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For clinicians

Delirium and thinking after surgery in older adults

What postoperative delirium and cognitive change are, and what trials of anesthesia type, brain monitoring and medicines have found.

3 minute read, written for clinicians7 sources, each checked word for wordLibrary checked October 18, 2026

A hospital room with an infusion pump and an empty bed

This is the clinician view. It keeps every sentence of the plain guide and adds, for each section, the study design and citations of its sources. Every added sentence is cited and checked like the rest. Back to plain language.

In short

  • Research has documented declines in thinking in older adults after anesthesia and surgery, sometimes identified years later.E2Good1
  • Delirium was similar after spinal and general anesthesia for hip fracture surgery.E1Strong2
  • Brain-wave-guided anesthesia and a single dose of ketamine did not reduce delirium in trials.E1Strong3,4

How sure each claim is:E1StrongE2GoodOfficial textReviewWhat the grades meanUnderlined words open a definition

What are delirium and postoperative cognitive change?

Studies have consistently documented declines in thinking in older patients after anesthesia and surgery, with changes identified up to 7.5 years afterwards.E2Good1

An international working group proposed the umbrella term perioperative neurocognitive disorders. It covers postoperative delirium (an acute event), delayed neurocognitive recovery (up to 30 days), and postoperative neurocognitive disorder (up to 12 months).E2Good1

The American Geriatrics Society publishes guidance on preventing postoperative delirium in older people at risk and on treating it.E2Good5

The evidence in this section (2 sources)
SourceDesignGradeCitations (NIH iCite)
1 Evered L, Br J Anaesth, 2018Consensus statementE2Good698 (RCR 33.38)
5 American Geriatrics Society Expert Panel on Postoperative Delirium in Older Adults, J Am Geriatr Soc, 2015GuidelineE2Good384 (RCR 18.98)

What have trials found?

Type of anesthesia. In older adults having hip fracture surgery, delirium was similar with spinal and with general anesthesia.E1Strong2

Brain monitoring. In the ENGAGES trial, adjusting anesthesia to brain-wave (EEG) monitoring did not lower delirium after major surgery compared with usual care.E1Strong3

Ketamine. In the PODCAST trial, a single low dose of ketamine did not reduce delirium in older adults after major surgery. It might cause harm through negative experiences.E1Strong4

Dexmedetomidine. In people over 65 admitted to intensive care after noncardiac surgery, low-dose dexmedetomidine significantly reduced delirium in the first 7 days.E1Strong6

Nerve blocks for hip fracture. A Cochrane review found that nerve blocks reduce acute confusion in adults with hip fracture.E1Strong7

The evidence in this section (5 sources)
SourceDesignGradeCitations (NIH iCite)
2 Neuman MD, N Engl J Med, 2021Randomized trialE1Strong372 (RCR 34.2)
3 Wildes TS, JAMA, 2019Randomized trialE1Strong380 (RCR 25.18)
4 Avidan MS, Lancet, 2017Randomized trialE1Strong371 (RCR 20.73)
6 Su X, Lancet, 2016Randomized trialE1Strong620 (RCR 30.18)
7 Guay J, Cochrane Database Syst Rev, 2020Systematic reviewE1StrongNot tracked

What is not known yet

Many hoped-for preventive steps, from anesthesia type to brain monitoring, have not reduced delirium in trials.E1Strong2,3

Questions you might bring to your anesthesia team

  1. What is my loved one's risk of delirium, and what will the team do to lower it?
  2. Can family stay, and bring glasses, hearing aids and familiar items?
  3. Is a nerve block part of the pain plan?
  4. What signs of confusion should we report after surgery?

Every claim in this guide was written from its sources and checked against them word for word. Its clinical review by Dr. Recio, a practicing nurse anesthesiologist (CRNA), is pending. This line changes when the review is done.

Sources

Each source opens on PubMed, DailyMed or the publisher's page. Under each one are the exact words from it that this page relies on, copied word for word and checked against the original.

