Research seeks to clear the fog of post operative cognitive dysfunction.
As a clinician, Lori Daiello F’08 ScM’12, PharmD, worked with countless families struggling to care for loved ones suffering from dementia and Alzheimer’s disease. She says she’d hear things like, “‘Mom’s memory was fine until after she had that knee replacement, or that shoulder surgery.’” The frequency of the complaints “really concerned me,” Daiello adds. “So I thought, well, maybe I’ll do research.”
Previous studies found that up to 45 percent of senior patients experience postoperative delirium (POD): temporary confusion, disorientation, and memory or attention problems during the week following surgery. Postoperative cognitive dysfunction (POCD), meanwhile, affects 5 to 55 percent of patients and may not be apparent until several months after they leave the hospital.
Although most patients with POCD will return to normal within six months of surgery, studies also showed that up to 15 percent will experience “a more serious condition that can lead to persistent problems with memory or thinking,” says Daiello, a researcher at the Rhode Island Hospital Alzheimer’s Disease and Memory Disorders Center.
Anesthesia appeared to be the reason some patients’ cognitive abilities declined after surgery. But recent research indicates it’s probably not the primary cause. “So if it isn’t anesthesia, what is it?” Daiello wondered.
The answer may lie in the blood-brain barrier, which is supposed to prevent noxious substances in the blood from entering the brain. However, for reasons that are unclear, the blood vessels that form this protective structure can become damaged over time. Daiello says that in some people, the combination of a “leaky” blood-brain barrier and high concentrations of certain inflammatory proteins found in the bloodstream after surgery may be at least partly responsible for postoperative cognitive problems.
Now Daiello, an associate professor of neurology and of health services, policy, and practice (research), can test the hypothesis, thanks to a $3.8 million grant from the National Institutes of Health.
Over the next five years, she and her team will scan the brains of 200 people undertaking major surgery, before and then three months after their operations. The researchers will also conduct paper-and-pencil memory tests and study inflammatory factors in the blood.
Anesthesia isn’t “entirely off the hook” as a possible contributor to memory loss, Daiello says. But she hopes that this research might help scientists find ways to prevent postoperative cognitive problems in senior surgical patients.