The 3D-CAM is a new 3-minute diagnostic assessment for Confusion Assessment Method-defined Delirium. The primary objective of this study is to translate the 3D-CAM into the German language, as well as to validate its use to detect postoperative delirium in the recovery room. The validation will be based on comparisons to the Nu-DESC (Nursing Delirium Screening Scale), CAM (Confusion Assessment Method), and DSM-5 criteria (Diagnostic and Statistical Manual of Mental Disorders).

Approximately 200 patients will be enrolled in the study. They will followed up until the third postoperative day.

Calculation and analysis of demographic and perioperative influencing factors on postoperative delirium according to routine parameters (age, sex, body height, body weight, diagnosis, physical status according to the American Society of Anaesthesiologists (ASA PS), duration of surgery, Physiological and Operative Severity Score (POSSUM), type of anesthesia, medication against pain and delirium) will be performed.

Inclusion criteria:

• Male and female patients with age ≥ 18 years
• Admission to recovery room (RR) or post anaesthesia care unit (PACU) following elective general anaesthesia and scheduled
• Inpatient treatment not less than 24 hours.

Exclusion criteria:

• Patients with psychiatric diseases and mental retardation
• Analphabetism
• Anacusis or Hypoacusis with hearing aid device,
• Amaurosis
• Lacking willingness to save and hand out data within the study
• Accommodation in an institution due to an official or judicial order
• Patients with unability speaking German or English language
• Participation in other clinical studies during the study period
• Coworker in the study site

Male and female adult patients undergoing elective general anaesthesia.