Methods

After sample size calculation, 74 mechanically ventilated patients with an expected ICU length of stay >48 hours were included in this prospective cohort study (NCT02143661). Amongst other reasons, patients with a substantial recent ICU exposure \cite{Pandharipande2013}, patients who were unlikely to survive for 24 hours and patients who could not be reliably assessed for delirium were excluded from study participation. Delirium was assessed every 8 hours by research physicians with the Confusion Assessment Method for the ICU (CAM-ICU).