Negative Insulin orders

PICNICRN, BSN, RN · Feb 25, 2009

I've never heard the term "negative insulin" order......... are you refering to the carb coverage ratio?

jode · Feb 25, 2009

Weight based? I dont know about negative insulin orders

mpollos · Feb 25, 2009

I know I hadn't either, that's why its still confusing to me. This is how I have been doing it, I take his BS before eating and his target is 120. If its 120 or less he gets no insulin. If above 120 you do the math to calculate the appropriate amount of insulin to cover the blood sugar. Then you wait until he is finished eating, count the carbs and do the math to calculate coverage for that and add the 2 together. But then there is a "negative" order, meaning if his blood sugar is "50 less than 150" (exact wording) he gets a "negative amount" or as I have been doing it, subtract 1 from the total amount of insulin to be given. So here is an example. BS is 83, so since it is below his target I know he is to get no insulin to cover his BS, and since it is "50 below 100" that the total amount of insulin to be given I should subtract 1 from. So he eats 50 carbs and I do the math (his orders are 1/2 unit per 20 carbs) to get 1.25. So no insulin for target BS, and 1.25 units for carb coverage. Then I subtract 1 for what the orders state as a "negative" order, making him get a total of .25 units of insulin. I believe I am doing it right, and sometimes just writing it down it makes more sense, but I still am unsure. Maybe the term "negative" insulin is not the correct term, and i'm getting hung up by that? Thanks for the response.

Marie P LPN =)

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RochesterRN-BSN, BSN, RN · Feb 25, 2009

Is this what most of us know as a sliding scale? Where in the world are you doing this and WHY!?!? Why not just use a sliding scale?? Sounds like a lot of time wasted trying to make his BG exactly perfect at all times.....kinda unrealistic really......sliding scale works pretty good.......

And how realistic is it for this kid to continue this as he/she get older? Yeah I see non-compliance. Thats why thy try to simplify things so patients will be more compliant. Yeah a nurse is doing it now but as he get older.......really, come on!!! LOL Good luck with that.......never heard of it myself.

mpollos · Feb 25, 2009

I know it is so different. It is in a school and I work with many disabled childern and this child is highly autistic, no chance he will ever be giving it to himself, but even still it has a high rate for someone to miscalculate because it is so wordy. I would LOVE a sliding scale for him, and yes your right it basically a sliding scale, it is just a roundabout way of getting him there. His last AIC was 5.8 so he is very well controlled so i'm not sure why we have these weird orders, plus his mother will only supply us with a novolog pen that can only be dialed to increments of 1 unit, so in the case of the example I just gave, I would give him 0 insulin. After all that! I guess its just one of these weird things I can put into my experience box. Thanks so much for responding.

blondy2061h, MSN, RN · Feb 25, 2009

Sliding scales suck. They are retroactive in coverage, depend on the person being hyperglycemic constantly to get any insulin at all, and have far too imprecise coverage for a kid or a type 1 diabetic.

The idea between negative insulin is that the person gets coverage separately for food and correction insulin, based on carbs eaten and blood sugar. These doses are added together to get a total dose. If the person is below their glucose target, insulin is simply subtracted from the food dose to let some of the food raise the blood sugar, instead of trying to compensate entirely for the food.

It sounds like you have the idea right.

This is pretty much standard insulin dosing for type 1 diabetics.

The term I hear for it usually is "reverse correction."

Basically, dosage would be (carbs eaten/20) +/- correction.

BrnEyedGirl, BSN, MSN, RN, APRN · Feb 25, 2009

I've never heard it called by that term,,..but this is very similar to how an insulin pump calculates insulin,...you enter your blood sugar and the carbs and the pump does the calculation and delivers the right amount of insulin,.often to .01 units,....very effective,.but a lot of work with out the pump!

blondy2061h, MSN, RN · Feb 25, 2009

I've never heard it called by that term,,..but this is very similar to how an insulin pump calculates insulin,...you enter your blood sugar and the carbs and the pump does the calculation and delivers the right amount of insulin,.often to .01 units,....very effective,.but a lot of work with out the pump!

Yeah, an insulin pump would be ideal for most people with type 1. I did (loosely) what's describe in this thread when I was on shots, trying to draw up half units in 30 unit syringes. Not so much fun. Unfortunately, Novo Nordisk doesn't make a disposable pen that has half units, but the Novopen Jr. does, they just don't seem to advertise it much anymore, and even then, it's only 1/2 unit increments after 1 unit.

