Post Op Delirium

• General Population Risk is 2.5 – 3% risk
• Increases with age, greater than 60 is at 10-20% risk 
• Other risk factors: Emergency surgery, complex surgery, femur fracture

• 30-day mortality increases if post op delirium is present by 7-10%
• Increase risk for functional decline as well.
• Increase cost by 2k-8k per case

Theories:

1. Neuroinflammation with increased neuromediations such as CRP, IL6
2. Neurotransmitters some research showing lower Ach activity
3. Subclinical CVAs with studies showing 7-10% radiological evidence without signs or symptoms of CVAs

Mangement: 

• Most ideal is itenfidying high risk and reducing the risk 

• Pre-op:
  • Avoid polypharmacy which is an independent  risk factor
  • Avoid prolong fluid (>6h) fasting
  • Multi-disciplinary team with complex geriatric assessment
  • Pre-op pain control
• Intra Operative
  • Depth of anesthesia
    • Consider BIS
  • Multimodal Opioid Sparing Analgesia
    • Increased post op pain increased risk for delirium
    • Use of opioids increase risk
    • Utilize regional or neuraxial when appropriate
  • NSAIDS
    • Decreased pain and inflammation including the theorized neuroinflammation
  • Dexmedetomidine
    • Neuroprotective in animal studies with decreased inflammatory markers (cortisol, CRP, TNF alpha)
    • Improves sleep disturbances (associated with delirium)
    • 18 clinical trials showing decreased delirium
  • Other Perioperative medications
    • Increased delirium with TCA, antihistamines, benzodiazepines, scopolamine, gabapentin
    • Some evidence showing subhyptnoic dose ketamine could improve post op delirium
    • Dexamethasone decreases inflammation
    • Melatonin 
  • Choice of General
    • Volatile has been theorized to exacerbate neuroinflmamation however observational studies haven’t demonstrated vs IV medications
    • Xenon showed neuro protective in animal studies
  • Fluids
    • Goal directed fluid therapy
    • Blood products can worsen due to systemic inflammation
• Post O
  • Nonpharm
    • Re-orientation, natural light, time keeping indicators (clocks, date)
  • Pharm
    • Antipyschotics
      • Some data supporting dopamine antagonists could improve use more as a rescue. Second generation better tolerated than first generation
    • Avoid Benzodiazepines which was the prior first line rescue treatment