than other types of blood pressure monitors on the market.
• Easy to use: The mechanical sphygmomanometer requires no batteries or power supply, just a manual pump to measure blood pressure. Therefore, the use of the mechanical sphygmomanometer is very simple and easy.
• High durability: The mechanical sphygmomanometer has high durability, good impact resistance thanks to being made of high-quality materials.

Mechanical sphygmomanometer with high durability, good impact resistance

Cons :

• Difficult to determine results: Users need to have a certain level of expertise or knowledge and use the blood pressure monitor properly.
• Inaccuracy: The results measured on a mechanical sphygmomanometer are often not as accurate as other digital sphygmomanometers on the market.
• Complicated: You need to regularly adjust the gauges to avoid instrument errors.

To use a blood pressure monitor, you need to have an understanding of how to use it

How to use a blood pressure monitor?

Prepare before measuring

Before measuring, you need to prepare all necessary tools such as: stethoscope, cuff, rubber ball, meter. People whose blood pressure is measured should sit in a relaxed position, can sit and relax for about 5 minutes to stabilize blood pressure. Then, place your hands neatly on a flat surface at chest height.

Before measuring, you should place your hands neatly on a flat surface at chest height

Take blood pressure measurement

First, you need to locate the pulse by gently pressing your index finger in the middle of the inner part of the elbow. Then, put the cuff on your arm, wrap it tightly and glue the edge to fix it so that the cuff is about 2-3cm from the elbow.

Insert the stethoscope speaker under the cuff, right where the pulse is identified, and place the stethoscope in the ear to make sure the pulse is clearly heard. After that, proceed to squeeze the inflatable balloon until you can no longer hear the beat, then continue to inflate to increase the pressure of the cuff by about 30mmHg .

When done, open the valve slowly to release air from the cuff at a moderate rate to avoid affecting the measurement.

First, you need to locate the circuit then measure according to the instructions

Read the results

After releasing the steam, pay close attention to the pulse sound through the stethoscope as well as the indicators displayed on the meter surface. Systolic blood pressure is calculated from the first two consecutive beats . Diastolic blood pressure is calculated from the time the last beat disappears .

After measuring, pay attention to the pulse sound through the stethoscope and observe the results

Some notes when using a blood pressure monitor

• Choosing the right size cuff for your upper arm will help ensure the accuracy of your measurements. Wrist cuffs that are too tight or too wide can lead to errors in measurement results.
• Relaxing the body before measuring is also an important note. If the body is tense, especially the biceps, the blood pressure readings will not be accurate.
• The posture to measure blood pressure also needs to be ensured correctly , so sit up straight, put your right hand on the left hand or on the left thigh to ensure that the hand is at the level of the heart and the cuff is above the thigh.
• Do not use stimulants or vigorous exercise 30 minutes before the measurement because it can cause a sudden increase in blood pressure, the meter gives inaccurate results, so you should also avoid these activities before measuring blood pressure.

Do not drink alcohol or any other stimulants before measuring blood pressure

Hopefully, the above article will help you get more useful information about muscle sphygmomanometer, structure and working principle of muscle sphygmomanometer. Any questions please leave a comment below!