Delirium Prevention in Orthopaedic Surgery

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

13 severity items (0-3 scale): Sleep-wake cycle, perceptual disturbances, delusions, lability of affect, language, thought process, motor agitation, motor retardation, orientation, attention, short-term memory, long-term memory, visuospatial ability

3 diagnostic items: Temporal onset, fluctuation, physical disorder

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

History from family/carers (essential):

• What is the patient's baseline cognitive function?
• When did the confusion start?
• Does it fluctuate during the day?
• Any new medications or recent changes?
• Alcohol use?

Bedside cognitive tests:

• Orientation (person, place, time)
• Attention (spell WORLD backwards, serial 7s, months backwards)
• Short-term memory (3-item recall)
• Clock drawing test

Physical examination:

• Vital signs (fever, hypoxia, hypotension)
• Hydration status
• Surgical site examination
• Neurological exam (focal signs)
• Evidence of retention (bladder, constipation)

Chart review:

• Medication list (look for BAD MEDS)
• Fluid balance
• Pain scores
• Sleep overnight
• Bowel movements

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

Regional vs General Anaesthesia for Delirium Prevention

The evidence: Multiple meta-analyses have examined whether regional anaesthesia (spinal, epidural) reduces delirium compared to general anaesthesia. The results are conflicting:

Regional anaesthesia (spinal/epidural):

• Avoids volatile anaesthetics and deep sedation
• Allows patient to remain awake and oriented
• Better early cognitive function
• BUT: most high-quality RCTs show no difference in delirium rates

General anaesthesia:

• Complete control of airway
• Better haemodynamic control
• Patient not aware of surgery
• BUT: concern about volatile agents and cognitive effects

Current evidence (Cochrane review, 2021):

• No significant difference in postoperative delirium between regional and GA
• No difference in mortality, cognitive outcomes, or complications
• Choice should be based on patient factors, surgical factors, and anaesthetist preference

When regional may be preferred:

• Frail patient with multiple comorbidities
• Difficult airway
• Severe respiratory disease
• Continuation as postoperative epidural analgesia

When GA may be preferred:

• Patient preference or anxiety
• Coagulopathy or antiplatelet use
• Prolonged surgery expected
• Neuraxial contraindications

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

Depth of Anaesthesia and Delirium

BIS monitoring (Bispectral Index): Some studies suggest that lighter anaesthesia (BIS 50-60) compared to deeper anaesthesia (BIS 30-40) may reduce delirium, but evidence is mixed.

Potential mechanisms:

• Volatile anaesthetics may have direct neurotoxic effects
• Deeper anaesthesia may represent greater "brain insult"
• Hypotension associated with deep anaesthesia

Evidence:

• ENGAGES trial (2019): BIS-guided anaesthesia (target 50) vs usual care - no difference in delirium
• CODA trial (2021): Light vs deep sedation - mixed results
• Meta-analyses: small reduction in delirium with lighter anaesthesia

Current practice:

• Avoid unnecessarily deep anaesthesia
• Maintain adequate depth for surgical conditions
• BIS monitoring may be useful but not mandatory
• Focus on maintaining haemodynamic stability

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

Intraoperative Factors Affecting Delirium Risk

Haemodynamic management:

• Avoid hypotension - maintain MAP over 65 mmHg (or within 20% of baseline)
• Intraoperative hypotension associated with increased delirium and stroke
• Cerebral autoregulation impaired in elderly - more susceptible to hypoperfusion

Hypoxia prevention:

• Maintain SpO2 over 94%
• Avoid prolonged desaturation
• Adequate ventilation

Anaemia:

• Transfuse if Hb less than 80 g/L (some argue less than 90 g/L in elderly)
• Anaemia associated with delirium and poor outcomes
• Liberal transfusion may not reduce delirium but improves oxygen delivery

Fluid management:

• Avoid hypovolaemia and hypervolaemia
• Goal-directed fluid therapy may improve outcomes
• Monitor urine output

Temperature:

• Maintain normothermia (36-37�C)
• Hypothermia increases delirium risk
• Active warming devices

Blood glucose:

• Avoid hypoglycaemia (less than 4 mmol/L)
• Avoid severe hyperglycaemia (over 15 mmol/L)
• Target 6-10 mmol/L perioperatively

Duration:

• Prolonged anaesthesia (over 3 hours) increases risk
• Expeditious but safe surgery

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

Postoperative Pain Management to Prevent Delirium

Multimodal analgesia is the key:

Non-opioid analgesics:

• Paracetamol 1g QID - cornerstone, minimal risk
• NSAIDs (if renal function allows) - COX-2 inhibitors (celecoxib) safer for elderly
• Consider temporary use despite age

Regional techniques:

• Fascia iliaca block for hip fractures - excellent analgesia, reduces opioid use
• Femoral nerve block - effective but may delay mobilization (quadriceps weakness)
• Continuous epidural (if regional anaesthetic used) - superior analgesia
• Local infiltration analgesia for arthroplasty

Opioids (use judiciously):

• Use lowest effective dose
• Regular small doses better than PRN large doses
• Avoid meperidine (pethidine) - neurotoxic metabolite
• Morphine, oxycodone, or hydromorphone acceptable
• Monitor for oversedation

Pain assessment:

• Regular pain scoring (even in cognitively impaired)
• Behavioral pain scales (PAINAD) for those unable to self-report
• Undertreated pain is a delirium risk factor

Balance: The challenge is balancing adequate analgesia (undertreated pain causes delirium) with minimizing opioids (excessive opioids cause delirium). Multimodal approach with regional techniques is ideal.

