How to manage a patient with repeated hyperglycemia (Random Blood Sugar (RBS) 480) after an initial reading of 390, and a normal Arterial Blood Gas (ABG) result, in a ward setting?

Management of Repeated Severe Hyperglycemia (RBS 480 after 390) with Normal ABG in Ward Setting

Start continuous intravenous insulin infusion immediately using a validated protocol, as this patient requires urgent glycemic control despite the normal ABG, and subcutaneous insulin alone is insufficient for blood glucose levels this severely elevated. 1

Immediate Assessment and Risk Stratification

• Check for diabetic ketoacidosis (DKA) immediately despite the normal ABG by obtaining serum bicarbonate, anion gap, and urine or serum ketones—a normal arterial pH does not exclude DKA if venous bicarbonate is low or anion gap is elevated 1, 2

• Obtain venous blood gas (VBG) if not already done, as VBG electrolytes are 97.8% sensitive and 100% specific for diagnosing DKA and can replace the need for separate chemistry panels 2

• Check serum electrolytes (particularly potassium), creatinine, and osmolality every 2-4 hours during treatment 1

• Assess for precipitating causes: infection (check vital signs, examine for sources), medication non-compliance, new medications (especially corticosteroids), acute illness, or inadequate prior insulin dosing 1, 3

Insulin Therapy Protocol

Intravenous insulin infusion is the preferred route for severe hyperglycemia >400 mg/dL in the ward setting:

• Start IV insulin infusion at 0.1 units/kg/hour without an initial bolus if DKA is not confirmed (if DKA is present, give 0.1 units/kg IV bolus first) 1, 4

• Target glucose reduction of 50-75 mg/dL per hour—avoid more rapid correction 1, 4

• Continue insulin infusion until glucose reaches 200-250 mg/dL, then reduce rate to 0.02-0.05 units/kg/hour 1, 4

• Do NOT stop insulin when glucose normalizes—continue at reduced rate and add dextrose to IV fluids to maintain glucose 140-180 mg/dL 1, 4

Fluid Resuscitation Strategy

• Start 0.9% normal saline at 500-1000 mL/hour for the first 1-2 hours if the patient shows signs of dehydration 1, 4

• After initial resuscitation, adjust rate to 250-500 mL/hour based on hydration status, cardiac function, and urine output 1

• When glucose reaches 200-250 mg/dL, switch to 5% dextrose in 0.45% saline to prevent hypoglycemia while continuing insulin 1, 4

Electrolyte Management

Potassium monitoring and replacement is critical:

• Check potassium level before starting insulin—if <3.3 mEq/L, hold insulin and replete potassium first to avoid life-threatening hypokalemia and cardiac arrhythmias 1, 3

• Once potassium is >3.3 mEq/L and urine output is adequate, add 20-30 mEq potassium per liter of IV fluid (use 2/3 KCl and 1/3 KPO4) 1, 4

• Target serum potassium 4-5 mEq/L throughout treatment 1, 4

• Insulin therapy causes intracellular potassium shift and can precipitate severe hypokalemia even if initial levels are normal 4, 3

Monitoring Parameters

Check every 1-2 hours initially, then every 2-4 hours once stable:

• Capillary or venous blood glucose 1

• Serum potassium, sodium, chloride, bicarbonate, anion gap 1, 4

• Venous pH if DKA suspected (venous pH is typically 0.03 units lower than arterial pH and is sufficient for monitoring) 1

• Urine output and vital signs 1

• Mental status changes 1

Critical Pitfalls to Avoid

• Never use sliding scale insulin alone for severe hyperglycemia—this approach is strongly discouraged and leads to poor outcomes 1

• Do not stop IV insulin abruptly when glucose normalizes—this causes rebound hyperglycemia 4

• Do not give potassium if serum level is >5.5 mEq/L or if urine output is inadequate 1, 4

• Do not correct glucose too rapidly (>75 mg/dL per hour)—this increases risk of cerebral edema, especially in younger patients 1

• Avoid using only capillary glucose measurements in critically ill or hemodynamically unstable patients—arterial or venous samples are more accurate 5

Transition to Subcutaneous Insulin

Once glucose is controlled and patient is stable:

• Give subcutaneous long-acting basal insulin 1-2 hours before stopping IV insulin to prevent rebound hyperglycemia 4

• Start basal-bolus regimen: 50% of total daily dose as basal insulin, 50% divided among meals as rapid-acting insulin 4

• Initial total daily dose approximately 0.5-0.8 units/kg for most patients 4

• For patients with poor oral intake or NPO status, use basal insulin plus correction doses every 4-6 hours instead of meal-time insulin 1, 6

Special Considerations

• If the patient has Type 1 diabetes, never stop insulin completely—even when NPO, continue basal insulin to prevent DKA 4, 3

• Consider A1C testing if not done in past 3 months to assess chronic glycemic control and guide discharge planning 1

• Severe hyperglycemia with normal ABG may represent early DKA, hyperosmolar hyperglycemic state (HHS), or severe insulin deficiency without ketosis—all require IV insulin 1, 7