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Canulas that fail and lead to DKA

Article by Lahle Wolfe, July 25, 2006
For permission to reprint this article e-mail Editor@isletsofhope.com

Elizabeth, my daughter, now age 7, was diagnosed with type 1 diabetes when she was 4 years old.  Like most children newly diagnosed with diabetes, she was heavily into diabetic ketoacidosis (DKA) when we arrived at the hospital the day of her diagnosis.  But only once since that fateful day has she ever tested positive for ketones – even with high sugars – and that was during her first week of living life as a human pincushion.  Until this week.

For more than 2-1/2 years she has been ketone-free.  We have beaten the DKA odds through proper use of an insulin pump and frequent blood sugar checks, and a little bit of luck -- and the right canula for the job.

Recently, I switched Elizabeth’s canula setup from the Rapid D to the Inset canula.  The Rapid D works like a thumb tac.  It has a hard, metal needle you shove straight into the insertion site.  No muss, no fuss; easy as pie.  Rapid Ds stay in fairly well and never crimp.  They last for 2-3 days without problems, we have never had an infection, and they are cheap.  I consider them the workhorse of canulas, under appreciated, and sadly, on their way out as more and more companies are pushing fancier and higher priced canula sets on patients.

The downside to using Rapid D is that Elizabeth only has enough body fat to take them in her tiny tushie.  Her bottom was beginning to show the tell-tale signs of overuse and we needed to find a new canula that she could use on her skinny tummy.  At the strong encouragement of our pump company to abandon the Rapid D, we tried several other sets (with disastrous and painful results) before deciding upon the Inset.  Using an Inset requires a lot of finesse and there is plenty of opportunity to do something wrong, but they don’t hurt and that is a big plus for any parent who dislikes the idea that they are hurting their child.

But I have found Insets are notorious crimpers and often can deliver insulin unpredictably; result: three times in the span of 5 days Elizabeth went into DKA overnight when the canula failed her.  Now, I am not a parent who sleeps through the night.  Like many parents, I check my daughter’s sugars religiously throughout the night at least 2-3 times.  On an insulin pump, this is often necessary in children who have dynamic diabetes, as does Elizabeth. 

Last night, I checked her blood sugars at midnight, 2 a.m. and again at 4 a.m.  She seemed fine, but at 4 a.m. had risen to 253 mg/dL so I gave her a correction bolus.  At 6 a.m. she was over 300 mg/dL.  Elizabeth often suffers from the Dawn Effect so I gave her a generous correction bolus and checked her an hour later:  303 mg/dL; the site had failed once again and so for at least two hours Elizabeth was not getting her basal insulin and in this short time frame she was already into DKA.  “I am peeing dark purple Mommy,” sighed Elizabeth through the bathroom door not pleased with the idea of another “emergency” site change.

This brings me to the point I wish to make.  For those on insulin pumps, especially children, the risk of entering DKA is greater than for those on shot therapy and you need to be vigilant about checking for ketones when sugars are over 240 mg/dL – especially if the site fails, the pump is unhooked, or any time normal basal insulin delivery is compromised.

Why?  Most pump users infuse only one kind of insulin -- rapid acting insulin.  This insulin works quickly but has the shortest life of all insulin available.  For pump users, this means that there is little circulating insulin in the body because the pump gives a constant mini drip drip to cover basal insulin requirements.  When that drip stops, so does basal insulin delivery.

People on shot therapy usually take more than one type of insulin including intermediate or long-acting insulin to cover basal needs.  Shot users have more “on board” basal insulin working in their body at any given time than do those on an insulin pump.

Because pump users do not have long-acting insulin in their body, shutting off the pump for any length of time is dangerous and you should only do so under the strict guidance of your child’s doctor.  Children pumpers can enter into DKA in only 1-2 hours, and at much lower blood sugar levels – even when under the “magic” 240 mg/dL.

If your child does register urine ketones, call your doctor immediately!  DKA often requires hospitalization because simply giving more insulin to bring a child out of DKA faster can actually do more damage than good.  Incorrectly treating DKA can lead to coma, edema of the brain, and death.

This morning we are back using the cheaper, reliable, and yes a little painful at times, Rapid D.  Like everything diabetes, balance is key.  Elizabeth hates the Rapid D, but not as much as being in the emergency room. 

My advice to other parents is to use what works, not what is "recommended" by insurance companies and diabetes suppliers who stand to benefit from having you switch to higher or lower priced canulas (Inset costs me $200 per 1 month supply; Rapid D costs $90).  Your child's doctor, and what you know to be best for your child, should be the determination for which canula to use.  

The canula is a medically necessary device. Using the wrong canula because of outside pressure related to the almighty dollar, could land your child in the hospital with DKA.  If your insurance company refuses to pay for a higher priced canula set that works for your child, you might kindly remind them that the average hospital stay for treatment of DKA will cost them far more than the price of doing what is right.

Replies welcome.  Contact Editor@IsletsofHope.com

Points to remember

• Pump users are at risk for DKA anytime basal rates are interrupted – even for short periods of time.
• Pump users can enter into DKA faster, and at lower blood sugar ranges, than people on shots who take long-acting insulin – even under 240 mg/dL.
• Never attempt to treat DKA by yourself:  DKA is dangerous and you should report urine ketones to your child’s doctor immediately.

Note:  This information also applies to adults on insulin pumps.

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