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Re: [IP] Pumping Questions
Thanks for the information!
At 08:13 PM 11/23/98 -0600, you wrote:
>From: Carl Baker <email @ redacted>
>To: email @ redacted <email @ redacted>
>Date: Monday, November 23, 1998 7:05 PM
>Subject: [IP] Pumping Questions
>>I'll be meeting with pump representatives in the near future. I feel that
>>each supplier with give me a sales pitch and claim their pump is superior.
>>With only two choices, I have a 50% chance of choosing the best one. Is
>>there really any major differences in the pumps? Please let me know your
>Every user swears by his pump. Minimed users report what I consider a
>disturbing frequency of no-delivery alarms, a problem I feel stems from its
>lower pumping pressures and use of plastic cartridges (see below). Even so,
>Minimed pumpers report being satisfied with the remediation to their
>problems and its users swear by their pumps also.
>After someone has made an investment of over four thousand dollars in a
>piece of equipment, he tends to be very defensive about his choice. So we
>tend to build up our choice. I would imagine what I have to say will
>engender some defensive writing.
>I have been using the Disetronic H-Tron plus V 100 for one year.
>Here's some (objective I think) considerations that persuaded me to choose
>Disetronic sends two pumps, as the pump is programmed to turn off for
>factory service after two years of pumping. After service at the factory
>each pump is returned with an additional two years of warranted service.
>The extra pump can be used anytime as a back up. Minimed sends one.
>NOTE: Some Minimed owners say the two pump approach turns them off; that
>the unit must be bad if users need a spare. Not so. The reality: I've
>never even powered up my spare. But if I need to send in a unit for
>service, I'm assured I won't have to go back to multiple injections, or
>worry how long they have to keep the pump. I haven't taken a single
>injection since I began pumping.
>Minimed uses a solenoid to push insulin a tenth of a unit at a time. If a
>user has a basal dose of 8-tenths of a unit hourly, the Minimed will click
>eight times an hour, or once about every seven and half minutes. In
>delivery of boluses of, say, 6-1/2 units, the Minimed will click 65 times
>and it will take several minutes to deliver.
>Disetronics pump an infinitely variable dose of insulin through a screw
>drive. Five percent of hourly basal dosages are delivered each three
>minutes. In the above case, 8/10 unit per hour, 4/100 unit is delivered
>each three minutes. The above cited bolus of 6-1/2 units is silently pumped
>in a matter of seconds.
>Minimed would not match the delivery frequency capabilities of the
>is, a click every three minutes) until the basal dosages exceed 2 units an
>hour. That's much higher than the basal rate of virtually every user.
>With this in mind, I concluded that the Disetronic's delivery is smoother,
>faster and closer to natural than Minimed's.
>I looked at the pumping pressures of the two pumps, in the belief that would
>have some bearing on pumping through any obstructions in the tubing.
>Disetronic pumps at 2-3x higher pressures. It turns out that more Minimed
>users are complaining about non-delivery alarms. I worried that the higher
>pressures would induce pain during boluses. It doesn't.
>The Disetronic can be operated without damage underwater without
>modification or addition of waterproof casings. There's a removable tappet
>designed to keep moisture out of the cartridge chamber, but even a flooded
>cartridge chamber has no detriment to the pump or its operation. Just
>remove the cartridge and towel off the chamber. All of the mechanical and
>electrical components are sealed. Minimed's are exposed and the unit can be
>operated underwater briefly only after the user adds an optional, additional
>sports guard. This turned out to be pretty important for me since I swim
>regularly for extended periods of time. Hanging the pump around one's neck,
>the Disetronic can be taken into the shower as well. Get your Minimed
>really wet and you'll have to return it for service.
>Humalog is the ideal insulin for use with the pump because it acts rapidly
>(<10 minute) and because such small amounts are used and in the body when
>delivered by pump. This also has implications in making hypos more
>There's another fairly important difference between the two pumps related to
>Humalog, with the Disetronic holding an advantage. The cartridges for the
>Disetronic can be plastic or glass. Glass costs more and is the preferred
>material. All Minimed cartridges are plastic.
>Plastic cartridges tend to degrade Humalog molecularly. The Humalog is
>attracted ionically to the plastic wall of the cartridge. The plastic ones
>also present more opportunity or propensity for contamination with air.
>Humalog has some degradability properties that are problematic for pump
>users. Many of the Minimed users find they have potency/delivery problems
>before their cartridges empty, and they have to change them sooner. Many
>also report they have to dilute their Humalog for various reasons.
>Here's a description of a regimen for filling cartridges from the Humalog
>vial. I fill three glass cartridges (315u/each) sequentially at the same
>sitting, and refrigerate all until placing each into the pump. In other
>words, I leave a cartridge filled with Humalog as long as two weeks before
>pumping from it, and each has as much potency as the one before it. I don't
>believe Minimed users can do it the same way and I don't think they can have
>the same result.
>Plastic cartridges cannot be prefilled with Humalog that far in advance.
>And even if they fill them just before placing the cartridge in the pump,
>the Humalog remaining in the used factory-filled vial may be degraded as
>well, perhaps by as much as 30 percent.
>BTW, my last hgba1c was 4.9%.
>>Also, I have the same question regarding infusion sets. What are
>>users having the most comfort and delivery with? Any information will be
>>appreciated. I will be asking more questions in the future.
>My opinion is those with Teflon catheters inserted at shallow angles
>(Minimed's silhouette and Disetronic's tender) are superior to metal needles
>or Teflon inserted perpendicular through the skin. Subjectively, I find
>them more comfortable. Objectively they are more slender. Appealing to me
>are their quick disconnects at the catheter (no pony-tail hanging off like
>on the Minimed sofset).
>OTOH, sofset users claim this is an advantage because they can disconnect
>even when they cannot reach the infusion set. How do they put them on and
>take them off? Additionally, the sofset can be inserted with help of a
>Again, the pumpers on this listserv are using all the different hardware and
>each swears by the one he is using.
>Insulin-Pumpers website http://www.insulin-pumpers.org/
Insulin-Pumpers website http://www.insulin-pumpers.org/