  1. Recommendations for the nomenclature of cognitive change associated with anaesthesia and surgery-2018. Evered L, Br J Anaesth, 2018. E2Good Consensus statementPMID 30336844; DOI 10.1016/j.bja.2017.11.087; cited 698 times, relative citation ratio 33.38 (NIH iCite, 2026-10-18)
    The words this page rests on
    This body of work consistently documented decline in cognitive function in elderly patients after anaesthesia and surgery, and cognitive changes have been identified up to 7.5 yr afterwards.
    The working group recommends that 'perioperative neurocognitive disorders' be used as an overarching term for cognitive impairment identified in the preoperative or postoperative period. This includes cognitive decline diagnosed before operation (described as neurocognitive disorder); any form of acute event (postoperative delirium) and cognitive decline diagnosed up to 30 days after the procedure (delayed neurocognitive recovery) and up to 12 months (postoperative neurocognitive disorder).
  2. Spinal Anesthesia or General Anesthesia for Hip Surgery in Older Adults. Neuman MD, N Engl J Med, 2021. E1Strong Randomized trialPMID 34623788; DOI 10.1056/NEJMoa2113514; cited 372 times, relative citation ratio 34.2 (NIH iCite, 2026-10-18)
    The words this page rests on
    Spinal anesthesia for hip-fracture surgery in older adults was not superior to general anesthesia with respect to survival and recovery of ambulation at 60 days. The incidence of postoperative delirium was similar with the two types of anesthesia.
  3. Effect of Electroencephalography-Guided Anesthetic Administration on Postoperative Delirium Among Older Adults Undergoing Major Surgery: The ENGAGES Randomized Clinical Trial. Wildes TS, JAMA, 2019. E1Strong Randomized trialPMID 30721296; DOI 10.1001/jama.2018.22005; cited 380 times, relative citation ratio 25.18 (NIH iCite, 2026-10-18)
    The words this page rests on
    Among older adults undergoing major surgery, EEG-guided anesthetic administration, compared with usual care, did not decrease the incidence of postoperative delirium.
  4. Intraoperative ketamine for prevention of postoperative delirium or pain after major surgery in older adults: an international, multicentre, double-blind, randomised clinical trial. Avidan MS, Lancet, 2017. E1Strong Randomized trialPMID 28576285; DOI 10.1016/S0140-6736(17)31467-8; cited 371 times, relative citation ratio 20.73 (NIH iCite, 2026-10-18)
    The words this page rests on
    A single subanaesthetic dose of ketamine did not decrease delirium in older adults after major surgery, and might cause harm by inducing negative experiences.
  5. American Geriatrics Society abstracted clinical practice guideline for postoperative delirium in older adults. American Geriatrics Society Expert Panel on Postoperative Delirium in Older Adults, J Am Geriatr Soc, 2015. E2Good GuidelinePMID 25495432; DOI 10.1111/jgs.13281; cited 384 times, relative citation ratio 18.98 (NIH iCite, 2026-10-18)
    The words this page rests on
    The abstracted set of recommendations presented here provides essential guidance both on the prevention of postoperative delirium in older patients at risk of delirium and on the treatment of older surgical patients with delirium, and is based on the 2014 American Geriatrics Society (AGS) Guideline.
  6. Dexmedetomidine for prevention of delirium in elderly patients after non-cardiac surgery: a randomised, double-blind, placebo-controlled trial. Su X, Lancet, 2016. E1Strong Randomized trialPMID 27542303; DOI 10.1016/S0140-6736(16)30580-3; cited 620 times, relative citation ratio 30.18 (NIH iCite, 2026-10-18)
    The words this page rests on
    For patients aged over 65 years who are admitted to the intensive care unit after non-cardiac surgery, prophylactic low-dose dexmedetomidine significantly decreases the occurrence of delirium during the first 7 days after surgery. The therapy is safe.
  7. Peripheral nerve blocks for hip fractures in adults. Guay J, Cochrane Database Syst Rev, 2020. E1Strong Systematic reviewPMID 33238043
    The words this page rests on
    PNBs reduce pain on movement within 30 minutes after block placement, risk of acute confusional state, and probably also reduce the risk of chest infection and time to first mobilization.