POSTOPERATIVE cognitive dysfunction or decline (POCD)
refers to decline in a variety of neuropsychological domains,
including memory, executive functioning, and speed of
processing, and should be distinguished from postoperative
delirium, which is an acute confusional state with
alterations in attention and consciousness.
The term
POCD has been described in the literature to include
acute (1 week), intermediate (3 months), and long-term
(1–2 yr) cognitive decline after surgery. The incidence of
POCD after major noncardiac surgery has been estimated
to be between 7% and 26%.For those who
experience POCD, the onset of cognitive decline likely
occurs soon after surgery, but is this condition reversible,
or does surgery and anesthesia accelerate further long-term
decline in cognitive status? Evidence for the
latter theory might be particularly important to the understanding
of the cause of cognitive decline in Alzheimer
disease, because the pathophysiology of this neurodegenerative
condition is not completely understood.
Specifically, if precipitating factors relating to surgery
and/or anesthesia can be identified that lead to POCD,
interventions can be designed to minimize the occurrence
of POCD. This issue of ANESTHESIOLOGY contains a
study by Avidan et al.5 providing a challenge to the
prevailing notion that long-term POCD is directly related
to the surgical event.