How is acidosis managed in a patient with Diabetic Ketoacidosis (DKA)?

Management of Acidosis in Diabetic Ketoacidosis (DKA)

Bicarbonate therapy should only be administered in DKA patients with severe acidosis (pH <6.9), while most DKA patients with pH ≥7.0 do not require bicarbonate therapy as insulin administration alone will resolve the acidosis by blocking lipolysis. 1, 2

Assessment of Acidosis Severity

Acidosis severity in DKA is classified based on arterial pH:

• Mild: pH 7.25-7.30
• Moderate: pH 7.00-7.24
• Severe: pH <7.00 2

Primary Management Approach

1. Fluid Resuscitation

• Initial fluid therapy with isotonic saline (0.9% NaCl) at 1-1.5 L during the first hour 2
• Continue at 4-14 ml/kg/h if corrected serum sodium is low 2
• Switch to 0.45% NaCl when corrected sodium is normal or elevated 2
• When glucose reaches 250 mg/dl, switch to 5% dextrose with 0.45-0.75% saline 2

2. Insulin Therapy

• For moderate to severe DKA: Initial IV bolus of 0.15 U/kg regular insulin followed by continuous infusion at 0.1 U/kg/hour 2
• For mild DKA: Subcutaneous or intramuscular regular insulin (initial dose 0.4-0.6 U/kg, then 0.1 U/kg/hour) 2
• Target glucose reduction: 50-75 mg/dl per hour 2
• If glucose doesn't decrease by 50 mg/dl in first hour, check hydration status and consider doubling insulin infusion rate 2

3. Electrolyte Replacement

• Potassium: Add 20-40 mEq/L to IV fluids when diuresis is confirmed and serum potassium <5.0 mEq/L 2
• Target potassium level: 4.0-5.0 mEq/L 2
• Delay insulin therapy if initial potassium is <3.3 mEq/L to avoid arrhythmias, cardiac arrest, and respiratory muscle weakness 1

Bicarbonate Therapy Guidelines

When to Use Bicarbonate

• Only consider if pH <6.9 after initial treatment 1, 2
• Not necessary if pH ≥7.0 1

Bicarbonate Dosing

For adults with pH <6.9:

• 100 mmol sodium bicarbonate in 400 ml sterile water given at 200 ml/h 1

For adults with pH 6.9-7.0:

• 50 mmol sodium bicarbonate in 200 ml sterile water given at 200 ml/h 1

Monitoring During Treatment

• Measure glucose, electrolytes, and venous pH every 2-4 hours 2
• Monitor for resolution of DKA, defined as:
  • Glucose <200 mg/dL
  • Serum bicarbonate ≥18 mEq/L
  • Venous pH ≥7.3
  • Normalization of anion gap 2

Potential Complications of Acidosis Management

Risks of Bicarbonate Administration

• May worsen hypokalemia
• Can cause paradoxical central nervous system acidosis
• May delay ketone clearance
• Can worsen tissue hypoxia

Risks of Fluid Administration

• Large volume normal saline can cause hyperchloremic metabolic acidosis due to high chloride content (154 mEq/L) 2
• Volume overload risk in patients with heart failure, cirrhosis, or renal dysfunction 2

Special Populations

Pediatric Patients

• Higher risk of cerebral edema with rapid correction of glucose levels 2
• No randomized studies on bicarbonate use in pediatric patients with pH <6.9 1
• More cautious fluid administration recommended

Patients with Renal Disease

• Require adjustment of electrolyte replacement 2
• May experience more significant sodium elevation with normal saline administration 2

Elderly Patients

• Require more careful monitoring during fluid resuscitation 2
• Higher risk of complications from fluid overload

Transition to Subcutaneous Insulin

Once DKA resolves (glucose <200 mg/dl, bicarbonate ≥18 mEq/l, venous pH ≥7.3, anion gap normalized):

• Transition to multiple-dose subcutaneous insulin regimen 2
• Continue IV insulin for 1-2 hours after initiating subcutaneous insulin 2

Remember that the primary treatment of acidosis in DKA is addressing the underlying cause through insulin administration, which blocks lipolysis and resolves ketoacidosis, with bicarbonate reserved only for severe cases with pH <6.9.