Anjali Mishra Content Writer-SME
Content Writer-SME | Updated On - Mar 17, 2025
A sphygmomanometer is a medical device that detects and measures blood pressure. It is also known as a blood pressure gauge, blood pressure meter, or blood pressure monitor. By measuring the force exerted by the heart in moving blood, this gadget is used to measure blood pressure. By regularly monitoring blood pressure, a person can keep track of heart rate and rhythm.
In general, a sphygmomanometer is also called a bp machine which is used to listen to heartbeat with the help of a stethoscope. A sphygmomanometer parts contain:
- An Inflatable arm cuff
- Measuring unit (which can be obtained from the Mercury Manometer, or Aneroid Gauge)
- Bulb pump
- Column of mercury
- Stethoscope
In this article, we will learn in detail about these components and different types of sphygmomanometer and its mechanism in recording blood pressure measurements.
Related Links
What is Sphygmomanometer?
[Click Here for Sample Questions]
The word sphygmomanometer was first derived from two Greek word “sphygmos” which meant “beating of the heart or the pulse”, while “manometer” is a device used for measuring pressure or tension. A sphygmomanometer is used to measure blood pressure.
- It can be observed in the mercury column level present in the manual version.
- Blood pressure can be calculated by measuring the force exerted by the heart to push blood to other parts of the body.
- The values can be expressed in “mm of Hg” where Hg represents the mercury element.
- When the ventricles contract, precise results are obtained.
- We can measure the least forces with a calm heart when blood flows from the centre to various body parts.
Sphygmomanometer
- To obtain reliable blood pressure readings, suitable blood pressure cuffs for sphygmomanometers can be used.
- A sphygmomanometer is extremely useful for detecting disorders in the human body.
- Controlling hypertension and monitoring the effectiveness of drugs both necessitate blood pressure monitoring.
- An inflating cuff, a handle bump, and the display unit are all included in the sphygmomanometer.
An important sphygmomanometer parts contain an inflatable cuff that doctors use to wrap the top part of the patient's arm. The cuff size should be proportional to the patient's arm size. Individual-sized cuffs may be required for some people.
The video below explains this:
Sphygmomanometer Detailed Video Explanation:
Frequently Asked Questions on SphygmomanometerQues. What is Normal Blood Pressure, and When Blood Pressure is Considered to be High? Ans. Blood pressure can be measured by the number of different days and at rest with the help of sphygmomanometer. Ideal blood pressure or Normal blood pressure of a healthy adult lies between 90/60mmHg and 120/80mmHg.
High blood pressure can often be unpredictable. However, in case it is too high, then it can cause symptoms such as dizziness or blurred vision. High blood pressure or hypertension increases the risk of cardiovascular problems such as heart attack, stroke, and heart and kidney failure. Ques. What is Blood Pressure? Ans. Blood pressure can be defined as the circulation of blood against the walls of blood vessels. Most of the pressure results from the pumping of blood through the circulatory system. |
Also Read:
| Read More about working principle behind Sphygmomanometer | ||
|---|---|---|
| Hydrostatic Pressure | Properties of Fluids | Barometer |
| Fluid Flow | Pascal’s Law | Hydraulic Machines |
| Bernoulli’s Principle | Venturimeter | Viscosity |
Types of Sphygmomanometer
[Click Here for Previous Year Questions]
Sphygmomanometers are used to measure blood pressure in humans. There are three types of sphygmomanometers.
Mercury Sphygmomanometer
Among all other types of sphygmomanometer, the mercury sphygmomanometer is considered the "gold standard," reflecting the conventional and time-tested way of measuring blood pressure.The presence of mercury in the sphygmomanometer column does not pose a health hazard if it is properly cleaned on a regular basis.
- The gadget is made up of an inflatable bladder and a mercury column.
- Varying pressures result in different mercury levels in the column.
- Once the column is built, it is not necessary to recalibrate it to its exact specifications.
Mercury Sphygmomanometer
Aneroid Sphygmomanometer
Aneroid sphygmomanometer is a device made up of a spring mechanism and a metal membrane that converts the signals from the cuff and operates a needle in the gauge. Due to the absence of liquid, this gadget can be readily transferred from one location to another.
- The results are sometimes imperfect as these devices require continous calibration checks.
- Before using the needle, it must be kept at zero.
- Calibrations are done regularly to ensure accurate findings.
Aneroid Sphygmomanometer
Digital Sphygmomanometer
Digital sphygmomanometer comes in handy when blood pressure needs to be tested at home. Diastolic and systolic blood pressures can also be measured. It is portable, convenient, can even be charged and requires no calibrations. The steps to use digital sphygmomanometer are as follows:
- Simply insert the rubber node into the monitor's hole and wrap the cuff over the upper arm.
