Delirium Prevention

Confusion Assessment Method (CAM)

The CAM is the most widely validated bedside tool for delirium diagnosis. Requires brief training and takes 5 minutes to administer.

Diagnostic Algorithm: Delirium is present if: (Feature 1 AND Feature 2) AND (Feature 3 OR Feature 4)

Feature 1: Acute onset and fluctuating course

• Is there evidence of acute change in mental status from baseline?
• Does the abnormal behavior fluctuate during the day?

Feature 2: Inattention

• Does the patient have difficulty focusing attention?
• Is the patient easily distracted or unable to keep track of conversation?

Feature 3: Disorganized thinking

• Is the patient's thinking disorganized or incoherent?
• Rambling, irrelevant conversation, unclear flow of ideas?

Feature 4: Altered level of consciousness

• Overall, how would you rate the patient's level of consciousness?
• Alert (normal), vigilant (hyperalert), lethargic, stupor, coma
• Any response other than "alert" is abnormal

Sensitivity: 94%, Specificity: 89% for delirium diagnosis.

4AT (Four A's Test)

The 4AT is a rapid screening tool taking less than 2 minutes, designed for use by all clinical staff without special training.

Components:

1. Alertness (0 or 4 points)

• Normal = 0
• Mild sleepiness for less than 10 seconds after waking = 0
• Clearly abnormal = 4

2. AMT4 - Abbreviated Mental Test (0, 1, or 2 points)

• Age, Date of birth, Place, Current year
• No mistakes = 0
• 1 mistake = 1
• 2 or more mistakes or untestable = 2

3. Attention (0, 1, or 2 points)

• Months of year backwards: October, September, August...
• 7 or more correct = 0
• Starts but less than 7 correct = 1
• Refuses or unable = 2

4. Acute change or fluctuating course (0 or 4 points)

• Evidence of significant change or fluctuation in alertness, cognition, other mental function over past 2 weeks, still evident in past 24 hours
• No = 0
• Yes = 4

Scoring:

• 0 = Delirium or severe cognitive impairment unlikely
• 1-3 = Possible cognitive impairment
• 4 or more = Possible delirium (plus or minus cognitive impairment)

The 4AT is ideal for rapid screening on ward rounds or in emergency department. Sensitivity 90%, specificity 84%.

Delirium Rating Scale - Revised-98 (DRS-R-98)

This is a more comprehensive 16-item scale used primarily in research and when detailed assessment is needed. It assesses:

• Severity of delirium symptoms
• Distinguishes delirium from dementia
• Tracks response to treatment

Maximum score 46. Score over 17 indicates delirium. Higher scores indicate greater severity.

Used primarily in specialized settings and research, not routine clinical practice.

Practical Clinical Assessment

The key is to establish this is an acute change from baseline with fluctuating course - information from family is invaluable.

Delirium Subtypes

Classification by Cause

Recognizing all delirium subtypes ensures no cases are missed, especially hypoactive.

DSM-5 Diagnostic Criteria

Severity Classification

Duration Classification

Understanding classification guides assessment, management intensity, and prognosis.

Screening Tools

Bedside Assessment

Regular screening with validated tools ensures early delirium recognition.

Comprehensive Assessment

Differentiating Delirium from Dementia

Thorough assessment identifies both the delirium and its underlying cause.

First-Line Investigations

Imaging and Other Tests

Investigations should be targeted based on clinical assessment findings.

Systematic Investigation Approach

Extended Workup

Thorough investigation identifies treatable causes and guides targeted management.

Antipsychotic Medications for Delirium

Haloperidol - most studied, first-line

• Typical (first-generation) antipsychotic
• Blocks D2 receptors
• Less sedating than atypicals
• Fewer anticholinergic effects than atypicals

Benzodiazepines - Generally AVOID

Benzodiazepines are contraindicated in delirium except for two specific indications:

Why avoid in other delirium?

