12.1 Delirium, Agitation, Sedation & Pain

ICU Delirium — Recognition and Subtypes

Delirium is an acute, fluctuating disturbance of attention and awareness with disorganized thinking that is driven by an underlying medical cause. It affects up to 80% of mechanically ventilated ICU patients and is an independent predictor of increased mortality, more ventilator days, longer length of stay, and long-term cognitive impairment resembling mild dementia. The CCRN blueprint files delirium under Behavioral/Psychosocial content and expects you to separate it from dementia (chronic, slowly progressive, attention preserved early) and depression (low mood, but orientation intact).

Three motor subtypes exist. Hyperactive delirium (agitation, pulling at lines, combativeness) is the most recognized but least common. Hypoactive delirium (withdrawn, flat, slowed, quietly inattentive) is the most common and most dangerous because it is easily mistaken for a calm, cooperative patient and carries the worst prognosis. Mixed delirium fluctuates between the two. Because hypoactive delirium hides in plain sight, routine objective screening — not clinical gestalt — is required.

Screening: CAM-ICU and ICDSC

The CAM-ICU (Confusion Assessment Method for the ICU) is the most heavily tested tool. Delirium is present when the patient shows Feature 1 (acute change or fluctuating course) AND Feature 2 (inattention), PLUS either Feature 3 (altered level of consciousness, i.e., a RASS other than 0) OR Feature 4 (disorganized thinking). A patient too deeply sedated to participate (RASS -4 or -5) is scored "unable to assess," not delirium-negative. The ICDSC (Intensive Care Delirium Screening Checklist) is an 8-item alternative scored across a shift, where 4 or more indicates delirium. Screen every patient at least once per shift.

Risk Factors and Prevention

Separate modifiable from non-modifiable risks — the exam rewards targeting the modifiable ones.

The cornerstone of prevention is the ABCDEF bundle: Assess/treat pain, Both spontaneous awakening trials (SAT) and spontaneous breathing trials (SBT), Choice of analgesia/sedation (avoid benzodiazepines), Delirium assess/prevent/manage, Early mobility and exercise, and Family engagement. Nonpharmacologic elements — reorientation, sleep hygiene (clustering care, cutting night-time noise and light), early mobilization, restoring glasses and hearing aids, and removing tethers — are always first-line. Antipsychotics do not prevent or shorten delirium (the MIND-USA trial found haloperidol and ziprasidone no better than placebo); reserve low-dose antipsychotics for dangerous agitation that threatens safety.

Sedation — Light, Goal-Directed, Analgesia-First

Deep sedation increases delirium, ventilator days, and mortality, so the standard is light, goal-directed sedation titrated to a validated scale. The Richmond Agitation-Sedation Scale (RASS) runs from +4 (combative) to -5 (unarousable); the usual target is 0 to -2 unless a specific indication (severe ARDS, refractory intracranial hypertension, status epilepticus, neuromuscular blockade) requires going deeper.

Two strategies keep patients light: a daily spontaneous awakening trial (SAT) — pausing sedation each morning to reassess, paired with an SBT — and analgosedation (analgesia-first), treating pain before adding a hypnotic. Agitation is frequently unrelieved pain, hypoxemia, hypercapnia, or ventilator dyssynchrony, so when a ventilated patient is "fighting the vent," first rule out and treat those causes rather than reflexively deepening sedation.

Choosing a Sedative

Dexmedetomidine gives cooperative, arousable sedation with no respiratory depression and less delirium than benzodiazepines; watch for bradycardia and hypotension, and remember it provides no reliable amnesia. Propofol allows rapid titration but causes dose-dependent hypotension, hypertriglyceridemia, and — critically — propofol-related infusion syndrome (PRIS): at high doses (>4-5 mg/kg/hr) beyond 48 hours, patients develop metabolic acidosis, rhabdomyolysis, hyperkalemia, acute kidney injury, and cardiac failure; green urine and a rising lactate/triglyceride are warning signs. Benzodiazepines (midazolam, lorazepam) are the strongest modifiable delirium risk and are reserved for alcohol withdrawal, status epilepticus, and deep-sedation needs; continuous lorazepam can cause propylene-glycol toxicity (an anion-gap acidosis). Patients on continuous neuromuscular blockade must always receive adequate sedation and analgesia — paralytics provide neither, and awareness while paralyzed is traumatic; monitor depth with train-of-four.

Pain Assessment in the Nonverbal Patient

Self-report on a 0-10 Numeric Rating Scale is the gold standard whenever the patient can communicate. When they cannot (intubated, sedated), use a validated behavioral tool. The CPOT (Critical-Care Pain Observation Tool) scores four domains — facial expression, body movements, muscle tension, and ventilator compliance (or vocalization if extubated) — from 0-8, with >2 indicating significant pain. The BPS (Behavioral Pain Scale) scores facial expression, upper-limb movement, and ventilator compliance from 3-12, with >5 unacceptable. Vital-sign changes alone are not valid pain indicators. Assess pain first, then sedation, at regular intervals and after every intervention.