NxStage: My Initial Experience - The Good, The Bad, The Ugly

By Peter Laird, MD

After an exceedingly long wait, I have now completed my first week of home dialysis training on the NxStage machine. My conclusion after this week, is that I have proven with my own experiment that daily dialysis is FANTASTIC and I never want to go back to to usual incenter hemodialysis no matter how well done. However, there are several issues that I have either observed or experienced in my first week which I will relate as the Good, the Bad and the Ugly.

First, the Good. As I began above, the differences of cognition and general well being can never be achieved with usual care in center that I have experienced with 5 days of continuous HD therapy. I ate my first orange, my first orange juice, my first banana and my first sliced tomato in over 3 years. Wow, I have been deprived is all I can say.

I must make a special note of how fantastic my trainer at Kaiser Sunset is. Her name is Rita and she makes me almost, but not quite forget that it took nearly nine months from the time of my request for NxStage until I started my home training. My wife and I felt a kindred spirit with her immediately, and she is the first dialysis person to give me a hug and peck on my cheek at the end of my first week of training. She is a breath of fresh air after over two years of some very unpleasant experiences at the hands of dialysis staff and I look forward to learning as much as I can from this kind lady.

There is much more that I will state over time on the "Good" of home dialysis, but for now let me turn to my criticisms. The Bad:

1. (NxStage) No air chamber in the system. It is impossible to get all of the micro-bubbles out of the system before the first pass is giving to me. I went through the snapping step very carefully 3 times and still after sitting for a few minutes, several grew back onto the tubing again. My question is what effect does this have on accumulated pulmonary function tests over years of use. Patients on the cardio-bypass machine have significant cognitive declines after Coronary Artery Bypass Grafting (CABG) from this simple issue of micro-bubbles going to the brain. I am left with an open question of what will the long term effect of micro-bubbles be on my pulmonary system? Why not eliminate this issue with air chambers that will reduce this issue during the priming stage.


2. (Kaiser) My long wait. It appears that some of the problem is in the referral practices where many patients are referred before they have a mature access or have any experience with self cannulation. This leads to training times of over 2 months in some cases. I believe that an upfront self cannulation and access maturation in the referring unit will improve the training times dramatically. With the integrated health care system of Kaiser, requiring this prior to referral will secondarily improve buttonhole use across the system. Nevertheless, Rita has made me forget almost all of my frustration on waiting so long. I wouldn’t trade her for anyone.


3. (Kaiser) I became aware that Kaiser has contracted with some excellent outside units for over a year now specifically for access to the NxStage only three weeks before I started my own training. It is a shame for Kaiser to lose the good press it deserves for going forward with this NxStage access system wide by not having adequate communication to all involved, especially to the patients. For issues 2&3, I will give my input to those that can make a difference at Kaiser that I know personally. Kaiser has a long history of improving dialysis care for all patients, so with Rita by my side, I will move on and hope that my own experience makes it a better experience for those that will follow me.

Now, for the Ugly!!! Within 30 seconds of hooking up to the NxStage and cranking the system up to speed, I experienced the onset of an overwhelming “taste” that I have never experienced before. In addition over the next minute, I developed nausea, a mild burning in my chest which was followed by 24 hours of chest congestion without phlegm production and mid abdominal discomfort lasting for the majority of my dialysis session. I did a progressive rinse protocol the rest of the week and was able to eliminate the physical side effects with 2.5 L rinse on Friday, but I still had a fairly strong plastic taste that reminds me of Nitrous Oxide.

I have looked into this on the internet and found several people who have complained of this on Home Dialysis Central and on IHD. However, I have yet to find any references to this on a PubMed and Google search. But to my surprise, after reviewing my NxStage handbook from cover to cover today (OK, I skipped a lot of the alarm section) I came across the following discussion in Appendix D, Synopsis of Clinical Study in their discussion on Unanticipated Adverse Device Effects (UADE):

One UADE, a plastic taste in mouth, was reported during the study. This was later independently adjudicated as dysgeusia and did not meet the definition of a UADE. This event was further classified as mild in severity, therapy-related, seemed to be quite transient and not associated with any serious or lasting consequences. The full analysis was provided to the FDA during the study.

