Management of Diabetic Ketoacidosis (DKA)

Diagnostic Criteria

• Hyperglycemia: blood glucose typically >250 mg/dL (can be lower in "euglycemic DKA," e.g., with SGLT2 inhibitors)
• Ketosis: serum/urine ketones positive
• Acidosis: pH <7.3, bicarbonate <18 mEq/L, elevated anion gap

Precipitating Causes (Must Be Identified and Treated)

• Infection (most common - pneumonia, UTI, skin)
• New-onset or poorly controlled Type 1 DM
• Insulin omission/non-adherence
• Myocardial infarction, stroke, pancreatitis
• Medications: corticosteroids, thiazides, SGLT2 inhibitors (euglycemic DKA)
• Pregnancy

Treatment Overview

1. Initial Assessment & Monitoring

• Serum glucose, electrolytes (Na+, K+, Cl-, HCO3-), BUN, creatinine
• Venous blood gas (correlates well with arterial pH; less invasive)
• Serum/urine ketones
• CBC with differential (note: leukocytosis reflects ketosis degree, not necessarily infection; only elevated band neutrophils indicate infection)
• Urinalysis, chest X-ray, ECG
• Lipase if pancreatitis suspected (amylase is non-specific in DKA)

• Sodium: Often falsely low due to hyperglycemia. Correct by adding 1.6 mEq/L for every 100 mg/dL glucose above normal
• Potassium: Often initially normal or high (shifted from intracellular by acidosis), but total body stores are depleted. Correct K+ by subtracting 0.6 mEq/L for every 0.1 decrease in pH
• Creatinine: May be falsely elevated on some analyzers

2. Fluid Resuscitation

• If in hypovolemic shock: Isotonic crystalloid (0.9% NS) as rapidly as possible in adults; 20 mL/kg boluses in children until systolic BP ≥80 mmHg
• Initial rate: 1-2 L NS IV over 1-3 hours (children: 20 mL/kg in first hour)
• Ongoing rate: 2-4 L in first 2-4 hours
• Switch to 0.45% NS once hemodynamically stable if corrected sodium is normal or elevated
• Add D5W (5% dextrose) when blood glucose falls to ≤250-300 mg/dL to prevent hypoglycemia while continuing insulin

Note: 0.9% NS remains the initial fluid of choice even with high osmolality, as it is still relatively hypotonic. Large volumes of NS may cause hyperchloremic metabolic acidosis; balanced crystalloids (e.g., Ringer's lactate) are an alternative once initial resuscitation is achieved.

3. Potassium Replacement

• Once urine output >0.5 mL/kg/h, begin K+ replacement
• Continuous cardiac monitoring required when K+ replacement rate >10 mEq/h
• Target: Maintain K+ between 4-5 mEq/L

4. Insulin Therapy

• IV infusion: Regular insulin at 0.1 units/kg/hour (fixed-rate infusion)
  • Alternatively, may give 0.1 units/kg IV bolus first, then 0.1 units/kg/h infusion
  • Barash formula: Blood glucose ÷ 150 units/hour as a variable-rate guide
• Subcutaneous option for mild DKA: Rapid-acting insulin analogue 0.1 units/kg SC, then 0.1 units/kg every 1 hour (or 0.2 units/kg every 2 hours)

• Target blood glucose fall of ~10% per hour (Goodman & Gilman's, p. 1034)
• Once glucose reaches 250 mg/dL → add dextrose-containing IV fluid AND reduce insulin infusion to 0.05 units/kg/hour to prevent hypoglycemia
• Continue insulin until ketones <1.0 mmol/L and acidosis resolved (pH >7.3, HCO3- >18)
• Target glucose in DKA: 8.3-11.0 mmol/L (150-200 mg/dL) until resolution

• Continue IV insulin for 1-2 hours after the first SC dose to avoid gap
• When patient can eat and drink, switch to usual diabetes regimen

5. Other Electrolytes

• Total body depletion occurs but routine supplementation is generally not recommended unless severely symptomatic (<1.0 mg/dL or cardiac/respiratory dysfunction)

• If hypomagnesemia: 1-2 g MgSO4 IV; serum levels may not reflect body stores

• Rarely indicated
• Consider only if pH <6.9 (50-100 mEq NaHCO3 in 200-400 mL sterile water over 2 hours)
• Bicarbonate use carries risks: paradoxical CNS acidosis, hypokalemia, alkalosis rebound, impaired O2 delivery (shifts oxyhemoglobin curve)
• Acidosis corrects with insulin and fluids alone in the vast majority

6. Resolution Criteria

• Blood glucose <200 mg/dL
• Serum bicarbonate ≥15 mEq/L
• Venous pH >7.3

7. Special Situations

• Avoid if possible - patients have strong respiratory drive and matching ventilator to Kussmaul breathing is difficult
• If required (comatose, vomiting): maintain hyperventilation to prevent worsening acidosis

