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Blood pressure self-measurement: repeat measurements are essential

Automatic blood pressure measurement results are frequently altered by significant variations. This is unsatisfactory, particularly when users are undergoing a self-monitored blood pressure treatment. A new method, MAM technology (Microlife Average Mode), reduces the extent of variations in measurement results, and is therefore recommended for the great majority of self-users.

I. Reasons for variations in measurement readings:

1. Blood pressure varies with each heartbeat
Blood pressure is not a static value but changes with each heartbeat, even in rest condition. Both the upper blood pressure value (systolic blood pressure) and the lower blood pressure value (diastolic blood pressure) vary by 5 to 10 mmHg with each heartbeat in healthy individuals. These variations may be considerably greater in the event of certain cardiovascular disorders.

2. Insufficient Rest Condition
This is the most frequent reason for improper use in self-administered blood pressure measurement. If circulation has not yet adjusted to a steady resting state, the systolic and diastolic blood pressure and pulse rate will deviate relative to the resting value. The user will register inaccurate readings while these variations occur! A resting time of at least 5 minutes should therefore be chosen before commencing blood pressure measurement.

3. Incidents in the course of measurement
Deliberate movements, muscle activities, coughing, sneezing and psychological demands such as speaking, listening and watching (e.g. TV) may lead to false readings when measuring blood pressure. Measurements should therefore be carried out under conditions of complete rest and without any distraction.

4. Irregular heartbeat (arrhythmias)
Cardiac rhythm disorders can cause inaccurate readings or may result in measurement failure. These cardiac rhythm disorders may occur without the self-user being aware of them.

II. Method for reducing measurement variations:

The above described measurement variations can be reduced by carrying out several measurements and an additional subsequent calculation of an average value. This technology is called MAM technology and involves not just one, but at least three measurements being carried out with intermittent pauses. If a severe artefact occurs, for example after inadvertent substantial movement by the user, a further repeat measurement is automatically taken. The degree of the single measurement's variations is always judged. Possible artefact - related variations are safely detected.

Usually a total of three (maximum five) measurements are taken, with a typical maximum measurement time of approximately 3 minutes.

III. Summary:

Repeat measurements should be taken whenever self-administered blood pressure measurements are carried out, since single readings may vary due to a broad number of reasons. Generally repetition measurements ensure the judgement of variations and should be applied by a physician's diagnosis and in self - measurement applications. For this reason, clinical blood pressure measurements are usually carried out with repeat measurements.

Single measurements must be usefully judged by assessing their variations. Measurement artefacts leading to abnormal variations must be recognized. The mean value of artefact - free results represent a very reliable estimation of the patient's arterial blood pressure.

The newly introduced MAM blood pressure technology provides this enhanced blood pressure diagnosis in a very acceptable time period (usually 3 minutes). The MAM arterial pressure measurement result is most likely free of singular artificial results, since they can be identified and then rejected by averaging.

The use of the MAM blood pressure technology is particularly recommended in all patients who tend to suffer from increased blood pressure variations, especially if they are undergoing a medical blood pressure treatment. These patients are provided with a more precise blood pressure value, which results in safer diagnosis and patient orientation. This also leads to a higher patient compliance towards their medication schemes, which is one precondition for an effective blood pressure therapy.

Klaus Forstner
Physician, M.D. cd

Forschungsinstitut für klinische Medizintechnik
Silberhälden 6
D - 71732 Tamm Germany

Tamm, May 16th, 2002