What is the initial approach to managing Diabetic Ketoacidosis (DKA) in a Canadian hospital based on the latest guidelines?

Initial Approach to Managing Diabetic Ketoacidosis in a Canadian Hospital

Begin immediate fluid resuscitation with isotonic crystalloid (0.9% normal saline or balanced electrolyte solution) at 15-20 mL/kg/hour for the first hour, followed by continuous intravenous regular insulin at 0.1 units/kg/hour without an initial bolus, while closely monitoring potassium and adding 20-30 mEq/L to fluids once levels fall below 5.3 mEq/L. 1, 2

Initial Assessment and Diagnosis

Perform comprehensive laboratory evaluation immediately upon presentation:

• Plasma glucose, blood urea nitrogen, creatinine, serum ketones (preferably β-hydroxybutyrate), electrolytes with calculated anion gap, osmolality 1, 2
• Arterial blood gases, complete blood count with differential, urinalysis with urine ketones 1, 2
• Electrocardiogram and continuous cardiac monitoring to detect arrhythmias early 2

Diagnostic criteria for DKA: plasma glucose >250 mg/dL, arterial pH <7.30, serum bicarbonate <18 mEq/L, and positive serum and urine ketones 1

Important caveat: Direct measurement of β-hydroxybutyrate is preferred over nitroprusside method, which only detects acetoacetic acid and acetone, missing the predominant ketone body 3, 2

Fluid Therapy Protocol

First Hour

• Administer isotonic crystalloid (0.9% NaCl or balanced electrolyte solution) at 15-20 mL/kg/hour 1, 2
• This restores intravascular volume and renal perfusion 1

Subsequent Fluid Management

• Continue fluid replacement to correct estimated deficits within 24 hours, targeting 1.5-2 times the 24-hour maintenance requirements 1
• Critical principle: Induced change in serum osmolality should not exceed 3 mOsm/kg/hour to prevent cerebral edema 2
• Add 5% dextrose to fluids when plasma glucose falls to 200-250 mg/dL while continuing insulin to clear ketosis 3, 2

Canadian context consideration: A 2019 Canadian multicentre study found median fluid administration of 7.0 L in the first 24 hours, generally aligned with guidelines 4

Insulin Therapy

Initial Dosing

• Start continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus 1, 2
• Important: Canadian data shows 23.3% of patients received insulin boluses, but current best practice recommends against this 4

Dose Adjustment

• If plasma glucose does not fall by 50 mg/dL in the first hour, double the insulin infusion hourly until steady glucose decline of 50-75 mg/hour is achieved 1, 2
• Never interrupt insulin infusion when glucose falls—instead add dextrose to prevent hypoglycemia while continuing insulin to clear ketosis 3

Emerging Evidence

• British guidelines suggest adding subcutaneous basal insulin analog (e.g., glargine) alongside IV insulin, which has shown faster DKA resolution and shorter hospital stays, though not yet standard in all North American protocols 2, 5

Electrolyte Management

Potassium Replacement (Critical Priority)

• Monitor potassium closely as insulin therapy and acidosis correction cause rapid shifts 1, 2
• Once serum potassium <5.3 mEq/L and adequate urine output confirmed: Add 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) to each liter of IV fluid 1, 3
• Target serum potassium 4-5 mEq/L throughout treatment 3
• If initial potassium <3.3 mEq/L: Delay insulin until potassium restored to prevent arrhythmias, cardiac arrest, and respiratory muscle weakness 2

Canadian pitfall identified: Hypokalemia occurred in 41.7% of cases in a 2019 Canadian study, indicating need for more proactive potassium repletion 4

Bicarbonate Therapy

• Generally NOT recommended for pH >6.9 as studies show no benefit on clinical outcomes 1, 2
• Consider only if pH <6.9: administer 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/hour 2
• Risks of bicarbonate: worsening ketosis, hypokalemia, and increased cerebral edema risk 5
• Exception: May consider if pH <7.2 pre/post-intubation to prevent hemodynamic collapse 5

