Disturbed circadian rhythm in ICU patients as indicated by melatonin levels: a prospective pilot study

The aim of this prospective pilot study was to test how melatonin levels follow the circadian cycle in ICU patients. There is strong evidence that changes of circadian rhythm are reflected in melatonin levels with peak levels at dawn and low levels during daytime [1]. The ICU stay is accompanied by disturbed circadian rhythm [2], which could potentially be the result of artificial lighting conditions.