Blood pressure & dialysis - the basics
A healthy blood pressure is basically a very important building block of our general health, everyone knows that nowadays. But what does blood pressure have to do with the kidneys? More than you may think! Our kidneys are very important for the regulation of blood pressure, in addition to numerous other functions that are essential for survival. If the kidneys no longer function properly, this can lead to high blood pressure. High blood pressure is also known as hypertension. Hypertension in turn can lead to further impairment of kidney function. But what exactly is blood pressure and what do you have to pay attention to? We give you important information and help you to get your blood pressure under control.
What exactly is blood pressure?
Blood pressure is the pressure that prevails in your blood vessels. In most cases, this means the arterial blood pressure in the large arteries, which can be measured using a simple blood pressure cuff, but in principle it can of course also be measured in various sections of the vascular system. As you surely know, blood pressure is always indicated with two numerical values: The first value is the maximum pressure that occurs in the aorta when the heart pumps blood out of the left ventricle. This value is also called systolic blood pressure. The second value indicates the minimum pressure that can be measured in the aorta when the heart is not pumping blood out of the left ventricle. This is the so-called diastolic blood pressure. The unit of measurement for blood pressure is milliliters of mercury (mmHg). In everyday life, we usually measure the pressure in the artery of the left upper arm. This value is usually sufficient for setting blood pressure.
Is my blood pressure the same all day?
Your blood pressure fluctuates naturally depending on what you are doing. So it changes throughout the day. It's usually lowest at night, or right after you wake up. When we are under physical or emotional stress, our blood pressure rises. Blood pressure fluctuations within normal limits are quite normal. It becomes particularly alarming when systolic and/or diastolic blood pressure show constantly high values even at rest or at night.
What does high blood pressure mean?
Good or normal blood pressure is defined as a maximum of 129 mmHg (systolic) or 84 mmHg (diastolic) in people with healthy kidneys. If the systolic values are between 130-139 mmHg or the diastolic values between 85-89 mmHg, this is called high-normal blood pressure, and if the values are at least 140 mmHg systolic or at least 90 mmHg diastolic, this is called level 1 or higher hypertension.
Normal blood pressure: ≤ 129 mmHg (systolic) / ≤ 84 mmHg (diastolic)
High-normal blood pressure: 130-139 mmHg (systolic) / 85-89 mmHg (diastolic)
Stage 1 hypertension: 140-159 mmHg (systolic) / 90-99 mmHg (diastolic)
Stage 2 hypertension or higher: ≥160 mmHg (systolic) / ≥ 100 mmHg (diastolic).
How high can my blood pressure be as a dialysis patient?
Many things can change your blood pressure. Your fluid balance plays a very important role. It cannot be well controlled by your body when you have kidney disease requiring dialysis. As your nephrologist nags you to reduce your drinking and eat a low-salt diet, the goal is usually to lower high blood pressure levels. For patients with renal insufficiency but not requiring dialysis, a target value of less than 120 mmHg (systolic) applies, as far as tolerable.
As a dialysis patient, before any dialysis treatment, your long-term blood pressure should be below 140 mmHg (systolic) to 90 mmHg (diastolic). After each dialysis treatment, your blood pressure should be below 130 mmHg (systolic) to 80 mmHg (diastolic). It may be that your nephrologist asks you to perform home blood pressure measurements. According to current studies, blood pressure should usually be adjusted individually by a nephrologist, especially in cases of renal insufficiency requiring dialysis.
During dialysis treatment, your blood pressure can fluctuate greatly in both directions. Although this should not happen over time, it can sometimes be difficult to prevent. Your dialysis team will make sure that you do not suffer from low or high blood pressure.
Here is a summary for you once again:
Target renal insufficiency (not yet requiring dialysis): < 120 mmHg (systolic) if tolerable
Target before starting any dialysis treatment: < 140 mmHg (systolic)/ < 90 mmHg (diastolic)
Target after any dialysis treatment: < 130 mmHg (systolic)/ < 80 mmHg (diastolic).
What are possible causes of hypertension?
Basically, it is often difficult to pinpoint a specific cause for hypertension. If the cause cannot be precisely determined, one speaks of essential or primary hypertension. In this case, unhealthy lifestyle factors such as smoking, frequent alcohol consumption, stress, obesity, high salt consumption and too little exercise are mainly assumed to be the cause. You should then strive to make changes in your diet and general lifestyle accordingly. If, on the other hand, there is a clearly identifiable cause, this is called secondary arterial hypertension. Several factors can be the cause of this, which you can then take targeted action against. These include:
Hormonal disorders of the thyroid gland
Disorders of the adrenal cortex
Narrowing of the renal vessels as well as disorders of kidney function
In patients with advanced kidney disease, hypertension can be both a cause and a consequence of kidney disease, as mentioned above. However, you should understand that the decrease in your kidney function leaves more sodium in your body, which is usually excreted through your kidneys. The same is true for the fluid within your body. This misregulation then eventually leads to an increase in your blood pressure and further damage to your kidneys.
Why is it so important that blood pressure is in the green zone?
As mentioned several times now, blood pressure affects your kidney function and thus your health. Especially as a person with kidney disease, you should make healthy blood pressure values a priority. This also has to do with the prevention of secondary diseases. Long-term high blood pressure in particular damages the entire body and thus also the small blood vessels, the capillaries. This often results in damage to the heart, brain or extremities, for example.
How do I know that I have high blood pressure?
High blood pressure often goes unnoticed for a long time, because there are no typical, unusual symptoms. Therefore, pay more attention to regular signs such as:
Dizziness, ringing in the ears and nausea.
How do I get my blood pressure under control?
To permanently ensure healthy blood pressure, you should basically pay attention to a healthy lifestyle. This includes:
A healthy diet
Reduction of carbohydrates and sugar
Low alcohol consumption
Prevention of excessive salt consumption
Healthy stress management
Where and how can I get support for high blood pressure?
If you have symptoms or already know that you have elevated blood pressure or high blood pressure, then your nephrologist certainly already has this on his or her radar. It is extremely important for your health that you bring your high blood pressure into a green range. The best way to do this is to regularly document your blood pressure in an analog or digital logbook. The Miku app can help you with this. The app also contains a lot of other relevant information, tips and tricks on the subject of blood pressure, drinking quantity regulation and dialysis. In general, the ideal blood pressure therapy always consists of a combination of lifestyle changes (exercise, diet, stress, etc.), medicinal measures and regulation of salt and fluid intake.
The important points summarised in 3 sentences
Healthy blood pressure levels are important for preventing secondary diseases as well as deterioration of kidney health
For people on dialysis, target values of 140/90 mmHg before dialysis and 130/80 mmHg after dialysis can be used as a guide
The important point in treating high blood pressure is to identify causes and treat them - often by making a few small adjustments for a healthier, more active lifestyle
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Dialysecentrum.de. Abgerufen am 15.4.2022
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