- When you press the button, it will calculate your blood pressure and heart rate using oscillometric detection.
- The monitor has an audio device that will display the results.
Digital Sphygmomanometer
Parts of a Sphygmomanometer
[Click Here for Sample Questions]
Following are some important sphygmomanometer parts that are discussed below:
- Bladder: An inflatable bag is used to compress the arm to obstruct the artery. Bladders must have particular dimension criteria to ensure full arterial compression.
- Cuff: The bladder is held in place by a cuff around the arm during the measurement. The cuff must be designed properly in terms of positioning and position to provide an accurate measurement.
- Manometer: A manometer is a device that measures air pressure in millimetres of mercury (mmHg). An aneroid sphygmomanometer's manometer is a watch-like mechanism that measures the air pressure delivered to the cuff. The gauge uses a sequence of copper or beryllium to expand the diaphragm, and gears translate the linear movement of the diaphragm into mmHg measurements.
- Valve: This is a deflation valve that is used to keep the cuff in place. This is crucial for obtaining an accurate measurement.
- Bulb: The air is pumped into the cuff by the bulb.
The above-mentioned sphygmomanometer parts make up the complete blood pressure measuring device.
Parts of Sphygmomanometer
Accuracy of Sphygmomanometer
It is often seen that, when properly measured, used and supported, the mercury device can serve as a “gold standard” for measuring blood pressure. Even though, its actual use may fall short of these requirements.
- The magnitude of inaccuracy is around 4–6 mm Hg in 32%, 7–12 mm Hg in 19% and 13 mm Hg in 7%.
- A majority of the mercury and aneroid sphygmomanometers display inaccuracy (21% vs 58%) and unreliability (64% vs 70%).
Uses of Sphygmomanometer
[Click Here for Previous Year Questions]
A sphygmomanometer uses and functions are in various aspects. Some include:
Measuring Blood Pressure
It helps to measure blood pressure.
- Apart from humans, It is also useful for veterinary needs to measure the blood pressure of animals.
- The sphygmomanometer is used by veterinarians to diagnose animals.
Monitoring the effectiveness of Medications
A sphygmomanometer helps in the monitoring of medication efficiency.
- The sphygmomanometer is used by doctors to track the impact of medications on patients.
- There are two sorts of readings in this device: systolic and diastolic.
- The upper number is the systolic reading.
- The numerator indicates the systolic pressure, while the denominator represents the diastolic pressure.
Systolic and Diastolic pressure
Aids in the Management of Hypertension
It also helps to manage hypertension.
- High blood pressure causes hypertension, which is a medical condition.
- Hypertension is a life-threatening illness that can lead to a stroke, heart attack, or even death.
- Diabetes and tobacco smoking are two of the most common causes of hypertension.
- The sphygmomanometer is used by the doctor to monitor hypertension.
- It will make it easier for both doctors and patients to comprehend what has to be done.
Aids in the Detection of a Variety of Diseases
It helps to detect a number of diseases.
- The underlying ailment may cause high blood pressure.
- Doctors can use the data produced by the sphygmomanometer to detect underlying ailments.
- During a medical check-up, blood pressure is always one of the first things to be tested and so monitored.
- Blood pressure checks are a simple way for doctors to detect the condition.
As First aid in Ambulances
It serves as part of the First Aid kit in ambulances, especially for an immediate response from the paramedic team.
- Doctors use a sphygmomanometer to diagnose patients in emergencies.
- Its readings assist them in rapidly administering effective first aid.
- It also assists them in determining which victims require additional attention and the type of first-aid treatment required.
- Some may even be able to forecast how much blood a victim is losing at any one time.
Work on Research
It is extensively used in medical research.
- Sphygmomanometers are used in medical research by large research organizations such as the WHO.
- Animals such as rabbits, mice, and pigs are being used to test the new treatments.
- The use of a sphygmomanometer allows researchers to see what kind of impact a treatment has on humans.
- When developing novel medications for animals, scientists measure their blood pressure.
How to use a Sphygmomanometer?
[Click Here for Sample Questions]
The process for using a Sphygmomanometer is as follows:
- Use the right blood pressure cuff size, and the bladder length of the cuff should be at least 80 percent of the circumference of your upper arm.
- Wrap the cuff over your upper arm and place the stethoscope's bell just below the cuff's border over the brachial artery.
How to use sphygmomanometer?
- The sphygmomanometer (blood pressure cuff) should be inflated to 180 mm Hg.
