Is it sufficient to manage the patient with only intravenous isotonic crystalloid fluids for hydration, without insulin or carbohydrate supplementation?

No, IV Fluids Alone Are Insufficient for DKA/HHS Management

Intravenous fluids without insulin therapy is inadequate and potentially dangerous for managing diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS). Both conditions require concurrent insulin administration alongside fluid resuscitation to resolve the underlying metabolic crisis.

Why Fluids Alone Fail

The pathophysiology of DKA and HHS involves insulin deficiency leading to:

• Uncontrolled lipolysis and ketone production (DKA)
• Severe hyperglycemia and hyperosmolality
• Electrolyte derangements, particularly potassium shifts

Fluid resuscitation addresses only the volume depletion component—it does not correct the fundamental metabolic derangements. While some older literature suggested withholding insulin until glucose stops dropping with fluids alone 1, current guidelines explicitly reject this approach for standard management.

The Evidence-Based Approach

For DKA (Mild, Moderate, or Severe):

According to the 2025 ADA Standards 1:

1. Start insulin immediately (do not wait):

   • Mild DKA: 0.1 units/kg subcutaneous rapid-acting insulin bolus, then 0.1 units/kg/hour subcutaneous every 1 hour OR 0.2 units/kg every 2 hours
   • Moderate/Severe DKA: 0.1 units/kg rapid-acting insulin bolus, then 0.1 units/kg/hour IV infusion

2. Concurrent fluid resuscitation:

   • 0.9% NaCl or other crystalloid at clinically appropriate rate
   • Aim to replace 50% of estimated fluid deficit in first 8-12 hours

3. Critical caveat: If potassium <3.5 mmol/L, start insulin but do not give potassium until renal function established; check serum K+ every 2 hours 1

For HHS:

• Similar approach: Start 0.05 units/kg/hour IV insulin 1
• Target glucose 200-250 mg/dL until resolution (higher than DKA target of 150-200 mg/dL)
• Some recommend withholding insulin until glucose stops dropping with fluids alone in HHS specifically 1, but this remains controversial

Clinical Outcomes Without Insulin

Research demonstrates that insulin is essential for metabolic resolution:

• Early subcutaneous insulin glargine combined with IV insulin reduced DKA resolution time (9.89 vs. 12.73 hours, p=0.022) and hospital stay (4.75 vs. 15.25 days, p=0.024) compared to IV insulin alone 2
• Patients receiving ≥3L of normal saline had significantly longer insulin infusion duration after anion gap closure (p=0.0101) 3

Without insulin, you cannot:

• Suppress ketogenesis (DKA)
• Facilitate cellular glucose uptake
• Correct the anion gap acidosis
• Prevent ongoing metabolic deterioration

Fluid Type Considerations

While debating fluid choice (normal saline vs. balanced crystalloids):

• Large-volume normal saline (≥3L) associated with longer ICU stays, prolonged insulin infusion, and non-anion gap metabolic acidosis 3
• Balanced crystalloids (Plasmalyte-148, lactated Ringer's) accelerated metabolic acidosis resolution (69% vs. 36% at 24 hours, p=0.002) 2
• However, both fluid types still require concurrent insulin therapy 4

The Bottom Line Algorithm

For any patient with DKA or HHS:

1. Assess potassium immediately

   • If K+ <3.5 mmol/L: Hold insulin, give potassium, recheck every 2 hours
   • If K+ ≥3.5 mmol/L: Start insulin AND fluids simultaneously

2. Never give fluids alone expecting metabolic resolution

3. Monitor glucose every 2-4 hours and adjust insulin accordingly 1

4. Add dextrose-containing fluids when glucose reaches 200-250 mg/dL (HHS) or 150-200 mg/dL (DKA) to prevent hypoglycemia while continuing insulin 1

The notion of "fluids only" management represents outdated thinking that predates our understanding of insulin's central role in resolving these life-threatening metabolic emergencies.