For some seniors, surgery can cause cognitive health loss

Two years ago, 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 percent.”

His father probably 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 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.

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.

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?

Some clarity should come in June, when a major paper outlining standard definitions for POCD is set to be published and when scientists will meet at a two-day POCD summit, according to Eckenhoff.

Here’s what scientists know about POCD:

• Background: POCD was first studied systematically about 20 years ago. But reports of patients who appeared cognitively compromised after having 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 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 in 1999 suggested that 25.8 percent of patients had this condition one week after a major non-cardiac surgery, such as a hip replacement, while 9.9 percent had it three months after surgery.

Two years later, a study by researchers at Duke University Medical Center found that 53 percent of adults who had heart-bypass surgery showed significant evidence of cognitive decline when they were discharged from the hospital; 36 percent were affected at six weeks; 24 percent, at six months; and 42 percent, five years after their operations.

Another Duke study of older adults who had knee and hip replacements found that 59 percent had cognitive dysfunction immediately after surgery; 34 percent, at three months; and 42 percent, at two years.

Other studies have produced different estimates. A project examining adults 55 and older who have major non-cardiac surgeries is finding that “upwards of 30 percent of patients are testing significantly worse than their baseline 3 months later,” according to its lead researcher, Stacie Deiner of 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 as are younger adults to develop POCD.

“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.