What is the initial treatment for a 44-year-old male patient diagnosed with diabetic ketoacidosis?

Initial Treatment for Diabetic Ketoacidosis in a 44-Year-Old Male

Begin immediate fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 liters in the first hour), followed by continuous intravenous regular insulin infusion at 0.1 units/kg/hour once potassium is ≥3.3 mEq/L. 1, 2, 3

Immediate Initial Assessment

Obtain the following laboratory tests immediately upon presentation 2, 3:

• Plasma glucose, arterial blood gases (pH, bicarbonate)
• Serum electrolytes with calculated anion gap
• Blood urea nitrogen, creatinine, osmolality
• Serum ketones (β-hydroxybutyrate preferred over nitroprusside method) 4, 3
• Complete blood count with differential
• Urinalysis with urine ketones
• Electrocardiogram
• Blood, urine, and throat cultures if infection suspected 2, 3

Fluid Resuscitation Protocol

First Hour: Administer isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (1-1.5 liters for average adult) to restore intravascular volume and renal perfusion 1, 2, 3

Subsequent Hours: 1, 3

• If corrected serum sodium is normal or elevated: use 0.45% NaCl at 4-14 mL/kg/hour
• If corrected serum sodium is low: continue 0.9% NaCl at similar rate
• When glucose reaches 250 mg/dL: switch to 5% dextrose with 0.45-0.75% NaCl to prevent hypoglycemia while continuing insulin 4, 3

Insulin Therapy

Critical prerequisite: Do NOT start insulin if serum potassium is <3.3 mEq/L—this can cause life-threatening cardiac arrhythmias and respiratory muscle weakness 3. Aggressively replace potassium first until levels reach ≥3.3 mEq/L 3.

Once potassium ≥3.3 mEq/L: 2, 3, 5

• Start continuous IV regular insulin infusion at 0.1 units/kg/hour
• If glucose does not fall by 50 mg/dL in the first hour, double the insulin infusion rate hourly until achieving a steady decline of 50-75 mg/dL per hour 3
• Continue insulin infusion until COMPLETE resolution of ketoacidosis (pH >7.3, bicarbonate ≥18 mEq/L, anion gap ≤12 mEq/L) regardless of glucose levels 2, 4, 3

Potassium Replacement Strategy

Despite often presenting with normal or elevated potassium, total body potassium depletion is universal in DKA 3. Insulin therapy will drive potassium intracellularly, causing rapid decline 2, 3.

Potassium management: 1, 2, 3

• If K+ <3.3 mEq/L: Hold insulin, give aggressive potassium replacement until ≥3.3 mEq/L
• If 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
• If K+ >5.5 mEq/L: Withhold potassium initially but monitor closely as levels will drop rapidly
• Target: Maintain serum potassium 4-5 mEq/L throughout treatment 4, 3

Monitoring Protocol

Every 1-2 hours: Blood glucose 4

Every 2-4 hours: 2, 3

• Serum electrolytes (especially potassium)
• Glucose, blood urea nitrogen, creatinine
• Venous pH (typically 0.03 units lower than arterial pH) 3
• Osmolality and anion gap

Critical Pitfalls to Avoid

Never stop IV insulin when glucose falls below 250 mg/dL—this is the most common error leading to persistent or recurrent ketoacidosis 2, 4. Instead, add dextrose-containing fluids and continue insulin until acidosis resolves 4, 3.

Do not use bicarbonate for pH >6.9-7.0, as studies show no benefit in resolution time and it may worsen ketosis, hypokalemia, and increase cerebral edema risk 3.

Inadequate potassium monitoring and replacement is a leading cause of mortality in DKA 3.

Resolution Criteria

DKA is resolved when ALL of the following are met 2, 3:

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3
• Anion gap ≤12 mEq/L

Transition to Subcutaneous Insulin

Once DKA is resolved and the patient can eat 2, 3:

• Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin infusion to prevent recurrence 2, 3
• Start multiple-dose insulin schedule combining short/rapid-acting and intermediate/long-acting insulin 2, 3