What is the difference between automatic and semiautomatic devices?
An automatic blood pressure monitor when compared to a semiautomatic device has the following singularities:
• Built-in compressor. Due to the built-in compressor, the cuff is inflated automatically after you press the START button. In semiautomatic devices, the cuff is inflated by manually pumped air using a rubber squeeze pump.
• LD automatic blood pressure monitors have a electronic air release valve. This feature allows the device to automatically maintain the required rate of air release from the cuff during measurement and automatically release air from the cuff after completion of the measurement. In semiautomatic LD blood pressure monitors the air release rate is adjusted by manually adjusting the screw valve. Air is released completely after you press the button.
• Selection of the maximum cuff inflation pressure. Certain models of LD automatic blood pressure monitors have a function which allows to install maximum cuff inflation pressure preliminary. It reduces the time of measurement, saves the battery life span, and does not expose your arm to extended pressure of the inflated cuff.
• Built-in compressor. Due to the built-in compressor, the cuff is inflated automatically after you press the START button. In semiautomatic devices, the cuff is inflated by manually pumped air using a rubber squeeze pump.
• LD automatic blood pressure monitors have a electronic air release valve. This feature allows the device to automatically maintain the required rate of air release from the cuff during measurement and automatically release air from the cuff after completion of the measurement. In semiautomatic LD blood pressure monitors the air release rate is adjusted by manually adjusting the screw valve. Air is released completely after you press the button.
• Selection of the maximum cuff inflation pressure. Certain models of LD automatic blood pressure monitors have a function which allows to install maximum cuff inflation pressure preliminary. It reduces the time of measurement, saves the battery life span, and does not expose your arm to extended pressure of the inflated cuff.
What advantages does a semiautomatic device have?
As compared to an automatic device the semiautomatic blood pressure monitor has the advantages of lower price and significantly longer service life of batteries.
What are the advantages of an automatic device?
Cuff can be inflated using by pressing only “one button”. Automatic adjustment of air release rate increases the accuracy of blood pressure measurement, especially in stout people.
What is the purpose of the Fuzzy algorithm?
Fuzzy algorithm considers individual heartbeats. Ideally, when cuff pressure gradually decreases, the pulse wave amplitude increases and then evenly decreases. However, pulse rate varies from person to person: pulse wave velocity can rapidly increase and after reaching maximum slowly decrease. It can be vice versa – increase slowly and decrease rapidly. This can result in inaccuracy in results on a regular basis. Fuzzy algorithm considers these subtle aspects and makes it possible to receive the most accurate measurement result.
What is the purpose of an electronic valve?
To measure blood pressure accurately it is necessary to obtain a constant rate of air release from the cuff (usually 4–5 mm Hg per second). A mechanical valve maintains this rate with a certain error that depends on the upper arm circumference (or wrist circumference, depending on the blood pressure monitor type). Therefore, if the measurement of the blood pressure is carried in a person with a plump arm, the mechanical valve will release air slightly faster than needed. And if the arm is too thin, the situation will be vice versa. In any case of the above, there will be a measurement error. As for the electronic valve, it will maintain the air release rate at the required level in both cases making the measurement more accurate. Moreover, the electronic valve is much more expensive than the mechanical one since it is a complex mechanism that requires a control circuit. As a result, the presence of an electronic valve for correct air release from the cuff is a sign of an accurate, expensive, and high-quality blood pressure monitor.
The standard size cuff is small for me. What can I do?
You can buy a larger size cuff. Available models are shown in the Catalog.
Why does the display show an error message?
The cuff may be insufficiently inflated. The cuff needs to be inflated 30–40 mm Hg higher than your supposed top (systolic) pressure. Moreover, the cause of the error may be related to unwanted noise or arm movement during measurement.
Why is the air rapidly deflated from the cuff?
Replace the batteries. If the device is used with the network adapter, this means that the adapter does not provide enough power. Also, there may be an air leak in the cuff. In this case, you need to contact the service center.
The device quickly runs out of batteries. Why?
In automatic devices air is injected by a compressor that consumes a lot of power. Cheap batteries usually do not withstand such a discharge for a long time and do not provide the normal operating time for the device. It is recommended to use high-quality alkaline batteries. Batteries will also “discharge” fast, if you do not replace all batteries at once.
The blood pressure monitor's results seem to be less than “normal” readings. What should be done?
