Need help, Carbon dioxide vs anion gap for DKA

[Aloe_sky]

I am at a new facility that follows a protocol I’m not familiar with. For DKA patients that are on insulin drip…. they do not bridge sub q insulin, they just d/c the drip. They also do not follow the anion gap at all, just the carbon dioxide on the BMP. They say it’s “more accurate” than the gap when it comes to DKA. Is this normal practice in some facilities. When I Google, people seem to focus on the anion gap. I can’t find answers for this. I’ve complained that this is so different but maybe it’s actually not and it’s common in different facilities, the physician assistant and nurse practitioner look at me like I’m stupid for not knowing this! Need help! 

[JBMmom, MSN, NP]

My thought would be that the anion gap as the overall measure of acid base balance is going to be a more comprehensive endpoint than the CO2 alone. However, they are both going to correct in parallel as the DKA resolves. If it's a protocol that they've used and people can stay off the insulin drip it must work. But you're not stupid for questioning. 

[mmc51264, BSN, MSN, RN]

Mom of two T1s and where I work is where I take them if I suspect DKA (only 3 times in 16 years thank goodness) and they look at anion gap. I would be curious the rationale behind their policy. 

When we have pts on an insulin gtt, we usually will use SQ insulin for meals (if they are allowed to eat) and then we usually give a long-acting (mostly glargine) when the gtt is turned off. 

I will ask our endo next week when my son has his f/u appt. Curious now. 

[MunoRN, RN]

And it used to be that ketones were the most followed lab, now we don't even check ketone levels.

Both anion gap and CO2 on a metabolic panel (which is actually a measurement of bicarbonate, not directly CO2) measure the resulting metabolic acidosis that occurs as a result of DKA, while theoretically at least excluding metabolic compensatory mechanisms.

No matter what measurement your using, the important thing to remember is that early in DKA treatment these measurements start to normalize because the body is getting insulin, it has really nothing to do with what their BG levels are.

If a patient has normal BG levels but still has a resolving acidosis, then they still need insulin, and that often means having to give them glucose in order to be able to keep giving insulin.

[Aloe_sky]

The patients anion gap was 7, the CO2 was 17 and they still refused to stop the insulin drip because the CO2 wasn’t atleast 18. They said the patient was still in acidosis, This is what’s confusing. They don’t order vbgs, they simply go off the CO2. They will keep the insulin drip on for days,I just don’t understand.