Every year around 184,000 people across the UK are admitted to an intensive care unit (ICU), with over 30 per cent needing a ventilator to help them breathe.

Mechanical ventilation is often a lifesaving intervention, but it can come with a hidden cost, as up to four in five ventilated patients experience delirium.

This is a frightening state of confusion affecting memory, mood and quality of life, which is frequently described as one of the most distressing parts of a patient’s ICU experience.

A team of clinicians at University Hospitals Plymouth NHS Trust (UHP) is determined to change this, with a research study designed and led in Plymouth.

The DAYDREAM study is being led by first-time Chief Investigator Dr Jessie Welbourne, Consultant in Intensive Care Medicine at UHP and Honorary Associate Professor at the University of Plymouth (UoP).

It is exploring whether a small change to how ICU patients are fed could make a significant difference to their recovery.

Recruitment began in November 2025 at UHP (the lead site) and in February at University Hospital Southampton NHS Foundation Trust, where the study is being overseen by Principal Investigator (PI) Dr Ahilanandan Dushianthan.

The study dietician is Dr Liesl Wandrag, an academic and specialised ICU dietician who works at King’s College London. Trial management is provided by the Peninsula Clinical Trials Unit (PenCTU).

“Right now, patients on ventilators receive their nutrition continuously, 24 hours a day,” Jessie said.

“We think this constant feeding may disrupt the body’s natural circadian rhythm, potentially causing delirium.

We want to know whether switching to daytime-only feeding is feasible, safe and benefits patients by preventing delirium.”

The research team are collecting data on nutrition delivery and biological rhythm markers, as well as environment factors such as light and sound, to understand how ICU environments affect the body’s internal clock.

They are also conducting qualitative research, using structured interviews led by Dr Rachel Clark, ICU Psychologist at UHP, to understand the staff experience of implementing this change.

Local ICU survivors shaped the study design from the beginning, directing its focus on prevention rather than symptom management.

“This study is the first of its kind, as no other ICU nutrition studies have properly examined circadian rhythms or the impact of continuous feeding on delirium,” Jessie said.

“This is exactly the kind of innovation we want to see coming from our own clinicians. It shows what is possible when a Trust invests in research and supports its staff.”

Motivated by her patients’ experiences with delirium and a desire to fundamentally improve patient care through clinical research, Jessie designed the study during her clinical academic fellowship, with support from experienced clinical researcher Professor Dan Martin OBE, Consultant in Intensive Care Medicine at UHP and Professor of Perioperative and Intensive Care Medicine at UoP.

Jessie also credits Dr Rob Jackson, Consultant in Intensive Care Medicine and Service Line Lead, for fostering a research-positive environment within the service line by championing protected research time. This has enabled her and others to develop their own projects.