What is the recommended step‑by‑step management protocol for diabetic ketoacidosis, including fluid resuscitation, insulin therapy, electrolyte correction, and monitoring?

DKA Management Protocol

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 for adults), followed by continuous IV insulin at 0.1 units/kg/hour once potassium is >3.3 mEq/L, with aggressive potassium replacement and frequent monitoring until complete resolution of ketoacidosis. 1, 2

Initial Assessment and Diagnosis

Obtain plasma glucose, electrolytes with calculated anion gap, arterial or venous blood gases, serum ketones, and osmolality to confirm DKA and characterize the metabolic derangement. 1 Calculate corrected sodium by adding 1.6 mEq/L to the measured sodium for every 100 mg/dL glucose above 100 mg/dL—most patients appear hyponatremic due to hyperglycemia drawing water into the intravascular space. 2, 3

Step 1: Fluid Resuscitation

First Hour

Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour regardless of measured sodium or presence of alkalosis to restore intravascular volume and renal perfusion. 1, 2 This is critical even in patients with cardiac compromise, though rates should be reduced by approximately 50% in chronic kidney disease. 2

Subsequent Fluid Management

After the initial hour, fluid selection depends on corrected serum sodium: 1, 2

• If corrected sodium is normal or elevated: Switch to 0.45% NaCl at 4-14 mL/kg/hour
• If corrected sodium is low: Continue 0.9% NaCl at 4-14 mL/kg/hour

Critical monitoring requirement: Ensure serum osmolality does not decrease faster than 3 mOsm/kg/hour to prevent cerebral edema, especially in children. 2, 3

When Glucose Reaches 150-200 mg/dL

Switch to 5% dextrose with 0.45% saline (or 0.75% saline based on sodium levels) but never interrupt insulin infusion—continue until complete resolution of ketoacidosis. 1, 2 In pediatric patients, use D10W maximum concentration to avoid vein irritation. 2

Step 2: Insulin Therapy

Critical Pre-Insulin Check

If initial potassium is <3.3 mEq/L, delay insulin therapy until potassium is repleted to >3.3 mEq/L to prevent life-threatening arrhythmias and cardiac arrest. 1 This is non-negotiable.

Insulin Initiation

Start continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus to avoid precipitating cerebral edema and worsening hypokalemia. 1 Continue this infusion at the same rate even after adding dextrose-containing fluids until complete resolution of ketoacidosis, not just until glucose normalizes. 1, 2

Step 3: Potassium Management

Once renal function is confirmed (adequate urine output) and serum potassium is <5.5 mEq/L, add 20-40 mEq/L potassium to IV fluids using a mixture of 2/3 KCl and 1/3 KPO₄, targeting serum potassium 4-5 mEq/L throughout treatment. 1, 2 This must be added to all fluids, including dextrose-containing solutions. 2

Never add potassium before confirming adequate renal function and urine output—this causes life-threatening hyperkalemia. 2

Step 4: Bicarbonate Therapy

Do NOT administer bicarbonate in DKA, even with concurrent alkalosis. 1 Bicarbonate is generally not recommended even in pure DKA with pH >6.9, as studies show no benefit on clinical outcomes and potential harm including worsening ketosis, hypokalemia, and increased cerebral edema risk. 1, 4 The only exception is pH <6.9 or when pH <7.2 pre/post-intubation to prevent hemodynamic collapse. 4

Step 5: Monitoring Protocol

Frequency

• Blood glucose: Every 1-2 hours initially 1, 3
• Electrolytes, glucose, BUN, creatinine, osmolality, venous pH: Every 2-4 hours 1, 2

Key Parameters

Use venous pH (typically 0.03 units lower than arterial pH) instead of repeated arterial blood gases for monitoring. 1 Monitor β-hydroxybutyrate if available rather than nitroprusside method, as the latter only measures acetoacetic acid and acetone, not the predominant ketone. 2

Step 6: Resolution Criteria

DKA is resolved when ALL of the following are met: 1, 3

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

Step 7: Transition to Subcutaneous Insulin

Administer subcutaneous basal insulin (intermediate or long-acting) 2-4 hours BEFORE stopping IV insulin to prevent rebound ketoacidosis and hyperglycemia. 1 This overlap period is essential—stopping IV insulin without prior subcutaneous administration causes immediate recurrence of ketoacidosis.

Critical Pitfalls to Avoid

• Never use measured sodium without calculating corrected value—this leads to inappropriate fluid selection and potential osmotic demyelination syndrome. 3
• Never exceed 3 mOsm/kg/hour decrease in osmolality—this causes cerebral edema, particularly in pediatric patients. 2, 3
• Never administer excessive fluid in renal or cardiac compromise—this precipitates pulmonary edema; reduce rates by 50% in chronic kidney disease. 2
• Never stop insulin when glucose reaches 200 mg/dL—continue until complete resolution of ketoacidosis with all four criteria met. 1
• Never exceed 50 mL/kg in the first 4 hours in pediatric patients—use more conservative fluid resuscitation to minimize cerebral edema risk. 2

Special Populations

In euglycemic DKA (SGLT-2 inhibitor use, pregnancy, prolonged fasting), start dextrose-containing fluids immediately alongside insulin to prevent hypoglycemia while correcting ketoacidosis. 2 In pregnancy, renal disease, congestive heart failure, acute coronary syndrome, and older age, tailor fluid rates and monitoring intensity accordingly. 5