postoperative cognitive impairment

Introduction

• cognitive decline that involves selective attention, vigilance, perception, learning, memory, executive function, verbal & language abilities, emotion, visuospatial & visuomotor skills.
• occurs postoperativeltin the absence of cranial trauma or other brain injuries

Etiology

• preexisting cognitive impairment, especially working memory impairment is associated with poor behavioral functional capacity 3 months after cardiac surgery
• postoperative delirium is associated with persistent cognitive impairment
• anesthesia
  • depth of general anesthesia potentially modifiable factor
  • no difference in general anesthesia vs regional anesthesia
  • inhalation anesthesia more likely implicated than intravenous anesthesia
• pharmaceuticals
  • pain management
    • patient-controlled postoperative analgesia independently increases the risk vs oral postoperative analgesia
    • pregabalin, given for postoperative pain, associated with adverse effects on cognition (spatial working memory & executive function)
    • persistent pain can result in cognitive impairment, inattention, memory loss, & information processing.
• high-risk surgeries
  • hip arthroplasty & knee arthroplasty
  • cardiac surgery, especially aortic-coronary bypass, cardiopulmonary bypass
• inhalation anesthesia with isoflurane or sevoflurane confers higher risk than intravenous anesthesia with propofol

Epidemiology

• common in early postoperative period in all age groups
• elderly more commonly suffer long-term cognitive impairment
• 65% of elderly (>= 65 years) experience postoperative delirium & 10% develop long-term cognitive decline after noncardiac surgery
• prevalence of 37% in young adults to 42% in older adults
• old age, less education, previous stroke predict long-term cognitive impairment after non-cardiac surgery

Pathology

• neuroinflammation may occur as a result of perioperative stress
• vascular disorders may contribute to postoperative cognitive impairment
• acceleration of neurocognitive decline may occur in patients with a previously undiagnosed neurodegenerative disorder, mild cognitive impairment or preclinical dementia
• 7% of elderly (>= 65 years) who undergo non-cardiac surgery suffer covert stroke with increased risk of postoperative delirium & long-term cognitive deficits

Clinical manifestations

• prolonged cognitive decline can last for weeks, months, or even years
• most patients return to preoperative cognitive baseline within 3 months
• report of postoperative cognitive impairment for up to 5 years

Complications

• postoperative cognitive impairment may be associated with increased risk of chronic postoperative pain
• decrease in quality of life, loss of function, & increased mortality

Differential diagnosis

• postoperative delirium
• deafness
• dementia
• amnesia

Management

• preoperative screening for frailty & dementia, geriatric consultation for elderly
• preoperative cognitive assessment is the best predictor of risk for postoperative delirium thus risk of peristent cognitive dysfunction
• preoperative physical activity, tobacco cessation, nutrition, & management of hypertension & diabetes improves postoperative outcomes
• preoperative cognitive exercises targeting memory, speed, attention, flexibility, & problem-solving reduces postoperative delirium
• perioperative period avoidance of benzodiazepines, centrally-acting cholinergics, meperidine, phenothiazines, & antipsychotics in the elderly (>= 65 years)
• family-involvement reduces postoperative delirium

More general terms

• cognitive impairment
• postoperative complication

Additional terms

• postoperative delirium