Postoperative cognitive disorders.

PURPOSE OF REVIEW

The elderly are the fastest growing segment of the population and undergo 25-30% of all surgical procedures. Postoperative cognitive problems are common in older patients following major surgery. The socioeconomic implications of these cognitive disorders are profound; cognitive decline is associated with a loss of independence, a reduction in the quality of life, and death. This review will focus on the two most common cognitive problems following surgery: postoperative delirium and postoperative cognitive dysfunction (POCD).

RECENT FINDINGS

For years, preoperative geriatric consultation/screening was the only intervention proven to decrease postoperative delirium. There are, however, several recent publications indicating that preoperative and postoperative pharmacological and medical (hydration, oxygenation) management can reduce postoperative delirium. Spinal anesthesia with minimal propofol sedation has been shown to decrease the incidence of postoperative delirium in hip-fracture patients. Likewise, dexmedetomidine sedation in mechanically ventilated patients in the ICU is associated with less postoperative delirium and shorter ventilator times. Preoperative levels of education and brain function (cognitive reserve) may predict patients at risk for postoperative cognitive problems. Reduced white matter integrity is reported to place patients at a higher risk for both postoperative delirium and POCD.

SUMMARY

The etiology of postoperative cognitive problems is unknown, but there is emerging evidence that decreased preoperative cognitive function contributes to the development of postoperative delirium and POCD. There is growing concern that inhalation anesthetics may be neurotoxic to the aging brain, but there are no human data evaluating this hypothesis to date. Randomized controlled trials evaluating interventions to improve long-term cognitive outcomes in elderly patients are urgently needed.