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NCT Number: NCT07791472

DElirium and LIGHT: Exploring Modifiable Risk Factors of Delirium - a Pilot Study

After a period of critical illness many people develop problems with memory, attention and thinking and this can make daily life more difficult. A risk factor for these problems is delirium. Delirium is a sudden change in the brain that causes confusion and difficulty focusing. People develop delirium when they are sick for another reason, such as a severe infection, or after surgery. Other risk factors for delirium are altered sleep/wake cycle, and absence of daylight. While delirium is very common in critical care, it's difficult to recognise and the reasons why it happens are not fully understood.

There are no treatments for delirium. Management focusses on reducing the impact of things that make it more likely for someone to develop delirium. For example, by making sure pain is well controlled and that family members can visit. While it comes with its challenges, maintaining a normal day and night cycle by turning lights off and reducing the number of interruptions during nighttime hours is also a strategy used and research has shown that sometimes this works. Unfortunately, the findings are not the same in every study, and the reasons why these interventions work to reduce delirium are not explored.

This study, called DELIGHT-P, wants to look at the relationship between delirium and light exposure to help to understand why absence of daylight is a risk factor for delirium. We think it has something to do with changes in the 'body clock' of patients in critical care. To find this out we will collect blood samples, measure light levels at the bedside, and assess participants for delirium. After discharge from critical care we will see participants again and ask them about their memory and do some thinking tests. We will also do another blood test. The blood samples will be tested for markers of changes to the 'body clock' and others will be tested for proteins that might be useful for recognising when someone has delirium.

As this is a pilot study, the research will be done with fewer people taking part. This is to check that the things we want to measure are the right things, and that it's possible to do the research. We hope that in the future we can do a larger study to be able to draw conclusions about what we find. The findings from this study may help us understand how light exposure and an altered body clock contributes to developing delirium. By checking for proteins that might be present in patients who have delirium, it might help us understand what processes are happening in the body to cause delirium. It is possible that through this work, we can identify potential treatment targets for delirium.

We hope that by doing this, we may be able to improve some of the memory and thinking problems that people have after a stay in critical care.

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Key information

Conditions

Circadian Rhythm Disruption Confusion Delirium Mental Disorders Nervous System Diseases Neurobehavioral Manifestations Neurocognitive Disorders Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

50 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

King's College Hospital NHS Foundation Trust

London, United Kingdom

Location status: Recruiting

Location contact

Sean Harrington

CONTACT

[email protected]

+442032999000

About this study

Background:

Delirium is a neuropsychiatric syndrome characterised by acute deficits in attention and other aspects of cognition. Patients with delirium have altered arousal, often displaying signs of hypervigilance and agitation, or indeed reduced levels of consciousness that look like coma. Many experience troubling symptoms in the form of hallucinations or delusions. Delirium is associated with longer hospital stays, increased mortality and long term cognitive impairment.

Delirium is highly prevalent in acute hospital environments. In critical care, it is reported that up to 70% of patients have delirium. Despite this, the mechanisms underpinning its onset and persistence are poorly understood. Recent evidence suggests that disruption in circadian rhythms - through altered light exposure, noise and sleep disturbance - may play a role in it's pathophysiology. There have been few studies which have directly measured light intensity and quality within clinical settings and correlated this to markers of circadian disruption and explored how this interacts with delirium risk.

In recent years, markers of neuronal damage have shown promise in helping to detect delirium, and understand the pathophysiological mechanisms underpinning it, but more work is needed to explore their use in critically ill patients at risk of delirium.

DELIGHT-P (DElirium and LIGHT: Exploring modifiable risk factors and mechanisms of delirium - A Pilot Study) is a pilot for a prospective observational cohort study. This observational cohort study will describe patterns of light exposure, endocrine rhythms, and delirium incidence in critically ill patients.

Results from this programme of work will inform the design of a powered observational study and potentially future studies examining whether circadian based interventions can reduce delirium incidence and improve outcomes. Beyond the critical care environment, the findings will support specialties across the NHS where delirium is highly prevalent, as well as guide hospital and critical care design, informing evidence-based policies on light exposure and sleep promoting care.

Importantly, findings from this work may also elucidate some of the mechanisms of delirium, offering insight to what is currently a very challenging syndrome with significant consequences.

Primary Objective:

To assess the feasibility of carrying out a study that exploring modifiable risk factors of delirium. To do this we will assess the recruitment capability, retention rate and evaluate the data collection procedures.

Secondary Objectives

To explore the relationship between light exposure, altered circadian rhythms and delirium in critically ill patients.
To explore the association between serum markers of inflammation, neuronal damage and delirium
To explore the cognitive outcomes of critically ill patients and the relationship with markers of neuronal damage.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adult patients >50 years old
Patients admitted to critical care in previous 24 hours
Patients with an arterial or venous access line suitable for blood sampling
Patients with an expected length of stay >36 hours

Exclusion criteria

Patients with a primary neurosurgical diagnosis
Patients with pre-existing cognitive impairment
Patients expected to die within 24 hours or receiving end of life treatment

Treatment and study plan

Primary outcomes

Recruitment and retention

Time frame: 6 months
Adherence to study procedures

Time frame: 6 months

Sponsors and collaborators

Lead sponsor

King's College Hospital NHS Trust

Other

Collaborators

King's College London

Registry information

Acronym: DELIGHT-P

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Aug 28, 2026
Registry last updated: Aug 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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