If during insulin pump therapy the glucose sensor reading is unexpectedly high, it should be verified with a fingertip blood glucose self-masurement. An unexpectedly high blood sugar refers to a value over 14 mmol/l that is not due to an underestimation of carbohydrates, a delay or omission of mealtime insulin, or insulin resistance caused by sick days.
The insulin used in pumps is rapid-acting, and there isn't the same kind of insulin reserve under the skin as there is when using long-acting basal insulin. When insulin delivery is interrupted, blood sugar can rise significantly within a couple of hours, and a lack of insulin leads to the accumulation of ketones. Diabetic ketoacidosis (DKA) can develop within a few hours.
In pump therapy, interruptions in insulin delivery can be due to pump malfunction, infusion set blockage, or problems related to the cannula site such as a bad site, cannula detachment, cannula bending, or poor insulin absorption due to tissue damage, for example.
If blood sugar rises above 14 mmol/l, identify and correct the cause.
Action Plan:
Inject rapid-acting insulin using a spare pen or insulin syringe from an insulin vial.
Check ketones with a ketone meter.
If ketones are above 1.5 mmol/l, take a larger than usual correction dose of insulin and drink plenty of water.
If ketones are above 3 mmol/l, contact the emergency department.
If you feel unwell or have symptoms of acid poisoning such as abdominal pain, nausea, or vomiting, go to the emergency department.
Check the pump and cannula operation:
Cannula and tubing
is it detached?
Is insulin leaking?
Is there air in the tubing or reservoir?
Insulin:
Has it been more than 3–4 days since the change?
Has it been exposed to heat or has it been frozen?
Cannula site:
Is there any hardening or swelling?
Is the cannula bent?
If no other cause is found, insert a new cannula at a new site.
Ensure the pump’s battery has power.
Measure blood sugar and ketones 1–2 hours after injecting the additional insulin.