During training for home programs what are you taught about preventing air from reaching you?
What machine are you referring too.
Well, besides the machine’s built-in ability to detect air in the veinous line past the veinous air chamber (in which case the pump is stopped immediately and the air detector alarm sounds), if you have done something wrong during the preparation and priming of the tubing, you will see if there is air in your lines (either bubbles, micro-bubbles or just a section of line that is air instead of saline). Part of the standard procedure is to inspect the lines after the priming/recirculation, before you needle. The arterial or pre-pump side also has an air chamber, but the air detector is post-pump, since that’s the line which brings the blood back to you. During my training, in my case, with a Fresenius 2008K machine, we did regular air detector alarm drills, and I automatically check all the lines for air before I put my needles in. During the treatment, any air that is not simply trapped in the two air chambers will be detected by the optical air detector. Once you start the treatment, pretty much the only way that air could get in the blood circuit is if some connection somewhere isn’t tight, or, if one of the air chambers emptied out of blood, or if while giving yourself saline for low blood pressure or for rince back of blood, you let the saline bag empty (alarm would go off for all of these anyway). But any air entering would still just build up in either air chamber, which you would see since the blood level in it would drop. Every time there is an alarm, you check the blood level in the air chambers and adjust if necessary. Also, every treatment, after all the priming is done with saline in the lines, the procedure I use includes checking that the air detector works by manually lowering the fluid level in the veinous air chamber, which should stop the blood pump instantly and sound an air detect alarm, so that I know it’s working.
Other than that, should all the safeguards fail, you are taught the signs of air getting into you, and if you have any of those signs, you phone 911 immediately.
Now, I’ve never seen the more so-called user-friendly machines in operation, so, I don’t know about those. However, it’s still bloodlines and a dialyzer, so, the principle of operation is the same. Some of the checks might be automated though, I don’t know.
It’s something that sounds scary when you read about it, but in practice, there are a lot of safeguards, both built-in, and in procedures. Failure of the optical air detector is more likely to be in the direction of triggering a false alarm than of failing to detect air.
Thank you for this good explanation on air detection, Pierre. By any chance were you taught about “burping the bag”? This is a method of getting air out of the saline bag when tx is being set up. I have wanted to learn all I can on this subject of air as I got air on 2 occassions and it was very scary- symptoms similar to the onset of a heart attack. Nurses stopped txs both times when they could not find the problem. The air detectors apparantly did not work eventhough they were set up properly both times.
You said how air is detected, but not clear on what you have said as far as how to get air out if it is detected during tx?
What were you taught are the signs of air getting into patient which would require calling 911? And wouldn’t it be difficult to call 911 if that happened if patient did not have a helper?
To be honest Jane, after going to in-centre dialysis for 2 and a half years, I think I would be more afraid of those kinds of events happening there than I would when I’m doing it myself. Nothing against the staff there, but, I mean, they can make a mistake too, and, even there, some of the nurses are under training. If it did happen, they would have to phone 911 the same as I would from home, since the dialysis centre I went to is not in a full-service general hospital.
No, I haven’t been taught to burp the bag (I don’t even know what that means). What I do is to make sure that when I setup the second saline bag after the priming is all done, I only fill the little chamber under the bag half full of saline. That way, I can easily tell when saline is flowing or not. Also, any air goes up to the top of the bag, so, it’s not going to go anywhere.
About what I do if there is air in the system… Ok, first the alarm sounds. I lower the blood flow (for when the pump restarts after I clear the alarm) and then I check the level of fluid in the veinous air chamber. If it’s not low enough to trigger the alarm, I can take the chamber out of the holder it’s in, and I clean both it and the optical sensor with an alcohol swab in case there’s dust or something (maybe that’s what is triggering the alarm). If I see an air bubble in there, I try to clear it up to the top of the air chamber by tapping on it (that’s where the air detector is, so if there’s air, that’s where it will be). I do all that quickly, because after all, the blood flow is stopped during this time. But, if that doesn’t fix the problem quickly and the air detector alarm goes off again as soon as I restart the pump, or, if before doing that I see microbubbles or too much air in there (more than just one little bubble), I’m supposed to take myself off immediately without retransfusing the blood. I just clamp and get off. Losing your blood circuit now and then is not a big deal. It happens. Better safe than sorry, and, with daily dialysis, losing the remaining dialysis time isn’t going to make much of a difference overall.
The signs of an air embolism that has already happened are:
if air to the brain: roaring in ears, dizziness, impaired speech, double vision, seizures.
if air to the heart or lungs: shortness of breath, chest tightness or chest pain, cough.
Now, I have to admit, other things might also cause similar symptoms, but in any case, if I had any of those, I wouldn’t play around with it. I would have to react somehow, unless I’m already dead or passed out.
Look, there are risks. We all know that. But, the risks of dialysis are there the same at the dialysis centres, and the procedure is the same if it happens. First of all, two things would have to happen. There would have to be both air entering the blood circuit after starting tx, and the air detector would have to fail. A good preparation helps ensure a good, problem-free treatment. I make sure all my connections are tight, and if no air is entering the system at the start of treatment, there isn’t much chance of it starting all of a sudden during treatment, and if it did, it’s unlikely that it would coincide with the air detector suddenly failing during the treatment.
In my program, if you have to dialyze at home alone (since they don’t require a trained partner anymore), they provide the Lifeline service at no cost. I guess it’s easier than dialing 911 on the phone because there’s only one button right at your wrist.
Also, since we can only practice it, who knows how I would react if I really had any of the above symptoms at home while on treatment. I guess I might remain calm and call 911, or I might panic and call 911. Either way, I’m going to end up in the same place: the ER. I’ve already ended up in the ER 3 times during my 2 plus years at the dialysis centre, so, it wouldn’t be a new experience
Getting air out of the saline bag is extremely easy, you simply insert the post on the saline line about half way in, then pull it back slightly so that the holes are slightly exposed on the sides of the post that allow the saline into the lines. Then you squeeze the bag slightly until the air is exposed and then fully insert the post.
I tend to put the bag between my knees and squeeze with my legs while using my hands to hold the post and top of the saline bag.
Yes, I was taught this, not sure why Pierre was not, and yes, of course you are taught how to prevent air from getting to you and in case you screw up and somehow get air what to do.
For example if you forget to release a clamp and the machine pushes your blood completely out of a chamber I was trained to always keep a clean large syringe on my tray and you can pull the air out of the lines and pull the blood back in. I’ve honestly had more trouble (prior to them changing out my air detector that was malfunctioning sometimes) with the chambers completely filling up with blood and again you simply use the syringe to insert air.
You don’t go through 4-6 weeks of training for nothing, they are there to teach you, test you and make sure you are ready to be at home. This isn’t new, people have been doing home dialysis for 30+ years and in spite of looking I’ve been unable to find examples of people dying at home on dialysis from anything other than strokes and heart attacks, things that would happen regardless.