Insulin pump therapy

Insulin pump therapy, also known as continuous subcutaneous insulin infusion, uses a small, computerised device to deliver insulin continuously in the way a functioning pancreas would. Only short-acting insulin is used for both the background and mealtime requirements.  

Insulin is administered via a plastic tubing connected to the pump on one side and a small cannula inserted through the skin. The subcutaneous site can be on the abdomen, outer thigh, outer arm, or top of buttock. The abdomen is usually the preferred site. The site needs to be changed every three to four days to prevent infection or inflammation.

A background basal rate is set up to give insulin continuously. This rate will vary over the 24 hours of a day depending on the requirements. 

For mealtimes, you will need to give a bolus insulin dose. To do this, the blood glucose value and amount of carbohydrates (in grams) is entered into the pump. The amount of insulin needed to cover the carbohydrates is pre-programmed. In the same way the on-board computer will calculate how much insulin is needed to correct a high blood glucose reading.

Some pumps can communicate with continuous glucose monitoring devices which has brought a new level of accuracy. The most sophisticated of these systems allows the pump to adjust basal insulin according to requirements, switch off insulin delivery if glucose levels drop to low and give small boluses of insulin to correct glucose levels starting to rise. This system has been dubbed the artificial pancreas. 

People with Type 1 diabetes are ideal candidates. However, people with Type 2 diabetes who inject insulin four times a day can also benefit. Unfortunately, pumps are expensive and only worth considering if you have medical aid that will cover the costs.

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