Closing DKA

[Interpolfanclub]

I'm MICU senior this month and wanted to see if you guys could offer some advice on closing DKA. I give em fluids, wait to see the K on the BMP then start insulin drip. When BS less than 250 I start D5NS, let them eat and then give sub Q insulin one hour before turning off the drip.
My question is do yall have a method to calculating how much sub Q insulin they get? Do you extrapolate from the insulin drip? Any other tips? Thanks.

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[BADMD]

I'm MICU senior this month and wanted to see if you guys could offer some advice on closing DKA. I give em fluids, wait to see the K on the BMP then start insulin drip. When BS less than 250 I start D5NS, let them eat and then give sub Q insulin one hour before turning off the drip.
My question is do yall have a method to calculating how much sub Q insulin they get? Do you extrapolate from the insulin drip? Any other tips? Thanks.

Usually a person's daily insulin requirement is known if they are previously diagnosed as a diabetic. 1/3 to 1/2 that in a long acting insulin is a reasonable way to go. If not, 20 Units of insulin glargine is usually a good starting pointing. Supplemental shorter acting insulin can be given as needed. The key is usually to make sure that they have some insulin to keep them from backsliding. You don't need to give the optimal amount

 

[kalico]

Bolus with 0.5 units/kg, then run the drip at 0.5 units/kg/hr. I started a few units less the other night and the guy's glucose didn't budge, once I dosed it for his weight, voila.

Usually a noted pitfall is letting the patient eat before the gap is closed. Ideally, run the D5 fluid until the gap is closed, keeping the glucose around 150-200 by adjusting the insulin drip (which should be getting closer to 2 units/hr). Then feed, subcutaneous long acting insulin... with sliding scale coverage... and drip off within 2 hours.

If you're feeding the guy, you should be within 1-2 hours of shutting the drip off.

 

[SoCuteMD]

I'm MICU senior this month and wanted to see if you guys could offer some advice on closing DKA. I give em fluids, wait to see the K on the BMP then start insulin drip. When BS less than 250 I start D5NS, let them eat and then give sub Q insulin one hour before turning off the drip.
My question is do yall have a method to calculating how much sub Q insulin they get? Do you extrapolate from the insulin drip? Any other tips? Thanks.

So, I may be confused, but why would you wait to initiate insulin for a pt in DKA? Are these pts coming from the ED having been bolused with SOME insulin shortly after arrival? Or have they arrived in DKA, had bloods drawn, and waited around for lab results before insulin is started?

 

[WilcoWorld]

So, I may be confused, but why would you wait to initiate insulin for a pt in DKA? Are these pts coming from the ED having been bolused with SOME insulin shortly after arrival? Or have they arrived in DKA, had bloods drawn, and waited around for lab results before insulin is started?

In some hospitals critically ill patients will go to the MICU pretty much as soon as they are identified as being critically ill. That certainly wasn't the case where I trained, but perhaps the OP works in one of those fantastically responsive MICU's, or was simply describing the care of DKA from his / her 1st step. In either case, you should not bolus insulin before seeing a potassium level.

DKA patients diurese themselves into a lot of trouble. The glucose spilling leads to dehydration, which leads to hypovolemia, which leads to compensatory sodium pump action, which trades potassium for sodium - thus patients in DKA loose potassium & end up total body K+ depleted. Once you give insulin, the glucose shifts into the cells, and the potassium goes with it. Thus the serum K+ decreases quickly. (This is why we treat hyperkalemia with insulin & glucose). If you precipitously drop the serum potassium of a patient who is already low on K+ you can cause serious problems (arrhythmia, respiratory failure, altered mental status and other badness (I will admit that I've never actually seen this happen when treating DKA, but the pathophys makes sense & I've heard enough horror stories / read enough guidelines to believe it)).

That's why DKA treatment should start with fluids - treat the hypovolemia - and with labs. Once you know that they are not hypokalemic, give them insulin, but watch the K+ closely, and start IV potassium as soon as they are both producing urine & not hyperkalemic.

 

[southerndoc]

There is no evidence to support the theory that bolus insulin reduces morbidity, but there is evidence that it increases morbidity and even mortality in type 1 diabetics with DKA. There is evidence to support basal bolus insulin in type 2 diabetes.

