DeCaf-Me: Can delirium be prevented with caffeine and melatonin? A randomised, placebo-controlled trial

DeCaf-Me: Prevent Delirium with Caffeine or Melatonin is a open label cross over factorial randomised controlled trial that is aiming to recruit 57 spinal or vascular participants over the age of 65 at Royal Prince Alfred Hospital. Participants will be recruited via the Department of Anaesthetics in the pre-admission clinic. They will be assessed for eligibility and risk at this time, informed consent will be done pre-operatively. Participants will be randomised to one of four arms - 1)100 mg caffeine at 7am and 2pm, 4 mg melatonin at 8pm, 2)100mg caffeine at 7am and 2pm, 3)4mg melatonin at 8pm or 4)no intervention. Primary outcomes are incidence of post-operative delirium on day 1 and secondary outcomes are Richmond Agitation and Sedation Score, differences in EEG power from 0.5-0.6Hz, changes in incidence of delirium, post-operative pain and opioid use. Patients will be monitored intraoperatively via BIS monitoring/EEG and on post operative days 1-3 receive delirium assessments on the ward/ICU. Additionally an EEG will be preformed on post-operative day 1 and a 10mL blood sample will be collected for biomarker analysis during standard blood collection intra-operatively and on post-operative day 1. Participants will be finished on post-operative day 7 after completing a cognitive assessment in person or over the phone. The rationale of this study is that the use of post-operative caffeine could have an effect on inflammation that could effect post-operative delirium severity and the consequential slowing of electroencephalogram readings. Additionally the use of caffeine and melatonin to help maintain circadian rhythms could help promote more restful sleep and reinforce normal sleep patterns which can reduce instances of post-operative delirium.