Delirium is characterized by changes in mental status, inattension, disorganized thinking, and altered consciousness. Prevalence of delirium in critically ill patients has varied from 20~80% depending on the severity of illness. Despite its high prevalence, delirium is often under-recognized by clinicians due to the difficulties in diagnosis and no interest. Delirium is associated with increased mechanical ventilation days, hospital length of stay, and mortality. The purpose of this study is to analyze the prevalence of delirium and risk factors for delirium in critically ill surgical patients.

The investigators performed a prospective cohort study involving the patients admitted to surgical ICU between april 2013 and august 2013.

The included patients were assessed independently by trained ICU nurses using the confusion Assessment Method for the ICU (CAM-ICU). The patients were recorded general characteristics, disease-related factors, and treatment and environment-related factors. Data were analyzed by SPSS 12.0 software, using t-test, Fisher's exact test and logistic regression.

Inclusion Criteria:

1. Above RASS -3 paitent
2. Verbally or nonverbally communication possible patients

Exclusion Criteria:

1. Under age 18
2. Neurological disorder e.g.) Brain injury, dementia and traumatic brain injury
3. Readmitted to ICU
4. History of delirium
5. Transplanted; isolation is required

Admitted to the surgical ICU from April to August 2013 and had the ability to express themselves verbally or nonverbally.