Miniaturized: long-term blood pressure monitor

Fluctuating blood pressure or blood pressure that is chronically too high or too low will at best only impair a person’s quality of life. But unfortunately the consequences are usually extensive second-ary damage to vital organs like the heart or the kidneys. Conventional electronic measuring devices for blood pressure monitoring only provide snapshot information at the time a single reading is taken, rather than blood pressure profiles over a period of several hours or days. To address this gap, Schiller AG in Baar, Switzerland, has developed a mobile blood pressure measuring device for long-term blood pressure monitoring. In order to keep the size of the device as small as possible, the developers went to microdrive specialist FAULHABER in search of the optimal drive solution. 

Everyday convenience

Blood pressure is influenced by a host of different factors. Any meaningful reading must therefore take into account normal everyday activities and be as unobtrusive as possible. For this reason alone, mobile, miniaturized solutions that do not im-pede patient movement are ideal. The solution developed by the Swiss specialists is based on two key components: sophis-ticated MT-300 analysis software for setting and evaluating the measuring sequence and readings, and the BR-102plus measuring device itself, complete with sensor and data memory. The lightweight, user-friendly device can be easily configured via PC software. It is equally capable of storing patient data, statis-tically analyzing the readings, recording the results in the form of patient diaries and many other functions. The actual measuring device is suitable for measur-ing blood pressure over a 24 or 48 hour period and offers the choice between auscultatoric or oscillometric measuring methods. This allows even patients with heart rhythm disorders or atrial fibrilla-tion to be monitored. The device can be easily operated on site, with only two buttons for convenient navigation through the menu. Up to four measuring programs can be saved to the built-in memory, and there is a special algorithm for both adults and children. Data can be transmitted from the device via a USB interface. Despite its compact design, the 3 v battery can handle up to 100 readings when fully charged.

The great versatility of the device is only possible thanks to precise mechanical execution of the electronic commands. Miniature components and microdrive technology were the key to solving this challenge of long-term, non-intrusive monitoring. The ex-perts at Schiller developed a special pressure regulator for the BR-102plus. An 8-mm drive that mechanically translates the electrical commands ensures sensitive operation of the high-precision component.

Precious metal commutated DC motor

The pressure within the measuring cuff is the reference point for every measurement. For this reason the settings have to be as precise and reproducible as possible. The developers discovered that a precious metal commutated DC-Micromotor was the ideal drive solution. Operated with controlled torque, it combines with the valve body and control tube to form a single unit. This means the overall system is very lightweight, compact and robust. The special features of this DC-Micro-motor from the FAULHABER product range are crucial to the success of the blood pressure monitor. The precious metal commutated drives provide minimal contact resistance on the collector/brush system, allowing them to run on very low voltage, which is a big advantage for battery-supported use. The efficiency ratio of over 50 % also enables the device to stay in use for extended periods. Brush wear and tear for short-term usage under normal conditions is relatively in-significant. What is more important is perfect start-up even after long periods of inactivity. Maintenance-free bearings with special lubricants and a precisely balanced rotor ensure smooth running. To sum up all its attributes, this is a high-performance, long-life, miniaturized drive that always executes the electronic commands by the same, reliable process. That is the only way to ensure a series of reliable readings that provides meaningful and comparable data sets. Modern microdrives are the perfect solution for many different applications and all forms of mechanical movements. As a miniature power source, they are equally suitable for dynamic tasks, slow to virtually static functions or pulse-operated processes.