[Interrater reliability and concurrent validity of 4AT for the detection of postoperative delirium: A prospective cohort study]

Interrater reliability and concurrent validity of 4AT for the detection of postoperative delirium: A prospective cohort study Abstract. Background: Numerous tools for detecting postoperative delirium are available. Guidelines recommend the 4 A's Test (4AT). However, there is little evidence on the validity and reliability of the German version of 4AT. Aim: To assess the interrater reliability of the German version of 4AT test for the detection of postoperative delirium in general surgical and orthopedic-traumatological patients, and the concurrent validity with the Delirium Observation Screening Scale (DOS). Methods: The present work is part of a prospective cohort study with a sample of 202 inpatients (≥ 65 years) who underwent surgery. The interrater reliability of the 4AT (intraclass coefficients) was determined with a subsample of 33 subjects who were rated by two nurses. Concurrent validity between the DOS scale and the 4AT was calculated using Pearson's correlation coefficient. Results: Interrater reliability for the 4AT total score and dichotomized total score were 0.92 (95% CI 0.84-0.96) and 0.98 (95% CI 0.95-0.98), respectively. The correlation between DOS and 4AT (Pearson) was 0.54 (p < 0.001). Conclusions: The 4A test can be used by nurses as a screening instrument for the detection of postoperative delirium in older patients on general surgery and orthopedic traumatology wards. In case of positive 4AT results further assessment by nurse experts or physicians is required.

Delirium in elderly postoperative patients: A prospective cohort study

AIM

To describe the incidence, time in days and risk factors for postoperative delirium in elderly patients.

DESIGN

Prospective cohort study.

METHODS

Patients over 65 years were daily screened with the 4A's Test and the Delirium Observation Screening Scale for postoperative delirium. A psychiatrist assessed according to the DSM-V. We performed descriptive and logistic regression analyses.

RESULTS

From 202 patients, 7.5% (N = 15) had a diagnosed postoperative delirium, whereby 73.3% (N = 11) developed the delirium during the first 48 hr after surgery. The median duration was 1 day. Patients over 80 years suffering from heart failure with surgical drains, bladder catheter, central venous catheter had higher odds for developing a postoperative delirium. The incidence of postoperative delirium in our sample was lower compared with other surgical and ortho-geriatric populations. Despite age, several modifiable postoperative factors were associated with the occurrence of postoperative delirium.