Canadian practice note: 24.3% of Canadian patients received bicarbonate, suggesting overuse relative to guidelines 4

Phosphate Replacement

• Routine replacement not recommended as studies show no clinical benefit 2
• Consider only if cardiac dysfunction, anemia, respiratory depression, or serum phosphate <1.0 mg/dL 2

Monitoring During Treatment

Frequency

• Blood glucose every 1-2 hours 1, 3
• Serum electrolytes, glucose, BUN, creatinine, osmolality, and venous pH every 2-4 hours 1, 3, 2
• Venous pH (typically 0.03 units lower than arterial) and anion gap to monitor acidosis resolution 2

Hemodynamic Monitoring

• Monitor fluid input/output, hemodynamic parameters, and clinical examination continuously 2
• Continuous cardiac monitoring essential to detect arrhythmias from electrolyte shifts 2

Resolution Criteria and Transition to Subcutaneous Insulin

DKA Resolution Defined As:

• Glucose <200 mg/dL 1, 2
• Serum bicarbonate ≥18 mEq/L 1, 2
• Venous pH >7.3 1, 2
• Anion gap ≤12 mEq/L 1, 2

Canadian median time to anion gap ≤12 mmol/L: 8.8 hours 4

Critical Transition Protocol

• Administer basal insulin (intermediate or long-acting) 2-4 hours BEFORE stopping IV insulin to prevent recurrence of ketoacidosis and rebound hyperglycemia 1, 3, 2
• Major Canadian pitfall: In 27.1% of cases, IV insulin was stopped before subcutaneous insulin was given, with median gap of 95 minutes—this practice should be avoided 4

Initial Subcutaneous Regimen

• For newly diagnosed patients: 0.5-1.0 units/kg/day using combination of short/rapid-acting and intermediate/long-acting insulin 2

Identification and Treatment of Precipitating Causes

• Obtain bacterial cultures (urine, blood, other sites) and administer appropriate antibiotics if infection suspected 2
• Search for myocardial infarction, stroke, or other acute stressors 2
• SGLT2 inhibitor consideration: Discontinue 3-4 days before surgery to prevent euglycemic DKA; monitor for euglycemic DKA (normal or mildly elevated glucose with ketoacidosis) 1, 2

Special Considerations for Euglycemic DKA

• Add dextrose-containing fluids (5% dextrose with 0.45-0.75% NaCl) earlier in treatment to maintain adequate glucose while continuing insulin to clear ketosis 3
• Continue insulin infusion until complete resolution of ketoacidosis regardless of glucose levels 3
• Direct β-hydroxybutyrate measurement essential as nitroprusside method will miss this 3

Prevention of Cerebral Edema (Rare but Fatal Complication)

Risk Factors

• Severity of acidosis, greater hypocapnia (after adjusting for acidosis), higher BUN at presentation 2, 6
• Treatment with bicarbonate 6
• Rapid overcorrection of hyperglycemia 5

Prevention Strategies

• Gradual correction of glucose and osmolality (not exceeding 3 mOsm/kg/hour) 2
• Judicious use of isotonic fluids 2
• Avoid excessive insulin boluses 4
• Rehydrate evenly over at least 48 hours in pediatric cases 6

Airway Management in Critically Ill Patients

• BiPAP NOT recommended due to aspiration risk 5
• For impending respiratory failure: intubation and mechanical ventilation with careful monitoring of acid-base and fluid status 5
• Consider sodium bicarbonate if pH <7.2 pre/post-intubation to prevent hemodynamic collapse during apnea 5

Canadian Practice Variability and Quality Improvement

A 2022 comparison of 36 Canadian DKA protocols representing 85 institutions revealed significant variability in:

• Initial fluid bolus rate and volume (0.5-2 L over 15 minutes to 2 hours) 7
• Insulin bolus inclusion 7
• Potassium supplementation thresholds 7
• Bicarbonate administration criteria 7

Recommendations for Canadian centres: Implement standardized protocols and preprinted order sets to reduce variability and improve outcomes, especially in smaller centres 4, 7