We recently got an e-mail from another person who's had problems with insulin pump bubbles.
If bubbles in the pump cause a few strange high blood glucose readings (say in the 200s or low 300s), that's probably not a big deal - almost every insulin-dependent diabetic has these from time to time when they mis-guess the number of carbs in a meal. But a number of 420 and a trip to the emergency room is a big deal, both health-wise and bottom-line-wise for patients and insurance companies, and - we can hope - for federal regulators who are supposed to watch out for problems with medical devices.
Here is what the person said (personal identifying information has been removed):
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Hello,
I just found your information about air bubbles in the Medtronic Insulin pump.
It was as you had read my mind!!
I was put on the pump in December ....
My problems were first found Jan.... I noticed a long air bubble in my tubing as I was about to bolus for a meal.
No telling how many more had gone through without my knowledge!
I even had to go to the E.R. one night with a 420 reading!
While there...I found a 2" air gap in my tubing line!
Since that time...it's been a pain, checking...purging....wasting insulin.
I called and talked to the help line also... actually talked to Christine...and yes she's a jewel!! Very nice helpful person.
Switched infusions, reservoirs with Medtronics...changed insulins...finally got a new pump. Still have bubbles...none as large as before...but yes, I do still have to check constantly to see if there is a air gap in the line. I actually have had 5" bubbles!!
Talk about a big problem if I hadn't checked!!
I'm sending your blog and your posting in the forum to the Diabetes Clinic that I go to...Just to let them know it's NOT just me!
One thing that was offered to me was to fill the reservoir ahead of time...let it sit (hoping the fizzie bubbles will all come to the top) before changing my sets. I'm like you...I think that bubbles come in from the o-ring. When I tap the bottle to remove bubbles...there seem to be more coming from the o-ring, and that doesn't make sense.
I hope to hear back from you, hopefully with information on this problem!!
Saturday, March 14, 2009
Friday, March 13, 2009
Insulin Pump Bubbles continued
OOPS! I accidentally put the material on insulin pump bubble problems into the section on regressions. Sorry about that. But more on the bubble subject anyway.
Since we sent the letter to Medtronic about the bubble problems, we got a letter back from Shirajul Karim, the "Sr. Dr. of Quality" dated January 16, 2009. Here's the important sentence in his letter:
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"While our experience with our products is not consistent with the observations and testing described in your letter, we will carefully and fully investigate your claims."
---------------------------------------
And here's the letter we sent back to him. He hasn't replied, nor is there any evidence they made any attempt to "carefully and fully investigate" our findings. Nada.
----------------------------------------
Shirajul Karim, Senior Director of Quality
Medtronic Minimed
18000 Devonshire Street
Northridge, CA 91325
Dear Mr. Karim:
Thank you for your letter of January 16 acknowledging our letter of December 24. Let us first note that, despite the bubble problems we (and others) have reported, we are pleased with our experience with the pump. The fine control over insulin delivery rates it offers is a vast improvement over that available with injections.
It is surprising that ongoing problems with bubbles and air pockets have not previously been brought to the attention of Medtronic Minimed Quality Control. The issue certainly has been addressed to your HelpLine personnel by other people in addition to us. Here’s a link that illustrates the point:
http://tudiabetes.com/group/minimedparadigmusers/forum/topics/583967:Topic:147765
And here’s another link where “Dave” gives a sure-fire method to avoid bubbles – we have followed all of his suggestions, with no difference in bubble formation:
http://tudiabetes.com/forum/topics/583967:Topic:256260
As our December 24 letter shows, the bubbles develop only after and only if the insertion set is in FFFF’s body, take several days to grow, and their growth appears to involve leakage of air at the o-ring-reservoir interface (at least, that’s where the large bubbles are found before they break loose and enter the tubing).
It obviously would be simple for Medtronic Minimed to survey 100 or so patients who use the pump to see if they have bubbles in their reservoirs (e.g., by asking callers to the HelpLine to look at their pump reservoirs). However, the failure of Medtronic Minimed to have a substantive response to our letter in more than a month, the content of your letter, and the protocols used by the HelpLine personnel indicate that Medtronic Minimed has already made up its mind that the only problem is “patient error.” Presumably the solution will be for an outside agency (e.g., the FDA) or health plan (e.g., Kaiser Permanente) to investigate bubble formation in reservoirs and the possible risks to their patients. As we noted previously, the largest bubble we’ve “primed out” was equivalent to more than 2 Units of insulin that would not have been delivered, enough to increase my BG reading by about 150 mg/dL.
In the meantime, we would be interested to know if Medtronic Minimed comes up with any ideas for how the bubbles develop. As you may know, our first pump has been tested and found to be working flawlessly – as we said in our letter we expected to be the case. Please let us know if we can give you any additional information.
Since we sent the letter to Medtronic about the bubble problems, we got a letter back from Shirajul Karim, the "Sr. Dr. of Quality" dated January 16, 2009. Here's the important sentence in his letter:
---------------------------------------
"While our experience with our products is not consistent with the observations and testing described in your letter, we will carefully and fully investigate your claims."
---------------------------------------
And here's the letter we sent back to him. He hasn't replied, nor is there any evidence they made any attempt to "carefully and fully investigate" our findings. Nada.
----------------------------------------
Shirajul Karim, Senior Director of Quality
Medtronic Minimed
18000 Devonshire Street
Northridge, CA 91325
Dear Mr. Karim:
Thank you for your letter of January 16 acknowledging our letter of December 24. Let us first note that, despite the bubble problems we (and others) have reported, we are pleased with our experience with the pump. The fine control over insulin delivery rates it offers is a vast improvement over that available with injections.
It is surprising that ongoing problems with bubbles and air pockets have not previously been brought to the attention of Medtronic Minimed Quality Control. The issue certainly has been addressed to your HelpLine personnel by other people in addition to us. Here’s a link that illustrates the point:
http://tudiabetes.com/group/minimedparadigmusers/forum/topics/583967:Topic:147765
And here’s another link where “Dave” gives a sure-fire method to avoid bubbles – we have followed all of his suggestions, with no difference in bubble formation:
http://tudiabetes.com/forum/topics/583967:Topic:256260
As our December 24 letter shows, the bubbles develop only after and only if the insertion set is in FFFF’s body, take several days to grow, and their growth appears to involve leakage of air at the o-ring-reservoir interface (at least, that’s where the large bubbles are found before they break loose and enter the tubing).
It obviously would be simple for Medtronic Minimed to survey 100 or so patients who use the pump to see if they have bubbles in their reservoirs (e.g., by asking callers to the HelpLine to look at their pump reservoirs). However, the failure of Medtronic Minimed to have a substantive response to our letter in more than a month, the content of your letter, and the protocols used by the HelpLine personnel indicate that Medtronic Minimed has already made up its mind that the only problem is “patient error.” Presumably the solution will be for an outside agency (e.g., the FDA) or health plan (e.g., Kaiser Permanente) to investigate bubble formation in reservoirs and the possible risks to their patients. As we noted previously, the largest bubble we’ve “primed out” was equivalent to more than 2 Units of insulin that would not have been delivered, enough to increase my BG reading by about 150 mg/dL.
In the meantime, we would be interested to know if Medtronic Minimed comes up with any ideas for how the bubbles develop. As you may know, our first pump has been tested and found to be working flawlessly – as we said in our letter we expected to be the case. Please let us know if we can give you any additional information.
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