If using a semiautomatic device, consider the arm circumference. The pressure release valve in the semiautomatic device is adjusted to the average size of an adult’s arm (from 23 to 32 cm). Therefore, if the arm size significantly differ from the specified ones, the air release rate, especially in the upper pressure region, will not correspond to the required one. In this case, to accurately determine the blood pressure, you will need a cuff that corresponds to the size of the arm with the pressure release valve adjusted. In addition, you need to check if the cuff is applied properly. Please refer to the relevant section of the device’s operation manual.
How should I select a power adapter for an automatic blood pressure monitor?
To use the digital blood pressure monitor with a power adapter supplied from the mains correctly and safely, the adapter must comply with the requirements listed in the blood pressure monitor’s specifications. For example, the LD51A blood pressure monitor specifications say: “Power supply: four AA batteries or a 6V, 600 mA power adapter. Adapter contacts polarity must be put according to the picture applied to the device housing (minus at the connector internal contact).” Remember that little-known manufacturers may not comply with the specifications on the adapter housing or in the adapter data sheet. In this case, we recommend buying an adapter with a power margin of up to 800 – 1000 mA or a more expensive adapter made by a more known manufacturer. The device manufacturer recommends using an LD-N057 power adapter.
What are the specifics of measuring the blood pressure in stout people?
To measure the blood pressure in people with arms of a big circumference, a larger cuff may be needed. The size of the cuff supplied with the device is specified in the device data sheet. To receive accurate measurement results, the cuff pneumatic chamber’s length must take up at least 80% of the circumference of the arm used for measurement. The cuff width should take up to about 40% of the arm circumference (average 12–14 cm). Usually, in digital semiautomatic devices, when replacing a standard cuff with a cuff of a different size, an adjustment of the pressure release valve must be carried out. The principle of pressure release valve adjustment depends on the specific model and is described in the device operation manual. It is important to remember that most digital blood pressure monitors for personal use are designed for adults with average body size. For stout people we recommend to use sphygmomanometers with a correctly selected cuff. The use of short and narrow cuffs will result in overestimated readings.
How to choose the right cuff?
To choose the right cuff for your device, you need to consider the following:
• There are cuffs with one and two connecting tubes. Usually, cuffs with two connecting tubes are used for mechanical aneroid and semiautomatic digital blood pressure monitors. Cuffs with one tube are used for automatic digital and some sphygmomanometers.
• To receive accurate measurement results, the cuff pneumatic chamber’s length must take up at least 80% of the circumference of the body part used for measurement. The cuff width should take up to about 40% of the arm circumference (average 12–14 cm). To facilitate the cuff size selection, the manufacturer usually indicates the arm circumference corresponding to a particular cuff on the packaging.
• for personal (at home) use of blood pressure monitor it is more convenient to use a cuff with a fixing metal ring. The fixing ring allows the cuff to be fitted correctly and without assistance. To increase durability, the ring must be welded at the junction point.
• The seamless version of the cuff chamber is much more durable.
• There are cuffs with one and two connecting tubes. Usually, cuffs with two connecting tubes are used for mechanical aneroid and semiautomatic digital blood pressure monitors. Cuffs with one tube are used for automatic digital and some sphygmomanometers.
• To receive accurate measurement results, the cuff pneumatic chamber’s length must take up at least 80% of the circumference of the body part used for measurement. The cuff width should take up to about 40% of the arm circumference (average 12–14 cm). To facilitate the cuff size selection, the manufacturer usually indicates the arm circumference corresponding to a particular cuff on the packaging.
• for personal (at home) use of blood pressure monitor it is more convenient to use a cuff with a fixing metal ring. The fixing ring allows the cuff to be fitted correctly and without assistance. To increase durability, the ring must be welded at the junction point.
• The seamless version of the cuff chamber is much more durable.
Why there is a dispersion in readings?
The dispersion in readings appears due to various interferences created by the arm or body movement, the environment (for example, table rapping), or talking during measurement. The dispersion in readings is inevitable when you perform repeated measurements. Before re-measuring, wait for 2–3 minutes for the blood flow to restore. However, people suffering from severe atherosclerosis, due to a significant loss of vascular elasticity, require longer intervals between measurements (10–15 minutes). The same goes for people who suffer from diabetes mellitus for a long time. For more accurate blood pressure measurement, we recommend you to make a series of 3 consecutive measurements and calculate the mean value. It is necessary to apply the cuff correctly and with the same tension.
Different cuff positions lead to dispersion in readings.
Different cuff positions lead to dispersion in readings.