Postoperative Delirium

Intro & Risk Factors - Delirium Drama Unveiled

Postoperative Delirium (POD): Acute confusional state. Fluctuating course, inattention, disorganized thinking/altered consciousness. Common, serious. ↑Morbidity, ↑mortality, ↑length of stay (LOS), ↑costs, potential long-term cognitive decline.

Risk Factors:

• Predisposing (Patient-Specific):
  • Age >65 years
  • Pre-existing cognitive impairment (e.g., dementia)
  • History of delirium
  • Sensory impairment (vision/hearing)
  • Multiple comorbidities / Frailty
  • Alcohol/substance use history
• Precipitating (Perioperative/Hospital):
  • Type of surgery (major, emergency, cardiac, orthopedic)
  • Culprit drugs: 📌 BOA (Benzodiazepines, Opioids, Anticholinergics)
  • Uncontrolled pain
  • Infections (UTI, pneumonia)
  • Metabolic disturbances (hypoxia, electrolytes)
  • Sleep deprivation, ICU environment
  • Use of physical restraints, catheters

⭐ > Advanced age (>65 years) is a primary non-modifiable risk factor for POD.

Pathophysiology & Etiology - Neuro-Chaos Culprits

• Multifactorial Origin: Patient vulnerability (e.g., advanced age, prior cognitive impairment) meets precipitating factors (e.g., major surgery, specific drugs, infection).
• Neurotransmitter Dysregulation:
  • Acetylcholine (ACh) ↓: Central cholinergic deficiency; critical for attention & memory.
  • Dopamine (DA) ↑: Often reciprocal to ACh levels; linked to agitation & psychosis.
  • Others: Serotonin, GABA, norepinephrine imbalances contribute.
• Neuroinflammation:
  • Systemic inflammation (e.g., post-surgery, sepsis) → ↑pro-inflammatory cytokines (IL-1β, IL-6, TNF-α).
  • Microglial cell activation & blood-brain barrier (BBB) disruption ensue.
• Network Disruption: Impaired brain connectivity & functional integration among neural networks.
• Other Contributing Factors: Cerebral hypoxia, metabolic derangements (electrolytes, glucose), ↑cortisol (stress response).

⭐ Central cholinergic deficiency is a cornerstone theory in the pathophysiology of postoperative delirium, highlighting the importance of acetylcholine in maintaining normal cognitive function.

Clinical Features & Diagnosis - Confusion Clue Hunt

• Core Features: Acute onset, fluctuating course, inattention, disorganized thinking, altered level of consciousness.
• Associated Symptoms:
  • Perceptual disturbances (hallucinations, illusions)
  • Sleep-wake cycle disruption
  • Psychomotor changes (agitation or retardation)
  • Emotional lability
• Diagnosis: Primarily clinical.
  • Standardized tools:
    • CAM (Confusion Assessment Method) - most common.
    • CAM-ICU for ventilated patients.
    • 4AT
  • Key: Rule out mimics (hypoxia, hypoglycemia, sepsis, stroke, drug effects).
  • 📌 DELIRIUMS Mnemonic: Drugs, Electrolyte imbalance, Lack of drugs (withdrawal), Infection, Reduced sensory input/Retention, Intracranial, Urinary/fecal retention, Myocardial/Pulmonary.

⭐ CAM diagnostic algorithm requires: 1) Acute onset & fluctuating course AND 2) Inattention, PLUS EITHER 3) Disorganized thinking OR 4) Altered level of consciousness.

Prevention & Management - Mind Menders' Manual

Prevention: 📌 Multicomponent Interventions

• Optimize pain management: Multimodal, opioid-sparing.
• Medication review: Avoid/minimize high-risk drugs (e.g., benzodiazepines, anticholinergics).
• Promote sleep: Maintain sleep-wake cycles, minimize nighttime disruptions.
• Early mobilization & activity.
• Sensory aids: Ensure use of glasses, hearing aids.
• Cognitive orientation: Frequent reorientation, familiar environment.
• Hydration & nutrition: Maintain.
• Prevent/treat infection, hypoxia, electrolyte imbalances.

Management Flowchart:

Pharmacological (Judicious Use):

• Haloperidol: 0.5-1 mg IV/IM/PO (max 3-5 mg/24h). ⚠️ Monitor QTc.
• Atypical antipsychotics (e.g., Risperidone 0.25-0.5 mg, Olanzapine 2.5-5 mg).
• Dexmedetomidine: Option for ICU delirium, especially if ventilated; less respiratory depression.

⭐ Benzodiazepines are generally contraindicated in non-alcohol/sedative withdrawal delirium as they can worsen it.

High‑Yield Points - ⚡ Biggest Takeaways

• Postoperative delirium: acute, fluctuating mental status change, especially in elderly post-surgery.
• Core features: inattention, disorganized thinking, altered consciousness, and perceptual disturbances.
• Key risks: advanced age, prior cognitive impairment, polypharmacy, major surgery (cardiac/orthopedic).
• Prevention: Multicomponent non-pharmacological strategies are paramount (reorientation, sleep, mobilization).
• Management: Treat underlying cause(s); low-dose antipsychotics for severe agitation; strictly avoid benzodiazepines.
• Prognosis: Linked to ↑morbidity, ↑mortality, prolonged hospital stay, and potential long-term cognitive decline.