Shock-proof blood pressure meter

Blood pressure meters are more sensitive than you might think. Dropping them damages their mechanics and often leads to false readings.

Researchers have now developed a delicate damping system, so shocks are no longer a problem. They will present the new device at the Medica trade fair (Hall 10, Stands F05 and G40) in Düsseldorf from November 14 to 17, 2007.

Everyday life in hospitals is tough: Doctors are usually in a hurry, have to act quickly and are often seen running through the corridors. As a result, the devices in their coat pockets are frequently put to the acid test. The most critical situations are when, say, blood pressure meters fall onto the floor. Pressure meters contain very fine mechanisms and therefore react sensitively to any form of shock. Just setting the device down brusquely can be enough to affect the sensitive components inside and cause them to produce false readings without the doctor noticing. This can have disastrous effects on patients’ treatment, as drug doses may have to be changed if the blood pressure exceeds a certain value.

Together with the Rudolf Riester company, researchers at the Fraunhofer Technology Development Group TEG in Stuttgart have now succeeded in developing suitable padding which dampens any potential impact and protects the mechanical parts against shock. “We used a high-speed camera to film what happens when a blood pressure meter suffers a heavy blow,” explains TEG project manager Andreas Reindl. “The parts bang into each other and are shaken violently.” The recordings, taken at 2000 frames per second, provided conclusive evidence that the indicator, too, is sometimes affected. Thanks to these films, the engineers were able to determine which areas of the device required padding, and developed a substantial cushioning element which they refer to as a ‘damping lip’. The most important pre-condition is that the overall construction should remain airtight, otherwise the air pressure will drop and this, too, will cause false readings.

Thanks to the shock-proof blood pressure meter, false readings are now a thing of the past. Numerous tests have shown that the readings of normal devices can deviate strongly after shocks and vibrations. It is not uncommon for them to indicate 130 mmHg instead of 120 mmHg. The damping system, in contrast, hardly permits any deviation. The needle is never out by more than 2 mmHg, which is just half a millimeter on the scale. The TEG researchers and Rudolf Riester GmbH & Co. KG will be presenting details of their new product in Hall 10 / F05 and Hall 10 / G40 respectively at Medica 2007.