Management of Diabetic Non-Ketotic Hyperosmolar Coma

Initial Assessment and Diagnosis

The American Diabetes Association recommends HHS diagnostic criteria: blood glucose >600 mg/dL, arterial pH >7.3, bicarbonate >15 mEq/L, effective serum osmolality >320 mOsm/kg H₂O, and mild ketonuria or ketonemia 1, 3
Obtain arterial blood gases, complete blood count with differential, urinalysis, plasma glucose, blood urea nitrogen, electrolytes, chemistry profile, and creatinine levels immediately 2, 4
Calculate effective serum osmolality using formula: 2[measured Na (mEq/L)] + glucose (mg/dL)/18 1, 3
Correct serum sodium for hyperglycemia (for each 100 mg/dL glucose >100 mg/dL, add 1.6 mEq to sodium value) 2, 4

The American Diabetes Association recommends beginning with isotonic saline (0.9% NaCl) at 15-20 mL/kg/h (1-1.5 L in average adult) during first hour to expand intravascular volume and restore renal perfusion 1, 3
After hemodynamic stabilization, switch to 0.45% NaCl if corrected serum sodium is normal or elevated 2, 4
Fluid replacement should correct estimated deficits within the first 24 hours 1, 3
Induced change in serum osmolality should not exceed 3 mOsm/kg/h to prevent cerebral edema 1, 3
Monitor fluid input/output, hemodynamic parameters, and mental status frequently during fluid resuscitation 1, 3
When blood glucose reaches 300 mg/dL, add 5-10% dextrose to IV fluids to prevent hypoglycemia while continuing insulin therapy 2, 4

Administer intravenous bolus of regular insulin at 0.15 units/kg body weight after excluding hypokalemia (K⁺ <3.3 mEq/L) 1, 2
Follow with continuous infusion of regular insulin at 0.1 unit/kg/h (5-7 units/h in adults) 1, 2
If plasma glucose does not fall by 50 mg/dL from initial value in first hour, check hydration status; if acceptable, double insulin infusion rate hourly until steady glucose decline of 50-75 mg/h is achieved 2, 4
When plasma glucose reaches 300 mg/dL in HHS, decrease insulin infusion rate to 0.05-0.1 unit/kg/h (3-6 units/h) 2, 4
Continue insulin therapy until mental obtundation and hyperosmolarity are resolved 2, 4

Once renal function is assured and serum potassium is known, add 20-40 mEq/L potassium (2/3 KCl or potassium acetate and 1/3 KPO₄) to IV fluids 1, 3
Check electrolytes every 2-4 hours during initial treatment 2, 4
Monitor for and correct other electrolyte imbalances (magnesium, phosphate, calcium) as needed 3

Draw blood every 2-4 hours to determine serum electrolytes, glucose, blood urea nitrogen, creatinine, and osmolality 2, 4
Assess mental status frequently to monitor improvement and detect complications 1, 3
Continue treatment until osmolality normalizes, mental status improves, and patient is hemodynamically stable 2, 4

For successful transition from IV to subcutaneous insulin, administer basal insulin 2-4 hours before stopping IV insulin to prevent rebound hyperglycemia 5, 6
When patient can eat, start multiple-dose insulin regimen with combination of short/rapid-acting and intermediate/long-acting insulin 7

Watch for cerebral edema, especially with rapid correction of osmolality 1, 3
Monitor for fluid overload in patients with renal or cardiac compromise 1, 3
Identify and treat precipitating causes (infection, stroke, myocardial infarction, medications) 5, 6