Part of the ICU Emergencies Hub — browse every related guide in one place.
Delirium is an acute, fluctuating disturbance in attention, awareness, and cognition that develops over hours to days and represents a change from the patient's baseline. It is NOT the same as dementia. It is a medical emergency indicating an acute underlying cause. Up to 50% of ICU patients and 30% of hospitalized elderly develop delirium. It significantly increases mortality, length of stay, and long-term cognitive impairment.
| Type | Presentation | Recognition Challenge | Prevalence |
|---|---|---|---|
| Hyperactive Delirium | Agitation, combativeness, trying to pull out lines, yelling, hallucinations, climbing out of bed; floridly abnormal behavior | Easy to recognize — nurses always notice this | ~25% of delirium cases |
| Hypoactive Delirium | Withdrawn, quiet, lethargic, flat affect, reduced responsiveness, psychomotor slowing; may appear "calm" or "just tired" | MOST MISSED type — often mistaken for depression, fatigue, or normal post-op sedation. Worse prognosis than hyperactive. | ~50% of delirium cases |
| Mixed Delirium | Fluctuates between hyperactive and hypoactive features throughout the day | The fluctuation pattern is diagnostic | ~25% of delirium cases |
| Category | Examples |
|---|---|
| Medications | Anticholinergics (diphenhydramine/Benadryl, atropine), benzodiazepines, opioids, corticosteroids, polypharmacy (>5 medications) |
| Metabolic/Physiologic | Hypoxia, hypercapnia, hypo/hyperglycemia, hypo/hypernatremia, uremia, hepatic failure, sepsis, pain, fever, hypothermia |
| Environment | Sleep deprivation, ICU noise/lighting, immobility, restraints, lack of familiar faces, glasses/hearing aids not in use |
| Procedures | Surgery (especially cardiac, orthopedic, major abdominal), anesthesia, urinary catheter, physical restraints |
| Neurologic | Stroke, seizures, meningitis/encephalitis, brain injury |
The CAM is the gold-standard validated tool for delirium screening. It has 4 features; delirium is diagnosed if features 1 AND 2 are present, PLUS feature 3 OR 4.
| Feature | Assessment | Required? |
|---|---|---|
| Feature 1: Acute Onset and Fluctuating Course | Is there an acute change from baseline? Does it fluctuate during the day? | YES — must be present |
| Feature 2: Inattention | Does the patient have difficulty focusing? Distracted easily? Can they list months of the year backward or squeeze your hand every time they hear a letter "A"? | YES — must be present |
| Feature 3: Disorganized Thinking | Rambling/incoherent speech, illogical flow of ideas, unpredictable topic switching, cannot answer simple yes/no questions correctly (e.g., "Will a stone float on water?") | Feature 3 OR 4 |
| Feature 4: Altered Level of Consciousness | Anything other than alert and calm: vigilant (hyper-alert), lethargic, stuporous, or comatose | Feature 3 OR 4 |
CAM-ICU: Modified version for intubated/non-verbal patients. Uses the RASS (Richmond Agitation-Sedation Scale) first, then assesses Features 1–4 with nonverbal testing. RASS must be ≥−3 for CAM-ICU to be valid (too deeply sedated cannot be assessed).
| Score | Level | Description |
|---|---|---|
| +4 | Combative | Overtly combative, violent, immediate danger to staff |
| +3 | Very Agitated | Pulls or removes tubes/catheters; aggressive |
| +2 | Agitated | Frequent nonpurposeful movement; fights ventilator |
| +1 | Restless | Anxious but movements not aggressive |
| 0 | Alert and Calm | TARGET for most non-sedated ICU patients |
| -1 | Drowsy | Not fully alert but awakens to voice >10 sec |
| -2 | Light Sedation | Briefly awakens to voice (<10 sec); eye contact |
| -3 | Moderate Sedation | Movement or eye opening to voice; no eye contact |
| -4 | Deep Sedation | No response to voice; moves to physical stimulation |
| -5 | Unarousable | No response to voice or physical stimulation |
| Letter | Element | Nursing Action |
|---|---|---|
| A | Assess, Prevent, and Manage Pain | Regular pain assessment; multimodal analgesia; minimize opioids when possible; CPOT for non-verbal patients |
| B | Both SAT + SBT (Spontaneous Awakening + Breathing Trials) | Daily sedation vacation + spontaneous breathing trial; coordinate with respiratory therapy |
| C | Choice of Analgesia and Sedation | Analgesia-first sedation; target lightest effective sedation (RASS 0 to −1); avoid benzodiazepines |
| D | Delirium: Assess, Prevent, Manage | CAM-ICU or CAM every shift; identify and treat causes; non-pharmacologic interventions first |
| E | Early Mobility and Exercise | Sit on edge of bed → chair → stand → ambulate as soon as medically safe; PT/OT consult |
| F | Family Engagement and Empowerment | Flexible visiting hours; family reorientation; family education; comfort items from home |
| Drug | Use | Key Points |
|---|---|---|
| Haloperidol (Haldol) | Hyperactive delirium with safety risk; most evidence-based in ICU | 0.5–2 mg IV/IM/PO; monitor QTc; extrapyramidal side effects; does NOT shorten delirium duration but controls agitation |
| Quetiapine (Seroquel) | Delirium with sleep disturbance; adjunct to haloperidol | 12.5–50 mg PO at bedtime; less EPS than haloperidol; QTc monitoring |
| Dexmedetomidine (Precedex) | ICU delirium; allows lighter sedation than benzodiazepines | Alpha-2 agonist; lighter sedation with preserved arousability; less delirium than benzodiazepines; bradycardia and hypotension |
| Benzodiazepines (lorazepam, diazepam) | Delirium tremens (alcohol withdrawal ONLY); otherwise AVOID | WORSEN delirium in most cases; avoid in elderly; do not use for routine delirium except alcohol withdrawal |
Get The ICU Notebook Newsletter
Clinical tools and career insights for ICU nurses. One email per week, no fluff.
Yes, send it freeNo spam. Unsubscribe any time.