How to manage diabetic ketoacidosis (DKA) in a level 1 hospital without arterial blood gas (ABG) results?

Managing DKA Without Arterial Blood Gas in a Level 1 Hospital

You can effectively manage DKA without arterial blood gas results by using venous pH and serum bicarbonate levels, which are the primary diagnostic criteria alongside blood glucose and ketones. 1

Diagnostic Criteria Without ABG

The American Diabetes Association diagnostic criteria for DKA can be established using readily available tests at any level 1 hospital 2:

• Blood glucose >250 mg/dL 2
• Serum bicarbonate <15 mEq/L 2
• Venous pH <7.3 (venous pH is typically only 0.03 units lower than arterial pH) 1
• Moderate ketonuria or ketonemia 2
• Calculated anion gap (from basic metabolic panel) 1

Venous blood gas is an acceptable alternative to arterial blood gas for monitoring DKA treatment, as the American Diabetes Association recommends following venous pH and anion gap to monitor resolution of acidosis 1.

Initial Assessment and Monitoring

Draw blood every 2-4 hours to determine 1:

• Serum electrolytes
• Glucose
• Blood urea nitrogen
• Creatinine
• Venous pH
• Calculated anion gap

Point-of-care glucose monitoring should be performed hourly during active treatment 1.

Fluid Resuscitation Protocol

Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in the average adult) during the first hour 2, 1:

• Subsequent fluid choice: Use 0.45% NaCl at 4-14 mL/kg/hour if corrected serum sodium is normal or elevated 2
• Use 0.9% NaCl at similar rate if corrected serum sodium is low 2
• When glucose reaches 250 mg/dL, switch to 5% dextrose with 0.45-0.75% NaCl while continuing insulin 1
• Target total fluid replacement to correct estimated deficits within 24 hours 2

Insulin Therapy

For Critically Ill or Obtunded Patients:

Continuous intravenous regular insulin at 0.1 units/kg/hour is the standard of care 1:

• If glucose does not fall by 50 mg/dL in the first hour, check hydration status and double insulin infusion rate hourly until steady decline of 50-75 mg/dL per hour is achieved 1
• Continue insulin infusion until resolution of ketoacidosis (pH >7.3, bicarbonate ≥18 mEq/L, anion gap ≤12 mEq/L) regardless of glucose levels 1
• Target glucose between 150-200 mg/dL until DKA resolution 1

For Mild-to-Moderate Uncomplicated DKA in Alert Patients:

Subcutaneous rapid-acting insulin analogs combined with aggressive fluid management are equally effective, safer, and more cost-effective than IV insulin 1:

• This approach requires adequate fluid replacement and frequent point-of-care glucose monitoring 1
• Particularly useful in resource-limited level 1 hospitals where ICU beds may be limited 3

Critical Potassium Management

Check potassium levels before starting insulin therapy 1:

• If K+ <3.3 mEq/L: Delay insulin therapy and aggressively replace potassium until ≥3.3 mEq/L to prevent life-threatening arrhythmias 1
• If K+ 3.3-5.5 mEq/L: Add 20-30 mEq potassium per liter of IV fluid (2/3 KCl and 1/3 KPO₄) once adequate urine output is confirmed 2, 1
• If K+ >5.5 mEq/L: Withhold potassium initially but monitor closely, as levels will drop rapidly with insulin therapy 1
• Target serum potassium of 4-5 mEq/L throughout treatment 1

Total body potassium depletion averages 3-5 mEq/kg body weight in DKA, and insulin therapy will unmask this depletion by driving potassium intracellularly 1.

Bicarbonate Administration

Bicarbonate is NOT recommended for DKA patients with pH >6.9-7.0, as multiple studies show no difference in resolution of acidosis or time to discharge, and it may worsen ketosis, cause hypokalemia, and increase cerebral edema risk 1, 4.

Exception: IV sodium bicarbonate can be considered if serum pH falls below 6.9, or when pH is <7.2 pre- and post-intubation to prevent hemodynamic collapse 4.

Resolution Criteria

DKA is resolved when all of the following are met 1:

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

Transition to Subcutaneous Insulin

Administer basal insulin (intermediate or long-acting) 2-4 hours BEFORE stopping IV insulin infusion to prevent recurrence of ketoacidosis and rebound hyperglycemia 1.

Common Pitfalls to Avoid

• Never stop IV insulin when glucose falls below 250 mg/dL—instead add dextrose to fluids while continuing insulin until ketoacidosis resolves 1
• Never start insulin if K+ <3.3 mEq/L without correcting potassium first 1
• Inadequate potassium monitoring and replacement is a leading cause of mortality in DKA 1
• Premature termination of insulin therapy before complete resolution of ketosis leads to recurrence 1

Identifying Precipitating Factors

Obtain bacterial cultures (urine, blood) if infection is suspected and administer appropriate antibiotics 1. Consider other triggers including myocardial infarction, stroke, pancreatitis, trauma, or insulin omission 1.