• Paradoxical agitation in elderly (30-40% of cases)
• Worsens confusion and disorientation
• Respiratory depression
• Increased fall risk
• Prolonged delirium duration
• Oversedation masks underlying problems

Common error: Using benzodiazepines for "anxiety" or "agitation" in a delirious elderly patient almost always makes things worse. The agitation is a symptom of delirium (due to hypoxia, infection, etc.), not primary anxiety.

Other Pharmacological Approaches

Always try non-pharmacological approaches first.

Post-Operative Delirium Prevention

Monitoring for Delirium

Vigilant postoperative monitoring enables early detection and intervention.

Discharge Planning

Follow-Up Care

Comprehensive postoperative care extends beyond hospital discharge.

Regional vs General Anaesthesia for Delirium Prevention

The key message: technique matters less than perioperative care (early surgery, pain control, mobilization, delirium prevention).

Depth of Anaesthesia and Delirium

The evidence does not support aggressive lightening of anaesthesia, but avoiding excessive depth is reasonable.

Intraoperative Factors Affecting Delirium Risk

These factors collectively have greater impact than choice of GA vs regional.

Postoperative Pain Management to Prevent Delirium

Global Epidemiology

Delirium is the most common acute neuropsychiatric complication of hospitalisation in older adults worldwide. Reported incidence varies by population: roughly 11-51% across postoperative cohorts, with hip fracture patients at the highest end (commonly 35-65%), elective hip/knee arthroplasty far lower (around 4-10%), and ICU/critically ill patients reaching 48% or more (MIND-USA cohort, PMID 30346242). Predisposing vulnerability (age, baseline cognitive impairment, sensory loss, frailty) and acute precipitants (surgery, sepsis, hypoxia, deliriogenic drugs) interact, so incidence reflects case-mix as much as care quality. Across settings, multicomponent prevention reduces incidence by roughly one-third (Cochrane RR 0.69, PMID 26967259).

Major Guidelines Side by Side

Where guidelines genuinely diverge it is on the surgical-timing threshold (NICE/SIGN favour 36 hours, ANZHFR and most ERAS pathways 48 hours) and on the strength of the anti-antipsychotic recommendation (AGS states this most explicitly). All converge on multicomponent non-pharmacological prevention, validated screening, and avoidance of deliriogenic drugs.

Registry and National-Audit Evidence

Hip fracture registries and national audits worldwide are the main vehicle for benchmarking the care processes that drive delirium - time to surgery, orthogeriatric review, and early mobilisation. They consistently show that hospitals delivering early surgery and orthogeriatric co-management have lower delirium, mortality and length of stay, mirroring the trial and meta-analysis evidence (orthogeriatric delirium RR 0.81, PMID 34591127).

Orthogeriatric Models (Global)

Global Practice Variation

• Surgical-timing thresholds differ by guideline and by system capacity (36h in NICE/SIGN, 48h in many ERAS/registry standards); achievement is strongly resource-dependent.
• Orthogeriatric access varies widely - near-universal in some high-income systems, limited or consultation-only where geriatrician workforce is scarce.
• Medication availability differs: melatonin and dexmedetomidine availability and cost vary by country; the underlying recommendation (avoid deliriogenic drugs, reserve antipsychotics for severe agitation) is universal.
• Documentation and handover of a delirium episode (to the primary-care physician and any residential-care facility) is recommended everywhere because persistent cognitive effects and recurrence risk carry medicolegal and clinical importance.

Internationally, delirium prevention is increasingly embedded in registry-benchmarked fragility-fracture pathways centred on early surgery and orthogeriatric co-management.

Summary of Key Evidence

The evidence strongly supports multicomponent non-pharmacological prevention bundles.

Landmark Trials and Systematic Reviews

Ongoing Research and Controversies:

Guidelines and Quality Standards

Quality of Evidence Summary:

The evidence base for delirium prevention is robust for multicomponent interventions and early surgery, while pharmacological prevention remains unsupported.