Diabetic Ketoacidosis (DKA): Typical Laboratory Findings and Response to Treatment

Authors: V. Dimov, M.D., Cleveland Clinic; R. Akhtar, M.D.
Reviewer: S. Randhawa, M.D.


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Dr. Tahir from Case Western Reserve University (St. Vincent/St. Luke) discusses DKA management (click the "play" button to listen to the MP3 file).

Laboratory results


CBC, BMP and arterial blood gas (ABG) analysis in diabetic ketoacidosis (DKA) (click to enlarge the images).


Blood glucose levels and response to insulin drip (click to enlarge the images).


Medications during the hospital stay (click to enlarge the images).

DKA Management

Treatment

Intravenous fluids (IVF): correct the 6-8 L fluid deficit which typically occurs in DKA.

Fluid of choice: Normal saline (NaCl 0.9%). You can calculate corrected sodium by using this formula: Corrected Sodium = Measured sodium + 0.016 * (Serum glucose - 100).

IV bolus followed by 250-500 cc/hr aiming for positive balance of 6-8 L.

Add D5W or D5 1/2NS when blood glucose falls below 250 mg/dL.

Insulin

Objective: to correct acidosis (bicarbonate level > 16) and/or to normalize the anion gap. Method: IV, no bolus necessary. If you decide to give an insulin bolus, the dose is 10-15 U.
Rate of infusion is 0.1 U/Kg/hr.

Stop IV insulin drip and switch to SQ insulin only when the above parameters are reached (bicarbonate greater than 16 mEq/L, normal anion gap).

Use a generous sliding scale (eg. 5-10 U for the first step) with overlap with IV for 2-3 hours. Continue frequent Accuchecks for the next 4-6 hrs. You can start NPH insulin immediately.

Start replacing potassium at high normal levels (5.0 mEq/L for our lab).

Replace phosphate if necessary (dangers: respiratory depression; cardiac arrythmias are rare).

Give bicarbonate if pH is less than 7.2 (bicarbonate is not usually needed). Target glucose drop: 70-100 mg/dl/hr. If more precipitous, then peril of cerebral edema. You can give simultaneous D5W or D5 1/2 NS to avoid this. If blood glucose drop is not sufficient, you can double insulin rate (at lower levels) or increase the rate significantly without doubling (at higher levels).

References

Diabetic Ketoacidosis. American Family Physician, May 1, 2005.
Diabetic Ketoacidosis. eMedicine.
Hyperosmolar Hyperglycemic State. American Family Physician, May 1, 2005.
Corrected Sodium for Glucose. MDCalc.com.

Further reading

Cases: Inpatient Diabetes Management. NYU Internal Medicine Blog.

Published: 05/30/2005
Updated: 12/20/2008

4 comments:

  1. A better glucose target is 200 mg/dL, as it "always" drops lower than expected.

    Phosphate will nearly always be low, but replacement will often trigger very unpleasant tetany about the time the patient becomes quite alert. They don't like it.
    The serum phosphate rises on the second day from phosphate moving back out of cells into the serum.

    ReplyDelete
  2. Withholding phosphate to avoid tetany is like withholding insulin to avoid hypoglycemia: both are simply a matter of using the right amount. Published cases of hypocalcemic tetany due to PO4 replacement all involve excessive PO4 doses. If you know of even a single case of tetany resulting from standard PO4 amounts (i.e., 50% of K replacement as K phosphate) please post and publish.

    PS: note that the time is stamped but neither date nor year. I have no idea if this was posted yesterday or 3 years ago.

    ReplyDelete
  3. Infections can trigger DKA so don't forget to look for UTIs, pneumonias, etc. esp in patients who are compliant with their insulin.

    ReplyDelete
  4. Thank you for your comments.

    ReplyDelete