Johns Hopkins study in hip fracture patients suggests 50 percent drop in risk of postoperative delirium
A common complication following surgery in elderly patients is postoperative delirium, a state of confusion that can lead to long-term health problems and cause some elderly patients to complain that they "never felt the same" again after an operation. But a new study by Johns Hopkins researchers suggests that simply limiting the depth of sedation during procedures could safely cut the risk of postoperative delirium by 50 percent.
"Merely by adjusting how a person is sedated can have a profound effect on their postoperative cognitive state," says study leader Frederick E. Sieber, M.D., an associate professor of anesthesia at the Johns Hopkins University School of Medicine and director of anesthesiology at Johns Hopkins Bayview Medical Center.
Sieber says propofol, a short-acting anesthetic commonly used to induce anesthesia and keep patients asleep, and similar anesthetics may not behave as the clear "on/off phenomena" they were long thought to be, with effects disappearing as soon as the drugs are withdrawn. "What our study indicates," he says, "is that there may be lingering effects of anesthesia that heretofore may not have been appreciated, especially in the elderly."
In a double-blind randomized study of 114 patients undergoing hip fracture repair at Johns Hopkins Bayview Medical Center, patients first received spinal block anesthesia and were then either lightly sedated with propofol or more deeply sedated with the same medication. The prevalence of postoperative delirium was significantly lower in the group that was lightly sedated. The findings, which appear in the January issue of Mayo Clinic Proceedings, suggest that one incident of delirium could be prevented for every 4.7 patients treated with light sedation. The average age of the patients in the study was 81.
In addition to decreasing the prevalence of postoperative delirium in the study's patients, lighter sedation was associated with a one-day reduction in the duration of delirium in those patients who still emerged from surgery confused and disoriented.
Deeply sedated patients were unresponsive during surgery, while the lightly sedated patients were able to respond to questions. Researchers judged how deeply sedated the patient became by placing an EEG monitor on the patient's forehead.