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."
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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.
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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.