Melatonin for Prevention of Post- Operative Delirium Pilot Study Protocol

Overview

To test the efficacy of melatonin compared to placebo in preventing post-operative delirium and reduction in intensity or duration of delirium in individuals 65 years of age and older who undergo orthopedic surgery after low energy lower extremity fractures (LELEF). Biomarkers may play important roles in the detection, prediction and management of delirium especially in frail elderly individuals. Predictive biomarkers may help characterize an individual's susceptibility to delirium and thereby help specialized treatment, care and management of such individuals during their hospitalization. They may also help predict treatment response to a specific modality and help in selection of such modality. Recent studies performed in the UK and published in 2011 have measured plasma cholinesterase activity and determined that these levels were lower in patients who developed delirium compared with remaining subjects. Other studies have indicated that CRP may also have a role in delirium prediction as they have found that CRP measured on admission to an ICU had predictable changes that occurred within 24 hours that in turn were predictors of delirium. One the aims of the study is to compare the predictive and treatment response values of groups of biomarkers that have been hypothesized to be of predictive value.

Surgery causes oxidative stress on the brain9 leading to inflammation. Post-operative delirium has been linked with inflammation in the brain. Delirium has been hypothesized to be a central nervous system response to systemic inflammation during a state of blood-brain barrier (BBB) compromise. Studies have shown a rise of inflammatory cytokines and fall of anti-inflammatory cytokines. Vice-versa, external cytokine administration has been shown to lead to delirium. Melatonin is known for its strong anti-oxidant and anti-inflammatory properties, this should account for its preventive properties in post-operative delirium. It has also been hypothesized that post-operative delirium in elderly is caused by circadian rhythm disturbances secondary to a relative lack of melatonin. Keeping in mind the above two possible pathophysiology for delirium, investigators are expecting melatonin supplementation should be able to reduce the incidence of post-operative delirium particularly in elderly population.