Immediate Management of Diabetic Ketoacidosis
Begin aggressive fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in the first hour), followed by continuous IV regular insulin at 0.1 units/kg/hour once potassium is ≥3.3 mEq/L, while simultaneously identifying and treating the precipitating cause. 1, 2, 3
Initial Assessment and Diagnostic Workup
Confirm DKA diagnosis immediately by checking: blood glucose >250 mg/dL, arterial pH <7.3, serum bicarbonate <15 mEq/L, and presence of ketonemia or ketonuria 1, 2. The complete initial laboratory panel must include plasma glucose, electrolytes with calculated anion gap, serum ketones (preferably β-hydroxybutyrate), blood urea nitrogen/creatinine, osmolality, arterial blood gases, complete blood count with differential, urinalysis with urine ketones, and electrocardiogram 1, 3.
Identify precipitating factors immediately: obtain bacterial cultures (urine, blood, throat) if infection is suspected and start appropriate antibiotics 1, 3. Consider other triggers including myocardial infarction, cerebrovascular accident, pancreatitis, trauma, insulin omission/inadequacy, alcohol abuse, or SGLT2 inhibitor use 1.
Fluid Resuscitation Protocol
Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour regardless of corrected sodium level, as patients typically have a 6-9 liter total body water deficit 1, 2, 3. This aggressive initial fluid replacement is critical to restore tissue perfusion and improve insulin sensitivity 1.
Subsequent fluid choice depends on hydration status, serum electrolyte levels, and urine output 1, 2. Target total fluid replacement of approximately 1.5 times the 24-hour maintenance requirements over 24 hours 2, 3.
When serum glucose reaches 200-250 mg/dL, switch to 5% dextrose with 0.45-0.75% NaCl while continuing insulin therapy to prevent hypoglycemia and allow complete ketoacidosis resolution 1, 2, 3. This is crucial because insulin alone cannot clear ketones without adequate carbohydrate substrate 2.
Potassium Management (Critical)
DO NOT start insulin if potassium is <3.3 mEq/L - this is an absolute contraindication that can cause life-threatening cardiac arrhythmias and death 1, 3. Despite total body potassium depletion being universal in DKA (averaging 3-5 mEq/kg body weight), only a small percentage present with hypokalemia, making this a high-risk scenario 1, 2.
If K+ <3.3 mEq/L: delay insulin therapy and aggressively replace potassium with 20-40 mEq/L in IV fluids until levels reach ≥3.3 mEq/L 1, 2, 3. Obtain an electrocardiogram to assess for cardiac effects 3.
If K+ 3.3-5.5 mEq/L: add 20-30 mEq/L potassium per liter of IV fluid (use 2/3 KCl and 1/3 KPO₄) once adequate urine output is confirmed 1, 2, 3. Target serum potassium of 4-5 mEq/L throughout treatment 1, 2.
If K+ >5.5 mEq/L: withhold potassium initially but monitor closely every 2-4 hours, as levels will drop rapidly with insulin therapy 1, 2.
Insulin Therapy Protocol
Start continuous IV regular insulin infusion at 0.1 units/kg/hour (with or without an initial 0.1 units/kg bolus) once potassium is ≥3.3 mEq/L 1, 2, 3. This is the standard of care for moderate-to-severe DKA or critically ill/mentally obtunded patients 1, 3.
Target glucose decline of 50-75 mg/dL per hour 1, 3. If plasma glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration status, then double the insulin infusion rate every hour until achieving steady decline 1, 2, 3.
Continue insulin infusion until complete resolution of ketoacidosis (pH >7.3, serum bicarbonate ≥18 mEq/L, anion gap ≤12 mEq/L) regardless of glucose levels 1, 2, 3. This is critical - premature termination of insulin therapy before complete resolution of ketosis is a common cause of DKA recurrence 1, 4.
Alternative for Mild-Moderate Uncomplicated DKA
For hemodynamically stable, alert patients with mild-moderate DKA, subcutaneous rapid-acting insulin analogs (0.15 units/kg every 2-3 hours) combined with aggressive fluid management are equally effective, safer, and more cost-effective than IV insulin 1, 2, 3. However, continuous IV insulin remains mandatory for critically ill and mentally obtunded patients 1, 3.
Bicarbonate Administration (Generally NOT Recommended)
DO NOT administer bicarbonate for pH >6.9-7.0 1, 2, 3. Multiple studies show no difference in resolution of acidosis or time to discharge with bicarbonate use, and it may worsen ketosis, cause hypokalemia, and increase cerebral edema risk 1, 2, 3, 5. Bicarbonate can be considered only if serum pH falls below 6.9, or when pH <7.2 pre- and post-intubation to prevent hemodynamic collapse 6, 5.
Monitoring During Treatment
Draw blood every 2-4 hours to measure serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 1, 2, 3. After initial diagnosis, venous pH (typically 0.03 units lower than arterial pH) and anion gap adequately monitor acidosis resolution without requiring repeated arterial blood gases 1, 2.
Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring DKA, as the nitroprusside method only measures acetoacetic acid and acetone, and can falsely suggest worsening ketosis during treatment as β-hydroxybutyrate converts to acetoacetate 1, 2.
Resolution Criteria
DKA is resolved when ALL of the following are met: glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap ≤12 mEq/L 1, 2, 3. Target glucose between 150-200 mg/dL until these parameters are achieved 1.
Transition to Subcutaneous Insulin (Critical Timing)
Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin infusion to prevent recurrence of ketoacidosis and rebound hyperglycemia 1, 2, 3. This overlap period is essential - stopping IV insulin without prior basal insulin administration is the most common error leading to DKA recurrence 1, 4.
Once the patient can eat, start a multiple-dose schedule using a combination of short/rapid-acting and intermediate/long-acting insulin 1, 3. Continue IV insulin for 1-2 hours after subcutaneous insulin is administered 3.
Critical Pitfalls to Avoid
- Stopping IV insulin when glucose normalizes - ketoacidosis takes longer to resolve than hyperglycemia; continue insulin until all resolution criteria are met 1, 2, 4
- Failure to add dextrose when glucose falls below 250 mg/dL - this perpetuates ketone production even with insulin administration 1, 2
- Inadequate potassium monitoring and replacement - this is a leading cause of mortality in DKA 1, 2
- Starting insulin with K+ <3.3 mEq/L - can cause fatal cardiac arrhythmias 1, 3
- Overly rapid correction of osmolality - increases risk of cerebral edema, particularly in children 1