Sleep is integral to biologic function, and sleep disruption can result in both physiological and psychologic dysfunction including cognitive decline. The brain’s capacity to successfully respond to cognitive challenges through compensatory recruitment becomes overwhelmed if the patient is not presented with appropriate and continual sleep. Surgery activates the innate immune system, inducing neuroinflammatory changes that interfere with cognition. Because surgical patients with sleep disorders have an increased likelihood of exhibiting postoperative delirium, an acute form of cognitive decline, the authors investigated the contribution of perioperative sleep fragmentation to the neuroinflammatory and cognitive responses of surgery.
The authors show that sleep fragmentation and surgery can independently produce significant memory impairment, but perioperative SF significantly increased hippocampal inflammation without further cognitive impairment. It may be possible that by day 3 the rebound REM and NREM sleep is enough to restore the brain to a state that is capable of appropriately processing sensory input.