Compare Risk identification & prevention thresholds for Delirium (peri-operative) across NICE, AGS, and RCoA. Built for Older adults. Setting: Secondary. Urgency: Routine.
Clear thresholds help clinicians answer "when do I act?" for delirium (peri-operative), aligning expectations between NICE, AGS, and RCoA. Use this side-by-side view to decide when to refer, escalate, monitor, or initiate treatment.
Peri-operative delirium affects approximately 15-50% of older adults undergoing major surgery, with incidence rising to 60% in high-risk populations such as those with pre-existing cognitive impairment. This common post-operative complication significantly increases hospital length of stay, healthcare costs, and mortality risk. The key clinical challenge lies in balancing early intervention against unnecessary resource allocation, particularly given the multifactorial nature of delirium risk factors.
Getting prevention thresholds right is critical because delayed or missed intervention can lead to prolonged delirium duration, increased fall risk, functional decline, and higher rates of institutionalisation. NICE adopts a comprehensive risk-stratification approach, AGS emphasises geriatric-specific vulnerabilities, while RCoA focuses on anaesthetic and intra-operative modifiable factors. Understanding these philosophical differences helps clinicians apply the most appropriate framework for individual patients.
| Guideline body | Primary focus | Typical setting | Publication/update |
|---|---|---|---|
| NICE | Comprehensive peri-operative care including delirium prevention | Secondary care | 2024 |
| AGS | Geriatric-specific peri-operative optimisation | Secondary care | 2023 |
| RCoA | Anaesthetic management and intra-operative factors | Secondary care | 2025 |
NICE provides the broadest framework suitable for general peri-operative teams, while AGS offers specialised guidance for geriatricians managing complex older adults. RCoA delivers essential anaesthetic-specific considerations. Cross-reference between guidelines when managing high-risk patients or when specialty input is required.
| Guideline body | Position | Population & urgency |
|---|---|---|
| NICE | Position on Risk identification & prevention thresholds for Delirium (peri-operative) | Older adults | Urgency: Routine | Setting: Secondary |
| AGS | Position on Risk identification & prevention thresholds for Delirium (peri-operative) | Older adults | Urgency: Routine | Setting: Secondary |
| RCoA | Position on Risk identification & prevention thresholds for Delirium (peri-operative) | Older adults | Urgency: Routine | Setting: Secondary |
| Risk factor threshold | NICE | AGS | RCoA | Notes |
|---|---|---|---|---|
| Age requiring prevention | ≥65 years | ≥70 years or ≥65 with frailty | All adults with risk factors | AGS uses lower threshold for frail patients |
| Cognitive impairment (MMSE) | <24/30 | <25/30 | Clinical judgement | NICE more stringent, RCoA contextual |
| Number of risk factors | ≥2 major factors | ≥1 major + 1 minor | Anaesthetic risk focus | Different weighting systems |
| Procedure risk level | Major surgery | Major/emergency surgery | Duration >2 hours | RCoA includes temporal element |
NICE Approach: Recommends pre-operative risk assessment 4-6 weeks before elective surgery using validated tools. For high-risk patients, implement multi-component interventions starting 2-4 weeks pre-operatively. Post-operative monitoring should occur at 4-hour intervals for the first 48 hours, then daily until discharge. Escalate frequency if any delirium symptoms appear.
AGS Approach: Advocates for comprehensive geriatric assessment 4-8 weeks pre-operatively, with frailty-focused interventions. Post-operative monitoring should be hourly for the first 6 hours in recovery, then 4-hourly for 72 hours. AGS specifically recommends night-time checks for sundowning symptoms in patients with cognitive impairment.
RCoA Approach: Focuses on intra-operative and immediate post-operative periods. Recommends anaesthetic review 2 weeks pre-operatively for high-risk patients. Post-operative monitoring in recovery should be continuous for the first hour, then 30-minute intervals for 4 hours. Regular assessments should continue 4-hourly for 24 hours post-emergence from anaesthesia.
| Escalation trigger | NICE | AGS | RCoA |
|---|---|---|---|
| CAM-positive assessment | Immediate multi-disciplinary review | Geriatrician referral within 4 hours | Anaesthetist review + consider ICU |
| Agitation/aggression | Rapid tranquillisation protocol | Non-pharmacological first then low-dose antipsychotics | Anaesthetic team for sedation review |
| Failed non-pharmacological measures | Psychiatry liaison within 24 hours | Geriatric psychiatry same day | Consider dexmedetomidine infusion |
| Persistent >48 hours | Formal delirium management plan | Comprehensive medication review | Re-evaluate pain management |
| Hypoactive delirium | Regular 4-hour assessments | Geriatrician review within 12 hours | Monitor for airway compromise |
Patient: 78-year-old female, MMSE 25/30, scheduled for elective hip replacement. No previous delirium history.
Analysis: NICE would not mandate prevention (MMSE ≥24), AGS would recommend geriatric assessment (MMSE <26), while RCoA would focus on anaesthetic optimisation. The most appropriate approach combines AGS's comprehensive assessment with RCoA's anaesthetic planning, implementing basic preventive measures given the borderline score.
Patient: 82-year-old male with hypertension, diabetes, mild cognitive impairment (MMSE 22/30), undergoing emergency laparotomy.
Analysis: All three bodies would classify as high-risk. NICE recommends standard multi-component prevention, AGS emphasises geriatric-led optimisation, RCoA focuses on intra-operative management. The optimal approach involves simultaneous implementation of all strategies with geriatrician leadership given the emergency context and multiple vulnerabilities.
Several validated tools assist clinicians in delirium risk stratification:
PRE-DELIRIC: NICE recommends this ICU prediction model for high-risk surgical patients. Calculates delirium risk based on 10 pre-operative and early post-operative factors. AGS suggests modification for geriatric populations by adding frailty measures.
CAM and 4AT: All three bodies endorse these assessment tools. CAM provides diagnostic confirmation, while 4AT offers rapid screening (≤2 minutes). RCoA specifically recommends 4AT in recovery areas for all patients ≥65.
Clinical judgement factors: When formal tools aren't available, consider: polypharmacy (≥5 medications), visual/hearing impairment, dehydration markers, infection presence, and metabolic disturbances. These factors increase predictive accuracy beyond age and cognitive scores alone.
Refer to the full guidelines for exact wording and local adaptations. This summary is for rapid orientation and multidisciplinary alignment.
Disclaimer: This comparison is intended for clinical decision support and education. Always refer to the full published guidelines for definitive recommendations and the most up-to-date evidence. Clinical decisions should be individualised based on patient context and preferences, following local governance frameworks.