A feasibility randomised controlled trial, of administering daytime only enteral feeding compared to standard continuous enteral feeding, to reduce delirium in mechanically ventilated, critically ill adults.

Primary research question In critically ill patients, who are receiving mechanical ventilation for at least 48-hours and enterally fed, will daytime only feeding (DoF) reduce the incidence of delirium compared to continuous enteral feeding (CEF)? Design: A two centre, feasibility randomised controlled trial of DoF compared to CEF. Setting: Intensive care units (ICUs) at University Hospitals Plymouth (UHP) and University Hospital Southampton (UHS). Target population: Adult patients requiring mechanical ventilation, which is clinically assessed as likely to be for >48-hours, and who are appropriate for enteral feeding. Sample size: 40 patients, 20 in each group. Background In critically ill patients, there is disruption to the 24-hour circadian rhythm. Delirium is associated with a reduced fluctuation in circadian rhythms. In animals, the time of feeding influences circadian patterns. Critically ill patients are routinely fed continuously and it is not known if feeding time influences circadian patterns in critically ill patients. We propose that feeding only during the day will improve circadian rhythms and so reduce the incidence of delirium. Aims and objectives This feasibility randomised controlled trial (RCT) will investigate areas of uncertainty for a future definitive RCT, exploring trial recruitment and retention, feasibility, and acceptability of data collection procedures and outcome measures, intervention fidelity, and short-term efficacy as an indicator of promise. Methods There are three workstreams within this study: A feasibility RCT Adult critically ill patients requiring mechanical ventilation and enteral feeding will be randomised to receive DoF or CEF. The outcome measure days free of coma and delirium will be assessed, with feasibility outcomes of recruitment, retention and fidelity of the intervention. A qualitative sub-study The ICU team who deliver the intervention of DoF will be invited to semi-structured interviews to understand the experience of delivering the intervention. This will inform delivery of a future RCT. C. The circadian data study. Light exposure, temperature, and serum cortisol levels will be taken on days 3 – 5 of the study. The data will be analysed to plot circadian fluctuations. The size and timings of fluctuations will be compared between the intervention and control groups, to inform future, more detailed mechanistic work. Research timetable Study will commence in April 2025: 6 months set-up, 12 months recruitment, 3 months to complete follow up, and 3 analysis and reporting. Anticipated impact and dissemination Outcomes that will inform a definitive RCT of DoF in critically ill patients, including mechanistic assessment and delirium-related outcomes. If this subsequently demonstrates that DoF is effective at reducing delirium in critically ill patients, it will result in: Reduced suffering (physical and mental) due to delirium, and long-term morbidity; and improving survival and quality of life. Reduced ICU and hospital length of stay, burden on health care systems, resource utilisation, less staff time required to provide care related to delirium. Change to local, national, and international guidelines (ASPEN, ESPEN, and GPICS). Further studies in different cohorts of patients receiving CEF e.g. medical, surgical and in community care settings.