Delirium can be caused
by some brain infection and effects of some drugs such as antidepressants.
The common features of
1. Disturbance of
consciousness, that is, reduced clarity of consciousness
3. Memory impairment
5. Slow thinking
Delirium is quite
common after cardiac surgery. Jane
Saczynski and colleagues conducted a study to assess the prevalence of
delirium and cognitive decline after cardiac surgery.
Though delirium has
been studied extensively, still few studies have been carried out on patient
undergoing cardiac surgery.
The experts enrolled
225 volunteers in the age group of 60 to 90 years who had either heart valve
replacement surgery or coronary artery bypass grafting (CABG) at the Beth Israel Deaconess Medical Center
(BIDMC), UMass Memorial Medical Center or the Boston VA Medical Center.
They were reviewed for
both cognitive impairment and delirium before and after surgery. The patients were followed up for a year
Examination (MMSE) was used to evaluate cognitive function. MMSE score ranged
from 0 to 30 with low score indicating poor performance. Confusion Assessment
Method was employed to determine delirium.
MD, section chief for research in BIDMC's Division of General Medicine and
Primary Care and professor of Medicine at Harvard Medical School, "One of
the real strengths of our study is that we assessed patients' cognitive
function preoperatively and an average of five times during the year after
A total of 103
participants who developed delirium postoperatively in the study had low
preoperative Mini-Mental State Examination scores. The delirium lasted for 1 to
2 days in 65% of these patients and 3 or more days in 35% patients. Most of
these patients were older, less educated, more likely to be women, and less
likely to be white. They were also more likely to have a history of stroke or
TIA and a lower level of preoperative cognitive function.
These 103 patients
showed a remarkable drop in cognitive performance. They also took longer time
to recuperate back to their preoperative level as compared to patients who did
not developed delirium.
The patients developing
delirium generally took long to recover back to their normal preoperative
levels of cognitive performance. The study findings suggested that substantial
benefits can be achieved by identification of high-risk patients for delirium
before surgery and promoting adequate interventions for the prevention of
delirium in cardiac surgery patients.
Cognitive screening at
the time of discharge can also help in identifying patients requiring closer
monitoring and care to facilitate the return of cognitive functions.
Jane Saczynski, PhD,
assistant professor of Medicine at the University of Massachusetts Medical
School said, "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."
One of the authors of
the paper said, "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.
"Another author stated, "The findings from this study highlight the
clinical importance of the identification of delirium and the potential of
preventive interventions like the Hospital Elder Life Program [HELP]."
Cognitive Trajectories after Postoperative
Delirium; Jane Saczynski et al; N Engl J Med 2012; 367:30-39