Initial Management of Hyperglycemic Crisis: Fluid Replacement and Sodium Correction
Begin with isotonic saline (0.9% NaCl) at 15-20 ml/kg/h for the first hour in all patients, then switch fluid type based on the corrected sodium level, not the measured sodium. 1
Critical First Step: Calculate Corrected Sodium
Before selecting subsequent fluids, you must calculate the corrected sodium to account for the dilutional effect of hyperglycemia on measured sodium levels. 2
- Formula: Corrected Na = Measured Na + 1.6 × [(Glucose in mg/dL - 100)/100] 2, 3
- For example, if measured Na is 135 mEq/L and glucose is 600 mg/dL, the corrected Na = 135 + 1.6 × [(600-100)/100] = 143 mEq/L 2
- This corrected value determines your fluid choice after the initial hour 2, 3
Initial Fluid Resuscitation (First Hour)
- Administer 0.9% NaCl at 15-20 ml/kg/h (approximately 1-1.5 liters in average adults) regardless of sodium levels 1
- In severely dehydrated patients, this may need to be repeated, but do not exceed 50 ml/kg over the first 4 hours 1
- This aggressive initial resuscitation expands intravascular volume and restores renal perfusion 1
Subsequent Fluid Selection (After First Hour)
The choice of fluid after initial resuscitation depends entirely on the corrected sodium: 2, 3
- If corrected sodium is LOW: Continue 0.9% NaCl at 4-14 ml/kg/h 2, 3
- If corrected sodium is NORMAL or ELEVATED: Switch to 0.45% NaCl at 4-14 ml/kg/h 2, 3
- An initial rise in measured sodium is expected and normal—this does not indicate need for hypotonic fluids unless the corrected sodium is elevated 4
Critical Safety Parameter: Osmolality Reduction Rate
The induced change in serum osmolality must not exceed 3 mOsm/kg/h to prevent cerebral edema, which carries significant mortality risk. 1, 2, 3
- Calculate effective serum osmolality using: 2[measured Na] + glucose (mg/dL)/18 1, 2
- Use the measured (uncorrected) sodium for osmolality calculations, not the corrected sodium 2
- Monitor osmolality every 2-4 hours initially and adjust fluid rates to maintain this safe reduction rate 3
- The goal is smooth rehydration with osmolality decrease of 3-8 mOsm/kg/h 5
Insulin Timing Considerations
In HHS specifically, withhold insulin until blood glucose stops falling with IV fluids alone, unless significant ketonemia is present (>3.0 mmol/L). 4, 5
- Fluid replacement alone will cause blood glucose to fall in HHS 4, 5
- Early insulin use before adequate fluid resuscitation may be detrimental 4
- In DKA, begin insulin concurrently with fluids after excluding hypokalemia (K >3.3 mEq/L) 1
- Standard insulin dosing: 0.1 U/kg/h continuous IV infusion after 0.15 U/kg bolus 1
Potassium Replacement
Once renal function is confirmed and serum potassium is known, add 20-40 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO4). 1, 3
- Do not add potassium if K <3.3 mEq/L—correct hypokalemia first before starting insulin 1, 3
- Hyperglycemic crises cause total body potassium deficits of 3-5 mEq/kg despite normal or elevated initial serum levels 1
- Insulin therapy drives potassium intracellularly, potentially causing life-threatening hypokalemia 1
Monitoring Requirements
Check the following parameters every 2-4 hours during initial management: 1
- Serum electrolytes (including calculated corrected sodium) 3
- Blood glucose 1
- Calculated effective osmolality 2
- Venous pH (for DKA) 1
- Urine output (target >0.5 ml/kg/h) 5
- Mental status changes 3
Common Pitfalls to Avoid
- Never use measured sodium alone to guide fluid choice—always calculate corrected sodium first 2, 3
- Never exceed 3 mOsm/kg/h osmolality reduction—rapid correction causes cerebral edema with high mortality 1, 2, 3
- Never start insulin before confirming K >3.3 mEq/L—this can precipitate fatal arrhythmias 1
- Never use 0.9% NaCl throughout if corrected sodium is normal/high—this worsens hyperosmolality 2, 3
- In HHS, avoid premature insulin administration before adequate fluid resuscitation 4, 5