- Slowly release air by moving the air valve in a clockwise direction, and watching the pressure drop.
- Listen with the stethoscope while keeping an eye on the mercury gauge.
- The systolic blood pressure is determined by the first sound you hear using a stethoscope.
- Continue to monitor your blood pressure until you no longer hear any sound. This is your diastolic blood pressure.
Guidelines for Measuring BP with Sphygmomanometer
[Click Here for Sample Questions]
To maintain accuracy while using a sphygmomanometer to measure blood pressure (BP), particular steps must be followed. Here is a complete set of guidelines:
Preparation:
- Make sure the space is peaceful, relaxing, and free of distractions.
- Before taking a measurement, have the patient sit comfortably for at least five minutes.
- They must refrain from smoking, exercise, and caffeine for at least half an hour before.
- The arm need to be relaxed, unclothed positioned at the level of the heart.
- Select the right cuff size. Around eighty to one hundred percent of the arm should be wrapped by the cuff bladder.
Applying Cuff:
- The cuff should be placed firmly around the upper arm, two to three centimeters above the elbow crease.
- Make sure the artery marker on the cuff lines up with the brachial artery, which is located inside the elbow.
BP Measurements:
- Measure the radial pulse and inflate the cuff.
- Once you know the pressure at which the pulse stops, add 20 to 30 mmHg.
- 2–3 mmHg per second is the rate at which you should deflate the cuff.
- Now, place the stethoscope over the brachial artery.
Recording Values:
- The first tapping sound of the heart is called the "lub" which is recorded as the systolic blood pressure through a sphygmomanometer.
- The “dub” is the second heart sound heard with a stethoscope. This is called diastolic blood pressure.
- Both systolic and diastolic pressures are recorded in a ratio.
- The upper value represents systole while the lower value represents diastole in BP measurement with a sphygmomanometer.
Also Read:
Things to Remember
- A sphygmomanometer is a medical instrument that detects and measures blood pressure.
- The types of Sphygmomanometer include mercury Sphygmomanometer, aneroid Sphygmomanometer and digital Sphygmomanometer.
- Bladder, cuff, manometer, valve, and bulb are the important parts of sphygmomanometer.
- Apart from humans, It is also useful for veterinary needs to measure the blood pressure of animals.
- Sphygmomanometers are used in medical research to measure the effects of new drugs and vaccines.
- The sphygmomanometer is used by doctors to track the impact of medications on patients.
Sample Questions on Sphygnomanometer
Ques. Which Sphygmomanometer is more precise and accurate? (1 mark)
Ans: A mercury Sphygmomanometer is more precise and accurate for measuring blood pressure. It is considered the “gold standard”.
Ques. What is the oscillometric method of measuring blood pressure? (1 mark)
Ans: The oscillometric method is a blood pressure measurement technique that relies on changes in the blood pressure cuff induced by blood flow through the brachial artery. The blood pressure readings are then estimated using an algorithm that was developed empirically. The oscillometric approach for blood pressure is used by the majority of automated blood pressure monitors because it is less vulnerable to external noise.
Ques. What is the most common location for a check-up using a sphygmomanometer? (2 marks)
Ans: Typically, paediatricians implant them on the right arm. Just in case the patient has a coarctation of the aorta, a constriction of the artery between the exits to the right and left arms. If there is a coarctation, the blood pressure in the right arm will be high, as well as higher than the blood pressure in the left arm. If that were the case, we would miss the elevated blood pressure and the discrepancy between the two limbs if we simply checked the left arm.
Leg blood pressure is occasionally examined, and if it is, it is usually done behind the knee.
Ques. What is the difference between a stethoscope and a sphygmomanometer? (2 marks)
Ans: A sphygmomanometer is a blood pressure measuring instrument that typically consists of an inflatable rubber cuff that is worn on the arm and connected to a mercury column next to a graduated scale, allowing the determination of systolic and diastolic blood pressure by gradually increasing and releasing the pressure in the cuff.
A stethoscope, on the other hand, is a medical instrument used to listen to the action of someone's heart or breathing. It normally consists of a small disc-shaped resonator placed on the chest and two tubes attached to earpieces.
Ques. What is meant by mean arterial pressure (MAP)? (2 marks)
Ans: The average arterial pressure throughout a single cardiac cycle is referred to as MAP (i.e., the average blood pressure in the arteries). It is a better indicator of overall health and risk of developing various cardiovascular diseases than the systolic measurement alone, and it is an excellent marker of both overall health and risk of developing various cardiovascular diseases. Diastolic + 1/3 is the formula for calculating MAP (Systolic minus Diastolic).
