>250 mg/dL (may be lower in SGLT2i-associated euglycemic DKA)
Arterial pH
7.25–7.30
7.00–7.24
<7.00
Serum bicarbonate
15–18 mEq/L
10–14 mEq/L
<10 mEq/L
Anion gap (AG)
>12 mEq/L (elevated)
Serum/urine ketones
Positive; beta-hydroxybutyrate (BHB) ≥3.0 mmol/L
Mental status
Alert
Alert/drowsy
Stupor/coma
Step 1: Before Starting Insulin, Check Potassium
K <3.3: HOLD insulinK 3.3–5.3: Replace + start insulinK >5.3: Start insulin, recheck in 2 h
Serum K+
Action
<3.3 mEq/L
Hold insulin. Replace K+ aggressively (20–40 mEq/h IV KCl via central line) until K+ ≥3.3, then start insulin. Insulin drives K+ intracellularly and will worsen hypokalemia.
3.3–5.3 mEq/L
Add 20–40 mEq KCl per liter of IV fluid. Start insulin concurrently. Goal: maintain K+ 4.0–5.0 mEq/L.
>5.3 mEq/L
Do not supplement K+. Start insulin. Recheck K+ every 2 hours; it will fall.
Step 2: Insulin Drip Initiation
Method
Protocol
Low-dose (preferred, ADA 2024)
Regular insulin 0.14 units/kg/h IV continuous infusion. No bolus.
Bolus + drip (alternative)
Regular insulin 0.1 units/kg IV bolus, then 0.1 units/kg/h continuous infusion.
Use regular insulin only (not analogs) for IV infusion. Mix 100 units regular insulin in 100 mL NS (1 unit/mL). Flush tubing with 20 mL of the insulin solution before connecting to patient (insulin adsorbs to IV tubing).
Step 3: Rate Adjustments
BG Trend
Action
BG not falling by 50–75 mg/dL in 1st hour
Double the rate every hour until BG drops 50–75 mg/dL/h.
BG falling >100 mg/dL/h
Reduce rate by 50%. Risk of cerebral edema (especially pediatrics) and rebound hypoglycemia.
BG reaches 200–250 mg/dL
Reduce rate to 0.02–0.05 units/kg/h AND add dextrose to IV fluids (D5 0.45% NS or D10 0.45% NS). Do NOT stop the drip. The goal is to keep BG 150–200 while continuing insulin to close the anion gap.
BG <70 mg/dL (hypoglycemia)
Give D50W 25 mL (12.5 g) IV push. Reduce insulin rate by 50%. Increase dextrose in maintenance fluids. Recheck BG in 15 min.
Step 4: Transition to Subcutaneous Insulin
Criteria (need ALL)
Detail
BG <200 mg/dL
Consistently for ≥1 hour
Anion gap closed
AG ≤12 mEq/L
Plus ≥2 of:
Venous pH >7.30, serum HCO3 ≥15 mEq/L, patient able to eat
Overlap rule: give the first dose of subcutaneous (subQ) basal insulin (or rapid-acting if mealtime) at least 2 hours before discontinuing the IV drip. Regular insulin IV has a half-life of approximately 5–10 minutes; stopping without overlap leads to rebound hyperglycemia and DKA relapse within hours.
SubQ Regimen
Starting Dose
Basal (glargine or detemir)
0.2–0.3 units/kg/day (known diabetic: resume home basal dose if reasonable)
BG decrease 50–75 mg/dL/h; maintain 150–200 after dextrose start
BMP (Na, K, Cl, CO2, BUN, Cr, Glucose)
Every 2–4 h
K+ 4.0–5.0; closing AG; rising HCO3
Venous blood gas (VBG)
Every 2–4 h until pH >7.30
pH improving toward >7.30
Beta-hydroxybutyrate (BHB)
Every 4–6 h (if available)
BHB <0.6 mmol/L = resolution; better than urine ketones
Phosphate, Magnesium
At baseline, then q6–12 h
Replace if low; severe hypophosphatemia can impair diaphragm function
Red Flags & Common Pitfalls
🛑
Gap not closed, BG normal: the most dangerous moment. BG normalizes 6–12 hours before the anion gap closes. Stopping insulin because BG is normal causes DKA bounce-back. Add dextrose and keep the drip running.
⚠️
No subQ overlap: stopping the drip without giving subQ insulin 2 hours prior is the number-one cause of DKA relapse on the floor. Order the subQ insulin as soon as transition criteria are met.
💣
Hypokalemia kills before acidosis does: never start insulin if K+ <3.3. Cardiac arrhythmia risk is immediate. Potassium replacement is the first priority.
💊
SGLT2 inhibitor (euglycemic) DKA: BG may be <250 or even normal. Diagnose by AG and ketones, not glucose alone. Hold the SGLT2i. Standard insulin drip protocol still applies.
💧
Bicarbonate: routine sodium bicarbonate is NOT recommended (ADA 2024). Consider only if pH <6.9 and hemodynamic compromise (100 mmol NaHCO3 in 400 mL H2O with 20 mEq KCl over 2 h; repeat q2h until pH >7.0).
🧬
Cerebral edema (pediatrics): rare but fatal. Avoid BG drops >100 mg/dL/h. Use isotonic fluids. Watch for headache, altered mental status, bradycardia in children.