Much easier with a pump. Does the math for you AND precise increments AND no injections.

lpnflorida · Feb 25, 2009

Example #1: Carbohydrate coverage at a meal

First, you have to calculate the carbohydrate coverage insulin dose using this formula:

CHO insulin dose =

Total grams of CHO in the meal

÷ grams of CHO disposed by 1 unit of insulin

(the grams of CHO disposed of by 1 unit of insulin is the bottom number or denominator of the Insulin:CHO ratio).

For Example #1, assume:

You are going to eat 60 grams of carbohydrate for lunch

Your Insulin: CHO ratio is 1:10

To get the CHO insulin dose, plug the numbers into the formula:

CHO insulin dose =

Total grams of CHO in the meal (60 g)

÷ grams of CHO disposed by 1 unit of insulin (10) = 6 units

You will need 6 units of rapid acting insulin to cover the carbohydrate.

Example #2: High blood sugar correction dose

Next, you have to calculate the high blood sugar correction dose.

High blood sugar correction dose =

Difference between actual blood sugar and target blood sugar*

÷ correction factor.

*Actual blood sugar minus target blood sugar

For Example #2, assume:

1 unit will drop your blood sugar 50 points (mg/dl) and the high blood sugar correction factor is 50.

Pre-meal blood sugar target is 120 mg/dl.

Your actual blood sugar before lunch is 220 mg/dl.

Now, calculate the difference between your actual blood sugar and target blood sugar:

220 minus 120 mg/dl = 100 mg/dl

To get the high blood sugar correction insulin dose, plug the numbers into this formula:

Correction dose =

Difference between actual and target blood glucose (100mg/dl)

÷ correction factor (50) = 2 units of rapid acting insulin

So, you will need an additional 2 units of rapid acting insulin to “correct” the blood sugar down to a target of 120 mg/dl.

Example #3: Total mealtime dose

Finally, to get the total mealtime insulin dose, add the CHO insulin dose together with the high blood sugar correction insulin dose:

CHO Insulin Dose

+ High Blood Sugar Correction Dose

= Total Meal Insulin Dose

For Example #3, assume:

The carbohydrate coverage dose is 6 units of rapid acting insulin.

The high blood sugar correction dose is 2 units of rapid acting insulin.

Now, add the two doses together to calculate your total meal dose.

Carbohydrate coverage dose (6 units)

+ high sugar correction dose (2 units)

= 8 units total meal dose!

The total lunch insulin dose is 8 units of rapid acting insulin.

Example #4: Formulas commonly used to create insulin dose recommendations

This example illustrates a method for calculating of your background/basal and bolus doses and estimated daily insulin dose when you need full insulin replacement. Bear in mind, this may be too much insulin if you are newly diagnosed or still making a lot of insulin on your own. And it may be too little if you are very resistant to the action of insulin. Talk to your provider about the best insulin dose for you as this is a general formula and may not meet your individual needs.

The initial calculation of the basal/background and bolus doses requires estimating your total daily insulin dose:

Total Daily Insulin Requirement

The general calculation for the body’s daily insulin requirement is:

Total Daily Insulin Requirement(in units of insulin)

= Weight in Pounds ÷ 4

Alternatively, if you measure your body weight in kilograms:

Total Daily Insulin Requirement (in units of insulin)

= 0.55 X Total Weight in Kilograms

Example 1:

If you are measuring your body weight in pounds:

Assume you weigh 160 lbs.

In this example:

TOTAL DAILY INSULIN DOSE = 160 lb ÷ 4 = 40 units of insulin/day

Example 2:

If you are measuring your body weight in kilograms:

Assume your weight is 70Kg

In this example:

TOTAL DAILY INSULIN DOSE

= 0.55 x 70 Kg = 38.5 units of insulin/day

If your body is very resistant to insulin, you may require a higher dose. If your body is sensitive to insulin, you may require a lower insulin dose.

Basal/Background and Bolus Insulin Doses

Next, you need to establish the basal/background dose, carbohydrate coverage dose (insulin to carbohydrate ratio) and high blood sugar correction dose (correction factor).

Basal/background insulin dose:

Basal/background Insulin Dose

= 40-50% of Total Daily Insulin Dose

Example

Assume you weigh 160 pounds

Your total daily insulin dose (TDI) = 160 lbs ÷ 4 = 40 units.

