DKA - Initial Rx - Insulin and Glucose or Fluids

[Jack P]

---

Members do not see this ad.

Lets say you have a patient come in with a PCo2 of 19, A Bicarb of 11 meq/l and a pH of 6.9 with an increased anion gap metabolic acidosis. You make the diagnosis of DKA and then you:

a. Give Insulin and Glucose
b. Give bicarb and fluids

I've seen it answered both ways, what is the correct answer for Step 1?

 

[Doc Ivy]

Always always always fluids first-- normal saline preferably.


DKAers are dehydrated due to both the high blood glucose but also the ketone bodies in the blood which are osmotically active. They are diuresing like crazy so you have to get them resuscitated volume-wise, then give insulin, glucose etc.

Just an FYI--- if an acidotic pt's pH is 7.2 or above, don't give bicarb. The fluid should be enough to correct the acid-base disturbance, but in this case, the pH is dangerously low so you would consider adding HCO3 to the IV.

On a related note, remember that eventhough they may be hyperkalemic due to potassium shifting out of the cells and acidosis, the total body K is depleted through the kidneys, so once you start insulin and potassium starts shifting back into cells you may have to replete K at some point

Hope it helps

 

[Jack P]

Thanks Doc...your answer is exactly what I expected; however, I was a bit disgruntled after taking a kaplan exam as the response was to correct hyperglycemia with insulin and glucose first (and piggyback Potassium I'm sure, as you suggested) and then correct with fluids subsequently. Their reasoning suggested that bicarbonate will only create a transient benefit in the pH level for the patient while eliminating the ketoacidosis will treat the underlying problem. Goljan, books, you have all concurred that we should set up fluids first, I wonder on step 1 which one will win...the bad thing is that we wouldn't know even if we were wrong. It's just one point anyway...

 

[Idiopathic]

Just an FYI--- if an acidotic pt's pH is 7.2 or above, don't give bicarb. The fluid should be enough to correct the acid-base disturbance, but in this case, the pH is dangerously low so you would consider adding HCO3 to the IV.

Very unlikely to have a pH of 6.9 with a double digit bicarbm BTW. Ive seen maybe two DKA with pH this low and they had either 0,1 or 2 for their measured HCO3- levels. It is in these patients (and these patients only) that you really want to consider bicarb. In someone with a pH above 7, you actually run the risk of shifting your O2-dissociation curve away from where it needs to be (i.e. the body thinks it isnt as acidotic anymore) and you can cause greater tissue ischemia. But when the pH starts to get below 7, even the most hard-core attendings will usually give a few amps...it makes everyone feel better.

So, the answer in DKA is always fluids. Watch for cerebral edema as a complication of liberal fluid resuscitation.

 

[Idiopathic]

And let me back up and say how absolutely wrong it is to give glucose in this case. You can (and should) give insulin all day long but should not add glucose until the serum glucose drops to 250. If that was the true answer to this question, then you should bring this up with who asked the question, because glucose and insulin is dead wrong. And you arent supposed to give insulin until the potassium is corrected, as its administration will lower K even more.

Awful answer, if its correct.

 

[Jack P]

Hi Idio...thanks for the great explanation. I think it's difficult with some of the question banks, who to believe, who not to believe, it's easy to just take Kaplan's word for it (it was their question and answer btw). I'm thinking it would be brilliant if these question banks would site references in their answer explanations...that gives me an idea, anyone want to go into business building a new question bank?