The $15,000 insulin pump catheter
Our diabetes technology is amazing. But it's no better than its weakest link. With diabetes therapy there are many potential stumbling blocks on the path to good control.
Case in point. The device above is an insulin pump catheter. The cost to make one one these is pennies. The sales price is a bit more. But this one created a $15,000 bill for one family. Insulin pumpers know exactly what I'm talking about.
The owner of this catheter changed an infusion site one evening and went on his business. The next morning, feeling nauseous, he chose not to say anything to his family and went to high school. His blood sugar was 279 mg/dl [15.5 mmol/L]. He took a correction dose of rapid-acting insulin via his insulin pump. By noon, his mother was making a phone call to the on call endocrinologist to report her son had been vomiting at school, too many times to quantify. She was told by the doctor to pick him up ASAP, go directly to the emergency room, and be prepared for an admission to hospital intensive care unit (ICU).
The medical team at the ICU successfully managed his diabetic ketoacidosis over the next 24 hours. During the course of his treatment, he was asked to remove the existing pump site and replace it. When he did, this is how the catheter appeared.
Like many others with diabetes, this family believed that DKA was something that "just happens" to people with diabetes. This experience taught a valuable lesson to the contrary.
For background, the patient measures blood sugar about once a day on average. He admits to missing 2-3 scheduled insulin doses (boluses) a week. He says he counts his carbohydrates but this can't be easily proven. He does own a continuous glucose monitoring device (CGM), but doesn't wear it anymore since he wouldn't calibrate it properly. He has had type 1 diabetes for over 5 years. Average level of glycemic control is reflected by A1C levels ranges between 8%-10%.
Although the patient and family had received formal instruction about insulin pump therapy, there were several behaviors or choices which ultimately resulted in his DKA.
First, he was in the habit of not checking his blood sugar. You might ask why was he on a pump, but his behavior is not uncommon and rarely are patients taken off pumps based on low monitoring frequency alone. Second, he did not check his blood glucose (BG) after the new infusion site insertion. This is a core insulin pumping principle. If he had done this the night before he would have likely discovered a rising BG level, suggesting a poorly functioning site. This would have hopefully prompted further action. But you already know this person checks BG infrequently, making it unlikely he ever checks a follow up reading after a new site insertion.
No doubt that over the years that he has used his pump he has not checked a BG 2-3 hours afterwards. This is the standard recommendation). So prior behaviors (and a bit of luck) reinforced the notion that what he was taught at the beginning regarding proper site insertion might not apply to him.
Third, when he was nauseous he chose not to say anything to his family. He just went on to school, It wasn't until multiple episodes of vomiting later had occurred that any action was taken. By then it was too late to manage this situation outside a hospital setting and a visit to the ICU was inevitable.
Had different choices been made at any time along this chain of events, a different outcome would have occurred. The chain could have been broken.
Checking the BG after site change could have shown a rising BG level and prompted action to correct it. Using the pump might be a reasonable first step, but after 1-2 hours and no improvement, the family would need to suspect the integrity of the pump system. Anything could go wrong, from catheter tip all the way to pump programming itself. Dislodged or disconnect infusion sites are the most common form of pump malfunction in my experience.