Monitoring blood pressure has become an important part of everyday healthcare routine, both at the hospital and at home. No matter who is measuring the blood pressure, the sphygmomanometer plays a central role. Being a widely used device, people might not be aware of the sphygmomanometer parts, its types and how it works. This guide explains everything one needs to know about it.
What is a sphygmomanometer?
A sphygmomanometer is a clinical device used to measure blood pressure by assessing the force of blood against the artery walls. There are four main sphygmomanometer parts:
- An inflatable cuff: Wraps around the upper arm to restrict blood flow.
- A pressure gauge (mercury column, aneroid dial, or digital screen): Displays the readings.
- A bulb and valve: Used to inflate and release air from the cuff in manual models.
- Flexible tubing: Connects the cuff to the gauge and other components.
By inflating the cuff and slowly releasing the pressure, the device allows healthcare professionals or digital monitors to detect systolic and diastolic pressure, which reflect how efficiently the heart pumps blood.
Types of sphygmomanometers
1. Mercury Sphygmomanometer
This regular wall sphygmomanometer uses a mercury column and is considered the gold standard in clinical settings due to its accuracy and consistency.
Considerations:
- Requires trained personnel
- Mercury disposal requires care
- Not portable due to weight
2. Aneroid (Dial) Sphygmomanometer
The aneroid model replaces mercury with a mechanical dial and is valued for portability. Clinics often use a regular diamond sphygmomanometer.
Considerations:
- Requires periodic calibration
- Can be damaged if mishandled
- Portable and lightweight
3. Digital Sphygmomanometer
Digital monitors automate blood pressure measurement and display results electronically, making them ideal for home use.
Considerations:
- Easy for non-professionals
- Requires batteries or power
- May be less accurate for arrhythmias
How to use a sphygmomanometer
The following steps apply to both mercury and aneroid models:
- Sit comfortably with back support and feet flat on the floor
- Place the cuff 2–3 cm above the elbow
- Position the stethoscope over the brachial artery
- Inflate the cuff 20–30 mmHg above expected systolic pressure
- Deflate slowly while listening to heartbeat sounds
- Record systolic (first sound) and diastolic (sound disappearance) readings
Uses of the sphygmomanometer
- Detecting hypertension
- Monitoring treatment effectiveness
- Routine medical check-ups
- Critical care monitoring
- Home healthcare use
FAQs
How often should I check my blood pressure?
Daily for hypertensive patients; once or twice weekly for general monitoring.
What affects BP accuracy?
Incorrect cuff placement, movement, talking, or outdated equipment.
Do sphygmomanometers need calibration?
Yes. Both manual and digital devices should be calibrated periodically to ensure reliable readings.