Hello everyone! I continue to summarize and post in a condensed form my experience in electronics repair. I present my Top 10 most common malfunctions of tonometers, which was born as a result of accidental repairs of medical equipment and communication with other Masters. I won’t say that I’m a great specialist in this area, but I came across some things and successfully fixed them. Let's start the rating. The locations of malfunctions of tonometers and blood pressure meters are sorted by the frequency of occurrence of the malfunction.
Initial setup
The best way is to buy a blood pressure monitor at a pharmacy or specialty store. There they are already checked and adjusted using a standard. This applies to mechanical models. Electronic ones, which are now the most popular, are tested by the manufacturer at the factory.
You can find out that the device has passed the accuracy test using the example of manual tonometers from Omron (leaders in sales on the Russian market). Each copy has a special sticker-seal, which confirms that no one used it after the repair by the master.
The only thing is that after the purchase the user needs to set the date and time. You can do this yourself:
- Remove the battery pack and insert it back.
- Turn on the device.
- After this, setting the date and time is activated.
- Using the “+” and “-” buttons, first the date is set, then the month. After adjusting each number, you need to press the “Start/Stop” button.
- After setting the date and pressing “Start/Stop”, the time indicator will appear. Indicators are set in the same way.
Important! When purchasing mechanical models, you need to pay attention to the dial. The pressure gauge needle should show exactly 0.
How to check the accuracy of the device
Since this question mainly arises during home use, all owners of the device will be able to use the options presented below.
The methods are as follows:
- go to a store that sells medical equipment, where the device will be checked on the equipment provided for this;
- ask for help from a pharmacist who will compare the readings of a new tested tonometer with a previously used one;
- independently if you have a proven tonometer, connecting both devices to the same cuff and comparing the results.
The ideal, but at the same time the most expensive way is to submit the device for testing to a regional standardization center, where the appropriate equipment is available.
Important! Electronic blood pressure monitors are battery operated. If the kit does not include a charging adapter, it means that the manufacturer provides for replacing the battery after a certain cycle of use. Its duration is usually indicated in the instructions.
Checking the accuracy of the tonometer
What determines the accuracy of a tonometer?
Cuff fixation
The cuff must be put on in accordance with all the rules provided in the tonometer user manual. If this is not done, then at best the tonometer (automatic or semi-automatic) will produce a measurement error, and at worst – incorrect results, on the basis of which an incorrect idea of the current state of health will be formed. The cuff should be located 1-2 cm above the ulnar fossa and fit snugly to the skin.
Cuff size
The cuff must strictly fit in size, otherwise, if the cuff is small, the pressure measurement result will be overestimated, and if the size is too large, it will be underestimated. The width of the cuff should be 40% of the arm circumference.
Compliance with all rules for measuring blood pressure
The user manual, which is included with the tonometer, shows the rules for measuring blood pressure. It is necessary STRICTLY follow all the listed recommendations, as well as adhere to the basic tips when preparing for blood pressure measurement:
- No smoking for 30 minutes;
- Do not drink coffee, strong tea and alcoholic beverages;
- Rest 15-20 minutes before measuring.
Battery charge
Automatic and semi-automatic blood pressure monitors are powered by batteries, and some models have an adapter for mains operation. If the batteries are low, the tonometer may give an incorrect measurement result.
Breakage of bulb, cuff, pressure gauge, electronic unit
If any malfunctions are noticed, it is recommended to immediately contact the service center. Under no circumstances should you repair the tonometer yourself, especially if it is under warranty.
What to do if it measures incorrectly
First, you need to make sure that the blood pressure measurement procedure itself is carried out correctly. Many people use wrist blood pressure monitors, which is not recommended for people over 45 years of age. In addition, the error of such devices can be up to 20 mmHg. Art.
The readings of everyone else can also be influenced by the psychological state at the time of measurement or by incorrect posture.
Having eliminated all factors, all that remains is to take the device to an accredited organization that has a license to service medical devices, where specialists will be able to identify and eliminate the error.
In what cases is repair of medical tonometers required?
Among the most common breakdowns of tonometers:
- The pressure gauge needle falls out (typical of mechanical tonometers).
- Loss of tightness resulting in air leakage. As a rule, damage occurs at the hose connection areas, in the bulb, and also in the cuff.
- Air bleed valve stuck. In most cases, such a malfunction requires replacement of the tonometer bulb.
- Bleeding air too quickly. In such a situation, it may be necessary to replace the air bleed valve or the entire blower.
- Displaying incorrect indicators on the digital screen of the device. If such a malfunction occurs, you should try replacing the batteries. If this does not help, the cause is most likely an air leak in the cuff, tube or bulb.
It should be remembered that blood pressure monitors are professional medical equipment, the repair of which should be carried out by experienced specialists of appropriate qualifications.
How to properly disassemble the AND tonometer?
Tonometer model AND UB 201
The AND UB 201 tonometer is a bracelet-type device for measuring blood pressure. Most often, the cuff fails with this model. To repair or replace it, it must be removed correctly. This is done in the following sequence:
- The batteries are removed from the camera.
- Remove the clips that secure the cuff (they are located on both sides of the body) by prying them off with a screwdriver.
- Pull the cuff towards you and release it from the tonometer body, to which it is attached with two more latches.
- The housing cover is attached with two bolts at the back; they need to be unscrewed with a screwdriver. Carefully open the cover and remove it.
- To completely disassemble the tonometer, you should press in the recesses at the top of the case with the same screwdriver, and it will easily fall apart.
Tonometer test
To find out which tonometer is more accurate and also most convenient to use, let’s compare devices from popular manufacturers: Omron M1 Eco, Nissei WS-820, AND UA-777, Microlife BP A100, B.Well WA-55, Citizen CH-437C.
As a result of the tests, the tonometer from Omron took the leading position. The functionality of this device is complemented by the ability to calculate the average blood pressure value from the last 3 measurements taken within 10 minutes, which guarantees high accuracy of the result. Also, one of the advantages is the device’s memory - measurement results (with date and time registration) are saved even in the event of a power outage. It is important that if the blood pressure level is elevated, the tonometer gives an alarm in the form of a flashing icon on the display.
The measurement results are most clearly shown by the AND tonometer, using the World Health Organization blood pressure classification, which uses a color scale consisting of three colors indicating the blood pressure level: green - low, yellow - optimal, red - high. The cursor stops next to a specific color corresponding to the blood pressure level. A huge plus is also the fact that this is the only model among the tested tonometers that has control buttons labeled in Russian.
The largest cuff was found in B.Well and Microlife tonometers. The size of the cuff allows the procedure to measure blood pressure in people with a large arm circumference.
Repairing a holey cuff
If the problem is bleeding air, then you need to find the location of the gap. When it is located directly on the cuff, it does not have to be replaced; it can be repaired. How to repair a leaky blood pressure cuff:
- If the hole is small and the cuff is strong and unworn, then you can seal it with a hot glue gun.
- You can glue a piece of rubber patch or other suitable material onto the gap with rubber cement.
- Take a strip of thick aluminum and bend it in half. Push the damaged area between them and clamp it with metal, help yourself with pliers. Cover this place with glue.
When air escapes at the factory soldering site, it can be vulcanized with a soldering iron at 180 degrees. It is important to remember that repairing a cuff is cheaper than replacing it, but it will not last too long after the intervention. Therefore, be prepared to replace this element.
