How should hyperglycemia be managed in an adult patient?

Management of Hyperglycemia in Adult Patients

For most adult ICU patients, initiate continuous intravenous insulin infusion when blood glucose exceeds 180 mg/dL, targeting a range of 140–180 mg/dL, while in non-ICU settings, use subcutaneous basal-bolus insulin regimens targeting the same range. 1

Critical Care (ICU) Setting

Insulin Infusion Protocol

• Start continuous IV insulin when glucose >180 mg/dL and maintain levels between 140–180 mg/dL for most ICU patients. 1
• A tighter target of 110–140 mg/dL may be appropriate for select populations (cardiac surgery patients, acute ischemic cardiac or neurological events) only if hypoglycemia can be reliably avoided. 1
• The short half-life of IV insulin (<15 minutes) allows rapid dose adjustments in response to changing clinical status or nutrition. 1
• Computer-based algorithms may reduce hypoglycemia rates and glycemic variability compared to standard protocols, though they have not demonstrated mortality benefit. 1

Avoid Subcutaneous Insulin in Critical Illness

• Do not use subcutaneous insulin in critically ill patients, particularly during hypotension or shock, as absorption is unreliable. 1

Non-Critical Care (General Ward) Setting

Subcutaneous Insulin Regimen

• Subcutaneous insulin is the preferred agent for non-ICU patients, using basal insulin once or twice daily, alone or combined with prandial insulin. 1
• Target glucose levels of 140–180 mg/dL for most hospitalized patients. 1
• Sliding scale insulin as a sole regimen is unacceptable—it causes undesirable hypoglycemia and hyperglycemia and increases hospital complications. 1

Specific Scenarios

For stroke patients:

• Initiate treatment when blood glucose >200 mg/dL, as persistent hyperglycemia (>200 mg/dL) during the first 24 hours independently predicts infarct expansion and poor neurological outcomes. 1
• A reasonable target range is 140–180 mg/dL, though the exact optimal level remains uncertain. 1
• Frequent monitoring and insulin adjustments are required; symptomatic hypoglycemia occurred in approximately 20% of patients in one trial using aggressive protocols. 1

For perioperative patients:

• Continue monitoring postoperatively to detect both hyperglycemia and hypoglycemia. 1
• When blood glucose >16.5 mmol/L (297 mg/dL) in type 1 diabetes or insulin-treated type 2 diabetes, check for ketosis immediately. 1
• In the absence of ketosis, administer ultra-rapid insulin analogue and ensure adequate hydration. 1
• If ketosis is present, suspect early ketoacidosis, call a duty physician, start ultra-rapid insulin, and consider ICU transfer. 1

Hyperglycemic Emergencies

Diabetic Ketoacidosis (DKA)

• Administer IV bolus of regular insulin 0.15 units/kg, followed by continuous infusion at 0.1 unit/kg/hour in adults (no bolus in pediatric patients). 1
• Fluid resuscitation: Start with 0.9% NaCl; switch to 0.45% NaCl at 4–14 mL/kg/hour once hemodynamically stable. 1
• Add 20–30 mEq/L potassium (2/3 KCl, 1/3 KPO₄) once renal function is assured and serum potassium is known. 1
• When glucose reaches 250 mg/dL, change to 5% dextrose with 0.45–0.75% NaCl. 1

Hyperosmolar Hyperglycemic State (HHS)

• Diagnostic criteria: glucose ≥600 mg/dL, arterial pH ≥7.3, bicarbonate ≥15 mEq/L, effective serum osmolality ≥320 mOsm/kg. 1
• Initial fluid therapy identical to DKA; insulin infusion started at 0.1 unit/kg/hour without bolus. 1
• The induced change in serum osmolality should not exceed 3 mOsm/kg/hour to avoid cerebral edema. 1

Special Populations

Older Adults

• For healthy older adults with intact cognition and function, target A1C <7.0–7.5% (fasting glucose 90–130 mg/dL, bedtime glucose 90–150 mg/dL). 1
• For those with multiple chronic illnesses, cognitive impairment, or functional dependence, use less stringent targets: A1C <8.0–8.5% (fasting glucose 90–150 mg/dL, bedtime glucose 100–180 mg/dL). 1
• Older adults have higher hypoglycemia risk due to renal impairment, malnutrition, and blunted counter-regulatory responses. 1
• Consider continuous glucose monitoring for older adults with type 1 diabetes to reduce hypoglycemia (reduces time <70 mg/dL by approximately 27 minutes per day). 1

Patients with Advanced Chronic Kidney Disease

• Target A1C 7–8% when eGFR <30 mL/min/1.73 m² to balance glycemic control against hypoglycemia risk. 2, 3
• Glucose metabolism is profoundly altered with reduced insulin clearance and impaired gluconeogenesis, increasing hypoglycemia risk. 3
• HbA1c becomes unreliable due to anemia, erythropoietin use, and altered red blood cell lifespan. 3

Hypoglycemia Management

Treatment Protocol

• For conscious patients with glucose <70 mg/dL, administer 15–20 g oral glucose, recheck after 15 minutes, and repeat if needed. 1, 2
• For unconscious patients or those unable to swallow, give IV glucose immediately. 1
• Prescribe glucagon for any patient at high risk of severe hypoglycemia. 2
• In patients with hypoglycemia unawareness, temporarily raise glycemic targets for several weeks to restore awareness. 1

Common Pitfalls

• Never discontinue basal insulin in type 1 diabetes—abrupt cessation precipitates rapid ketoacidosis within hours. 2
• Avoid overly aggressive glucose lowering in elderly or critically ill patients, as hypoglycemia is associated with increased mortality (though causality remains uncertain). 1
• Do not rely solely on continuous glucose monitor readings for diagnostic purposes; confirm with venous plasma glucose. 2, 4
• Stress-induced hyperglycemia in non-diabetic patients is an independent predictor of morbidity and mortality and warrants treatment. 2, 5
• Persistent hyperglycemia >200 mg/dL during the first 24 hours after stroke independently predicts worse outcomes, even after adjusting for stroke severity. 1