As a physician who has observed many adverse reactions to medications, I would not define my experience as simple dysgeusia. It was by all accounts an Unanticipated Adverse Device Effects (UADE). With the severe and overwhelming taste resulting in nausea, abdominal discomfort, burning in the chest with congestion lasting for several hours, I would report this as an adverse reaction to therapy if any of my own patients had experienced this sort of reaction after I prescribed a therapy for them. I am aware that not all patients even notice the taste, and even fewer have such adverse physical complaints. It brings to a head the entire issue of BPA/Phthalates in dialysis equipment. I will spend more time on this issue over the course of my training. However, in preparation for this, I would recommend reading a few quick links on the adverse effects of BPA (here, here and here)

So, in summary, I am quite excited about feeling somewhat like a real person again with NxStage. Aside from the issues above, I will adapt my own habits to minimize any adverse effects and stay on the NxStage until perhaps someone else invents a better mousetrap. I look forward to gaining my independence that has been sorely tested in the last two years of incenter care. NxStage is a step foreword, but I believe that there are several issues that need to be addressed to improve it more.

Comments

[Kevin Hartzog]

My wife (the patient) and I have being using the NxStage machine for almost 2 years. I am usually in charge of removing the air bubbles. Some air will get into the system through loose connections. This is the most frustrating air to remove because more keeps seeping in. Always check connections to make sure they are tight before priming. I focus my air bubble removal on three areas, the pressure pod (bang it on the handle), the top of the filter (slap your hand with it), and the bag (flick it). You can snap the lines over and over, but if you have bubbles in any of the three areas they will keep recycling. I've seen bubbles go on a round trip several times. If you kink the line you will cause cavitation which will make more tiny bubbles, so don't kink the lines when you are snapping them. I used to do the snap and tap loop twice. Now, I get the air bubbles out of the bag, pressure pod and cap, then snap all of the lines together at the same time and then do two loops. The first three months we used the machine (doing two loops) I would have to manually take the bubbles out of the top of the filter cap with a syringe. We rarely have to do that now.

I'm always curious what Jenn's treatment tastes like whether it's saline, plastic or heparin. Once we primed the machine and turned it off at 23 and let it sit overnight and then turned it back on and did treatment the next day. Jenn said that resulted in a very strong plastic taste, so I would say if you don't like the taste or are worried about plasticizers in your body to do dialysis as soon after priming as possible.

The ugliest thing we have had with NxStage is some filters in some cartridge lots will cause minor irritations to the blood resulting in white blood cells clotting the top of the filter cap. NxStage will send you a box with ice packs so you can send the filter to them and the problem will disappear with a new lot of cartridges.

[Miriam Lippel Blum]

Peter,
When we rinse the 2.5 L of saline through the dialyzer we put the machine speed up to 600. After we reattach the venous tube to the saline bag, we let the machine run a couple of minutes at 600. This forces a lot of the air bubbles up into the saline bag. Then we have fewer bubbles during our final round of snap and tap.

Maybe this will work for you, too. But I totally agree that there should be no bubble issue at all. It causes vascular inflammation whih contributes to cardiovascular disease, among other unpleasant things.

[wallyz]

Peter- glad you are finally able to dialyze at home.

This is the first I have heard about the taste. I notice a distinct uremic taste (my wife calls it "diaper breath") when I am underdialyzed. Is this connected in some way?

[Peter Laird, MD]

Thank you all for your comments.

As far as the bubbles go, I have looked but not yet been able to find what if any health consequences microbubbles may have on the cardiopulmonary system. It just seems such an easy fix, that I don't know why it hasn't been done. Perhaps in trying to "dummy proof" the machine, dealing with an air chamber too high or too low is felt to be a risk. I would simply like to know what the consequences of micro-bubbles has on our system. As of yet, I haven't been able to find out any specific info. If anyone has any links, please post so that we can all be better informed.

As far as the taste, my wife calls my breath "ammonia breath" which is quite apt really. On the other hand, the NxStage issue is an overwhelming plastic taste that actually begings to come out of my lungs in a vapour I am pretty sure thus making it a volatile substance. I would simply like to know what it is so that I can make my own risk benefit assessment for myself which is part of informed consent.

