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.
Understanding Medical Technology: Insulin Pumps
Insulin is needed even between meals and during sleep because the liver releases a small amount of glucose into the blood all the time. The body’s insulin need can change hour by hour. It may rise before waking because of hormones that prepare the body for the day.
It may fall during or after exercise because muscles take in more glucose. A pump can use different background settings at different times, but those settings need careful testing with a diabetes care team. A setting that works on a quiet school day may not work during sports, illness, stress, or puberty.
Many modern pumps can connect to a continuous glucose monitor. This sensor measures glucose in fluid just under the skin every few minutes. Software uses those readings to predict whether glucose is likely to rise or fall.
Some systems can reduce background delivery when a low level is predicted. Others can increase or decrease delivery within safe limits. These systems are helpful, but they do not copy a healthy pancreas perfectly.
Sensor readings can lag behind blood glucose, especially when levels are changing quickly. Food, exercise, and unexpected errors still require the user to notice patterns and respond.
Meal dosing involves more than entering the amount of carbohydrate. Foods high in fat or protein can slow digestion, so glucose may rise later than expected. A pizza meal, for example, may need a different plan from fruit juice with the same carbohydrate amount.
Physical activity soon after eating can make insulin act more strongly. Students learn to check labels, estimate portions, and record what happened after meals.
This builds useful evidence over time. It helps them see whether a dose pattern, meal type, or activity caused a result instead of blaming one glucose reading alone.
Pump safety depends on remembering that only rapid acting insulin is usually used. If delivery stops because a cannula bends, tubing disconnects, insulin runs out, or the pump is damaged, the body has no long lasting backup insulin from the pump. Glucose can then rise quickly, and ketones may form when cells cannot use glucose well.
Ketones are chemicals made when the body breaks down fat for energy. High glucose with ketones can become a serious emergency called diabetic ketoacidosis.
Users need a backup plan that includes checking glucose, checking ketones when advised, taking injected insulin if needed, and getting adult or medical help promptly. Keeping supplies nearby at school, on trips, and during sport is part of responsible pump use.
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.