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

Dosing:

• Start with 0.5mg PO/IM/IV in elderly
• Can repeat in 20-30 minutes if inadequate response
• Usual dose range 0.5-2mg
• Maximum 3-5mg per 24 hours in elderly
• Reduce dose in renal/hepatic impairment

Monitoring:

• ECG before starting (QTc prolongation risk)
• Risk of torsades de pointes (rare but serious)
• Extrapyramidal side effects (rare at low doses)

Atypical antipsychotics (alternatives):

• Quetiapine 12.5-50mg - more sedating, useful at night
• Risperidone 0.25-0.5mg - similar efficacy to haloperidol
• Olanzapine 2.5-5mg - more sedating, anticholinergic effects

Evidence:

• Multiple RCTs show antipsychotics reduce agitation symptoms but do not shorten delirium duration or improve outcomes
• No difference between typical and atypical antipsychotics
• Use for symptom control only, not to "treat" delirium

Australian context:

• PBS does not restrict antipsychotics for delirium
• eTG recommends haloperidol 0.5-1mg as first-line for severe agitation
• Document indication and review daily

Benzodiazepines - Generally AVOID

Benzodiazepines are contraindicated in delirium except for two specific indications:

1. Alcohol withdrawal delirium (delirium tremens):

• CIWA protocol
• Diazepam 10-20mg or lorazepam 2-4mg
• Titrate to symptom control

2. Benzodiazepine withdrawal:

• Taper slowly
• Reinstitute and wean

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

Dexmedetomidine (Precedex):

• Alpha-2 agonist
• Some evidence for reduction in ICU delirium
• Requires ICU setting and monitoring
• Not for routine ward use
• Expensive

Melatonin:

• May help prevent delirium in some studies
• 3-5mg at bedtime
• Safe, minimal side effects
• Not PBS-subsidized in Australia
• Mixed evidence

Cholinesterase inhibitors:

• Donepezil, rivastigmine studied for delirium prevention
• RCTs showed no benefit and possible harm
• Do NOT use for delirium prevention or treatment

Trazodone:

• Sedating antidepressant
• Sometimes used for sleep in delirium
• 25-50mg at night
• Limited evidence

Avoid:

• Anticholinergic medications (worsen delirium)
• Diphenhydramine (Benadryl) - strongly anticholinergic
• Promethazine (Phenergan) - anticholinergic
• Sedative-hypnotics (zopiclone, zolpidem) - similar to benzodiazepines

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.

Summary of Key Evidence

What the evidence clearly supports:

• Multicomponent non-pharmacological interventions (HELP protocol)
• Early surgery for hip fractures (within 48 hours)
• Orthogeriatric co-management
• Avoiding deliriogenic medications
• Fascia iliaca blocks for pain control

What the evidence does NOT support:

• Prophylactic antipsychotics
• Any specific anaesthetic technique (regional vs general equivalent)
• Routine melatonin supplementation (insufficient evidence)
• Single-component interventions (must be multimodal)

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.

Australian Hip Fracture Care Standards

Therapeutic Guidelines (eTG) Recommendations

Delirium Prevention:

• Multicomponent non-pharmacological intervention for all at-risk patients
• Avoid benzodiazepines for sleep (use non-pharmacological measures)
• Avoid anticholinergic medications where possible
• Review and rationalise medication lists

Delirium Treatment:

• Investigate and treat underlying cause first
• Non-pharmacological measures as first-line
• Haloperidol 0.5-1mg PO/IM for severe agitation (lowest effective dose)
• Avoid benzodiazepines unless alcohol/benzodiazepine withdrawal

Australian standards emphasise orthogeriatric co-management and early surgery as cornerstones of delirium prevention.

ANZHFR Data and Benchmarking

State and Territory Variations:

• Performance varies significantly between states
• Metropolitan hospitals generally outperform regional
• Hospital volume correlates with better outcomes
• Some hospitals achieve 95% surgery within 48 hours

Australian Geriatric Medicine Integration

PBS and Medication Considerations

PBS Restrictions Relevant to Delirium:

• Antipsychotics have specific PBS criteria for BPSD
• Benzodiazepines: authority required for extended use in elderly
• Melatonin: limited PBS availability

Medication Review Programs:

• Home Medicines Review (HMR) pre-operatively if time permits
• Residential Medication Management Review (RMMR)
• MedsCheck in community pharmacy
• Stopping anticholinergics, benzodiazepines key focus

RACGP and Primary Care Integration

Post-Discharge Care:

• GP follow-up within 7-14 days post-discharge
• Medication reconciliation critical
• Cognitive assessment at 3 months
• Falls prevention program referral
• Bone health assessment and treatment

Transition of Care:

• Discharge summary with delirium episode documented
• Handover to GP regarding cognitive changes
• RACF communication if applicable
• Community aged care referral if new needs

Australian Research and Registries

Active Australian Delirium Research:

• ANZHFR ongoing data collection
• DELPH-i trial (delirium prediction)
• Australian-New Zealand delirium consortium
• State-based quality improvement projects

Quality Improvement Initiatives:

• NSW Hip Fracture Integrated Care Project
• Victorian Hip Fracture Guidelines
• South Australian orthogeriatric network
• Queensland Fragility Fracture Service Model

Australian systems increasingly integrate orthogeriatric care, with ongoing quality improvement driven by ANZHFR benchmarking data.