Without fail, we all have our blood pressure measured before, during (usually hourly) and immediately after dialysis.
There are several reasons for this. It’s taken before starting to see what effect the fluid we are carrying is having on our blood pressure. High blood pressure is usually caused by too much fluid, so it is a good indicator for staff that we need to lose some.
I put on between one and two litres between sessions. That’s a fairly small amount, but then I dialyse five days per week, primarily so that I don’t put on too much fluid. As a consequence, my starting blood pressure rarely rises above 150/75 and my pulse is usually around 55bpm.
The difficulty of putting on more than this between runs is what it does to the heart. The body can’t dispose of the fluids and toxins, so they go into the bloodstream. In order to cope, the heart swells up and pumps harder, so blood pressure climbs. When there is just too much fluid, it seeps through the cells of the body to pool in the spongy bits – the lungs, making it hard to breathe, into various cavities and into expandable bits some distance from the heart, like ankles, arms, fingers, etc.).
Initially, the heart can handle this swelling and extra work. But if it becomes a constant problem, we get complications. Like Atrial Fibrillation (AF) and heart attack. In fact, the biggest cause of death among BigD members is not directly related failed kidneys at all; it’s heart failure.
So the before-dialysis blood pressure is a strong indicator of fluid level, and every dialysis nurse and technician keeps a close eye on it (the reverse also applies: low BP and you get a smiley face).
The main reason staff take blood pressures during BigD is to make sure that it does not fall too low, which can happen if too much fluid is taken off too quickly. Very low BP can cause a loss of oxygen to the brain, then a loss of consciousness. Called “going flat”, first you feel tired, then faint, then you slip into unconsciousness. It can all happen within a few minutes.
In most cases people recover quickly. Staff press a special setting on the chair which lays the patient flat, then raises their legs above their head to get some blood to the brain. Then they place an oxygen mask over the face, stop the machine taking off fluid and usually give the patient a few hundred mls of saline to build up the fluid volume.
There are some indicators for staff when someone goes or is going flat. Some people make a loud snoring sound. Others freeze in a fixed position, sometimes with their eyes open. If a staff member thinks a person is going flat they usually call their name loudly a few times, tap their foot or arm, etc. If they respond, things are fine. If not they have to act fast.
How often does this happen? In my experience, someone goes flat (or nearly flat) about once every few months. All are dealt with quickly and they are fine within a few minutes, with no lasting effects.
However going flat is serious and if left unattended can be fatal.
A couple of years ago in a hospital BigD unit one of the older patients used to sleep with a blanket over his head to cut down distractions. Unfortunately, one day he went flat in this position, and because no one realised it, he passed away. Since then facial coverings have been banned in units around Australia.
So don’t be upset next time someone wakes you up or taps your foot to take your blood pressure.
Typically after BigD, staff measure blood pressure, firstly to make sure we are ok to get out of the chair and remain upright, and so are OK to go home. Secondly it is a check: if the BP is within an acceptable range, then it is likely that the correct amount of fluid has been removed and we will probably now be at our required dry weight. They confirm this when we weigh before departure.
BP can be elevated for many reasons other than being overweight: I find that if I am watching an exciting movie, having an animated conversation or are concerned or tense (eg potentially late for an appointment) my BP is high. After a few minutes it usually reverts to normal.
BP and AF
I mentioned AF before. AF is where the heart beats both fast and out of rhythm. It can cause palpitations or a fluttering or irregular heartbeat, chest pains, dizziness or fainting spells. Untreated, complications may include stroke (because the inefficient heartbeat allows blood to pool and develop clots, which can flow to the brain) and permanent heart damage or heart failure (if the heart rate ends up being very very rapid for a long period). Treatment options include medication, surgery and electric shock therapy.
AF is very common in us BigD patients because of the regular fluid overload on the heart. I’ve had it several times. It can sneak up on you. Because it comes so irregularly, it often takes me a couple of weeks to recognise it. Usually I think I have a bug, because I’m easily tired, run out of puff, find it hard to get out of bed, etc.
But the AF light goes on when I go on dialysis because every time I have AF my BP drops and my pulse rises. For me, the raised pulse is the big clue, because my irregular heartbeat is so inefficient that it has to beat faster just to keep the blood moving.
So for BigD patients there is a hidden side effect of AF: the drop in our BP increases our risk of going flat.
The message here is to be aware: if you feel unwell and your before-dialysis BP falls, check your pulse for AF. If it’s erratic, tell the nurse or technician that you may be at risk of going flat and ask for regular checks through the run.
It’s a little extra hassle, but so what? if you’re like me, you have enough drama in your life already.