This article notes that almost half of older persons in surgery show delirium during recovery. That isn't all that new, though the percentage is certainly disturbing. My real point in posting it is their conclusion. They think that such delirium is not cause for reexamining their use of general anesthetics. Rather, they believe that the delirium is an indicator for nursing home placement.
Anesthetics are known to produce delirium if you aren't knocked out fast enough, and post recovery confusion is common enough regardless of age. Also, there is more and more evidence that repeated general anesthesia produces long term negative changes in cognition. These findings would suggest a general review of currently available surgical anesthetics, not increased referral to nursing homes.
Delirium occurring early after surgery is linked to decreased cognitive (mental) function and an increased rate of nursing home admission, according to the study by Dr Karin J. Neufeld of Johns Hopkins University and colleagues. They write, "Recognizing delirium in the PACU may be important for identifying patients at higher risk of in-hospital harms...as well as cognitive impairment and institutionalization at hospital discharge."