Insulin Pump Therapy

Overview

Diabetes mellitus is known as an affluent disease or, simply put, a condition that affects the wealthy. However, doesn’t it seriously contradict the proverb ‘health is wealth’? This lifestyle condition has been increasingly affecting populations from both the developed and the developing world with the availability of more unhealthy or junk food options, and people being less active in modern-day society. 

With comparably less advanced treatment options in the developing world, the negative implications of diabetes on patients from these countries have been significantly high. It is a known fact that diabetes is associated with a higher risk of cardiovascular diseases and hence it is important to manage your condition to avoid future adverse effects. 

What is insulin pump therapy? 

The major rationale behind diabetic management lies in reaching strict glycemic control to avoid long-term complications that are related to this condition and keep the occurrence of hypo and hyperglycemic episodes at bay.¹ 

Insulin Pump Therapy, scientifically known as subcutaneous insulin infusion (CSII), is the most advanced breakthrough the medical world has seen in the management of diabetes mellitus.² CSII is a small and handy device that delivers a continuous supply of insulin to the body throughout the day and sometimes comes with a monitoring device that can monitor blood glucose levels. CSII or insulin pump therapy was developed to treat diabetes mellitus and was introduced in the late 1970s.³ These devices were designed to mimic the physiologic functioning of the pancreas in secreting insulin. Although the initial prototype was a huge device that had to be carried in a backpack, CSII soon saw a steep advancement with added elements such as a biostator, which acts like a closed-loop pancreatic system that enables the continuous monitoring of blood glucose level and an intravenous infusion of insulin.^3,4 

Multiple daily injections (MDI) have been the most common regimen for managing diabetes with external insulin, however, this has multiple drawbacks. The CSII’s convenience factor and several other advantages make it a preferred method of diabetic management. 

Components of an insulin pump

The main components of an insulin pump (as shown above) include the pump itself which comes in the shape of a battery-powered cassette. The pump contains the reservoir where insulin is stored and has functional control buttons or keys. The insulin reservoir is connected to a delivery tube that delivers insulin to the patient’s body through the infusion set which has a subcutaneous cannula or a needle attachment.⁵ 

How insulin pump therapy works

As mentioned above, most insulin pump devices come with separate cassette-like pumps and infusion sets that are connected by a delivery tube, which is plastic tubing that delivers insulin from the insulin reservoir to the patient’s body. However, there are other types of devices available in the market that combine both of these components to create a tubeless pump that is more convenient for the patient.⁵ 

The infusion set is affixed on the patient's body with an adhesive and delivers insulin via a cannula that goes into the subcutaneous tissue of the patient’s upper arm, abdomen, lower back or upper thigh.⁵ 

The pump is battery-run and contains the insulin reservoir which should be changed once every two or three days, as a typical reservoir can hold only 2 to 3 days' worth of rapid-acting insulin supply, according to the patient’s specific total daily insulin requirements.⁵ 

The rapid-acting insulin analogue is replaced after all the insulin is used up in the reservoir. The device comes with a screen that will allow a review of basal insulin settings and past dose history. This can be controlled using several buttons that appear on the pump cassette. The insulin type loaded into the reservoir is typically any type of rapid-acting insulin such as lispro, glulisine or aspart. 

Insulin delivery happens in two different ways; basal and bolus insulin delivery. Basal insulin delivery is a continuous delivery of insulin to the body at a rate that is either pre-set or auto-adjusted for 24 hours.⁵ On the other hand, bolus or mealtime delivery is the delivery of insulin at mealtimes and is calculated according to the amount of carbs the patient enters into the pump of the system.⁵ There is a special formula in place to calculate the insulin-to-carb ratio (ICR), and it shows the number of grams of carbs to be covered by one unit of insulin to be delivered into the body.⁵ The formula for reference is ICR: 450/TDD, where TDD is the total daily dose. 

Advantages of insulin pump therapy vs MDI

Initiating insulin pump therapy

Before an insulin pump therapy treatment is advised and initiated, there are certain factors to consider and goals to be achieved to make sure that the patient is indeed ready to embark on a long journey of an embedded pump in their body, and that the pump itself is ready for usage. 

Patient selection criteria

Insulin pumps were originally invented and developed for type 1 diabetic patients. However, it is good to note that people with type 2 diabetes who could not achieve an improvement in their glycemic control using oral diabetic medications could benefit from CSII. There are benchmarks set to identify ideal insulin pump candidates including:

• Willingness to carry around the device on their body at most times with the adhesive on their skin
• Motivated to have regular follow-ups with their healthcare team and complete education programmes about this therapy
• Insurance coverage or eligibility to access free pumps under the NHS in the UK, or adequate out-of-pocket funding to get insulin pumps²
• Willingness to self-monitor blood glucose level 4-6 times a day if the device does not include an automatic monitor
• Be willing to embed an automatic continuous glucose monitor (CGM) in their body if required.²
• Willingness to keep track of their carbohydrate intake 

