From the choice of tonometers — devices for measuring blood pressure — both on the shelves of pharmacies and on marketplaces, eyes run wide. Let’s say all these devices have been tested and certified, and measure pressure accurately. But only a few of them have a very important and convenient function. Which? More on this below.
Doctors are aware of the so-called «white coat effect» — an increase in blood pressure, often quite significant, when measured by a doctor or nurse. The “First Dimension Effect” is a variant of it, and it occurs in about a quarter of all people, which is quite often. The essence of the effect is that the first measurement by an automatic device gives an overestimated, and not true, value of blood pressure.
To avoid erroneous conclusions about the level of blood pressure, some blood pressure monitors have a serial mode. It can be called differently: serial, cyclic, multi-dimensional. The bottom line is that the device automatically takes several measurements at a given interval, discards the highest blood pressure, and takes the average for the rest. That is what true blood pressure is.
Who exactly needs to choose a tonometer with a cyclic mode?
There are several categories of people to whom doctors recommend always taking several measurements. It:
• hypertension, because the intensity of treatment depends on the accuracy of blood pressure measurement;
• persons with a slight increase in blood pressure (medics say «high normal blood pressure»), their error may be associated with the appointment or untimely appointment of treatment;
• patients with arrhythmias, in whom single measurements are often erroneous;
• impressionable people in whom the effect of the first dimension occurs more often.
By the way, we recall that blood pressure should always be measured on the same arm, and after about a five-minute rest while sitting. This rule should be followed even if a doctor or trainer recommended taking pressure after exercise, for example, after a run or interval training.
What else to look for when choosing a tonometer?
There are devices for which the number of measurements in a series is always rigidly set: say, there will always be three measurements. And there are devices with the dependence of the number of measurements in a series on the current state. This allows you to get the most accurate result in the shortest time. Indeed, if the first two measurements showed almost the same values, then why measure again? And if there is a large spread or arrhythmia in three dimensions, then it is often better to take another measurement in order to get the most accurate result.
It is also worth paying attention to the presence of a Bluetooth tonometer and an application for a smartphone. It is much more convenient to monitor your pressure in the application: the graph is much clearer than just the pressure numbers in the table, and it is easier to discuss it with doctors.