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:
- Insulin non-compliance
- Infection
- Ischemia
- Intra-abd process
- (Lipase/amylase not specific in pts w/ DKA)
- Iatrogenic (steroids)
- 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
DKA Algorithm
Source
Adapted from Chavira, Rosen, Mistry, Ip, Donaldson, Pani, UpToDate