Management of Diabetic Ketoacidosis in Adults
Initiate aggressive fluid resuscitation with isotonic saline at 15-20 mL/kg/h in the first hour, followed by continuous intravenous regular insulin at 0.1 units/kg/h after confirming potassium ≥3.3 mEq/L, and add dextrose when glucose reaches 250 mg/dL while continuing insulin until ketoacidosis resolves. 1
Initial Assessment and Diagnosis
Confirm DKA diagnosis with the triad: blood glucose >250 mg/dL (though euglycemic DKA can occur with SGLT2 inhibitors), arterial pH <7.3, serum bicarbonate <15 mEq/L, and moderate ketonuria or ketonemia 1, 2. Obtain arterial blood gases, complete blood count with differential, urinalysis, blood glucose, electrolytes with calculated anion gap, blood urea nitrogen, creatinine, serum osmolality, and electrocardiogram immediately 1. Measure β-hydroxybutyrate in blood rather than relying on nitroprusside urine ketone testing, as the latter only detects acetoacetate and can be misleading during treatment 2.
Fluid Resuscitation
Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg body weight per hour (approximately 1-1.5 liters) during the first hour in adults without cardiac compromise 1. After initial volume expansion, switch to 0.45% NaCl at 4-14 mL/kg/h if corrected serum sodium is normal or elevated; continue 0.9% NaCl at similar rates if corrected sodium is low 1. Correct serum sodium for hyperglycemia by adding 1.6 mEq to the measured sodium value for each 100 mg/dL glucose above 100 mg/dL 1. Ensure the change in serum osmolality does not exceed 3 mOsm/kg/h to avoid cerebral edema 1.
Insulin Therapy
Do not start insulin until potassium is ≥3.3 mEq/L 1. Administer an intravenous bolus of regular insulin at 0.15 units/kg body weight, followed immediately by continuous infusion at 0.1 units/kg/h (5-7 units/h in average adults) 1. This low-dose regimen decreases plasma glucose at 50-75 mg/dL per hour 1. If glucose does not fall by 50 mg/dL in the first hour and hydration is adequate, double the insulin infusion rate hourly until achieving steady glucose decline of 50-75 mg/dL per hour 1.
When plasma glucose reaches 250 mg/dL, decrease insulin infusion to 0.05-0.1 units/kg/h and add 5-10% dextrose to intravenous fluids 1, 3. Continue insulin infusion until ketoacidosis resolves (glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3) 2. The recent Joint British Diabetes Societies guideline recommends considering de-escalation from 0.1 to 0.05 units/kg/h when glucose drops below 14 mmol/L (252 mg/dL) to reduce hypoglycemia risk 4.
Potassium Replacement
Once renal function is confirmed and potassium is known, add 20-30 mEq/L potassium to intravenous fluids (two-thirds KCl and one-third KPO₄) 1. In pediatric patients, use 20-40 mEq/L potassium 1. Hypokalaemia occurs in approximately 50% of patients during DKA treatment and severe hypokalaemia (<2.5 mEq/L) is associated with increased mortality 5. Monitor potassium levels closely and adjust replacement accordingly.
Bicarbonate Therapy
Bicarbonate therapy is generally not recommended 6, 3. Multiple studies show no difference in resolution of acidosis or time to discharge with bicarbonate use 6. Consider bicarbonate only if pH <6.9, though evidence supporting benefit even at this threshold is limited 2.
Phosphate Replacement
Routine phosphate replacement has not shown benefit on clinical outcomes 2. However, consider careful phosphate replacement in patients with cardiac dysfunction, anemia, respiratory depression, or serum phosphate <1.0 mg/dL to avoid cardiac and skeletal muscle weakness 2.
Transition to Subcutaneous Insulin
Administer basal subcutaneous insulin 2-4 hours before stopping intravenous insulin to prevent rebound hyperglycemia and recurrent ketoacidosis 6, 3. Calculate the total daily subcutaneous insulin dose from the average hourly intravenous insulin rate over the preceding 12 hours (e.g., 1.5 units/h × 24 hours = 36 units daily) 5. Use a basal-bolus regimen with approximately 50% as long-acting basal insulin and 50% as rapid-acting prandial insulin divided among meals 7.
Monitoring
Monitor blood glucose every 2-4 hours during treatment 2. Draw blood every 2-4 hours for serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 2. Venous pH (typically 0.03 units lower than arterial) and anion gap can be followed instead of repeated arterial blood gases 2.
Special Considerations
SGLT2 inhibitors should be discontinued 3-4 days before elective surgery and held during acute illness 3 as they increase risk of euglycemic DKA 4, 8. In patients with mild DKA, subcutaneous rapid-acting insulin every hour may be as effective as intravenous administration and can be used in emergency departments or step-down units 2, 6, though this requires adequate fluid replacement, frequent monitoring, and appropriate follow-up 6.