Insulin pump


An insulin pump is a medical device used for the administration of insulin in the treatment of diabetes mellitus, also known as continuous subcutaneous insulin therapy.
The device configuration may vary depending on design. A traditional pump includes:
  • the pump
  • a disposable reservoir for insulin
  • a disposable infusion set, including a cannula for subcutaneous insertion and a tubing system to connect the insulin reservoir to the cannula.
Other configurations are possible. More recent models may include disposable or semi-disposable designs for the pumping mechanism and may eliminate tubing from the infusion set.
An insulin pump is an alternative to multiple daily injections of insulin by insulin syringes or an insulin pen and allows for flexible insulin therapy when used in conjunction with blood glucose monitoring and carbohydrate counting.

Medical uses

Insulin pumps are used to deliver insulin on a continuous basis to a person with type I diabetes.

Advantages

  • Users report better quality of life compared to using other devices for administering insulin. The improvement in QOL is reported in type 1 and insulin-requiring type 2 diabetes subjects on pumps.
  • The use of rapid-acting insulin for basal needs offers relative freedom from a structured meal and exercise regime previously needed to control blood sugar with slow-acting insulin.
  • Programmable basal rates allow for scheduled insulin deliveries of varying amounts at different times of the day. This is especially useful in controlling events such as the dawn phenomenon resulting in fewer and less severe low blood sugar events during the night.
  • Many users feel that bolusing insulin from a pump is more convenient and discreet than injection.
  • Insulin pumps make it possible to deliver more precise amounts of insulin than can be injected using a syringe. This supports tighter control over blood sugar and hemoglobin A1c levels, reducing the chance of long-term complications associated with diabetes. This is predicted to result in a long-term cost savings relative to multiple daily injections.
  • Many modern insulin pumps have a "bolus wizard" that calculates how much bolus insulin is needed, taking into account expected carbohydrate intake, blood sugar level, and still-active insulin.
  • Insulin pumps can provide a record of insulin usage through their history menus. On many insulin pumps, this history can be uploaded to a computer and graphed for trend analysis.
  • Neuropathy is a troublesome complication of diabetes resistant to usual treatment. There are reports of alleviation or even total disappearance of resistant neuropathic pain with the use of insulin pumps.
  • Recent studies of use of insulin pumps in Type 2 diabetes have shown profound improvements in HbA1c, sexual performance, and neuropathy pain.

    Disadvantages

Insulin pumps, cartridges, and infusion sets may be far more expensive than syringes used for insulin injection with several insulin pumps costing more than $6,000; necessary supplies can cost over $300. Another disadvantage of insulin pump use is a higher risk of developing diabetic ketoacidosis if the pump malfunctions. This can happen if the pump battery is discharged, if the insulin is inactivated by heat exposure, if the insulin reservoir runs empty, the tubing becomes loose and insulin leaks rather than being injected, or if the cannula becomes bent or kinked in the body, preventing delivery. Therefore, pump users typically monitor their blood sugars more frequently to evaluate the effectiveness of insulin delivery.
  • Since the insulin pump needs to be worn most of the time, pump users need strategies to participate in activities that may damage the pump, such as rough sports and activities in the water. Some users may find that wearing the pump all the time is uncomfortable or unwieldy.
  • Possibility of insulin pump malfunctioning, and having to resort back to multiple daily injections until a replacement becomes available. However most pump manufacturers will have a program that will get a new pump to the user within 24 hours or allow the user to buy a second pump as a backup for a small fee. Additionally the pump itself will make many safety checks throughout the day, in some cases up to 4,000,000 and may have a second microprocessor dedicated to this.
  • Users may experience scar tissue buildup around the inserted cannula, resulting in a hard bump under the skin after the cannula is removed. The scar tissue does not heal particularly fast, so years of wearing the pump and changing the infusion site will cause the user to start running out of viable "spots" to wear the pump. In addition, the areas with scar tissue buildup generally have lower insulin sensitivity and may affect basal rates and bolus amounts. In some extreme cases the insulin delivery will appear to have no/little effect on lowering blood glucose levels and the site must be changed.
  • Users may experience allergic reactions and other skin irritation from the adhesive on the back of an infusion set. Experience may vary according to the individual, the pump manufacturer, and the type of infusion set used.
  • A larger supply of insulin may be required in order to use the pump. Many units of insulin can be wasted while refilling the pump's reservoir, filling the tubing, or changing an infusion site. This may affect prescription and dosage information.
  • In February 2025 the FDA alerted patients of a safety concern of insulin that rely on a smartphone to deliver critical safety alerts, because reports showed that people were missing alerts due to technology configuration issues.
  • When flying in airplanes the cabin pressure changes can cause under- or over-delivery of insulin in certain pumps, putting insulin pump users at risk of unexpected hypoglycemia or hyperglycemia.

