Why do we use insulin drips?

tewdles, RN · Feb 19, 2013

Hi everyone! I'm a new nurse working on a Post-Transplant/Surgical unit (kidneys and pancreases only). I'm curious about insulin gtts. A few weeks ago I had a patient on an insulin drip--hx: infected abdominal wound, new colostomy, history of DM type 2, NPO status, receiving TPN. And yesterday my co-worker was caring for a kidney rejection patient (I think?) who was on an insulin drip, not sure what else was going on.
Why do we use insulin drips? I know its obvious: to obtain tighter glycemic control. But why do we use insulin drips versus other methods? I've been doing research--insulin drips work faster for patients with DKA. But why are patients on insulin drips for long periods of time, even after BG's are under control and no ketones? Does NPO status have anything to do with it? And if so, why? I just don't fully understand the benefits of insulin drips.
If anyone could shed some light on this, I'd appreciate it. I'm very interested in endocrine nursing. Thanks :)

Rather than answer your question directly, let me ask you a few questions.

Would you expect the Blood Glucose of an acutely ill DM with infection, npo, and TPN to be stable?

What other methods are you considering? Oral meds? Why?

sdstudent91 · Feb 19, 2013

I am a nursing student, and I have one more year to go. I have been searching for over an hour to the questions, "Explain when an Insulin gtt would be utilized. What insulin has to be used in an insulin gtt?"

All I can figure out is that it would be used in DKA or HHS.

Thanks!

turnforthenurse, MSN, NP · Feb 19, 2013

I am a nursing student, and I have one more year to go. I have been searching for over an hour to the questions, "Explain when an Insulin gtt would be utilized. What insulin has to be used in an insulin gtt?"

All I can figure out is that it would be used in DKA or HHS.
Thanks!

DKA and HHNKS are typically when you will see an insulin drip being utilized. There are other times, too, as mentioned in the OP. As for the type of insulin...which type of insulin should only be given IV?

eatmysoxRN, ASN, RN · Feb 19, 2013

I had a patient on an insulin drip when I floated to SICU one night. The experienced nurse that gave me report said she didn't really know why the patient was on it. I asked some other nurses who also gave inadequate answers. The patient had multiple comorbidities.

During my lunch I tried to look it up with few answers. At the end of my shift I was honestly still lost. I followed protocol and maintained fairly tight glycemic control but I prefer to understand why something is going on. Additionally, I considered it could contribute to increasing potassium levels since despite multiple potassium boluses the potassium stayed around 3.

I'd love more info from experienced nurses as well.

~ No One Can Make You Feel Inferior Without Your Consent -Eleanor Roosevelt ~

Penelope_Pitstop, BSN, RN · Feb 19, 2013

What other methods are you considering? Oral meds? Why?

What she said...

Also, IV acts faster and is eliminated faster. If you depend on subcutaneous insulin, it peaks much later and if too much is given, that makes things more complicated.

EGVnurse · Feb 19, 2013

Her BG's were definitely not stable for me on the first day I was caring for her, they were running in the 300's and she felt terrible. I kept titrating the insulin gtt up as per protocol and thinking "This is so much, this lady is going to drop soon" and when I came back the next morning, she had gone into the 40's over night (the night nurse hadn't hung a bag of D5/half NS when BG was less than 180). I also learned that the patient's TPN bag had had insulin in it so they resolved this. The next day her BG's were perfectly in range and stayed there! I was so happy. But why would they keep this woman on an insulin drip for several weeks? I see it as a short-term solution for DKA or HHS but not long-term just for infx and NPO status.

I would consider weaning her off the insulin gtt and starting her on SC insulin and fluids once she left the ICU and came to our unit. A good SC basal-bolus insulin regimen could stabilize her blood sugars just as an insulin gtt but with less of the risk of swinging between highs and lows. Since she's NPO and on TPN, I imagine it might be easier to determine appropriate doses of short-acting and long-acting insulin to match the carbs in her TPN as well as her metabolic needs. Giver her a higher dose of Lantus or long-acting insulin to cover the stress/infection-induced hyperglycemia. An insulin gtt just seems to carry a higher risk for error. :-/

turnforthenurse, MSN, NP · Feb 23, 2013

I had a patient on an insulin drip when I floated to SICU one night. The experienced nurse that gave me report said she didn't really know why the patient was on it. I asked some other nurses who also gave inadequate answers. The patient had multiple comorbidities.
During my lunch I tried to look it up with few answers. At the end of my shift I was honestly still lost. I followed protocol and maintained fairly tight glycemic control but I prefer to understand why something is going on. Additionally, I considered it could contribute to increasing potassium levels since despite multiple potassium boluses the potassium stayed around 3.
I'd love more info from experienced nurses as well.
~ No One Can Make You Feel Inferior Without Your Consent -Eleanor Roosevelt ~

Insulin helps push potassium into the cell, so it will lower serum potassium levels. That's why it is one of the treatments used in hyperkalemia (usually regular insulin IV) along with D50 and calcium chloride. With a patient on an insulin gtt, it would make sense to monitor for hypokalemia.

