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.