    Accessibility

Use of insulin pumps is increasing because of:
  • Easy delivery of multiple insulin injections for those using intensive insulin therapy.
  • Accurate delivery of very small boluses, helpful for infants.
  • Growing support among doctors and insurance companies due to the benefits contributing to reducing the incidence of long-term complications.
  • Improvements in blood glucose monitoring. New meters require smaller drops of blood, and the corresponding lancet poke in the fingers is smaller and less painful. These meters also support alternate site testing for the most routine tests for practically painless testing.

    History

In the early 1960s, Dr. Arnold Kadish, a physician working at Loma Linda University, developed a closed-loop device for blood glucose control using a double-lumen autoanalyzer to measure blood glucose linked to an intravenous insulin infusion pump. Although it worked, the prototype was considered so bulky, worn as a backpack, and complicated, that it was never commercialized. In 1976, the first commercialized insulin pump was created and was named the Biostator. The pump was a 60 kg bedside device. It also had the capability of monitoring blood glucose levels, so this also doubles as the first continuous glucose monitor. Between 1978 and 1988, Robert Channon, working with Guy's Hospital and the Bristol Royal Infirmary, developed a series of miniature insulin infusion pumps. Today, insulin pumps are so small that they can fit in a pocket or a purse.
In 1984, an Infusaid implantable infusion device was used to treat a 22-year-old patient successfully.
The insulin pump was first endorsed in the United Kingdom in 2003 by the National Institute for Health and Care Excellence.

Developments

New insulin pumps are becoming "smart" as new features are added to their design. These simplify the tasks involved in delivering an insulin bolus.
  • Insulin on board: This calculation is based on the size of a bolus, the time elapsed since the completion of the bolus, and a programmable metabolic rate. The pump software will estimate the insulin remaining in the bloodstream and relay it to the user. This supports the process of performing a new bolus before the effects of the last bolus are complete and, thereby, helps prevent the user from overcompensating for high blood sugar with unnecessary correction boluses.
  • Bolus calculators: Pump software helps by calculating the dose for the next insulin bolus. The user enters the grams of carbohydrates to be consumed, and the bolus "wizard" calculates the units of insulin needed. It adjusts for the most recent blood glucose level and the insulin on board, and then suggests the best insulin dose to the user to approve and deliver.
  • Custom alarms: The pump can monitor for activities during specific times of day and alarm the user if an expected activity did not occur. Examples include a missed meal bolus, a missed blood glucose test, a new blood glucose test 15 minutes after a low blood glucose test, etc. The alarms are customized for each user.
  • Touch bolus: For persons with visual impairments, this button on the pump can be used to bolus for insulin without using the display. This works with a system of beeps or vibrations to confirm the bolus parameters to the pump user. This feature is described as 'touch', 'audio', or 'easy' bolus depending on brand. The feature was first introduced in the mid- to late 1990s.
  • Interface to personal computers: Since the late 1990s, most pumps can interface with personal computers for managing and documenting pump programming and/or to upload data from the pump. This simplifies record keeping and can be interfaced with diabetes management software.
  • Integration with blood glucose meters: Blood glucose data can be manually entered into the pump to support the bolus wizard for calculation of the next insulin bolus. Some pumps support an interface between the insulin pump and a blood glucose meter, with either wired or radio frequency communication.
  • Integration with continuous glucose monitoring systems: Some insulin pumps can be used as a display for interstitial glucose values obtained from a continuous glucose monitoring system or sensor.