Author: Connor Brenna, MD
The Daily Dose
Perioperative neurocognitive disorders are among the most common complications following anesthesia and surgery, especially in older and medically vulnerable patients. These disorders also provide an important opportunity to understand how anesthetic medications, surgical stress, illness, sleep, and preexisting neurologic disease can combine to impair brain function.
At the 2026 IARS and SOCCA Annual Meeting, three experts discussed post-anesthetic cognitive recovery from clinical, physiologic, and laboratory perspectives.
Stacie Deiner, MD, MS, reviewed the modern classification of cognitive problems occurring after surgery. The older term postoperative cognitive dysfunction, or POCD, was broad and inconsistently defined. Updated terminology now distinguishes among postoperative delirium, delayed neurocognitive recovery, and longer-term postoperative neurocognitive disorders.
Patients’ subjective complaints of cognitive difficulty are important, but they are not specific enough to establish a diagnosis. Researchers must also distinguish cognitive changes caused by surgery from the gradual decline that can occur with normal aging.
The strongest recognized risk factors include preexisting cognitive impairment and frailty. Because there are currently no medications specifically approved to treat perioperative neurocognitive disorders, prevention, early detection, and supportive care remain essential.
Recommended clinical strategies include preoperative cognitive screening, reviewing medications that may increase delirium risk, considering regional anesthesia and dexmedetomidine when appropriate, screening for delirium after surgery, and providing effective pain control. Early mobility, hydration, sleep promotion, orientation, and other nonpharmacologic measures are also important.
Michael Devinney, MD, PhD, examined the relationship between sleep, attention, and postoperative delirium. Sleep disorders before surgery have been associated with an increased risk of delirium, while sleep deprivation can impair attention, one of the main cognitive functions affected during delirium.
However, a secondary analysis of the REPOSE Trial produced an unexpected result. Patients who developed postoperative delirium slept longer and experienced fewer sleep interruptions during the first two postoperative days than patients who did not develop delirium.
Electroencephalographic analysis suggested that much of this additional sleep was N2-stage sleep, with a possible increase in REM sleep. These findings challenge the assumption that more sleep after surgery is necessarily restorative or protective.
The increased sleep observed in delirious patients may instead reflect abnormal regulation of the brain’s arousal pathways. This raises the possibility that future treatments could focus on restoring normal arousal and attention rather than simply increasing sleep duration.
Kathleen Vincent, PhD, described how animal models can help researchers separate the effects of anesthesia from those of surgery and investigate the neural circuits responsible for attention, arousal, and recovery.
Transgenic mouse models of Alzheimer’s disease recovered more slowly from anesthesia than healthy mice. These animals also demonstrated impaired attention and reduced activity.
Researchers then selectively activated dopamine-producing neurons in the ventral tegmental area using chemogenetic techniques known as Designer Receptors Exclusively Activated by Designer Drugs, or DREADDs. Activating these neurons accelerated recovery from anesthesia, even in cognitively vulnerable mice.
Pharmacologic stimulation of the same dopamine pathways with methylphenidate produced similar results. These findings suggest that dopamine-related arousal circuits may eventually become therapeutic targets for improving emergence and cognitive recovery after anesthesia.
The presentations demonstrated how perioperative neuroscience can progress from recognizing clinical patterns to identifying the specific brain circuits responsible for them.
At present, prevention remains the most effective strategy. Clinicians should identify cognitive impairment and frailty before surgery, minimize medications associated with delirium, screen patients after surgery, provide appropriate pain management, and support mobility, hydration, orientation, and normal sleep.
Future treatments may involve medications that directly stimulate or regulate the brain’s arousal systems. Although the animal research is promising, additional human studies will be necessary before dopamine-targeted therapies can be routinely used to accelerate post-anesthetic recovery or prevent perioperative neurocognitive disorders.
Thank you to The Daily Dose and IARS for allowing us to summarize this important discussion on perioperative brain health.