Exogenous Melatonin in Intensive Care Unit Chronodisruption

Inclusion Criteria: * Patients or their parents who have signed an informed consent allowing us to exploit and analyse their clinical, biological and pharmacological data (see Appendix 1) * Patients staying more than 48 hours in ICU (acute ICU confusion occurs in the 48-72h following admission) * Drugs affecting sleep architecture (co-variables): * Opiates: increase N2, decrease REM * NSAIDs: reduce sleep efficacy, increase arousal * Beta blockers: insomnia, REM sleep disappearance * Corticosteroids (varies according to half life and dose): REM sleep disappearance, induce awakening, stimulant effect * Haloperidol: increases sleep efficacy, increases N2 duration * Respiratory assistance: ventilated patients v/s non ventilated patients (co-variables) * Patients presenting with delirium or sleep disorders at admission will not be excluded, but a note will be taken on the baseline case report form (CRF) Exclusion Criteria: * Patients less than 18 years old * Patients with central neurological disease: post traumatic patients, Parkinson disease, patients presenting with CVA, patients with neurodegenerative diseases, etc. * Patients taking drugs capable of altering or inducing delirium: * Atypical antipsychotics (olanzapine, risperidone, etc.), which increase sleep efficacy, total sleep time, and NREM sleep, and reduce prevalence of ICU psychosis * BZD-like drugs (zolpidem, zopiclone) which induce delirium * Melatonin allergy * Any disorders capable of altering o…