Research has shown that a lack of sleep (both pre- and post-op) can worsen pain after surgery. This new study from the Department of Anesthesiology at Michigan Medicine set out to see if there were any interventions that could minimise the effect of sleep loss and reduce the severity of pain experienced after surgery. The team focused on caffeine as a potential treatment, which may seem surprising given that caffeine is a stimulant to increase alertness. Earlier studies indicated that drinking coffee may lead to a longer life and lower risk of death from heart disease and cancer.
“Most people would be confused by the idea of using caffeine while we insist on the dangers of not getting enough sleep,” noted study author Giancarlo Vanini, M.D. However, as caffeine blocks the actions of the sleep-inducing neurotransmitter adenosine, causing us to feel more awake, the team proposed that caffeine might counteract the negative impact of sleep deprivation on surgical pain. “Insufficient sleep enhances pain perception, so we reasoned that caffeine might also be useful for reversing the increase in pain caused by sleep loss,” Vanini said.
The team used a rat model of surgical pain to test whether sleep deprivation before surgery would increase postoperative pain, and whether being given caffeine pre-emptively, before the sleep deprivation, would block the increase in postoperative pain caused by this lack of sleep. The results showed that sleep deprivation before surgery did indeed increase postoperative pain, and also extended recovery time after surgery. However, as the team hypothesised, caffeine helped mitigate the negative effects of insufficient sleep prior to surgery, blocking the increase in surgical pain.
Vanini explained that caffeine’s positive effect may be due to its role in blocking neurochemical changes caused by sleep deprivation in the brain areas that control sleep and wakefulness, and are connected to major pain-related areas. “These results are relevant because sleep disorders and insufficient sleep are highly prevalent problems in our society,” he added. “Additionally, patients travel long distances during the night or early morning before being admitted into the hospital for elective surgery. In one way or another, most patients do not get adequate sleep before surgery.”
The team now plan to carry out more research to better understand caffeine’s effect on reducing pain in surgical patients. The results are online in the journal Sleep.