In this example:

Basal/background insulin dose

= 50% of TDI (40 units) = 20 units

of either long acting insulin,(such as glargine or detemir) or rapid acting insulin if you are using an insulin pump (continuous subcutaneous insulin infusion device).

The carbohydate coverage ratio:

500 ÷ Total Daily Insulin Dose

= 1 unit insulin covers so many grams of carbohydrate

This can be calculated using the Rule of “500”: Carbohydrate Bolus Calculation

Example:

Assume your total daily insulin dose (TDI)

= 160 lbs ÷ 4 = 40 units

In this example:

Carbohydrate coverage ratio

= 500 ÷ TDI (40 units)

= 1unit insulin/ 12 g CHO

This example above assumes that you have a constant response to insulin throughout the day. In reality, individual insulin sensitivity varies. Someone who is resistant in the morning, but sensitive at mid-day, will need to adjust the insulin-to-carbohydrate ratio at different meal times. In such a case, the background insulin dose would still be approximately 20 units; however, the breakfast insulin-to-carbohydrate ratio might be breakfast 1:8 grams, lunch 1:15 grams and dinner 1:12 grams.

The insulin to carbohydrate ratio may vary during the day.

The high blood sugar correction factor:

Correction Factor = 1800 ÷Total Daily Insulin Dose = 1 unit of insulin will reduce the blood sugar so many mg/dl

This can be calculated using the Rule of “1800”.

Example:

Assume your total daily insulin dose(TDI) = 160 lbs ÷ 4 = 40 units

In this example:

Correction Factor

= 1800 ÷ TDI(40 units)

= 1 unit insulin will drop reduce the blood sugar level by 45 mg/dl

While the calculation is 1 unit will drop the blood sugar 45 mg/dl, to make it easier most people will round up or round down the number so the suggested correction factor may be 1 unit of rapid acting insulin will drop the blood sugar 40-50 mg/dl.

Please keep in mind, the estimated insulin regimen is an initial “best guess” and the dose may need to be modified to keep your blood sugar on target.

Also, there are many variations of insulin therapy. You will need to work out your specific insulin requirements and dose regimen with your medical provider and diabetes team.

I have worked with the basal bolus method, and have seen our patients with an insulin pumps who do their own calculations.

thanks for reminding me their are more than just sliding scales for insulins. P.S, I found these examples on the web.

PICNICRN, BSN, RN · Feb 25, 2009

I know I hadn't either, that's why its still confusing to me. This is how I have been doing it, I take his BS before eating and his target is 120. If its 120 or less he gets no insulin. If above 120 you do the math to calculate the appropriate amount of insulin to cover the blood sugar. Then you wait until he is finished eating, count the carbs and do the math to calculate coverage for that and add the 2 together. But then there is a "negative" order, meaning if his blood sugar is "50 less than 150" (exact wording) he gets a "negative amount" or as I have been doing it, subtract 1 from the total amount of insulin to be given. So here is an example. BS is 83, so since it is below his target I know he is to get no insulin to cover his BS, and since it is "50 below 100" that the total amount of insulin to be given I should subtract 1 from. So he eats 50 carbs and I do the math (his orders are 1/2 unit per 20 carbs) to get 1.25. So no insulin for target BS, and 1.25 units for carb coverage. Then I subtract 1 for what the orders state as a "negative" order, making him get a total of .25 units of insulin. I believe I am doing it right, and sometimes just writing it down it makes more sense, but I still am unsure. Maybe the term "negative" insulin is not the correct term, and i'm getting hung up by that? Thanks for the response.
Marie P LPN =)
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This is kinda what I was thinking you were refering to. Sounds like you are doing it the right way- our orders are worded a little different though- there is no "negative" amount.... more like the example #3 you posted above. I am wondering why you wait until after the meal to calculate and give the dose? We teach them to check the sugar, calculate what they are going to eat, and draw up the dose and give it- THEN eat. I am also wondering why no insulin pump? Most kids are on one unless they prove noncompliant- sure would make your job alot easier:D!! I agree, it is so hard to get used to and I also worry that I didn't calculate correctly... we double check our calculations with another RN with EACH dose(and also the kid/parent) so that mistakes don't happen. Sounds like you are right on the money!

classicdame, MSN, EdD · Feb 25, 2009

Sliding scale is obsolete. See the ADA and Am. Academy of Endocrinologists websites.

As for the order you have - it is not clear and should be verified by the MD. No agreements by committee or guessing.