Ques. What is the definition of arteriosclerosis? (2 marks)
Ans: The thickening, hardening, and loss of flexibility of artery walls are known as arteriosclerosis. The buildup of fatty plaques, cholesterol, and other compounds in and on the artery walls cause atherosclerosis, which is a specific kind of arteriosclerosis caused by the deposition of fatty plaques, cholesterol, and other things in and on the artery walls. It can be caused by smoking, a poor diet, or a variety of genetic factors.
Ques. What is Coarctation of the aorta? (2 marks)
Ans: Aortic narrowing, commonly known as coarctation of the aorta (CoA or CoAo), is a congenital disorder in which the aorta narrows, usually where the ductus arteriosus (ligamentum arteriosum following regression) enters. "Pressing or drawing together; narrowing" is the definition of coarctation. The aortic arch is the most prevalent site of coarctations. In newborns with coarctations, the arch may be tiny. When coarctation is present, other cardiac abnormalities might emerge, most commonly on the left side of the heart.
Ques. Is a digital or manual sphygmomanometer (blood pressure machine) better? (3 marks)
Ans: A conventional manual (mercury) sphygmomanometer may be more precise than a digital machine, but they are no longer widely used due to the risk of mercury poisoning if the unit is broken.
A digital sphygmomanometer's accuracy (or lack thereof) is determined by the quality control used in its manufacture, and the quality of certain less expensive devices varies.
In practice, it is rarely necessary to measure blood pressure to the nearest mm/Hg, therefore "better" does not always imply "most accurate."
Ques. Why would someone prefer to use mercury in a Sphygmomanometer instead of water? (3 marks)
Ans: Actual mercury columns were employed in the early measurements since they had been demonstrated to be accurate in measuring atmospheric pressure. The data points remained the same when the system moved to similar dial gauges to ensure consistency over previously gathered data. There's no need to alter it.
Because of the wide range of human circulatory pressure, mercury, specifically millimetres of mercury, provides a superior reading on a much smaller scale. Because mercury is significantly denser than water, it allows for a much shorter column.
Blood pressure in the usual range (for example, 120/80 mm Hg, or 4.75 inches/3.15 inches) would be tolerable. However, if water were employed, the water column would be 64.3/42.9 inches, making it infeasible, especially for house calls.
Ques. What is the cardiac cycle? (3 marks)
Ans: From the start of one heartbeat to the start of the next, the cardiac cycle is the human heart's performance. It is divided into two phases: diastole, when the heart muscle relaxes and fills with blood, and systole, when the heart muscle contracts and pumps blood vigorously. After emptying, the heart relaxes and expands to receive blood returning from the lungs and other body systems, before contracting again to pump blood to the lungs and other body systems. Before it can efficiently pump again, a normally functioning heart must be fully enlarged.
Ques. What is the meaning of ‘Pulsus Paradoxus’? (3 marks)
Ans: During inspiration, Pulsus Paradoxus, also known as paradoxical pulse or paradoxical pulse, is characterized by an abnormally significant reduction in stroke volume, systolic blood pressure, and pulse wave amplitude.
- The normal pressure drop is less than 10 millimetres of mercury.
- Pulsus Paradoxus refers to a drop in blood pressure of more than 10 mmHg.
- Pulsus Paradoxus is not caused by a paradoxical rise in systolic pressure and has nothing to do with pulse rate or heart rate.
Ques. What are the 3 types of Sphygmomanometer? (3 marks)
Ans: The three types of Sphygmomanometer are:
- Mercury Sphygmomanometer
- Digital Sphygmomanometer and
- Aneroid Sphygmomanometer
Ques. What is Hypertension? (5 marks)
Ans: Hypertension (HTN or HT), commonly known as high blood pressure (HBP), is a long-term medical disorder characterized by persistently excessive blood pressure in the arteries.
- The majority of the time, high blood pressure does not create any symptoms. Stroke, coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, chronic renal disease, and dementia are all linked to long-term high blood pressure.
- Primary (essential) hypertension and secondary hypertension are two types of high blood pressure.
- Primary hypertension is characterized as high blood pressure caused by nonspecific lifestyle and genetic variables in 90–95 percent of patients.
- Excess salt in the diet, excessive body weight, smoking, and alcohol consumption are all risk factors.
- Secondary high blood pressure, defined as high blood pressure caused by an identifiable cause such as chronic renal disease, constriction of the kidney arteries, an endocrine problem, or the use of birth control pills, accounts for the remaining 5–10% of cases.
Do Check:
Comments