Delirium is a neurobehavioural syndrome that frequently develops in the postoperative and/or
ICU setting. The incidence of elderly patients who develop delirium during hospital stay
ranges from 11-82%. Delirium was first described more than half a century ago in the cardiac
surgery population, where it was already discovered as a state that might be accompanied by
serious complications such as prolonged ICU and hospital stay, reduced quality of life and
increased mortality. Furthermore, the duration of delirium is associated with worse long-term
cognitive function in the general ICU population. This long-term experience with delirium
suggests a high socioeconomic liability and has been a focus of many studies. The
aforementioned consequences of delirium are observed in all of three subtypes: hypoactive,
hyperactive, and mixed. Pharmacological treatment options for hypoactive delirium are
lacking. Since patients in hypoactive delirium suffer from disturbed circadian rhythm, the
investigators suggest that the administration of melatonin as a promising possibility in
these patients to shorten delirium duration and to lower its severity. Previous
investigations confirmed loss of melatonin rhythm in patients that had developed delirium
thus reasoning the study hypothesis.
In this randomized study, the investigators aim to test the hypothesis that the reinstitution
of a normal circadian rhythm by the administration of melatonin compared to placebo after
diagnosis of hypoactive delirium, decreases the duration of delirium and reduces the
transmission to a form of agitated delirium. The administration might have to be repeated
several times to achieve resolution of delirium.