There are many unanswered questions about
postoperative cognitive dysfunction, or POCD.
Two years ago, Dr.
Daniel Cole’s 85-year-old father had heart bypass surgery. He hasn’t been quite
the same since.
“He forgets things
and will ask you the same thing several times,” said Cole, a professor of
clinical anesthesiology at UCLA and a past president of the American Society of
Anesthesiologists.
“He never got back to
his cognitive baseline,” Cole continued, noting that his father was sharp as a
tack before the operation. “He’s more like 80%.”
The man likely
has postoperative cognitive
dysfunction (POCD)
— a little-known condition that affects a substantial number of older adults
after surgery, Cole said.
Some patients with
POCD experience memory problems; others have difficulty multitasking, learning
new things, following multistep procedures or setting priorities.
“There is no single
presentation for POCD. Different patients are affected in different ways,” said
Dr. Miles Berger, a POCD specialist and assistant professor of anesthesiology
at Duke University School of Medicine.
Unlike delirium — an
acute, sudden-onset disorder that affects consciousness and attention — POCD
can involve subtle, difficult-to-recognize symptoms that develop days to weeks
after surgery.
Unlike delirium — an acute, sudden-onset disorder that
affects consciousness and attention — POCD can involve subtle, difficult-to-recognize
symptoms.
Most of the time,
POCD is transient and patients get better in several months. But sometimes —
how often hasn’t been determined — this condition lasts up to a year or longer.
Dr. Roderic
Eckenhoff, vice chair for research and a professor of anesthesiology at the
Perelman School of Medicine at the University of Pennsylvania, told of an email
he received recently from a 69-year-old man who had read about his research.
“This guy — a very
articulate man — said he was the intellectual equal of his wife before a
surgery 10 years ago, a significant operation involving general anesthesia.
Since then, he’s had difficulty with cognitively demanding tasks at work, such
as detailed question-and-answer sessions with his colleagues,” Eckenhoff said.
“He noticed these changes immediately after the surgery and claims he did not
get better.”
There are many
unanswered questions about POCD. How should it best be measured? Is it truly a
stand-alone condition or part of a continuum of brain disorders after surgery?
Can it be prevented or treated? Can it be distinguished in the long term from
the deterioration in cognitive function that can accompany illness and advanced
aging?
Here’s what
scientists currently know about POCD:
Background
POCD first began to
be studied systematically about 20 years ago. But reports of patients who
appeared cognitively compromised after surgery date back about 100 years,
Eckenhoff said.
An influential 1955 report in The
Lancet noted
common complaints by family or friends after someone dear to them had surgery:
“He’s become so forgetful. … She’s lost all interest in the family. … He can’t
concentrate on anything. … He’s just not the same person since.”
How to recognize the condition
There is no short,
simple test for POCD. Typically, a series of neuropsychological tests are
administered before and after surgery — a time-consuming process. Often, tests
are given one week and again three months after surgery. But the tests used and
time frames differ in various studies. Studies also define POCD differently,
using varying criteria to assess the kind and extent of cognitive impairment
that patients experience.
How common is it?
The first international study of older adults
with POCD (those age 60 and older) in 1999 suggested that 25.8% of patients had
this condition one week after a major non-cardiac surgery, such as a hip
replacement, while 9.9% had it three months after surgery.
Two years
later, a study by researchers at Duke
University Medical Center, published in the New England Journal of Medicine,
found that 53% of adults who had heart bypass surgery showed significant
evidence of cognitive decline when they were discharged from the hospital; 36%
were affected at six weeks; 24%, at six months; and 42%, five years after their
operations.
Another Duke study of older adults
who had knee and hip replacements found that 59% had cognitive dysfunction
immediately after surgery; 34%, at three months; and 42%, at two years.
Other studies have
produced different estimates. A current research project examining adults 55
and older who have major non-cardiac surgeries is finding that “upwards of 30%
of patients are testing significantly worse than their baseline 3 months
later,” according to its lead researcher, Dr. Stacie Deiner, vice chair for
research and associate professor of anesthesiology, geriatrics and palliative
care, and neurosurgery at the Icahn School of Medicine at Mount Sinai in New
York City.
Vulnerabilities
The risk of
experiencing POCD after surgery is enhanced in those who are older, have low
levels of education or have cognitive concerns that predate surgery. Adults age
60 and older are twice as likely to develop POCD as are younger adults — a
development that increases the risk of dying or having a poor quality of life
after surgery.
“People who are
older, with some unrecognized brain pathology, or people who have some
trajectory of cognitive decline at baseline, those are the patients who you’re
going to see some change in one, two or three years out,” said Charles Hugh
Brown IV, assistant professor of anesthesiology and critical care medicine at
Johns Hopkins Medicine.
Researchers have
examined whether the type of anesthetic used during surgery or the depth of
anesthesia — the degree to which a patient is put under — affects the risk of
developing POCD. So far, results have been inconclusive. Also under
investigation are techniques to optimize blood flow to the brain during
surgery.
Mechanisms at work
What’s responsible
for POCD? The drugs administered during anesthesia or the surgery itself?
Currently, the evidence implicates the stress of surgery rather than the
anesthesia.
“Most surgery causes
peripheral inflammation,” Eckenhoff explained. “In young people, the brain
remains largely isolated from that inflammation, but with older people, our
blood-brain barrier becomes kind of leaky. That contributes to
neuroinflammation, which activates a whole cascade of events in the brain that
can accelerate the ongoing aging process.”
At Mount Sinai,
Deiner has been administering two-hour-long general anesthesia to healthy
seniors and evaluating its impact, in the absence of surgery. Older adults are
getting cognitive tests and brain scans before and after. While findings
haven’t been published, early results show “very good and rapid cognitive
recovery in older adults after anesthesia,” Deiner said. The implication is
that “the surgery or the medical conditions surrounding surgery” are
responsible for subsequent cognitive dysfunction, she noted.
Advice
Currently, most
patients are not told of the post-surgical risk of POCD during the process of
informed consent. That should change, several experts advise.
“Beyond question,
patients should be informed that the ‘safety step’ of not undergoing surgery is
theirs to choose,” wrote Dr. Kirk Hogan, professor of anesthesiology at the
University of Wisconsin-Madison School of Medicine and Public Health, in
an article published
earlier this year.
“Each patient must determine if the proposed benefits of a procedure outweigh
the foreseeable and material risks of cognitive decline after surgery.”
“Surgery is a good
thing — it improves quality of life — and most older patients do really well,”
said Brown of Hopkins. “Our trick is to understand who we really need to
identify as high-risk and what we can do about modifiable factors.
“If you’re older and
suspect you have cognitive issues, it’s important to let your family physician
as well as your surgeon and anesthesiologist know that you’re concerned about
this and you don’t want to get worse. That should open up a conversation about
the goals of surgery, alternatives to surgery and what can be done to optimize
your condition before surgery, if that’s what you want to pursue.”
“We want people to
know this does happen but not be too concerned because, typically, it does go
away,” said Eckenhoff. “That said, don’t try to make cognitively demanding
decisions in the first 30 days after an operation. And make sure your
caregivers are prepared to help with anything from paying bills and balancing
the checkbook to ensuring that you’re caring for yourself adequately and
communicating well with your doctor.”
Kaiser Health News is a nonprofit
news service covering health issues. It is an editorially independent program
of the Kaiser Family Foundation, which is not affiliated with Kaiser
Permanente.
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