Why is this patent noteworthy?

A Hungarian innovation to improve the accuracy of blood pressure measurement

In the early 1980s, engineers at Medicor Works developed an invention intended to improve the accuracy and speed of non-invasive blood pressure measurement. The patent was authored by Dr András Juhász, a mechanical engineer, and Attila Kovács, an electrical engineering technologist. The application was filed in 1981 and the patent was published as HU 184480.

What was the problem?

During conventional cuff-based blood pressure measurement, cuff pressure changes continuously. As a result, systolic and diastolic pressures are not determined exactly at the true blood pressure values, but in their vicinity. This introduces a certain error into every measurement.

The Hungarian engineers’ insight

The inventors demonstrated that the magnitude of the measurement error is related to:

• pulse rate,
• the rate of change in cuff pressure.

On this basis, they developed a correction method that mathematically adjusts the measured results.

The essence of the invention

The system determines the pressure difference produced by the cuff during one cardiac cycle. Half of this value is used as a correction factor:

• to increase the systolic value,
• to decrease the diastolic value.

As a result, even in the worst case, the measurement error can be reduced to half of its previous magnitude.

Why is it still significant today?

Although modern digital blood pressure monitors use advanced electronics and microprocessors, the concept of algorithmically correcting measurement errors remains fundamental. Patent HU184480 demonstrates that Hungarian engineers were already addressing, more than forty years ago, issues that are still central to the development of today’s intelligent measuring devices.

This is not a patent for a “new blood pressure monitor”, but an early patent for a measurement algorithm..

For a 1981 filing, this was a distinctly forward-looking approach, since today much of the accuracy of medical devices depends not only on sensors, but also on software-based corrections.

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HU184480B – Plain-Language Summary

What was the problem?

In conventional blood pressure measurement, cuff pressure changes continuously.

While the device attempts to determine:

• systolic (upper) blood pressure,
• diastolic (lower) blood pressure,

the cuff pressure is already different from what it was one heartbeat earlier.

This can cause measurement inaccuracy.

What did the inventors discover?

Dr András Juhász and Attila Kovács recognised that the magnitude of the measurement error could be calculated.

The error depends on:

• how quickly cuff pressure changes,
• how fast the heart beats.

What is the essence of the invention?

The device determines:

• how much the cuff pressure changes during one cardiac cycle.

From this, it calculates a correction value.

Using this value:

• the systolic value is adjusted upward,
• the diastolic value is adjusted downward.

This brings the measured blood pressure closer to the true value.

What were its advantages?

According to the patent:

• more accurate blood pressure measurement,
• faster measurement,
• significantly reduced measurement error.

Why was this important in 1981?

The electronics in blood pressure monitors of that era were much simpler than those in today’s devices.

The inventors did not create a new cuff or sensor, but a method that improved measurement accuracy by means of mathematical correction.

At the time, this represented a particularly advanced engineering approach.