Fluid Management in Diabetic Ketoacidosis
Initial Fluid Resuscitation
Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour, which translates to approximately 1-1.5 liters for average-sized adults. 1
- This initial bolus is critical for expanding intravascular volume and restoring renal perfusion 1
- Do not administer this initial bolus if cardiac compromise is present—this will precipitate pulmonary edema 1
- In patients with chronic kidney disease, reduce this rate by approximately 50% (10-15 mL/kg/hour) to prevent volume overload 2
Subsequent Fluid Management (After First Hour)
The choice of fluid after the initial hour depends on corrected serum sodium:
- If corrected serum sodium is normal or elevated: Switch to 0.45% NaCl (half-normal saline) at 4-14 mL/kg/hour 1
- If corrected serum sodium is low: Continue 0.9% NaCl at 4-14 mL/kg/hour 1
- Calculate corrected serum sodium by adding 1.6 mEq to the measured sodium value for each 100 mg/dL glucose above 100 mg/dL 1
The goal is to correct estimated fluid deficits within 24 hours 1
Potassium Replacement Strategy
Critical timing: Potassium replacement must be carefully coordinated with insulin therapy and renal function:
- If serum K+ is <3.3 mEq/L: Do NOT start insulin therapy until potassium is corrected, as insulin will further lower potassium levels 1
- Once renal function is assured (adequate urine output): Add 20-30 mEq/L potassium to IV fluids 1
- Use a mixture of 2/3 KCl and 1/3 KPO4 1, 2
- In CKD patients, initiate potassium replacement only when serum potassium falls below 5.0 mEq/L and adequate urine output is confirmed 2
Critical Monitoring Parameters
The induced change in serum osmolality must not exceed 3 mOsm/kg/hour—exceeding this rate causes cerebral edema, particularly in children 1, 2
Monitor the following every 2-4 hours:
- Serum electrolytes, glucose, BUN, creatinine 3, 2
- Venous pH and anion gap (arterial blood gases are generally unnecessary) 3
- Blood pressure, fluid input/output, mental status 1, 2
Special Population Considerations
Pediatric Patients (≤20 years)
Use more conservative fluid resuscitation to minimize cerebral edema risk:
- Initial fluid: 0.9% NaCl at 10-20 mL/kg/hour for the first hour 1
- Never exceed 50 mL/kg over the first 4 hours 1
- Calculate subsequent fluid resuscitation to rehydrate evenly over at least 48 hours 4
- Use solutions with tonicity of at least 0.45% saline after initial resuscitation 4
- Research shows that excessive fluid therapy (>10 mL/kg in first hour at many centers) is common and not in keeping with recommendations 5
Chronic Kidney Disease Patients
- Reduce standard fluid administration rates by approximately 50% 1, 2
- Initial rate: 10-15 mL/kg/hour for first hour, followed by 2-4 mL/kg/hour 2
- Avoid large volumes of salt-containing solutions as they worsen fluid retention 2
- More frequent monitoring is required for CKD stage ≥G4 2
Integration with Insulin Therapy
Fluid and insulin management must be coordinated:
- When plasma glucose reaches 250 mg/dL in DKA, adjust fluid composition 3
- Continue insulin infusion at 0.1 unit/kg/hour until ketoacidosis resolves 3, 4
- Monitor β-hydroxybutyrate (preferred) rather than nitroprusside method, as the latter only measures acetoacetic acid and acetone, not the predominant ketone 3
Common Pitfalls to Avoid
Never administer excessive fluid in patients with renal or cardiac compromise—this precipitates pulmonary edema 1, 2
Never add potassium to IV fluids before confirming adequate renal function and urine output—this can cause life-threatening hyperkalemia 1
Never allow osmolality to decrease faster than 3 mOsm/kg/hour—this causes cerebral edema, especially in children 1, 2
Never use standard adult DKA fluid protocols in pediatric patients without modification—children require more conservative rates 1
Never give aggressive potassium replacement without frequent monitoring in CKD patients—these patients have impaired potassium excretion 2