What is the best approach to manage acute hyperglycemia in a patient, considering their renal function and potential allergies?

Management of Acute Hyperglycemia

For critically ill patients with acute hyperglycemia, initiate continuous intravenous insulin infusion when blood glucose persistently exceeds 180 mg/dL, targeting a glucose range of 140-180 mg/dL, while for noncritically ill hospitalized patients, use scheduled subcutaneous basal-bolus insulin regimens rather than sliding scale insulin alone. 1

Critical Care Setting (ICU Patients)

When to Initiate Insulin Therapy

• Start insulin therapy when blood glucose is persistently ≥180 mg/dL (≥10.0 mmol/L), confirmed on two consecutive measurements within 24 hours. 1, 2
• The trigger threshold is intentionally lower than the treatment target to prevent prolonged hyperglycemia above goal range. 1

Target Glucose Range

• Maintain blood glucose between 140-180 mg/dL (7.8-10.0 mmol/L) for most critically ill patients. 1, 2
• This moderate target is based on the NICE-SUGAR trial, which demonstrated that intensive glucose control (80-110 mg/dL) resulted in 27.5% mortality versus 25% with moderate control, along with 10-15 fold higher hypoglycemia rates. 1, 2
• More stringent targets of 110-140 mg/dL may be considered only for highly selected patients (cardiac surgery, previously excellent glycemic control) if achievable without significant hypoglycemia risk. 1, 2

Insulin Delivery Method

• Continuous intravenous insulin infusion is the preferred and most effective method for critically ill patients. 1, 2
• Use validated written or computerized protocols that allow predefined adjustments based on glycemic fluctuations and insulin infusion rates. 1
• Never use sliding scale (correction) insulin alone in the ICU setting—this approach is strongly discouraged and associated with poor outcomes. 1, 2

Glucose Monitoring

• Monitor blood glucose every 30 minutes to 2 hours during IV insulin therapy using FDA-approved point-of-care hospital-calibrated glucose meters. 1, 2
• More frequent monitoring (every 30 minutes to 2 hours) is the required standard for safe IV insulin use. 1

Noncritical Care Setting (General Medicine/Surgery Wards)

When to Initiate Insulin Therapy

• Initiate or intensify insulin therapy for persistent hyperglycemia ≥180 mg/dL (≥10.0 mmol/L) confirmed on two occasions within 24 hours. 1

Target Glucose Range

• Target 140-180 mg/dL (7.8-10.0 mmol/L) for most noncritically ill hospitalized patients. 1
• In terminally ill patients, those with severe comorbidities, or settings without frequent monitoring capability, higher ranges up to 200 mg/dL may be acceptable. 1

Insulin Regimen Selection

• Use scheduled subcutaneous basal-bolus insulin regimens as the preferred approach. 1
• For patients eating regular meals: basal insulin plus rapid-acting prandial insulin before meals, plus correction insulin. 1
• For patients with poor or no oral intake: basal insulin alone or basal plus correction insulin is preferred. 1
• Prolonged use of correction (sliding scale) insulin without basal insulin is strongly discouraged, except for mild stress hyperglycemia in type 2 diabetes. 1

Insulin Dosing Considerations

• Basal insulin dosing is typically based on body weight and expected insulin sensitivity. 1
• Patients with renal insufficiency require lower insulin doses due to decreased clearance. 1
• For continuous enteral feeding: consider 5 units NPH/detemir every 12 hours or 10 units glargine/degludec daily as basal, plus regular insulin every 6 hours or rapid-acting every 4 hours for nutritional coverage. 1

Hyperglycemic Crises (DKA/HHS)

Fluid Resuscitation

• Begin with isotonic saline (0.9% NaCl) at 10-20 mL/kg/hour for the first hour. 1
• Initial reexpansion should not exceed 50 mL/kg over the first 4 hours. 1
• Continue fluid therapy calculated to replace deficit evenly over 48 hours, typically at 1.5 times 24-hour maintenance requirements. 1

Insulin Therapy for Moderate-to-Severe DKA/HHS

• Use continuous intravenous insulin infusion for moderate-to-severe cases. 1
• After excluding hypokalemia (K+ <3.3 mEq/L), give IV bolus of regular insulin 0.15 U/kg, followed by continuous infusion at 0.1 U/kg/hour (5-7 U/hour in adults). 1
• This should decrease plasma glucose by 50-75 mg/dL/hour. 1
• If glucose does not fall by 50 mg/dL in the first hour, double the insulin infusion rate hourly until steady decline of 50-75 mg/hour is achieved. 1

Insulin Therapy for Mild-to-Moderate DKA

• Subcutaneous rapid-acting insulin every 1-2 hours is an acceptable alternative for uncomplicated mild DKA. 1
• Give priming dose of 0.4-0.6 U/kg (half IV bolus, half subcutaneous/intramuscular), then 0.1 U/kg/hour subcutaneously. 1

Glucose Management During DKA/HHS Treatment

• When plasma glucose reaches 250 mg/dL in DKA or 300 mg/dL in HHS, decrease insulin infusion to 0.05-0.1 U/kg/hour and add dextrose (5-10%) to IV fluids. 1
• Continue insulin until acidosis resolves in DKA or mental status normalizes in HHS, not just until glucose normalizes. 1

Electrolyte Management

• Once renal function is assured and serum potassium is known, add 20-40 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO4). 1
• Hypokalaemia occurs in approximately 50% of patients during treatment and severe hypokalaemia (<2.5 mEq/L) is associated with increased mortality—monitor potassium carefully. 1

Monitoring During Crisis Management

• Draw blood every 2-4 hours for electrolytes, glucose, BUN, creatinine, osmolality, and venous pH. 1
• Venous pH (typically 0.03 units lower than arterial) and anion gap can be followed—repeat arterial blood gases are generally unnecessary. 1

Critical Pitfalls to Avoid

• Never target glucose <110 mg/dL in general ICU populations—this increases mortality, hypoglycemia, and ICU length of stay. 1, 2
• Never hold basal insulin in patients with type 1 diabetes, even when NPO (nothing by mouth)—this can precipitate DKA. 1
• Do not use bicarbonate routinely in DKA—studies show no difference in acidosis resolution or time to discharge. 1
• Avoid using nitroprusside method to assess ketone response to therapy—it measures acetoacetate but not β-hydroxybutyrate, which may falsely suggest worsening ketosis during treatment. 1

Transition from IV to Subcutaneous Insulin

Criteria for Transition

• Stable glucose measurements for at least 4-6 hours consecutively. 1
• Normal anion gap and resolution of acidosis (for DKA). 1
• Hemodynamic stability (not requiring vasopressors). 1
• Stable nutrition plan and stable IV insulin infusion rates. 1

Calculating Subcutaneous Dose

• Estimate total daily subcutaneous insulin requirement from the average insulin infused during the 12 hours before transition. 1
• Example: If receiving average of 1.5 units/hour, estimated daily dose = 36 units/24 hours. 1
• Divide between basal and prandial insulin based on insulin type and nutritional status. 1

Special Considerations for Renal Function

• Patients with renal insufficiency require lower insulin doses due to decreased insulin clearance and should be monitored more closely for hypoglycemia. 1
• Adjust basal insulin dosing downward based on degree of renal impairment. 1