An insulin pump is a small medical device that delivers insulin to people with diabetes through thin tubing and a tiny catheter placed under the skin. It helps replace some of the work normally done by the pancreas, which releases insulin to move glucose from the blood into cells. Pumps matter because they can provide steady insulin throughout the day and extra insulin at meals.
This can improve glucose control when the user measures glucose, counts carbohydrates, and programs doses correctly.
The pump delivers rapid-acting insulin in two main ways: a basal rate for background needs and a bolus dose for meals or corrections. A motor inside the pump pushes very small amounts of insulin from a reservoir through an infusion set into the fatty tissue under the skin. The user or an automated system adjusts dosing based on glucose readings, carbohydrate intake, activity, illness, and medical guidance.
Because insulin is powerful, safe pump use depends on careful site changes, dose checks, and attention to alarms or tubing problems.
Key Facts
- Basal insulin is delivered slowly throughout the day to cover background insulin needs.
- Bolus insulin is delivered in larger programmed doses for meals or high blood glucose corrections.
- Total daily insulin dose = total basal insulin + total bolus insulin.
- Meal bolus = grams of carbohydrate ÷ insulin-to-carbohydrate ratio.
- Correction bolus = (current glucose - target glucose) ÷ correction factor.
- Most pump infusion sites are changed every 2 to 3 days to reduce irritation, infection risk, and poor insulin absorption.
Vocabulary
- Insulin pump
- A programmable device that delivers rapid-acting insulin through tubing and a small catheter under the skin.
- Basal rate
- The background insulin delivery rate that helps control blood glucose between meals and overnight.
- Bolus dose
- An extra dose of insulin given for food intake or to correct blood glucose that is above target.
- Infusion set
- The tubing, connector, and small catheter that carry insulin from the pump into tissue under the skin.
- Continuous glucose monitor
- A sensor system that estimates glucose levels in body fluid and can help guide insulin dosing decisions.
Common Mistakes to Avoid
- Confusing basal and bolus insulin, which is wrong because basal covers background needs while bolus covers meals or corrections.
- Forgetting to count carbohydrates before a meal bolus, which is wrong because the pump needs an accurate carbohydrate amount to calculate a safe dose.
- Ignoring pump alarms or kinked tubing, which is wrong because interrupted insulin flow can cause blood glucose to rise quickly.
- Leaving the infusion site in too long, which is wrong because old sites can become irritated, infected, or less effective at absorbing insulin.
Practice Questions
- 1 A student's meal contains 60 g of carbohydrate. If the insulin-to-carbohydrate ratio is 1 unit for every 12 g, what meal bolus should the pump deliver?
- 2 A pump is set to deliver basal insulin at 0.8 units per hour for 24 hours. How many units of basal insulin are delivered in one day?
- 3 A pump user has high blood glucose after exercise and notices the tubing is disconnected. Explain why checking the infusion set is important before giving a correction bolus.