What is the initial treatment for hyperglycemia (high blood sugar) in the Emergency Department (ED)?

Initial Treatment for Hyperglycemia in the Emergency Department

For patients presenting to the ED with severe hyperglycemia (DKA or HHS), begin with aggressive isotonic saline (0.9% NaCl) at 15-20 ml/kg/h during the first hour (1-1.5 liters in average adults), followed by continuous intravenous regular insulin at 0.1 units/kg/h after excluding hypokalemia (K+ >3.3 mEq/L). 1

Initial Assessment and Fluid Resuscitation

The first priority is restoring intravascular volume and tissue perfusion, not lowering glucose. 1

• Obtain immediate labs: arterial blood gases, complete blood count with differential, urinalysis, plasma glucose, blood urea nitrogen, electrolytes with calculated anion gap, creatinine, osmolality, and electrocardiogram 1
• Start isotonic saline (0.9% NaCl) at 15-20 ml/kg body weight per hour during the first hour in the absence of cardiac compromise 1
• This aggressive initial fluid rate may need to be repeated in severely dehydrated patients, but initial reexpansion should not exceed 50 ml/kg over the first 4 hours 1

Insulin Therapy Initiation

Continuous intravenous insulin is the treatment of choice for moderate to severe hyperglycemia in the ED setting. 1

For DKA or Severe Hyperglycemia:

• First, exclude hypokalemia (K+ must be >3.3 mEq/L) before starting insulin to prevent life-threatening cardiac arrhythmias 1
• Give an intravenous bolus of regular insulin at 0.15 units/kg body weight 1
• Follow immediately with continuous IV infusion at 0.1 units/kg/h (typically 5-7 units/hour in adults) 1
• This low-dose regimen decreases plasma glucose at 50-75 mg/dL per hour, similar to higher doses but with better safety 1

For Mild DKA (glucose >250 mg/dL, pH 7.25-7.30, bicarbonate 15-18 mEq/L):

• Subcutaneous or intramuscular regular insulin is equally effective as IV administration 1
• Give a "priming" dose of 0.4-0.6 units/kg body weight: half as IV bolus, half as subcutaneous or intramuscular injection 1
• Follow with 0.1 units/kg/h subcutaneously or intramuscularly 1

Monitoring and Adjustment

If plasma glucose does not fall by at least 50 mg/dL in the first hour, double the insulin infusion rate every hour until achieving steady glucose decline of 50-75 mg/h 1

• Check blood glucose every 2-4 hours along with electrolytes, BUN, creatinine, osmolality, and venous pH 1
• When glucose reaches 250 mg/dL (DKA) or 300 mg/dL (HHS), decrease insulin infusion to 0.05-0.1 units/kg/h and add 5-10% dextrose to IV fluids 1

Electrolyte Management

Once renal function is confirmed and serum potassium known, add 20-40 mEq/L potassium to IV fluids (2/3 KCl or potassium-acetate and 1/3 KPO4) 1

• Potassium replacement is critical because insulin drives potassium intracellularly, potentially causing life-threatening hypokalemia 1
• Continue monitoring potassium levels every 2-4 hours during treatment 1

For Non-Critical Hyperglycemia Without DKA/HHS

In stable ED patients with moderate hyperglycemia (glucose 400-600 mg/dL) without acidosis:

• Oral fluids are equally effective as IV fluids for glucose reduction in stable patients who can tolerate oral intake 2
• Both oral and IV fluids produce modest glucose reductions (mean decrease 3-4 mmol/L over 2 hours) 2
• Subcutaneous insulin (10 units) reduces glucose by approximately 33 mg/dL, while 1 liter of IV fluid reduces glucose by approximately 27 mg/dL 3
• IV fluids significantly increase ED length of stay (45 minutes per liter), while insulin administration does not 3

Critical Pitfalls to Avoid

Never start insulin before excluding hypokalemia (K+ <3.3 mEq/L), as this can precipitate fatal cardiac arrhythmias 1

• Hypoglycemia occurs in 17% of patients receiving IV insulin in the ED, particularly with lower pre-treatment glucose, higher insulin doses, and inadequate dextrose administration 4
• Avoid sliding-scale insulin alone in the inpatient setting—it is strongly discouraged and ineffective 1
• Do not use nitroprusside method to monitor ketone resolution, as it doesn't measure β-hydroxybutyrate (the predominant ketoacid) and can falsely suggest worsening ketosis during treatment 1
• Prevent cerebral edema by avoiding overly rapid correction—osmolality decrease should not exceed 3 mOsm/kg/h 1

Transition from IV to Subcutaneous Insulin

When transitioning from IV to subcutaneous insulin, administer basal insulin 2-4 hours before discontinuing the IV infusion to prevent rebound hyperglycemia and recurrent ketoacidosis 1

• Converting to basal insulin at 60-80% of the total daily IV insulin dose is effective 1
• Continue IV insulin for 1-2 hours after starting subcutaneous regimen to ensure adequate plasma insulin levels 1