Diabetic ketoacidosis

Background

Hyperosmolality and insulin deficiency causes hyperkalemia; as reverses K+ goes back into cell

Most pts 3-6L depleted

Look for precipitating causes:

1. Insulin non-compliance
2. Infection
3. Ischemia
4. Intra-abd process
   1. (Lipase/amylase not specific in pts w/ DKA)
5. Iatrogenic (steroids)
6. Etoh/drug abuse

Workup

• PRECIPITANT
  • (Fever is rare even in the presence of infection due to

peripheral vasoconstriction 2/2 hypovolemia

• CBC
• Chem 10
• Urine acetone/b-OH
  • If urine ketones + then obtain serum ketones
• Plasma osmolality
• hCG
• UA
• ECG
• ?VBG
• ?CXR

Treatment

Initial

Mild (ketosis): gap <12

Mod: gap 12-18

Severe: gap >18

1) Labs:

• Glucose check Q1hr
• Chem 10 Q4hr
• Corrected Na+
  • Add 1.6mEq for each glucose 100mg/dl >100)

2) IV Fluids

• If severe hypovolemia: 1L NS / hr for up to 3 hr
• If mild dehydration then evaluate corrected Na+
  • If hypernatremic: 1/2NS @ 250-500ml/hr
  • If hyponatremic: NS @ 250-500ml/hr
• When BS < 200 switch to D5½NS@ 150-200 ml/hr(+/- KCl)
• Bolus NS as needed for unstable VS

3) Insulin

• Check K+ prior to insulin Tx!
  • If K < 3.3 do not administer insulin
• IV Route
  • IV gtt 0.14 U/kg/hr =10 U/hr in 70kg pt
    • Bolus dose unnecessary
  • If BS does not decrease by 50-70/hr then double infusion rate qhr until achieved
  • When BS <200, reduce to 0.02-0.05 U/kg/hr IV OR give subQ 0.1 U/kg q2hr
    • Maintain BS between 150 and 200 until resolution of DKA
• SubQ route (appropriate only for mild DKA)
  • Insulin lispro or aspart 0.3 U/kg initially
    • 0.2 U/kg one hr later
      • 0.2 U/kg q2hr thereafter
  • If BS does not decrease by 50-70/hr then double dose qhr until achieved

4) Potassium (initial)

• >5.5: don't give, but recheck q2hr
• 3.3-5.5: give 30 meq/hr in each liter bag
  • 1/2NS is preferred b/c adding 30meq to NS = hypertonic soln
• <3.3: hold insulin and give 30 meq/hr until K >3.3

6) Bicarb

• if pH <6.9: 100 meq NaHCO3 in 400mL H2O @ 200 mL/hr
  • Dose as needed until pH > 7.00

7) Phosphate

• Repletion is controversial
  • Has not been shown to be beneficial
  • Hypophosphatemia following insulin tx usually asymptomatic
  • Repletion is associated with hypoCa and hypoMg
• Consider repletion (KPO4 20-30 meq/L)if:
  • Phosphate <1.0
  • Cardiac dysfunction
  • Respiratory dysfunction
  • Evidence of hemolysis or rhabdo

When gap closes and patient able to eat:

• Begin multidose insulin regimen
• Continue IV infusion for 1-2 hr after SC insulin tx is begun

Complications

• Cerebral Edema
  • Almost all affected pts are <20yrs
• Noncardiogenic pulmonary edema

SLIDING SCALE

200- 250- 4u sq

251- 300- 6

301- 350- 8

351- 400- 10

> 400- call MD

Source

Adapted from Chavira, Rosen, Mistry, Ip, Donaldson, Pani, UpToDate