[Daylight therapy in intensive care units: a review]

As a neuropsychiatric syndrome, delirium worsens the prognosis of critically ill patients in the intensive care unit (ICU). Risk factors such as sleep deprivation increase the incidence of delirium. Targeted light exposure influences the circadian rhythm, and daylight interventions can help to restore the natural daily rhythm. To date, a review of daylight therapy for German-speaking countries is lacking.

This work aims to provide an overview of the currently available evidence on the use of daylight therapy in critically ill patients on the ICU, with a medical focus on cardiology or thoracic and cardiovascular surgery. The potential effects of daylight therapy on delirium and sleep are discussed.

A systematic literature search was conducted in the databases CareLit (hpsmedia, Hungen, Germany), Cochrane Library (The Cochrane Collaboration, London, U.K.), Livivo (German National Library of Medicine - Information Centre for Life Science, Cologne, Germany), and Medline via PubMed (U.S. National Library of Medicine, Bethesda, MD, USA). German- and English-language literature involving ICU patients at least 18 years of age in the context of light therapy was included. A critical appraisal was performed using the assessment tools developed by Behrens and Langer.

Fourteen full texts were included, most of which involved multiple nonpharmacological interventions. The studies varied in terms of light application mode, timing, and duration. No significant effects on the delirium incidence were found, but positive effects on sleep promotion and psychological outcomes were observed.

There are few conclusive studies on daylight therapy in the ICU. Most involved multicomponent intervention strategies. The prevailing evidence suggests beneficial effects on sleep promotion and psychological outcomes, which could contribute to delirium prevention strategies. Further research is needed.