I was going to suggest tight glycemic control, too. I know ICU patients with a blood sugar consistently >180 have a higher mortality rate compared to those with better glycemic control.

Her BG's were definitely not stable for me on the first day I was caring for her, they were running in the 300's and she felt terrible. I kept titrating the insulin gtt up as per protocol and thinking "This is so much, this lady is going to drop soon" and when I came back the next morning, she had gone into the 40's over night (the night nurse hadn't hung a bag of D5/half NS when BG was less than 180). I also learned that the patient's TPN bag had had insulin in it so they resolved this. The next day her BG's were perfectly in range and stayed there! I was so happy. But why would they keep this woman on an insulin drip for several weeks? I see it as a short-term solution for DKA or HHS but not long-term just for infx and NPO status.

Maybe the patient's blood sugars were out of control for that period of time?

I would consider weaning her off the insulin gtt and starting her on SC insulin and fluids once she left the ICU and came to our unit. A good SC basal-bolus insulin regimen could stabilize her blood sugars just as an insulin gtt but with less of the risk of swinging between highs and lows. Since she's NPO and on TPN, I imagine it might be easier to determine appropriate doses of short-acting and long-acting insulin to match the carbs in her TPN as well as her metabolic needs. Giver her a higher dose of Lantus or long-acting insulin to cover the stress/infection-induced hyperglycemia. An insulin gtt just seems to carry a higher risk for error. :-/

Yes, I agree, but in a patient with DKA or HHNKS with a crazy high blood sugar, you need an insulin drip to help bring the blood sugars down...REASONABLY, of course. The blood sugar should not be brought down by more than 70-100mg/dL/hr to prevent dysrhythmias (secondary to hypokalemia because remember, insulin helps push potassium back into the cell, lowering serum K levels) cerebral edema secondary to hypoglycemia. In addition, these patients need fluids due to the osmotic diuresis from their crazy high blood sugars. Once the patient's sugars are within a certain range (where I work we switch the fluids over to D5 1/2 NS when the blood sugar is

classicdame, MSN, EdD · Feb 25, 2013

remember that when people are on a drip we are checking glucose levels frequently and can correct them faster. People with renal and liver disease on insulin may RETAIN the insulin, and have a greater-than-expected drop in glucose level. If not caught quickly this could be fatal. Over time, (hours or days) the MD will be able to look at the levels vs. the drip dose and determine what subq dose is most appropriate, if any.

Vespertinas · Mar 5, 2013

Additionally, I considered it could contribute to increasing potassium levels since despite multiple potassium boluses the potassium stayed around 3.

You mean decreasing potassium levels? Yeah as long as she's getting insulin, that potassium is going to keep getting shifted intracellularly. Lets just hope she got an appropriate dose of lantus after the gtt was discontinued or you'll see all that K+ come back to bite ya!

HelenaHandbasket · Mar 12, 2013

I'm going to venture a novice guess here and suggest that it is simply because of rapidly changing conditions within the body and the fact that the patient is not taking food PO. A traditional insulin to carb ratio wouldn't work since carbs are processed differently via TPN than through the gut. Rapid acting insulin also will hopefully prevent any stacking from going on which can occur with different absorption rates SQ. Add to that, on a transplant unit the likely use of corticosteriods which messes up BG levels as well would make it easier to titrate dosing based on continuous glucose monitoring or frequent testing.

I also think it would be easier to set a lantus dose once you can average the gtt rates to determine a basal rate. I guess I think of it as a reverse equation for setting up insulin pump basal rates considering the Total Daily Insulin amount.

In terms of what insulin type to use, regular insulin is the only solution. The rest are suspensions. When administered IV, onset of action is about 15 mins with duration of action 30-60 mins, which I'd think makes it easier to calculate hourly rates. With that rapid of effect, it would seem unnecessary to use anything faster like the rapid-onsets.

Maybe? :shy:

mammac5 · Mar 15, 2013

I treat inpatient diabetes, almost exclusively for pts requiring IV insulin. We use it for pts in metabolic disarray...even those who are not diabetic! Those having major chest surgeries, pts having lesser surgeries but who have CBGs >150, etc., have better outcomes with less post-op infections when glucose is tightly managed.

Then we manage how to safely bring them off the drip afterward, address any diabetes issues present prior to admit...such as being uncontrolled, need for new med regimen, etc. That's my life.