Insulin Therapy

INSULIN THERAPY

Basically, insulin should be given to all patients with type 1 diabetes, which is due to autoimmune islet-cell injury that eventually leads to virtually complete insulin deficiency. The insulin administration may be given in different way depending on the needs or conditions.

Patients on fixed insulin doses should be taught on carbohydrate awareness, or size of 15g carbohydrate portions, without exact carbohydrate counting. In this case, the goal is to keep carbohydrate portions consistent, meal to meal, and not adjust insulin dose.

The table below show the important information about type of insulin with different onset, peak and duration and also its usage.

(Diabetes WebMD, 2011)

There are several factors that may effects the insulin absorption as shown in table below:

(Irl B. Hirsch, M.D; Jay S. Skyler, M.D. et al, 2009)

How to inject insulin?

Insulin injections should be given into the fatty layer under the skin not into muscle, as this tends to speed up the insulin absorption. A pinch of skin should be taken and injection at a 90 degree angle should be done.

HOW TO INJECT INSULIN USING PEN INJECTION

STEPS & GUIDE TO INJECT INSULIN USING SYRINGE

MNT recommendation:

• Insulin therapy may be integrated into an individual’s dietary and physical activity pattern so that it matching each other and result in better condition.
• Adjust the dose of rapid-acting insulin based on carbohydrate content in meals and snacks.
• When on fixed daily insulin doses, keep your carbohydrate content consistent with respect to time and amount preferred.
• Adjust insulin for planned exercise. For unplanned exercise, extra carbohydrate may be needed.

INSULIN PUMP

What is insulin pump?

The insulin pump is a medical device used for the administration of insulin as a treatment of diabetes mellitus. It is also known as continuous subcutaneous insulin infusion (CSII) therapy and commonly used by patient with type1 DM of all age groups and also type 2 DM patients.

Insulin pump therapy is a constant, continuous infusion of short-acting insulin driven by mechanical force and delivered via a needle or soft cannula under the skin. 

The uses of insulin pump

Insulin pump therapy is the most natural form of insulin treatment available nowaday. It is an alternative way to multiple daily injections of insulin by using insulin syringe or an insulin pen. It allows for intensive insulin therapy when used in conjunction with blood glucose monitoring and carbohydrate counting.

By using an insulin pump, it will deal with your insulin to your lifestyle rather than adjusting your lifestyle to your body's response to insulin injections. Thus, insulin pump is able to keep your blood glucose levels within the target ranges both day and night.

How an insulin pump works

1.      Firstly the insulin cartridge is filled with fast-acting insulin and fitted inside the pump. The needle or cannula is inserted under the skin and held in place with an adhesive patch, which fixes to the surrounding skin. 

2.    The other end of the tube is connected to the pump which then delivers insulin through this infusion set according to its programming.

3.      An insulin pump consists of the main pump unit which holds an insulin reservoir (usually 3ml capacity like the cartridges used in an insulin pen).

·         The pump neither measure blood glucose levels nor produce insulin automatically. 

Insulin Doses

Insulin doses are separated into

Basal rates

The basal rate is the tiny, precise doses that the pump delivers at very frequent intervals.  Basal insulin is delivered continuously over 24 hours based on what doses of long acting insulin before, and keeps your blood glucose levels in range between meals and overnight. Often, the rate can be set different amounts of insulin at different times of the day and night.

Bolus doses to cover carbohydrate in meals

A bolus is the same as having insulin shot from an insulin pen. So when you eat, you will give a dose (bolus) by press the button on insulin pump.  If you eat more than you planned, you can simply program a larger bolus of insulin to cover it.

Correction or supplemental doses

You also take a bolus to treat high blood glucose levels. If you have high blood glucose levels before you eat, you give a correction or supplemental bolus of insulin to bring it back to your target range.

Advantages and indication of using insulin pump instead of insulin injections:

• Insulin pump can be replaced to people those fail with intensive insulin regimens.
• Accurately delivery than injections and can be prescribed at very small boluses. 
• Insulin pump allow for adjustable boluses to cover the ingested carbohydrate.
• Insulin pumps often improve HbA1C value.
• Using an insulin pump usually results in fewer large swings in the blood glucose levels.
• Insulin pump therapy can improve the quality of life as we do not need to spend more time and experience pain due to injection.
• Improvements in blood glucose monitoring– If your glucose level is high or you feel like eating something, figure out how much insulin you need and push the little button on the pump.
• Insulin pumps allow you to exercise without have to eat large amounts of carbohydrate.
• Insulin pump will reduces severe hypoglycaemia (low blood glucose episodes)
• Insulin pump therapy is more predictable with fever errors on intermediate- or long-acting insulin

Disadvantages and problem of using an Insulin Pump:

• Can cause weight gain
• Can cause diabetic ketoacidosis (DKA) if the catheter comes out and if the pump user does not receive sufficient fast acting insulin for many hours
• Insulin pumps, cartridges, and infusion sets are far more expensive than syringes used for insulin injection.
• Quite bothersome since the pump is attached to the body in the most of the time.
• Need very good monitoring-- require a hospital stay or maybe a full day in the outpatient centre to be trained.
• Pump users must be limited when participate in activities such rough sport and activities in the water that may damage the pump.
• Scar tissues may build up around the inserted cannula, resulting in a hard bump under the skin after the cannula is removed. In addition, the areas of scar tissue build up generally have lower insulin sensitivity and may affect the basal rates and bolus amounts.
• Users may experience allergic reactions and the other skin irritation from the adhesive on the back of an  infusion set. 

    The pump can be effectively combined with partial basal insulin from the pump and partial basal insulin from long-acting insulin such as Lantus and Levemir. This is becoming known as the untethered regimen.

Source:

• http://www.diabetes.co.uk/insulin/how-insulin-pumps-work.html  How Insulin Pumps Work + Pump Terminology 
• With contributions from Diabetes Expert: Sue Marshall