Postoperative delirium may be linked to prolonged loss of cognitive function in cardiac surgery patients, according to a study.
The findings suggest interventions to prevent delirium in advance of surgery could help cardiac patients avoid long-term cognitive consequences, according to researchers with the University of Massachusetts Medical School, Beth Israel Deaconess Medical Center and the Aging Brain Center at Hebrew SeniorLife.
Delirium is one of the most common complications in hospitalized patients over age 65. "Our findings now suggest that postoperative delirium, once thought of as an acute, transient cognitive disorder, may have longer-term effects on cognitive function in patients undergoing cardiac surgery," Jane Saczynski, PhD, assistant professor of medicine at the University of Massachusetts Medical School, said in a news release.
Although delirium has been studied extensively in other patient populations, including general medical and surgical patients and orthopedic surgery patients, few studies of delirium have targeted cardiac surgery patients, the researchers noted.
"With the aging of the patient population undergoing cardiac surgery and increases in survival after surgery, clinicians and patients are increasingly concerned with factors associated with quality of life, including cognitive status, as major outcomes of surgery," the authors wrote. "Whether postoperative delirium is associated with prolonged cognitive dysfunction has been unclear."
The researchers followed 225 patients, ages 60 to 90, for one year after their surgeries, assessing them for both delirium and cognitive impairment. The patients had undergone either coronary artery bypass grafting or heart valve replacement surgery at Beth Israel Deaconess Medical Center, UMass Memorial Medical Center or the Boston VA Medical Center.
The results showed that compared with patients who did not experience delirium, the 103 patients (46%) who developed delirium after cardiac surgery experienced a more significant drop in cognitive performance immediately following surgery, as determined by the Mini-Mental State Examination.
Those patients also took significantly longer to regain their presurgical level of function than did patients who did not develop delirium. For example, five days after surgery, nearly half of those who did not develop delirium had returned to preoperative levels of function, compared with less than 20% of those who did develop delirium. Six months after surgery, more than three-quarters of those without delirium had recovered cognitively, compared with only 60% of those with delirium.
Although patients who developed delirium took longer to recover to their preoperative levels of cognitive performance, they continued to improve in the weeks and months after surgery. Cognitive performance reached preoperative levels and stabilized one month after surgery in patients who did not develop delirium, but continued to improve until six months after surgery in those with delirium.
These findings suggest that identifying patients at high risk for delirium before surgery and promoting the use of interventions to prevent delirium in cardiac surgical patients may have substantial benefits. Such a practice could improve the recovery rate of cognitive abilities and enhance functional recovery following surgery.
Further cognitive screening at discharge may also identify patients who require closer, postoperative monitoring or tailored transitional care to enhance the return of cognitive functions.
"Since patients who experience delirium continue to show improvement in cognitive function six months after surgery, extending additional rehabilitation services to these patients may have added benefits," said co-senior author Richard N. Jones, ScD, director of mental health and aging at Hebrew SeniorLife and assistant professor of medicine at Harvard Medical School.
The study appears in the July 5 issue of the New England Journal of Medicine. To read the abstract and access the study via subscription or purchase, visit http://bit.ly/LklS5n.
The findings suggest interventions to prevent delirium in advance of surgery could help cardiac patients avoid long-term cognitive consequences, according to researchers with the University of Massachusetts Medical School, Beth Israel Deaconess Medical Center and the Aging Brain Center at Hebrew SeniorLife.
Delirium is one of the most common complications in hospitalized patients over age 65. "Our findings now suggest that postoperative delirium, once thought of as an acute, transient cognitive disorder, may have longer-term effects on cognitive function in patients undergoing cardiac surgery," Jane Saczynski, PhD, assistant professor of medicine at the University of Massachusetts Medical School, said in a news release.
Although delirium has been studied extensively in other patient populations, including general medical and surgical patients and orthopedic surgery patients, few studies of delirium have targeted cardiac surgery patients, the researchers noted.
"With the aging of the patient population undergoing cardiac surgery and increases in survival after surgery, clinicians and patients are increasingly concerned with factors associated with quality of life, including cognitive status, as major outcomes of surgery," the authors wrote. "Whether postoperative delirium is associated with prolonged cognitive dysfunction has been unclear."
The researchers followed 225 patients, ages 60 to 90, for one year after their surgeries, assessing them for both delirium and cognitive impairment. The patients had undergone either coronary artery bypass grafting or heart valve replacement surgery at Beth Israel Deaconess Medical Center, UMass Memorial Medical Center or the Boston VA Medical Center.
The results showed that compared with patients who did not experience delirium, the 103 patients (46%) who developed delirium after cardiac surgery experienced a more significant drop in cognitive performance immediately following surgery, as determined by the Mini-Mental State Examination.
Those patients also took significantly longer to regain their presurgical level of function than did patients who did not develop delirium. For example, five days after surgery, nearly half of those who did not develop delirium had returned to preoperative levels of function, compared with less than 20% of those who did develop delirium. Six months after surgery, more than three-quarters of those without delirium had recovered cognitively, compared with only 60% of those with delirium.
Although patients who developed delirium took longer to recover to their preoperative levels of cognitive performance, they continued to improve in the weeks and months after surgery. Cognitive performance reached preoperative levels and stabilized one month after surgery in patients who did not develop delirium, but continued to improve until six months after surgery in those with delirium.
These findings suggest that identifying patients at high risk for delirium before surgery and promoting the use of interventions to prevent delirium in cardiac surgical patients may have substantial benefits. Such a practice could improve the recovery rate of cognitive abilities and enhance functional recovery following surgery.
Further cognitive screening at discharge may also identify patients who require closer, postoperative monitoring or tailored transitional care to enhance the return of cognitive functions.
"Since patients who experience delirium continue to show improvement in cognitive function six months after surgery, extending additional rehabilitation services to these patients may have added benefits," said co-senior author Richard N. Jones, ScD, director of mental health and aging at Hebrew SeniorLife and assistant professor of medicine at Harvard Medical School.
The study appears in the July 5 issue of the New England Journal of Medicine. To read the abstract and access the study via subscription or purchase, visit http://bit.ly/LklS5n.
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