Management of Diabetic Ketoacidosis
Begin with aggressive isotonic saline resuscitation at 15–20 mL/kg/hour for the first hour, followed by continuous intravenous regular insulin at 0.1 units/kg/hour once serum potassium is ≥3.3 mEq/L, while adding 20–30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) to IV fluids once adequate urine output is confirmed. 1
Initial Assessment and Diagnosis
Obtain plasma glucose, serum electrolytes (including potassium), blood urea nitrogen, creatinine, serum ketones (preferably β-hydroxybutyrate), venous pH, bicarbonate, anion gap, osmolality, urinalysis with urine ketones, complete blood count, and electrocardiogram immediately upon presentation. 1, 2 If infection is suspected, obtain bacterial cultures of urine, blood, and throat, and initiate appropriate antibiotics. 1, 2 A chest X-ray should be obtained only if clinically indicated, not routinely. 1, 3
Fluid Resuscitation Protocol
First Hour
Administer isotonic saline (0.9% NaCl) at 15–20 mL/kg body weight per hour (approximately 1–1.5 liters for an average adult) to rapidly restore intravascular volume and renal perfusion. 1, 4, 2 This initial aggressive fluid replacement is the single most important therapeutic intervention and should not be delayed. 4
Subsequent Hours
Calculate corrected serum sodium by adding 1.6 mEq/L for each 100 mg/dL glucose above 100 mg/dL. 1, 4, 2 If corrected sodium is normal or elevated, switch to 0.45% NaCl (half-normal saline) at 4–14 mL/kg/hour. 1, 4 If corrected sodium is low, continue 0.9% NaCl at the same rate. 1, 4 The goal is to replace the estimated fluid deficit (approximately 6 liters or 100 mL/kg) within 24 hours. 4
Transition to Dextrose-Containing Fluids
When plasma glucose falls to approximately 250 mg/dL, switch to 5% dextrose in 0.45% saline (D5 ½-normal saline) while continuing the insulin infusion at the same rate. 1, 4, 2 Never reduce or stop insulin when glucose normalizes—continuous insulin is required to clear ketones and prevent rebound ketoacidosis. 2, 5
Potassium Management (Class A Evidence)
Critical Pre-Insulin Assessment
If serum potassium is <3.3 mEq/L, insulin therapy must be withheld until potassium is aggressively repleted to ≥3.3 mEq/L—this is an absolute contraindication supported by Class A evidence. 1, 6, 2 Starting insulin with severe hypokalemia can precipitate life-threatening cardiac arrhythmias and death. 6, 2
Potassium Replacement Algorithm
- K⁺ <3.3 mEq/L: Hold insulin, start isotonic saline at 15–20 mL/kg/hour, confirm urine output ≥0.5 mL/kg/hour, obtain electrocardiogram, and aggressively replace potassium intravenously until K⁺ ≥3.3 mEq/L. 6, 2
- K⁺ 3.3–5.5 mEq/L: Insulin may be started safely. Once adequate urine output is confirmed, add 20–30 mEq/L potassium to each liter of IV fluid using a mixture of 2/3 potassium chloride (or potassium acetate) and 1/3 potassium phosphate. 1, 6, 4, 2
- K⁺ >5.5 mEq/L: Start insulin immediately without delay, but defer potassium supplementation until the level falls below 5.5 mEq/L. 6, 2
Monitor serum potassium every 2–4 hours throughout treatment, targeting a range of 4.0–5.0 mEq/L. 1, 6, 2 Total body potassium depletion in DKA averages 3–5 mEq/kg despite initially normal or elevated serum levels. 6, 2
Insulin Therapy
Standard Adult Protocol
Administer an IV bolus of regular insulin at 0.1 units/kg, followed immediately by continuous infusion at 0.1 units/kg/hour. 1, 2, 5 Only regular (short-acting) insulin should be used for IV infusion—rapid-acting analogs must not be administered intravenously. 2 Prepare the solution by adding 100 units regular insulin to 100 mL normal saline (1 U/mL concentration), and prime the tubing with 20 mL before patient connection. 2
Target a glucose decline of 50–75 mg/dL per hour. 2, 5 If glucose does not fall by at least 50 mg/dL in the first hour, verify adequate hydration and double the insulin infusion rate hourly until achieving steady decline. 2
