Study of Sleep and Delirium in the Intensive Care Unit (ICU) (SID)

• ICU delirium [ Time Frame: Daily measurement during study ] [ Designated as safety issue: No ]
  ICU delirium will be measured using the CAM-ICU. This measurement will be done twice daily.
  
  

• Intensive Care Unit (ICU) length of stay [ Time Frame: Assessed at discharge from ICU ] [ Designated as safety issue: No ]
  The day of admission to the ICU until the day of discharge from the ICU.
  
  
• Hospital Length of Stay [ Time Frame: Assesses at discharge from hospital ] [ Designated as safety issue: No ]
  This is the persons length of stay in the hospital, from admission date until discharge date.
  
  
• ICU mortality [ Time Frame: Assessed at discharge from ICU ] [ Designated as safety issue: No ]
  We will collect data on mortality during the stay in the Intensive Care Unit
  
  
• Hospital mortality [ Time Frame: Assessed at discharge from hospital ] [ Designated as safety issue: No ]
  We will assess the mortality during the hospital stay.
  
  
• One year mortality [ Time Frame: Assessed at 1 year from admission to hospital ] [ Designated as safety issue: No ]
  We will assess mortality at one year from hospital admission.
  
  

Delirium and sleep disruption are both common in the intensive care unit (ICU). Delirium is a state of acute confusion, experienced especially by older adults admitted to the hospital, with the potential to adversely impact patients' outcome. Of hospitalized patients, the highest rate of delirium occurs in elderly patients in the ICU. Development of ICU delirium is associated with longer ICU and hospital length of stay, significantly higher risk of functional decline, loss of independent living, and increased mortality. Previous studies have focused on describing the clinical manifestations, risk factors and outcomes of ICU delirium; yet, the contribution of sleep timing, as well as its quality and quantity, to the development of delirium, has not previously been rigorously investigated. Sleep disturbance, including changes in sleep patterns and architecture, and decreased quality of sleep are commonly observed in older subjects. In the ICU, environmental factors (such as noise levels and continuous ambient light) and health care practices (such as frequent performance of medical procedures and tests) further contribute to sleep disruption in the critically ill older patients. Additionally, many sedative and analgesic agents potently suppress slow wave sleep. In preliminary data acquired from ICU patients, the investigators have observed that fragmented sleep is prevalent due to frequent arousals and awakenings, and that sleep architecture is altered with an increase in light sleep, and a decrease in restorative slow wave sleep. Despite the common occurrence of both ICU delirium and sleep disruption, it is not known whether sleep disruption increases the risk of developing delirium in the critically ill older patients. In this exploratory study, the investigators propose to test the hypothesis that the severity and duration of sleep disruption is an independent predictor of the onset and duration of ICU delirium in a cohort of older ICU patients. The investigators will measure sleep disruption using continuous processed electroencephalography and measure ICU delirium using a well-validated and reliable standardized instrument. Results from this study will inform the contribution of sleep disruption in the development of ICU delirium in the older critically ill patients.