Second, if I remember correctly, the accepted dose for insulin is 0.1 units/kg/hr and not 0.5 units/kg/hr. Perhaps you are practicing something that I haven't read in the literature yet.

Finally, the author's question wasn't about insulin drip dosing, but subcutaneous insulin dosing.

I was taught to use the average hourly rate for the previous 6 hours, multiply that by 20, and that will give you the total daily dose of insulin needed subcutaneously. Alternatively, you can also do it based on weight without taking into consideration the insulin drip rate. For the average adult, it's 0.4 units/kg/day (0.5 for those overweight). Remembering that insulin is renally cleared, any calculated dose should be reduced for anyone who has evidence of end-stage renal disease. It's important to give the Lantus 2 hours before turning off the insulin drip.

50% of the total daily dose is given as long-acting (Lantus) at night OR as NPH with 2/3 of the NPH dose is given in the morning and 1/3 in the evening. The remaining 50% is given as regular (Humalog) in 3 equal doses prior to meals, or you can simply give it based on carb load (1 unit for every 15 g of carbohydrates).

If any FSBS is <80 during any day, then give 80% the prior day's dose (the 80/80 rule). If it's >180 but none <80, then give 110% the prior day's dose.

 

[Jeff698]

One thing to add to WilcoWorld's great answer to SoCute's question, these folks are fluid down. As you aggressively correct that volume depletion, the kidneys (assuming no chronic renal failure) will be able to drop the glucose down to around 250-ish with no insulin at all.

So, not only can you get into hypokalemia trouble with premature insulin therapy, there really isn't much benefit to it as long as you're being aggressive with your fluids.

Take care,
Jeff

 

[DrQuinn]

The #1 cause of mortality in DKA patients in hospital is....

hypokalemia.

That's why its important to know their K. I even give them a piggyback of K when tehy are in the 3s on their initial BMP. My patient population seems to always be in mild DKA, but they ALWAYS want to eat, so I start em, and try to feed them ASAP to get their K up.

Q

 

[SoCuteMD]

Thanks for the input

It definitely varies from what I was taught, so I'm glad I asked. The rules I remember from what I was taughtare: 1) initiate insulin to reverse the acidosis - don't worry about the hyperglycemia for now
2) Check K+ q2
3) Can have K+ in their IVF ONLY if they've peed
4) Once K+ approaches 4-4.5, initiate K in IVF if you haven't already

I'm fairly certain we weren't told that it was imperative/important to check K prior to insulin.

As for what you said, Jeff, I was under the impression that the insulin in DKA was not to correct the hyperglycemia but to reverse the acidosis. If they have little to no endogenous insulin, this will not be reversed until insulin is added.

ETA: Thanks Wilco. I don't think I've ever worked in a hospital that routinely had MICU beds available. Actually this weekend we closed several gaps in the ED. Patients who had been MICU-bound pending available beds when I arrived for my shift were actually re-classified as floor patients by the time I left my shift.

 

[Strength&Speed]

just to reiterate a key point about DKA. Even though K+ may be high or normal due to K moving out of cells during an acidosis, they are total body K depleted. So watching it closely when starting insulin is key. Even if K is normal, you should be infusing 20 meq k with your fluids.

And yes, insulin's main effect is reversing the acidosis, which is what's going to kill the patient. This is assuming youre giving adequate volume.

 

[Strength&Speed]

Bolus with 0.5 units/kg, then run the drip at 0.5 units/kg/hr. I started a few units less the other night and the guy's glucose didn't budge, once I dosed it for his weight, voila.

Usually a noted pitfall is letting the patient eat before the gap is closed. Ideally, run the D5 fluid until the gap is closed, keeping the glucose around 150-200 by adjusting the insulin drip (which should be getting closer to 2 units/hr). Then feed, subcutaneous long acting insulin... with sliding scale coverage... and drip off within 2 hours.

If you're feeding the guy, you should be within 1-2 hours of shutting the drip off.

I believe you mean 0.1 u/kg for each. that's a bit steep. I know you know better too, because you said turn off insulin drip when it gets to 2 units/hr. 0.5 would be 35 units/hr in a 70 kg person

 

[BADMD]

0.5 would be 35 units/hr in a 70 kg person

That would be low end tox dosing. I had a lady at 3 units/kg/hr a few days ago and once put someone up to 6 units/kg/hr.

