Part of the ICU Emergencies Hub — browse every related guide in one place.
| Patient Population | Target Blood Glucose | Notes |
|---|---|---|
| Non-critical care (general ward) | 140–180 mg/dL | Tighter targets (110–140) may be appropriate in select patients per physician order |
| Critical care / ICU | 140–180 mg/dL | Previous tighter targets (80–110) shown to increase hypoglycemia and mortality — current evidence supports 140–180; notify MD for below 70 or above 200 |
| Acute stroke | 140–180 mg/dL | Both hyperglycemia and hypoglycemia worsen neurological outcomes after stroke |
| Post-cardiac surgery | Below 180 mg/dL (per institutional protocol) | Insulin infusion protocols common; tight glucose control reduces wound infection and improves outcomes |
Definition: Blood glucose below 70 mg/dL. Severe hypoglycemia: below 54 mg/dL or any glucose level causing altered mental status or unconsciousness.
Clinical signs: Mild-moderate: diaphoresis (early, most reliable sign), tremor, tachycardia, pallor, hunger, headache, anxiety, irritability. Severe: confusion, altered mental status, seizures, loss of consciousness, unresponsiveness. Note: altered mental status from hypoglycemia can mimic stroke — always check blood glucose in any patient with sudden neurological change.
Treatment — Rule of 15: For conscious patients with blood glucose below 70 mg/dL: give 15 grams of fast-acting carbohydrate (4 oz orange juice, 4 oz regular (not diet) soda, 3–4 glucose tablets, 1 tablespoon sugar). Wait 15 minutes. Recheck glucose. Repeat if still below 70 mg/dL. Once above 70 mg/dL, follow with a snack containing protein and complex carbohydrate if the next meal is more than 1 hour away.
For unconscious or NPO patients: IV dextrose — D50W 25g IV push (one 50 mL ampule of 50% dextrose) is the standard rescue treatment. Glucagon 1 mg IM or SubQ is an alternative when IV access is unavailable; onset is slower (10–15 minutes) and requires endogenous glucose stores (less effective in malnourished or alcohol-dependent patients).
| Insulin Type | Brand Examples | Onset | Peak | Duration | Use |
|---|---|---|---|---|---|
| Rapid-acting | Lispro (Humalog), Aspart (NovoLog), Glulisine (Apidra) | 10–30 min | 30 min–3 hr | 3–5 hr | Mealtime bolus; given immediately before or with a meal; must have food available |
| Short-acting (Regular) | Regular (Humulin R, Novolin R) | 30–60 min | 2–4 hr | 5–8 hr | Mealtime bolus (older); correction doses; IV insulin drips |
| Intermediate-acting | NPH (Humulin N, Novolin N) | 1–3 hr | 4–12 hr | 12–18 hr | Twice-daily dosing; combined with short-acting in premixed formulations |
| Long-acting | Glargine (Lantus, Basaglar), Detemir (Levemir), Degludec (Tresiba) | 1–4 hr | No pronounced peak (glargine/degludec); Detemir mild peak | 20–24+ hr | Basal insulin; given once daily (glargine/degludec) or twice daily (detemir); provides 24-hour background coverage |
| Premixed insulin | 70/30 (NPH/Regular), Humalog Mix 75/25 | Variable | Variable (dual peaks) | 10–16 hr | Fixed-ratio combinations; used in stable outpatients; require meal consistency; less flexible |
Clinical signs: Polydipsia (excessive thirst), polyuria (frequent urination), polyphagia (excessive hunger), blurred vision, fatigue, slow wound healing. Mild hyperglycemia (180–250 mg/dL) may have few or no symptoms. Severe hyperglycemia leads to osmotic diuresis, dehydration, and progression toward DKA or HHS (hyperosmolar hyperglycemic state).
Nursing response: Notify provider for blood glucose consistently above the ordered target (usually above 200–250 mg/dL in most protocols); administer correction doses of rapid-acting insulin per sliding scale or provider order; assess for signs of DKA or HHS; increase monitoring frequency; assess contributing factors (missed doses, infection, dietary deviation, stress-related hyperglycemia).
DKA is an acute, life-threatening complication of diabetes — primarily Type 1, but increasingly seen in Type 2 (particularly with SGLT-2 inhibitors). DKA results from insulin deficiency + glucagon excess → uncontrolled lipolysis → ketone production → metabolic acidosis.
Classic DKA triad: Hyperglycemia (glucose typically 250–800 mg/dL, but can be lower in SGLT-2 inhibitor-associated DKA), ketosis (ketonemia and ketonuria), metabolic acidosis (pH below 7.3, HCO3- below 18 mEq/L).
Clinical presentation: Kussmaul respirations (deep, rapid breathing — respiratory compensation for metabolic acidosis), fruity or acetone breath (ketones), nausea/vomiting, abdominal pain, dehydration signs (dry mucous membranes, tachycardia, hypotension), altered consciousness in severe cases.
DKA nursing priorities: Aggressive IV fluid resuscitation (normal saline 1 L/hr initial rate for most adult patients until hemodynamic stabilization); insulin infusion (regular insulin IV — NOT subcutaneous for DKA; SC absorption is unreliable when the patient is dehydrated and hypoperfused); potassium replacement (insulin drives K+ into cells — K+ falls with DKA treatment; must be repleted before insulin is safe; HOLD insulin if K+ below 3.5); frequent labs (glucose q1h, basic metabolic panel q2-4h, ABG for pH monitoring); monitor for resolution (pH above 7.3, HCO3- above 18, closure of the anion gap, glucose below 200).
Related guides: Fluids and electrolytes | Acid-base balance | Medication errors | ICU nurse skills
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