Postoperative Delirium in the older patient'

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Postoperative Delirium in the older patient.

• Topic review 26/5/48
• Suthinee Ithimakin, MD

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Postoperative delirium

• Acute disorder of cognition and attention after
  operation
• Anytime in perioperative period
• Most commonly occurs during postsurgical period
• Underdiagnosed 78
• 40 routinely screen for delirium

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Postoperative delirium

• Associated with
• Poor cognitive and functional recovery
• Longer hospital stay
• Greater hospital costs
• Risk factor for institutionalization and
  morbidity
• Reduced risk by early identification, assessment
  and treatment

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Incidence/ prevalence

• ¼ of adult older than 65 year experience delirium
  during hospitalization
• Wide range estimate of postoperative delirium
  pending on type of operation
• Delirium is likely to increase in future

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Pathogenesis

• CNS changes with age
• Loss of nerve cells
• Decreased in cerebral blood flow
• Changes in neurotransmitter system
• Decreased acetylcholinesterase activity
• Carbonic anhydrase activity
• Muscarinic receptor
• Serotonin receptors

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Pathogenesis

• Abnormal levels of endorphins, serotonin,
  neuropeptides in CSF
• EEG slowing of dominant posterior alpha rhythm
  and abnormal slow wave activity

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Cause of CNS dysfunction after surgery
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Risk factors
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Risk factors

• Older age
• Cognitive impairment
• Functional impairment
• Decreased postoperative hemoglobin
• Markedly abnormal sodium, potassium and glucose
• Alcohol abuse
• Noncardiac thoracic operation
• History of delirium
• Preoperative used of narcotic
• Preoperative used of benzodiazepine
• Low postoperative oxygen saturation
• History of cardiovascular disease
• Untreated pain

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Drug associated with delirium

• Drugs with anticholinergic activity
• Tricyclic antidepressants
• Cimetidine
• Corticosteroids
• Digoxin
• Diphenhydramine
• Belladonna
• Dipyridamole
• Theophylline
• Promethazine
• Amantadine
• Oxybutyrin

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Drugs associated with delirium

• Analgesics
• Narcotics (especially meperidine)
• NSAIDs
• Benzodiazepines
• Antiparkinsonian agents

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Diagnosis
Modified from Diagnostic and Statistical Manual
of Mental Disorder, 4TH ed
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features depression delirium
dementia
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Clinical features

• Change of consciousness and recognition
• Cognitive abnormalities
• Disorientation
• Language difficulty
• Impairment of learning and memory

Fluctuating course
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Clinical features

• Emotional disturbances
• Anxiety
• Fear
• Anger
• Irritability
• Depression

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Clinical features

• 4 different types
• Hypoactive delirium
• Hyperactive delirium
• Mixed delirium
• Delirium without psychomotor change

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History

• Description of patients behavior
• Earlier episode of delirium
• Evidence of cognitive impairment
• Information to rule out alcohol or drug withdrawal

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Physical examination

• Vital signs
• Oxygen saturation
• Sign of trauma or infection
• State of hydration
• New neurological signs

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Confusion assessment method
Sensitivity 94-100 Specificity 90-95
Item 1 and 2 and 3 or 4
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Diagnostic tests

• To identify potentially correctable factors
• CBC, electrolytes, creatinine, glucose, and
  urinalysis
• Neuroimaging may be used selectively

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Prevention

• Tarketing modifiable risk factors prevent some
  case of delirium
• Standardized protocols of known risk factors for
  delirium
• Reduction in delirium episodes (15?9.9)
• No effect on delirium severity and rate of
  recurrence

Sleep deprivation Immobility Dehydration Visual
impairment Cognitive impairment Hearing
impairment
N Engl J Med 1999340669-676
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Prevention

• Patients with fracture neck of femur
• Outcome Postoperative delirium ??
• Pre and postoperative geriatric assessments,
• Oxygen therapy
• Early operation
• Prevention treatment of perioperative BP fall
• Treatment of postoperative complication

J Am Geriatr Soc 199139655-62
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Prevention
Interventions
Decreased postoperative delirium from 61 to 48
J Am Geriatr Soc 199139655-62
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Prevention

• Identify and reduce risk factors can decrease
  postoperative delirium in elderly
• Preoperative educate the patients

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Management
Identify causes and treat

• Treat contributing illness
• Providing supportive measures
• Symptom control

Safe environment Appropiate stimulation Nutrition
Reserve for agitated or disruptive individuals
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Supportive measures
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Medication for symptom control

• Antipsychotics
• Haloperidol or newer antipsychotic agent ??
• Goal is to control disruptive symptoms and avoid
  obtundation
• Taper in 3-5 days
• Benzodiazepine
• Paradoxical agitation
• Treat withdrawal from alcohol of sedative drugs

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Prevention and treatment of postoperative delirium
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Outcome

• Sequels of delirium can persist for 6 months
• Risk for future cognitive decline
• Associated with increase mortality (10-65)
• Longer hospital stay and higher nursing home
  placement

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Outcomes of delirium

• Relationship between delirium and dementia in 3
  years with 203 patients age 65 in medical
  services

Incidence of dementia
5.6 per year in patient without delirium 18.1
per year in delirium group
Age aging 199928551-556
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Outcomes of delirium

• 78 patients with femoral neck fractures

Postoperative delirium
Without Postoperative delirium
5 years
20
69
Dementia
J Am Geriatr Soc 2003511002-1006
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Conclusion

• Risk of postoperative delirium can be reduced
  with careful attention to risk factors
• Intervention to target problems
• Systemic approach to diagnostic workup
• Early identification, assessment and management