What is the management plan for a patient with hyperglycemia (elevated blood sugar) not on insulin?

Blood Sugar Management for Non-Insulin Patient with Blood Glucose of 300 mg/dL

For a patient not on insulin with blood glucose of 300 mg/dL, initiate basal insulin at 0.2-0.3 U/kg/day combined with correction doses of rapid-acting insulin before meals or every 6 hours, while continuing metformin if already prescribed. 1

Immediate Assessment and Classification

This blood glucose level of 300 mg/dL represents severe hyperglycemia requiring prompt insulin therapy. 1 First, assess for:

• Ketosis, vomiting, or altered consciousness – if present, this requires immediate medical care for potential diabetic ketoacidosis or hyperosmolar state 1
• Symptoms of metabolic decompensation – polyuria, polydipsia, weight loss, or ketonuria indicate need for urgent insulin initiation 1
• Acute stressors – infection, dehydration, trauma, surgery, or steroid use that may be precipitating the hyperglycemia 1

Insulin Initiation Protocol

Starting regimen for blood glucose >300 mg/dL:

• Basal insulin dose: Start at 0.3 U/kg/day if insulin-naive, or reduce home insulin total daily dose (TDD) by 20% if already on insulin 1
• Split the total daily dose: Give half as basal insulin (once daily) and half as bolus insulin (divided before meals) 1
• Add correction doses: Use rapid-acting insulin before meals or every 6 hours to address persistent elevations 1

For example, a 100 kg patient would receive approximately 30 units total daily: 15 units basal insulin (glargine or similar) once daily, plus 5 units rapid-acting insulin before each of three meals. 1

Oral Medication Considerations

Continue metformin if:

• No contraindications exist (eGFR >30 mL/min/1.73 m², no sepsis, hypoxia, or shock) 1
• Patient is not at risk for lactic acidosis 1

Discontinue sulfonylureas immediately when starting insulin to avoid severe hypoglycemia, as these medications potentiate insulin's hypoglycemic effects and are associated with unacceptably high rates of iatrogenic hypoglycemia in hospital settings. 1, 2

Monitoring Requirements

• Frequent blood glucose monitoring: Check before meals and at bedtime, or every 4-6 hours if not eating 1
• Assess for ketones if patient has type 1 diabetes or is ketosis-prone 1
• Monitor for hypoglycemia: Blood glucose <70 mg/dL requires immediate treatment with 15-20g carbohydrate 1

Dose Adjustment Strategy

Titrate insulin every 1-2 days based on fasting glucose:

• If fasting glucose remains >180 mg/dL: Increase basal insulin by 2-4 units 1, 3
• If pre-meal glucose >180 mg/dL: Increase corresponding bolus insulin dose by 1-2 units 1
• Target glucose range: 110-180 mg/dL for most hospitalized patients 3

Critical Pitfalls to Avoid

Do NOT use sliding scale insulin alone for blood glucose of 300 mg/dL – this reactive approach is associated with poor glycemic control and increased complications compared to scheduled basal-bolus regimens. 1 Sliding scale may only be appropriate for patients with HbA1c <7% on minimal oral agents, which does not apply here. 1

Do NOT use premixed insulin (70/30) in the hospital setting due to unacceptably high rates of hypoglycemia. 1

Do NOT continue SGLT2 inhibitors in the hospital due to increased risk of diabetic ketoacidosis. 1

Transition Planning

Once glucose stabilizes below 200 mg/dL consistently:

• Reassess insulin requirements every 24-48 hours 1
• Consider simplification to basal-plus regimen (basal insulin with correction doses only) if patient is eating poorly 1
• Arrange outpatient follow-up within 1 week to 1 month with primary care or endocrinology 1
• Provide discharge education on insulin administration, glucose monitoring, hypoglycemia recognition and treatment, and sick day management 1

Special Circumstances

If patient is hospitalized: Continuous IV insulin infusion may be preferred over subcutaneous insulin for severe hyperglycemia with metabolic decompensation, critical illness, or during surgical procedures. 1, 3

If outpatient setting: Ensure adequate fluid intake, monitor for dehydration, and consider same-day endocrinology consultation or emergency department referral if patient appears ill, has altered mental status, or cannot reliably self-administer insulin. 1