Adjusting Correction Insulin MDI
Adjusting Insulin (MDI): correction insulin & sliding scales
Allison Husband, RN, MN, CDE (Clinical Nurse Specialist formerly at the Diabetes Clinic, Alberta Children’s Hospital)
Correction insulin is an extra dose of insulin given to reduce high blood glucose. How well is your current correction dose working? That is, does it correct the high blood glucose down to target? Or does it over- or under-correct? Here we look at how to assess your child's Correction Formula, Correction Number, or Sliding Scale, plus how to adjust the dose if needed, all within a Multiple Daily Injection (MDI) program.
Before Reading This Article...
If you have not done so already, we recommend that you read the following WaltzingTheDragon.ca pages on insulin adjustment within Basal-Bolus/MDI programs as background for the information that follows:
How Insulin Action Impacts Blood Glucose in an MDI Program
What is Correction Insulin?
Correction insulin is an extra dose of insulin given to reduce high blood glucose.
Your child’s diabetes health care team may have assigned a Correction Formula, a Correction Number (also known as Insulin Sensitivity Factor—ISF) or Sliding Scale. These are different approaches to the same goal: correcting high blood glucose. In each case, extra rapid-acting insulin is given (along with meal insulin, or by itself outside of meal times) to correct elevated blood sugar to target range.
Do I Need to Adjust the Correction Insulin?
You need to periodically assess if your correction is working. That is, does it correct the high blood glucose down to target? Or instead does it under-correct (resulting in the blood glucose remaining high) or over-correct (resulting in lows)? Your correction or sliding scale should work at least 50% of the time.
Background info on Correction Formulas and what the numbers represent:
I use a Correction Formula: How do I adjust it if it is not working?
Example formula:
Your diabetes health care provider may have given you a Correction Formula that looks something like this:
(blood glucose - 6)
3
If the blood glucose is 15, using this formula you will calculate: 15 – 6, and then divide that by 3, (that is, 9 ÷ 3, which = 3). You would then give 3 extra units of rapid-acting insulin to correct this particular high blood glucose.
If the blood glucose is still consistently high after using the formula then you may need to lower the denominator of this formula (the 3) to, let’s say, 2. So, for example, for a blood sugar of 15 you would now give 4.5 units of rapid-acting insulin to correct. (15 – 6) ÷ 2 = 4.5
If the blood glucose drops too low after using the formula on two recent occasions, then you may need to raise the denominator of this formula (the 3) to 4, for example. So for a blood sugar of 15 you would now give 2 units of rapid-acting insulin to correct. (15 – 6 ) ÷ 4 = 2.25, rounded down to the nearest half-unit equals 2.
I use a Correction Number: How do I adjust it if it is not working?
Your health care provider may have assigned a correction number and instructed you to correct to a target number or range.
Example correction number:
4 (means 1 unit of rapid-acting insulin would lower the blood glucose 4 mmol/L)
In this example, if the blood glucose is 18 and you give 1 extra unit of rapid-acting insulin, it will lower it (by 4 points) to 14; 2 extra will lower it to 10; and 3 extra will lower it to 6 (which we will say is the target blood glucose for this example, so we stop here.).
If the blood glucose is still consistently high after using the correction number, then you would lower the number from (for example) 4 to 3. So if the blood glucose is 18, 1 extra unit of rapid-acting insulin would lower it to 15, 2 extra would lower it to 12, 3 extra would lower it to 9, and 4 extra would lower it to the example target blood glucose of 6.
If the blood glucose drops too low after using the correction number on two recent occasions, then you would raise the number from 4 to 5, for example. So if the blood glucose is 18, 1 extra unit of rapid-acting insulin would lower it to 13, and 2 extra would lower it to 8. (You may stop here, or, if you wish the blood glucose to be lower, you can give an extra ½ unit to lower it to 5.5).
I use a Sliding Scale: How do I adjust it if it is not working?
Example sliding scale:
| If Blood Glucose (in mmol/L) is.... | |
|---|---|
| 8.0 – 10.0 | 0.5 units |
| 10.1 – 12.0 | 1.0 unit |
| 12.1 – 14.0 | 1.5 units |
| 14.1 – 16.0 | 2.0 units |
| 16.1 – 18.0 | 2.5 units |
| 18.1 – 20.0 | 3.0 units |
| > 20 | 3.5 units |
If the blood glucose is still consistently high after using the sliding scale, then you may need to change it to give more insulin. You could try adding 0.5 units, for example, to each dose.
Changes to the above example result in:
Example sliding scale, adjusted up:
| If Blood Glucose (in mmol/L) is.... | |
|---|---|
| 8.0 – 10.0 | 1.0 unit |
| 10.1 – 12.0 | 1.5 units |
| 12.1 – 14.0 | 2.0 units |
| 14.1 – 16.0 | 2.5 units |
| and so on... |
If the blood glucose drops too low after using the sliding scale on two recent occasions, then you may need to change it to give less insulin. You could try subtracting 0.5 units, for example, from each dose.
Changes to the above example result in:
Example sliding scale, adjusted down:
| If Blood Glucose (in mmol/L) is.... | |
|---|---|
| 8.0 – 10.0 | 0 units |
| 10.1 – 12.0 | 0.5 units |
| 12.1 – 14.0 | 1.0 unit |
| 14.1 – 16.0 | 1.5 units |
| and so on... |
Note: Adjusting correction insulin can be more challenging than a simple pattern adjustment with set doses of insulin. Contact your health care provider if you are uncertain about what to do or you have made some insulin adjustments and they have not resulted in more target blood glucose results.
The above information was reviewed for content accuracy by clinical staff of the Alberta Children’s Hospital Diabetes Clinic.
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