Too dismiss it as a bad taste only without easily available information on what is the cause is not in the usual frame work that I am used to dealing with in medicine. The only other time I have not been able to tell what compound was causing a toxic reaction in one of my patients was in the military aerospace industry. I was told that the substance was classified and that ended that search. I advised the patient to find another job.

As far as a portable home dialysis machine, we have no other alternatives at this time, so all of us on the NxStage should have this information available upon request and actually as part of our informed consent since will are exposed to what ever chemical this is on a daily basis with high volume exposure. For NxStage to tell me it is harmless is quite paternalistic which went out decades ago as an acceptable ethical paradigm.

[Peter Laird, MD]

Just in follow up, here in California, you read a sign that there are carcinogenic substances in a restaurant before you enter. They are speaking of alcohol for one. If you must be warned to enter a restaurant
"at your own risk" then why do I not have an answer to my question after over a week of searching for the answer? It should be readily and easily found, period.

[Miriam Lippel Blum]

Peter,
Check out this article in CHEST JOURNAL. Here's the link and the abstract.

Miriam

http://www.chestjournal.org/content/128/4/2918.full

Microbubbles*
Pathophysiology and Clinical Implications

1. Michal Barak, MD and
2. Yeshayahu Katz, MD, DSc

1.
*From the Department of Anesthesiology (Dr. Barak), Rambam Medical Center, Haifa; and Bruce Rappaport Faculty of Medicine (Dr. Katz), Technion-Israel Institute of Technology, Haifa, Israel.

Abstract

Gas embolism is a known complication of various invasive procedures, and its management is well established. The consequence of gas microemboli, microbubbles, is underrecognized and usually overlooked in daily practice. We present the current data regarding the pathophysiology of microemboli and their clinical consequences. Microbubbles originate mainly in extracorporeal lines and devices, such as cardiopulmonary bypass and dialysis machines, but may be endogenous in cases of decompression sickness or mechanical heart valves. Circulating in the blood stream, microbubbles lodge in the capillary bed of various organs, mainly the lungs. The microbubble obstructs blood flow in the capillary, thus causing tissue ischemia, followed by inflammatory response and complement activation. Aggregation of platelets and clot formation occurs as well, leading to further obstruction of microcirculation and tissue damage. In this review, we present evidence of the biological and clinical detrimental effects of microbubbles as demonstrated by studies in animal models and humans, and discuss management of the microbubble problem with regard to detection, prevention, and treatment.

[Kevin Hartzog]

We worried about DEHP plasticizer in the blood circuit when Jenn was pregnant with our daughter and doing dialysis using NxStage. Our daughter is fine and just turned one. We did find an FDA warning back then on dialysis tubing for pregnant women. It theorized a higher chance of adverse effects with male fetuses. Here is the recent FDA warning: http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm062182.htm

It says, "Most importantly, you should not avoid the procedures cited above [hemodialysis] simply because of the possibility of health risks associated with DEHP exposure. The risk of not doing a needed procedure is far greater than the risk associated with exposure to DEHP."

There aren't any real alternatives to the vinyl blood tubing yet. I'm not autoclaving custom made glass tubing every day and the old Aksys "biofilm" tube lining theory is not one we want to explore. Any biomedical engineers care to comment?

[paula debling]

Hi, glad you have started your training, and will be home soon. We are looking into the NX Stage machine, but can it or have you tried double priming?

[paula debling]

our patients go on within 30 minutes of set up (standard hhd), but would rita allow you to bleed out?, so you don't receive the prime?
Good luck.

[Peter Laird, MD]

Actually, we rinse 3 L through after the machine is prepped and before you hook red to blue before setting the needles. That has eliminated my physical reaction to the plastic taste and reduced the taste itself but not completely eliminating it.

I understand that NxStage does not recommend rinsing the system before use, but I believe it is a good practice for all dialysate lines, incenter or home hemo to rinse out at least 500 ml before hooking up. For me, 500 ml did not reduce the effect enough, that is why I used sequentially larger rinses until it became satisfactory.

Thank you,

Peter