Training and education for patients

Training programmes are available to ensure appropriate and adequate usage of insulin pumps. Patients must be willing to take this programme religiously before embedding an insulin pump in their bodies. This type of education programmes is designed to help patients or their caregivers with:

• Accurate operation of the specific kind of insulin pump device they have chosen
• Knowledge of inserting the cannula properly into subcutaneous tissue
• Self-monitoring blood glucose levels
• Ability to manage additional information from CGM
• Insulin-to-carb ratio calculation
• Bolus insulin delivery calculation 
• Measures to take in case of hypoglycemia or hyperglycemia.² 

Considerations and challenges

Like any other breakthrough technology, CSII also has several challenges that must be addressed. These include the following: 

• Cost and accessibility
• Adherence to lifestyle factors
• Potential complications and troubleshooting

Cost and accessibility

Insulin pump therapy, similar to its counterpart MDI, is expensive. According to the Diabetes Journals, the mean annual costs for insulin therapy were higher than that of MDI, and around 73% of this cost was accounted for by medication and disposables.¹⁰ Therefore, it is a huge challenge for patients who do not have any insurance coverage to cover the therapy cost. 

Another challenge is the accessibility of insulin pumps in several countries. For example, to qualify for an insulin pump from the NHS, the patient must meet the National Institute for Health and Care Excellence (NICE) criteria, and the healthcare provider must recommend the patient for the pump therapy. 

Adherence and lifestyle factors

Self-care measures and lifestyle factors play a crucial role in the effectiveness of an insulin pump in the maintenance of glycemic control and ensuring patient safety. Carbohydrate intake calculation and insulin-to-carb ratio calculation are crucial for bolus insulin delivery and preventing adverse effects such as hyper- or hypo-glycemia.² 

Periodic blood glucose monitoring is the most important factor patients or caregivers need to consider when using insulin pumps to maintain optimal glycemic control. It is of the utmost importance to provide proper training programmes and educational materials for patients or caregivers to ensure that the technology is being utilised accurately with adherence to the proper lifestyle requirements advised by their healthcare providers.² 

Potential complications and troubleshooting

Insulin pumps might lead to adverse effects such as skin irritability or hypersensitivity in patients due to the long wear-time of the device on the patient's body.⁹ There are safety implications relating to the infusion set and cannula as they might get detached, crimped or even lead to leakage of insulin.⁹ 

Other concerns include infection at the infusion site, induration, erythema or tenderness to palpation.⁵ Moreover, the settings of the device might be overly complicated for some patients. The utilisation of the numerous buttons on the pump to change settings and replacing the insulin reservoir once it runs out of insulin are other technical issues patients might face. To overcome these challenges, it is important that patients attend the training sessions provided by their healthcare providers and strictly abide by the rules advised to them. 

Summary 

Insulin pump therapy is a small and handy device that delivers a continuous supply of insulin to the body throughout the day and sometimes comes with an automatic continuous monitoring (CGM) device that can monitor blood glucose levels on the side. This device acts in a closed-loop pancreatic way, mimicking the function of a healthy pancreas. Although this technology was initially invented to manage type 1 diabetes, it can also be useful for type 2 diabetes patients who struggle to maintain healthy glycemic control using oral medication. Most insulin pump devices come with separate pumps and infusion sets that are connected by a delivery tube that delivers insulin from the insulin reservoir to the patient body. Insulin delivery happens in two different ways; basal and bolus insulin delivery.

Insulin pumps have several advantages including improved blood glucose control, enhanced flexibility in insulin delivery, and reduction in hypoglycemia. However, there are certain limitations to this therapy such as cost and accessibility, patient adherence to advised lifestyle conditions, and other potential complications. This can be overcome with proper education and training programmes being given to patients to ensure appropriate usage of this device. 

FAQs 

1. What is insulin pump therapy?

Insulin pump therapy, also known as continuous subcutaneous insulin infusion (CSII), is a method of delivering insulin to manage diabetes. It involves using a small device to deliver a continuous supply of insulin throughout the day.

2. How does an insulin pump work?

An insulin pump continuously delivers insulin through a small tube (infusion set) inserted under the skin to subcutaneous tissues. It provides both basal (background) and bolus (mealtime) insulin, offering more precise control over blood glucose levels.

3. What are the advantages of insulin pump therapy?

Insulin pump therapy offers improved blood glucose control, flexibility in insulin delivery, and a reduced risk of hypoglycemia. It allows for personalised adjustments in insulin dosages and mimics the natural insulin secretion of a healthy pancreas.

4. How is insulin pump therapy initiated?

Patients undergo a selection process based on specific criteria. Training and education are essential, covering pump operation, insertion of infusion sets, and understanding basal and bolus insulin adjustments.

5. What considerations and challenges are associated with insulin pump therapy?

Cost and accessibility, adherence, and potential complications are key considerations. Patients may face challenges related to lifestyle adjustments and troubleshooting issues with the pump.