 

[Strength&Speed]

That would be low end tox dosing. I had a lady at 3 units/kg/hr a few days ago and once put someone up to 6 units/kg/hr.[/QUOTE]

420 units of insulin per hour in 70 kg person?? I agree not having a fixed rate is good, but that seems a bit much. If you say so...

 

[group_theory]

Remember that the insulin is mainly to stop ketosis (and reverse the metabolic acidosis).

There is also slight variation in the pediatric world on how DKA are approached (it involves the 2 bags of fluids and Y-ing system) to have better control on the rate of decline in glucose

I usually like to start insulin drip at 0.05 unit/kg/hr (and increase as needed based on the rate of gap closure and rate of decline in glucose)

 

[BADMD]

420 units of insulin per hour in 70 kg person?? I agree not having a fixed rate is good, but that seems a bit much. If you say so...

Not for DKA. Insulin seems to work as a very nice inotrope in the face of calcium blocker and/or betablocker toxicity.

 

[Jeff698]

As for what you said, Jeff, I was under the impression that the insulin in DKA was not to correct the hyperglycemia but to reverse the acidosis. If they have little to no endogenous insulin, this will not be reversed until insulin is added.

Yes, it is to correct the acidosis.

However, you can start to lower glucose with only fluids. Most DKA patients are pretty dry and aren't peeing much. The kidneys will spill a fair amount of glucose once they start peeing again.

My point was that you can start to bring glucose down with fluids alone, thus re-emphasizing that you have time before starting insulin to check the K.

Take care,
Jeff

 

[SoCuteMD]

Yes, it is to correct the acidosis.

However, you can start to lower glucose with only fluids. Most DKA patients are pretty dry and aren't peeing much. The kidneys will spill a fair amount of glucose once they start peeing again.

My point was that you can start to bring glucose down with fluids alone, thus re-emphasizing that you have time before starting insulin to check the K.

Take care,
Jeff

Right, but my point was that the glucose level is pretty much not a factor in why these patients are sick - it's the acidosis. That doesn't reverse until insulin is given. Sure, fluids will probably save you some insulin in the long run but what these patients really need is reversal of a metabolic acidosis.

My guess is that I'm probably coming from a different setting than most of you are. How long does it take you to get a stat BMP back?

I timed it today out of curiosity. 2 hours.

 

[southerndoc]

Right, but my point was that the glucose level is pretty much not a factor in why these patients are sick - it's the acidosis. That doesn't reverse until insulin is given. Sure, fluids will probably save you some insulin in the long run but what these patients really need is reversal of a metabolic acidosis.

My guess is that I'm probably coming from a different setting than most of you are. How long does it take you to get a stat BMP back?

I timed it today out of curiosity. 2 hours.

2 hours at my residency site, 30 minutes at our community site, and 30 minutes at my present hospital. If you suspect DKA, you should send a venous blood gas, which takes about 10 minutes to get the results of. Many places can also get a K off the blood gas. I don't remember the specifics anymore, but I think venous and arterial blood gases are comparable by around 0.01-0.02.

 

[WilcoWorld]

Agree with above - you should be getting a blood gas (venous is fine, no need for repeated ABG's on these peeps) with your initial eval to check a pH. This has always answered my K question in a timely fashion. Perhaps I should have clarified this earlier, but I did not mean to suggest you should be waiting 2 hours for a BMP before starting insulin.

 

[SoCuteMD]

Agree with above - you should be getting a blood gas (venous is fine, no need for repeated ABG's on these peeps) with your initial eval to check a pH. This has always answered my K question in a timely fashion. Perhaps I should have clarified this earlier, but I did not mean to suggest you should be waiting 2 hours for a BMP before starting insulin.

There we go! That was the missing piece!

We've added a stat creatinine onto a blood gas, but never a K. I should have realized it could be done. I was sitting here thinking, "Gosh, I understand the reasoning but if someone looks THAT crappy I'm certainly not going to wait for a stat BMP to come back from OUR lab to do something!!!"

 

[DeLaughterDO]

we can have an ISTAT (abg + lytes + hgb) in about 3 minutes - love our ISTAT machine in the trauma bay