• Stop SGLT2 inhibitors immediately
• Advise withholding SGLT2 inhibitors and/or reducing insulin during illness or perioperatively (stop 3 days before surgery)
• Management same as standard DKA

• Treatment: dextrose + parenteral fluids; insulin is NOT indicated (unless patient has established DM)
• Predominant ketone is β-hydroxybutyrate (may be missed by standard nitroprusside reaction)

8. Monitoring During Treatment

• Vital signs and urine output (target >0.5 mL/kg/h)
• Glucose every 1-2 hours
• Electrolytes (K+, Na+, HCO3-, Cl-) every 2-4 hours
• Venous pH every 2-4 hours
• Insulin amount administered

Summary Algorithm

DKA Confirmed
     ↓
1. IV Fluids — 0.9% NS 1-2 L/h × 1-3 h
     ↓
2. Check K+
   K+ <3.3 → Replace K+ first, hold insulin
   K+ 3.3-5.5 → Start insulin + add K+ to fluids
   K+ >5.5 → Start insulin, hold K+
     ↓
3. Insulin — 0.1 units/kg/h IV infusion
     ↓
4. Glucose ≤250 mg/dL → Add D5W, reduce insulin to 0.05 U/kg/h
     ↓
5. Bicarbonate only if pH <6.9
     ↓
6. Identify & treat precipitant
     ↓
7. Resolution: glucose <200, HCO3 ≥15, pH >7.3 → Switch to SC insulin

Insulin IV Drip (Continuous Intravenous Insulin Infusion)

Why IV Instead of Subcutaneous?

• DKA and hyperglycemic emergencies
• ICU or clinically unstable patients
• Perioperative management for major/prolonged surgery (>4 hours)
• Patients unable to eat (NPO)
• Any situation with poor skin/muscle perfusion (where SC absorption becomes unpredictable)

The half-life of IV regular insulin is very short (minutes), which makes it highly titratable. SC absorption is variable in critically ill patients - this is the key advantage of IV delivery.

Drug: ONLY Regular Insulin

• Insulin analogues (lispro, aspart, glargine, detemir) are not given IV
• Regular insulin is used because it is less expensive and equally effective for IV delivery
• Concentration: 1 unit/mL (100 units regular insulin in 100 mL 0.9% NS - standard preparation)

Preparation

• 100 units Regular insulin + 100 mL 0.9% NS = 1 unit/mL concentration
• Can also use 50 units in 50 mL NS (same concentration)

1. Fill tubing with the insulin infusion solution
2. Wait 30 minutes
3. Flush the line
4. Then connect to patient and start infusion

Dosing

In DKA (primary indication)

Formula-Based Dosing (Perioperative)

Units/hour = Plasma glucose (mg/dL) ÷ 150

• Target intraoperative glucose: 85-180 mg/dL
• 1 unit of IV regular insulin lowers plasma glucose by ~25-30 mg/dL in an adult

In Critically Ill / ICU Patients

• Preferred over SC because of precise, rapid titration
• Adjust based on glucose trend (not just current value) - use institutional infusion algorithms
• Algorithms should incorporate the patient's insulin sensitivity
• Check glucose every 1-2 hours during infusion

In Labor (Obstetric)

Concomitant Potassium

• Insulin drives K+ intracellularly - always anticipate hypokalemia
• Add 20 mEq KCl per liter of maintenance fluid when giving insulin infusions in surgical patients
• In DKA: replace K+ aggressively (see DKA protocol)

Monitoring During Infusion

• Blood glucose every 1-2 hours (capillary or serum)
• Electrolytes (K+, Na+, HCO3-) every 2-4 hours in DKA
• Do NOT use continuous glucose monitor (CGM) interstitial readings for management decisions - there is a ~10-minute lag and medications (e.g., acetaminophen) can cause inaccurate readings; use capillary or serum glucose
• Urine output hourly

Stopping the Drip - Transition to SC Insulin

Give long-acting SC insulin 2-4 hours BEFORE stopping the IV infusion.

• Continue IV insulin until anion gap closed, HCO3- >14-18 mEq/L, patient tolerating oral intake
• Administer SC dose (basal insulin) ≥1 hour before stopping drip (some guidelines say 2-4 hours)
• If insulin pump patient: restart pump ~1 hour before stopping IV drip

• Switch back to SC insulin when patient is eating
• Resume usual home regimen (basal + prandial dosing)

Insulin Pump Patients in DKA

• Assume pump malfunction - disconnect the pump
• Start IV insulin infusion per standard DKA protocol
• Do not give IV bolus before starting drip (no clinical benefit)
• Consider SC long-acting insulin at the time of drip initiation if pump therapy not expected to resume

Summary Card