bolus insulin for meals

highlandlass1592, BSN, RN · Dec 4, 2008

I have a question regarding boluses to cover meals. Say a pt is getting glucometer checks before meals. At what point would you hold off on giving meal coverage? example: Say pt's blood sugar is 70 before a meal. Would you still give insulin to cover their meals? I'd say yes. Now...what if there blood sugar before meal was less than 70? ("hypoglycemia")??
Of course for any questions, I call the Dr. but just wondering opinions. One one hand, if they start out low and they eat, the food could bring them back WNL...on the other, holding all meal coveage could cause them to spike too high.

I think you've got a couple of great pointers from others. I'd just like to add a couple of thoughts: you really do need to look at the type of insulin being administered and remember when it takes effect. Quick acting insulin like Novolog, you really want to make sure the patient is eaten or already have eaten before you administer. Regular you have a bit more time to play with. I think the key is finding out the range ordered and remember that some areas don't treat a blood glucose till it's less than 70. We run our desired range 90-120. We've got a great endocrine staff that our surgery dept. has worked with and I've learned more about titrating insulins in the past couple of years than I have in all the years I've practiced.

Are you working sliding scales? If so, they really should give you parameters for what to do with certain ranges....ie, don't cover a glucose till it's over 120. Our scales are broken down with the ranges easy to understand.

Also, something else to keep in mind is what is going on with the patient. We've seen in fresh surgical patients that glucose can be really difficult to control due to surgical stress. Sepsis is another one that can really throw off treatment. So you do have to keep these issues in mind. I like to think of glucose management as an art form now....so much has changed. ( I noticed you're spec. is psych so I'm not sure if you see post-ops or septic pts, just mentioning in passing)

Hope this helps a bit.

blondy2061h, MSN, RN · Dec 4, 2008

Anyone who is on a pump (or using a similar method to calculate insulin needs at meals) should have what's called an insulin sensitivity factor in addition to a carb factor.

You explained the carb factor bit in an earlier post, saying that your patient gets 1 unit to cover 60 grams of carb.

The insulin sensitivity factor is what comes into play here. ISF is how much one unit of insulin will lower your blood sugar. It can also be reversed, however, and determine how much with holding one unit will raise blood glucose.

The roper thing to do here is determine insulin needs for the meal. Let's say her carb ratio is 1:60 and she's eating 120 grams of carb. She'd need 2 units of insulin for the meal.

Now let's say her glucose is 70 and she know her ISF is 100. Therefore, we know with holding 1 unit of insulin will raise her to 170 (and with holding both units the meal requires will raise her to 270). What about with holding half a unit? That would raise her to 120 (raise her by 50). That sounds about right.

So in this hypothetical situation, the proper thing to do would be with hold 0.5 units and give the other 1.5

The formula, with CR being carb ratio and ISF being insulin sensitivty and TG being target glucose:

(Carbs eatten/CR)+[(Current glucose-TG)/ISF]-Insulin On Board=dose

IOB, or insulin on board, is any insulin presummed to be still working from a previous bolus.

Again, her pump more than likely can calculate all this.