What is the appropriate fluid resuscitation regimen for a child with diabetic ketoacidosis?

Fluid Resuscitation in Pediatric Diabetic Ketoacidosis

Initial Fluid Resuscitation (First Hour)

Begin with isotonic saline (0.9% NaCl) at 10–20 mL/kg/hour for the first hour, not exceeding 50 mL/kg over the initial 4 hours. 1

• Pediatric DKA requires a more conservative approach than adult protocols to minimize cerebral edema risk, which is the leading cause of DKA-related mortality in children. 1
• The American Diabetes Association specifically recommends 0.9% NaCl at 10–20 mL/kg/hour during the first hour for patients under 20 years of age. 1
• Never exceed 50 mL/kg total fluid volume in the first 4 hours—this is a critical safety threshold to prevent osmotic shifts that precipitate cerebral edema. 1

Subsequent Fluid Management (Hours 1–48)

After the initial hour, adjust fluid composition based on corrected serum sodium:

• Calculate corrected sodium by adding 1.6 mEq/L for each 100 mg/dL glucose above 100 mg/dL. 1
• If corrected sodium is low: Continue 0.9% NaCl at 4–14 mL/kg/hour. 1
• If corrected sodium is normal or elevated: Switch to 0.45% NaCl (half-normal saline) at 4–14 mL/kg/hour. 1
• Replace the remaining estimated fluid deficit evenly over 48 hours (not 24 hours as in adults). 1

Transition to Dextrose-Containing Fluids

When plasma glucose falls to ≤250 mg/dL, switch to 5% dextrose with 0.45–0.75% NaCl while continuing insulin infusion. 1

• The saline concentration (0.45% vs 0.75%) should be adjusted based on serum sodium levels. 1
• Never use D50W in pediatric patients—it is too hypertonic and causes vein irritation; maximum concentration is D25W, preferably D10W. 1
• Continue insulin infusion at 0.1 units/kg/hour until ketoacidosis resolves (pH >7.3, bicarbonate ≥18 mEq/L), not just until glucose normalizes. 1

Potassium Replacement Protocol

Add 20–30 mEq/L potassium to IV fluids once urine output is confirmed (≥0.5 mL/kg/hour). 1

• Use a mixture of 2/3 potassium chloride (KCl) + 1/3 potassium phosphate (KPO₄) to address concurrent phosphate depletion. 1
• Never add potassium before confirming adequate urine output—this can precipitate life-threatening hyperkalemia. 1
• If serum K⁺ is <3.3 mEq/L, delay insulin therapy until potassium is corrected, as insulin will further lower potassium levels. 1

Critical Osmolality Management

Serum osmolality must not change faster than 3 mOsm/kg/hour—this is the single most important safety parameter to prevent cerebral edema. 1

• Calculate effective osmolality: 2 × [Na (mEq/L)] + [Glucose (mg/dL)] ÷ 18. 1
• Monitor osmolality every 2–4 hours during active resuscitation. 1
• Cerebral edema is the leading cause of DKA mortality in children and occurs when osmolality drops too rapidly. 1

Monitoring Parameters

Assess the following every 1–2 hours during initial resuscitation:

• Hemodynamic status: Blood pressure, heart rate, capillary refill (<2 seconds is goal). 2
• Perfusion markers: Mental status, skin temperature, urine output (goal ≥0.5 mL/kg/hour). 2
• Laboratory values: Serum electrolytes, glucose, BUN, creatinine, venous pH, anion gap every 2–4 hours. 1
• Fluid balance: Strict input/output monitoring to avoid fluid overload. 1

Common Pitfalls to Avoid

Never Use Adult DKA Protocols Without Modification

• Adult protocols call for 15–20 mL/kg/hour in the first hour and up to 1–1.5 L total—this volume is excessive and dangerous in children. 1
• The 50 mL/kg limit over 4 hours is non-negotiable in pediatric patients. 1

Never Administer Excessive Fluid Rates

• Rapid fluid administration beyond recommended rates increases cerebral edema risk exponentially. 1
• Even in severe dehydration, slower is safer in pediatric DKA. 1

Never Ignore Corrected Sodium Calculations

• Uncorrected sodium values are misleading in hyperglycemia and will lead to inappropriate fluid selection. 1
• Always correct sodium before deciding between 0.9% and 0.45% NaCl. 1

Never Allow Osmolality to Drop Rapidly

• Osmotic demyelination syndrome and cerebral edema are irreversible complications of overly aggressive correction. 1
• The 3 mOsm/kg/hour threshold applies to both increases and decreases in osmolality. 1

Practical Example: 30 kg Child with DKA

Time Frame	Fluid & Rate	Calculation	Additional Details
Hour 0–1	0.9% NaCl at 300–600 mL/hour	10–20 mL/kg/h × 30 kg	Initial volume expansion [1]
Hour 1–4	0.45% NaCl at 120–420 mL/hour (if corrected Na⁺ normal/high)	4–14 mL/kg/h × 30 kg	Total not to exceed 1500 mL over 4 hours [1]
When glucose ≤250 mg/dL	D5 0.45% NaCl at 120–300 mL/hour + 20–30 mEq/L K⁺	Continue insulin 0.1 units/kg/h	Prevent hypoglycemia [1]

• Total 4-hour fluid goal: Maximum 1500 mL (50 mL/kg × 30 kg). 1
• 48-hour total fluid goal: Approximately 3–4 L to replace estimated deficit of 100 mL/kg. 1

Balanced Crystalloids vs. Normal Saline

While recent evidence suggests balanced electrolyte solutions (lactated Ringer's) may shorten DKA resolution time by approximately 5 hours and produce more favorable electrolyte profiles, 1 the American Diabetes Association continues to endorse isotonic saline (0.9% NaCl) as the first-line resuscitation fluid for pediatric DKA. 1

• If balanced solutions are used, apply the same volume and rate restrictions as for normal saline. 1
• The primary advantage of balanced solutions is avoidance of hyperchloremic acidosis, which is less clinically significant in DKA than the risk of cerebral edema from excessive fluid rates. 1, 3