What is the treatment for Diabetic Ketoacidosis (DKA) in a 75 kg patient?

Treatment of Diabetic Ketoacidosis in a 75 kg Patient

For a 75 kg patient with DKA, begin immediate fluid resuscitation with 0.9% NaCl at 1125-1500 mL/hour for the first hour, followed by continuous IV regular insulin at 7.5 units/hour (0.1 units/kg/hour) without an initial bolus, while aggressively monitoring and replacing potassium to maintain levels between 4-5 mEq/L. 1

Initial Fluid Resuscitation

• Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour, which translates to 1125-1500 mL/hour for this 75 kg patient to restore intravascular volume and renal perfusion 1
• After the initial hour, switch to 0.45% NaCl at 4-14 mL/kg/hour (300-1050 mL/hour) if corrected serum sodium is normal or elevated; continue 0.9% NaCl if corrected sodium is low 1
• Balanced electrolyte solutions may be considered as an alternative to 0.9% saline, as they have shown faster DKA resolution in some studies 1, 2

Insulin Therapy Protocol

• Start continuous IV regular insulin at 0.1 units/kg/hour (7.5 units/hour for this 75 kg patient) WITHOUT an initial bolus 1, 2
• If plasma glucose does not fall by 50 mg/dL from the initial value in the first hour, double the insulin infusion every hour until achieving a steady glucose decline of 50-75 mg/hour 3, 2
• When plasma glucose reaches 250 mg/dL, decrease insulin infusion to 0.05-0.1 units/kg/hour (3.75-7.5 units/hour) and add 5-10% dextrose to IV fluids 3
• Never interrupt insulin infusion when glucose falls—instead add dextrose-containing fluids (5% dextrose with 0.45-0.75% NaCl) to maintain glucose 150-200 mg/dL while continuing insulin to clear ketosis 1

Critical Potassium Management

• Check potassium level immediately—if K+ <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, 2
• Once K+ is <5.5 mEq/L and renal function is assured, add 20-40 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO4) 1, 2
• Target serum potassium 4-5 mEq/L throughout treatment 1, 2

Bicarbonate Therapy (Generally NOT Recommended)

• Bicarbonate is generally not recommended for pH >6.9, as studies show no benefit on clinical outcomes and potential harm including worsening ketosis, hypokalemia, and cerebral edema risk 1, 2
• Consider bicarbonate ONLY if pH <6.9: give 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/hour 1, 2
• For pH 6.9-7.0, give 50 mmol sodium bicarbonate in 200 mL sterile water at 200 mL/hour 2

Monitoring Protocol

• Check blood glucose every 1-2 hours 1, 2
• Draw blood every 2-4 hours for electrolytes, glucose, BUN, creatinine, osmolality, and venous pH 1, 2
• Venous pH (typically 0.03 units lower than arterial pH) and anion gap can be followed instead of repeated arterial blood gases 1, 2
• Continuous cardiac monitoring is crucial to detect arrhythmias early, especially given the risk of electrolyte-induced cardiac complications 2

Resolution Criteria

DKA is resolved when ALL of the following are met 1, 2:

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

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, 2
• For newly diagnosed patients, initiate approximately 0.5-1.0 units/kg/day (37.5-75 units/day for this 75 kg patient) as a multidose regimen of short- and intermediate/long-acting insulin 3, 2

Identify and Treat Precipitating Causes

• Obtain cultures (blood, urine, throat) and start antibiotics if infection suspected 1, 2
• Review medications—SGLT2 inhibitors can cause euglycemic DKA and should be discontinued 1, 2
• Search for myocardial infarction, stroke, or other acute stressors 2

Common Pitfalls to Avoid

• Premature termination of insulin therapy before complete resolution of ketosis—continue insulin until all resolution criteria are met, not just glucose normalization 1, 4
• Starting insulin before correcting severe hypokalemia (K+ <3.3 mEq/L)—this can precipitate fatal arrhythmias 1, 2
• Stopping IV insulin without prior subcutaneous basal insulin administration—this causes rebound ketoacidosis 1, 2
• Relying on nitroprusside method to measure ketones—this doesn't detect β-hydroxybutyrate, the predominant ketone body in DKA; direct β-hydroxybutyrate measurement is preferred 4, 2
• Correcting osmolality too rapidly—induced change in serum osmolality should not exceed 3 mOsm/kg/hour to prevent cerebral edema 2