Aneroid Sphygmomanometer – Fujikawa

Description

An aneroid sphygmomanometer is a medical device used to measure blood pressure manually. Unlike digital blood pressure monitors, it relies on mechanical components rather than electronics to provide readings. It consists of a cuff, a rubber bulb for inflation, and a gauge that displays the blood pressure measurement.

Key Components of an Aneroid Sphygmomanometer:

1. Cuff:
   • A fabric (usually nylon or cloth) band that wraps around the patient’s upper arm. Inside, it has an inflatable bladder that applies pressure to the arteries when pumped up.
   • Cuffs come in different sizes (pediatric, adult, large adult) to accommodate different arm circumferences for accurate readings.
2. Inflation Bulb:
   • A rubber bulb that is manually squeezed to inflate the cuff. Air is pumped into the bladder of the cuff, which increases pressure on the arm.
3. Aneroid Gauge (Manometer):
   • A mechanical gauge with a dial that displays the blood pressure reading in millimeters of mercury (mmHg).
   • The gauge needle moves in response to the pressure in the cuff, showing both systolic (upper) and diastolic (lower) pressure readings.
   • Aneroid means “without liquid,” indicating that the device doesn’t use mercury but instead measures pressure using mechanical means.
4. Release Valve:
   • A valve on the inflation bulb that controls the release of air from the cuff. This allows the gradual decrease in pressure needed for accurate measurement.
5. Stethoscope (used in conjunction):
   • While not technically part of the sphygmomanometer itself, a stethoscope is used during manual blood pressure measurement to listen to the Korotkoff sounds (the noises heard in the arteries during cuff deflation).

How to Use an Aneroid Sphygmomanometer:

1. Wrap the Cuff:
   • The cuff is wrapped snugly around the patient’s upper arm, ideally positioned at heart level, with the lower edge of the cuff about an inch above the elbow.
2. Inflation:
   • Using the rubber bulb, inflate the cuff until the pressure exceeds the expected systolic blood pressure (usually around 180 mmHg). This stops blood flow in the artery, which is necessary for the next step.
3. Deflation:
   • Slowly release the air from the cuff by turning the release valve. As the pressure decreases, blood will start to flow through the artery again.
4. Measurement:
   • Using a stethoscope placed over the brachial artery (just below the cuff), listen for the Korotkoff sounds:
     • The first sound heard (as blood begins to flow through the artery again) indicates the systolic pressure.
     • The point where the sound disappears marks the diastolic pressure.

Uses of an Aneroid Sphygmomanometer:

1. Blood Pressure Monitoring:
   • Primarily used to measure a patient’s blood pressure manually in clinical settings or at home.
2. Hypertension Diagnosis:
   • Helps in the diagnosis and monitoring of hypertension (high blood pressure) and other cardiovascular conditions.
3. General Health Checks:
   • Commonly used in routine physical examinations and check-ups.
4. Emergency Care:
   • Often included in emergency medical kits due to its portability and reliability without requiring power or batteries.

Advantages of an Aneroid Sphygmomanometer:

1. Accurate and Reliable:
   • When used correctly, it can provide very accurate blood pressure readings, especially compared to some digital models.
2. Cost-Effective:
   • Generally more affordable than digital blood pressure monitors, making it accessible for both professionals and home use.
3. Portable:
   • Lightweight and portable, making it easy to transport and use in various settings (hospitals, clinics, homes).
4. No Batteries Required:
   • Unlike digital monitors, an aneroid sphygmomanometer doesn’t require batteries or electricity, making it convenient for long-term use and in remote locations.
5. Durable:
   • Made with mechanical parts, it can last for many years with proper care and calibration.

Disadvantages of an Aneroid Sphygmomanometer:

1. Manual Operation:
   • Requires training and skill to use correctly, as the operator must inflate the cuff, listen to the Korotkoff sounds, and interpret the reading.
2. Calibration:
   • Over time, the gauge can lose accuracy and may require regular calibration to ensure correct readings.
3. Fragility:
   • The mechanical gauge can be fragile and susceptible to damage from drops or rough handling, potentially leading to inaccurate readings.
4. User Error:
   • Improper use, such as incorrect cuff placement, inflation, or listening for the Korotkoff sounds, can lead to inaccurate blood pressure measurements.

Conclusion:

An aneroid sphygmomanometer is a reliable and widely used tool for manually measuring blood pressure. Its mechanical operation, lack of battery requirements, and portability make it ideal for both clinical and home settings. However, proper technique, regular calibration, and careful handling are essential to ensure accurate blood pressure readings.