Pediatric Modifications
In children and adolescents (<20 years), omit the initial insulin bolus and start continuous infusion at 0.05–0.1 units/kg/hour to minimize cerebral edema risk. 1, 2 Use more conservative fluid resuscitation: 0.9% NaCl at 10–20 mL/kg/hour for the first hour, not exceeding 50 mL/kg over the first 4 hours. 4, 2
Alternative Approach for Mild-Moderate DKA
For hemodynamically stable, alert patients with mild-moderate DKA, subcutaneous rapid-acting insulin analogs (0.1–0.2 U/kg every 1–2 hours) combined with aggressive IV fluid replacement can be as effective and more cost-effective than continuous IV insulin. 1, 2, 5 This approach requires adequate fluid replacement, frequent bedside glucose monitoring, and appropriate follow-up. 1
Monitoring Requirements
Check blood glucose every 2–4 hours while the patient is NPO. 1, 2 Measure serum electrolytes (especially potassium), venous pH, bicarbonate, anion gap, BUN, creatinine, and osmolality every 2–4 hours until metabolically stable. 1, 2, 3 Direct measurement of β-hydroxybutyrate in blood is preferred over urine ketone testing, as urine ketones lag behind serum clearance and can be misleading. 2, 5
Ensure that serum osmolality does not change faster than 3 mOsm/kg/hour to prevent cerebral edema, especially in pediatric patients. 4
Resolution Criteria
DKA is considered resolved when all of the following criteria are met simultaneously: glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, anion gap ≤12 mEq/L, and β-hydroxybutyrate <1.0 mmol/L. 2 Meeting every criterion is required before transitioning to subcutaneous insulin. 2
Transition to Subcutaneous Insulin
Administer long-acting basal insulin (glargine or detemir) subcutaneously 2–4 hours before stopping the IV insulin infusion to prevent recurrence of ketoacidosis and rebound hyperglycemia. 1, 2 Continue the IV insulin infusion for an additional 1–2 hours after the basal dose to allow adequate absorption. 1, 2 Failure to overlap basal insulin before stopping IV insulin is the most common error leading to DKA recurrence. 1, 2
Calculate the basal insulin dose as approximately 50% of the total 24-hour IV insulin amount given as a single daily injection; divide the remaining 50% equally among three meals as rapid-acting prandial insulin. 2
Special Considerations
Euglycemic DKA
For patients presenting with DKA and initial glucose <250 mg/dL (often associated with SGLT-2 inhibitor use, pregnancy, or prolonged fasting), start dextrose-containing fluids (D5W with 0.45–0.75% NaCl) immediately alongside insulin therapy to prevent hypoglycemia while continuing ketone clearance. 4, 5
Severe Acidosis (pH <6.9)
Consider administering 100 mmol sodium bicarbonate diluted in 400 mL sterile water, infused at 200 mL/hour. 2 However, routine bicarbonate use in DKA has not been shown to improve outcomes and is generally not recommended. 1
Patients with Renal or Cardiac Compromise
Reduce standard fluid administration rates by approximately 50% and monitor closely for signs of volume overload (pulmonary edema, jugular venous distension). 4
Critical Pitfalls to Avoid
- Never start insulin when serum potassium is <3.3 mEq/L—this can cause fatal cardiac arrhythmias. 6, 2
- Never stop IV insulin without prior basal insulin overlap—this is the most common cause of recurrent DKA. 1, 2
- Never reduce or hold insulin when glucose normalizes—continue insulin until ketoacidosis fully resolves (pH >7.3, bicarbonate ≥18 mEq/L). 1, 2, 7
- Never add potassium to IV fluids before confirming adequate urine output (≥0.5 mL/kg/hour)—this may precipitate life-threatening hyperkalemia. 1, 4
- Never allow serum osmolality to decrease faster than 3 mOsm/kg/hour—this causes cerebral edema, especially in children. 4
- Never use standard adult fluid protocols in pediatric patients without modification—children require more conservative fluid rates. 4