DKA Pharmacology Study Guide for Nursing School
Immediate Treatment Protocol
Begin with aggressive isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in the first hour) to restore intravascular volume and tissue perfusion, followed by continuous IV regular insulin at 0.1 units/kg/hour once potassium is ≥3.3 mEq/L. 1
Step 1: Initial Fluid Resuscitation (FIRST PRIORITY)
Start fluids BEFORE insulin - this is critical for improving insulin sensitivity and preventing complications 1
- First hour: Isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour 1, 2
- Subsequent fluids: Adjust based on hydration status, electrolytes, and urine output 1
- When glucose reaches 250 mg/dL: Switch to 5% dextrose with 0.45-0.75% NaCl to prevent hypoglycemia while continuing insulin 1
- Goal: Correct estimated fluid deficits within 24 hours 1
Critical Pitfall: Failure to add dextrose when glucose falls below 250 mg/dL while continuing insulin leads to hypoglycemia and persistent ketoacidosis 1
Step 2: Potassium Management (BEFORE INSULIN)
NEVER start insulin if potassium is <3.3 mEq/L - this can cause fatal cardiac arrhythmias 1, 2
Potassium Decision Algorithm:
- K+ <3.3 mEq/L: HOLD insulin, aggressively replace potassium until ≥3.3 mEq/L 1
- K+ 3.3-5.5 mEq/L: Add 20-30 mEq/L potassium to IV fluids (use 2/3 KCl and 1/3 KPO₄) once urine output confirmed 1, 2
- K+ >5.5 mEq/L: Withhold potassium initially but monitor closely - levels will drop rapidly with insulin 1
Target: Maintain serum potassium 4-5 mEq/L throughout treatment 1
Critical Concept: Despite often presenting with normal or elevated potassium, total body potassium depletion averages 3-5 mEq/kg in DKA, and insulin will unmask this by driving potassium intracellularly 1
Step 3: Insulin Therapy
Standard IV Insulin Protocol (Moderate-Severe DKA):
- Initial bolus: 0.1 units/kg IV regular insulin 2
- Continuous infusion: 0.1 units/kg/hour IV regular insulin 1, 2
- Target glucose decline: 50-75 mg/dL per hour 1, 2
If Glucose Not Declining Adequately:
- Check hydration status first 1
- If hydration acceptable, double insulin infusion rate every hour until steady decline achieved 1
Alternative for Mild-Moderate Uncomplicated DKA:
- Subcutaneous rapid-acting insulin analogs combined with aggressive fluids are equally effective, safer, and more cost-effective for hemodynamically stable, alert patients 1
- This requires frequent point-of-care glucose monitoring and treatment of concurrent infections 1
Critical Pitfall: Stopping insulin when glucose normalizes before ketoacidosis resolves is a common error - continue insulin until ALL resolution criteria are met 1
Step 4: Monitoring Requirements
- Blood glucose
- Serum electrolytes (especially potassium)
- Venous pH (typically 0.03 units lower than arterial pH)
- Anion gap
- BUN/creatinine
- Serum osmolality
Preferred ketone monitoring: Direct measurement of β-hydroxybutyrate in blood (nitroprusside method only measures acetoacetic acid and acetone) 1
Step 5: DKA Resolution Criteria
ALL of the following must be met: 1, 2
- Glucose <200 mg/dL
- Serum bicarbonate ≥18 mEq/L
- Venous pH >7.3
- Anion gap ≤12 mEq/L
Target glucose during treatment: 150-200 mg/dL until resolution parameters met 1
Step 6: Transition to Subcutaneous Insulin
Critical Timing: Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin to prevent DKA recurrence and rebound hyperglycemia 1, 2
Transition Protocol:
- Confirm ALL resolution criteria met AND patient can eat 1, 2
- Give subcutaneous basal insulin 2-4 hours before stopping IV 1
- Continue IV insulin for 1-2 hours after subcutaneous dose 2
- Start multiple-dose regimen: combination of short/rapid-acting + intermediate/long-acting insulin 1
Alternative: Adding low-dose basal insulin analog during IV insulin infusion may prevent rebound hyperglycemia without increasing hypoglycemia risk 1
Most Common Error: Stopping IV insulin without prior basal insulin administration leads to immediate DKA recurrence 1
Bicarbonate: When NOT to Give
DO NOT give bicarbonate if pH >6.9-7.0 1, 3, 2
Rationale: Studies show no benefit in resolution time or outcomes, and bicarbonate may: 1
- Worsen ketosis
- Cause hypokalemia
- Increase cerebral edema risk
Special Considerations
Euglycemic DKA (euDKA):
- Can occur with SGLT2 inhibitors 3
- Same treatment principles apply but requires adequate carbohydrate administration alongside insulin to prevent perpetuating ketosis 3
- SGLT2 inhibitors must be discontinued 3-4 days before planned surgery 1
Precipitating Factors to Address:
Obtain cultures (urine, blood, throat) if infection suspected and give appropriate antibiotics 1
Common triggers: 1
- Infection (most common)
- Insulin omission/inadequacy
- Myocardial infarction
- Stroke
- Pancreatitis
- Trauma
Key Medications Summary
Regular Insulin (IV):
- Dose: 0.1 units/kg/hour continuous infusion 1, 4
- Route: IV only for moderate-severe DKA 1
- Monitoring: Glucose every 2-4 hours 2
- Duration: Until ALL resolution criteria met, regardless of glucose levels 1
Potassium Replacement:
- Dose: 20-30 mEq/L in IV fluids 1, 2
- Formulation: 2/3 KCl (or potassium-acetate) and 1/3 KPO₄ 1, 2
- Timing: Once urine output confirmed 1
Isotonic Saline:
- Initial rate: 15-20 mL/kg/hour first hour 1, 2
- Total replacement: Approximately 1.5 times 24-hour maintenance 2
Dextrose:
- When to add: When glucose reaches 250 mg/dL 1
- Formulation: 5% dextrose with 0.45-0.75% NaCl 1
- Purpose: Prevent hypoglycemia while continuing insulin to clear ketones 1
Critical Nursing Considerations
Hypoglycemia symptoms to monitor: 4
- Sweating, tremor, palpitations
- Confusion, drowsiness, slurred speech
- Severe: disorientation, seizures, unconsciousness
Hyperglycemia/DKA symptoms: 4
- Drowsy feeling, flushed face, thirst
- Fruity breath odor
- Heavy breathing, rapid pulse
- Nausea, vomiting, abdominal pain
Electrolyte monitoring is paramount: Inadequate potassium monitoring and replacement is a leading cause of mortality in DKA 1