Is "pump head" syndrome for real?
That's the term used to describe the temporary memory loss, blurred vision and slurred speech that occurs in some patients who undergo a heart-bypass operation.
Some medical experts believe the mental confusion results from patients being hooked up to a heart-lung machine, which is used to pump blood and supply the body with oxygen while the heart is stopped during surgery. They think the machine, or so-called "pump," somehow alters the blood so that brain functions are impaired for a prolonged period after surgery. One research team has raised concerns it may cause permanent brain damage.
But a new study suggests that pump head syndrome doesn't exist – or, at least, the heart-lung machine can't be blamed for any cognitive problems observed in patients following surgery.
Researchers at the Johns Hopkins University's school of medicine in Baltimore compared the mental state of patients who had surgery either on or off the pump.
That means some patients underwent standard heart-bypass surgery while connected to the pump. For the other patients, doctors performed a more complex procedure in which they operated on the heart while it continued to beat on its own, eliminating the need for the heart-lung machine.
(During heart bypass surgery, blood vessels removed from elsewhere in the body are grafted to the outside of the heart in order to supply the heart muscle with adequate blood flow to areas where existing arteries are blocked or restricted.)
According to the findings published in Annals of Thoracic Surgery, "there was no difference in the cognitive outcomes between the two procedures, either in the short term or the long term," lead researcher Ola Selnes said.
That's not to say that some patients don't experience confusion immediately following surgery. After all, an operation can be stressful on the body and the mind.
However, Dr. Selnes said, "we're pretty confident the pump itself is probably not a major culprit."
He added that certain patients may have other health problems – such as restricted blood vessels in the brain – that make them prone to feeling disoriented after a major operation. For the most part, though, the side effects are temporary.
The study "ought to reassure patients … and help remove some of the stigma from conventional bypass surgery," Dr. Selnes said.